diff options
Diffstat (limited to 'kernel/bpf/verifier.c')
| -rw-r--r-- | kernel/bpf/verifier.c | 2355 |
1 files changed, 1495 insertions, 860 deletions
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index a7d6e0c5928b..399f03e62508 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -44,6 +44,12 @@ static const struct bpf_verifier_ops * const bpf_verifier_ops[] = { #undef BPF_LINK_TYPE }; +enum bpf_features { + BPF_FEAT_RDONLY_CAST_TO_VOID = 0, + BPF_FEAT_STREAMS = 1, + __MAX_BPF_FEAT, +}; + struct bpf_mem_alloc bpf_global_percpu_ma; static bool bpf_global_percpu_ma_set; @@ -405,7 +411,8 @@ static bool reg_not_null(const struct bpf_reg_state *reg) type == PTR_TO_MAP_KEY || type == PTR_TO_SOCK_COMMON || (type == PTR_TO_BTF_ID && is_trusted_reg(reg)) || - type == PTR_TO_MEM; + (type == PTR_TO_MEM && !(reg->type & PTR_UNTRUSTED)) || + type == CONST_PTR_TO_MAP; } static struct btf_record *reg_btf_record(const struct bpf_reg_state *reg) @@ -855,7 +862,7 @@ static int unmark_stack_slots_dynptr(struct bpf_verifier_env *env, struct bpf_re * dynptr */ if (state->stack[i].slot_type[0] != STACK_DYNPTR) { - verbose(env, "verifier internal error: misconfigured ref_obj_id\n"); + verifier_bug(env, "misconfigured ref_obj_id"); return -EFAULT; } if (state->stack[i].spilled_ptr.dynptr.first_slot) @@ -1403,7 +1410,7 @@ static void *realloc_array(void *arr, size_t old_n, size_t new_n, size_t size) goto out; alloc_size = kmalloc_size_roundup(size_mul(new_n, size)); - new_arr = krealloc(arr, alloc_size, GFP_KERNEL); + new_arr = krealloc(arr, alloc_size, GFP_KERNEL_ACCOUNT); if (!new_arr) { kfree(arr); return NULL; @@ -1420,7 +1427,7 @@ out: static int copy_reference_state(struct bpf_verifier_state *dst, const struct bpf_verifier_state *src) { dst->refs = copy_array(dst->refs, src->refs, src->acquired_refs, - sizeof(struct bpf_reference_state), GFP_KERNEL); + sizeof(struct bpf_reference_state), GFP_KERNEL_ACCOUNT); if (!dst->refs) return -ENOMEM; @@ -1439,7 +1446,7 @@ static int copy_stack_state(struct bpf_func_state *dst, const struct bpf_func_st size_t n = src->allocated_stack / BPF_REG_SIZE; dst->stack = copy_array(dst->stack, src->stack, n, sizeof(struct bpf_stack_state), - GFP_KERNEL); + GFP_KERNEL_ACCOUNT); if (!dst->stack) return -ENOMEM; @@ -1647,7 +1654,7 @@ static void update_peak_states(struct bpf_verifier_env *env) { u32 cur_states; - cur_states = env->explored_states_size + env->free_list_size; + cur_states = env->explored_states_size + env->free_list_size + env->num_backedges; env->peak_states = max(env->peak_states, cur_states); } @@ -1659,6 +1666,13 @@ static void free_func_state(struct bpf_func_state *state) kfree(state); } +static void clear_jmp_history(struct bpf_verifier_state *state) +{ + kfree(state->jmp_history); + state->jmp_history = NULL; + state->jmp_history_cnt = 0; +} + static void free_verifier_state(struct bpf_verifier_state *state, bool free_self) { @@ -1669,11 +1683,12 @@ static void free_verifier_state(struct bpf_verifier_state *state, state->frame[i] = NULL; } kfree(state->refs); + clear_jmp_history(state); if (free_self) kfree(state); } -/* struct bpf_verifier_state->{parent,loop_entry} refer to states +/* struct bpf_verifier_state->parent refers to states * that are in either of env->{expored_states,free_list}. * In both cases the state is contained in struct bpf_verifier_state_list. */ @@ -1684,37 +1699,24 @@ static struct bpf_verifier_state_list *state_parent_as_list(struct bpf_verifier_ return NULL; } -static struct bpf_verifier_state_list *state_loop_entry_as_list(struct bpf_verifier_state *st) -{ - if (st->loop_entry) - return container_of(st->loop_entry, struct bpf_verifier_state_list, state); - return NULL; -} +static bool incomplete_read_marks(struct bpf_verifier_env *env, + struct bpf_verifier_state *st); /* A state can be freed if it is no longer referenced: * - is in the env->free_list; * - has no children states; - * - is not used as loop_entry. - * - * Freeing a state can make it's loop_entry free-able. */ static void maybe_free_verifier_state(struct bpf_verifier_env *env, struct bpf_verifier_state_list *sl) { - struct bpf_verifier_state_list *loop_entry_sl; - - while (sl && sl->in_free_list && - sl->state.branches == 0 && - sl->state.used_as_loop_entry == 0) { - loop_entry_sl = state_loop_entry_as_list(&sl->state); - if (loop_entry_sl) - loop_entry_sl->state.used_as_loop_entry--; - list_del(&sl->node); - free_verifier_state(&sl->state, false); - kfree(sl); - env->free_list_size--; - sl = loop_entry_sl; - } + if (!sl->in_free_list + || sl->state.branches != 0 + || incomplete_read_marks(env, &sl->state)) + return; + list_del(&sl->node); + free_verifier_state(&sl->state, false); + kfree(sl); + env->free_list_size--; } /* copy verifier state from src to dst growing dst stack space @@ -1733,6 +1735,13 @@ static int copy_verifier_state(struct bpf_verifier_state *dst_state, struct bpf_func_state *dst; int i, err; + dst_state->jmp_history = copy_array(dst_state->jmp_history, src->jmp_history, + src->jmp_history_cnt, sizeof(*dst_state->jmp_history), + GFP_KERNEL_ACCOUNT); + if (!dst_state->jmp_history) + return -ENOMEM; + dst_state->jmp_history_cnt = src->jmp_history_cnt; + /* if dst has more stack frames then src frame, free them, this is also * necessary in case of exceptional exits using bpf_throw. */ @@ -1750,17 +1759,14 @@ static int copy_verifier_state(struct bpf_verifier_state *dst_state, dst_state->parent = src->parent; dst_state->first_insn_idx = src->first_insn_idx; dst_state->last_insn_idx = src->last_insn_idx; - dst_state->insn_hist_start = src->insn_hist_start; - dst_state->insn_hist_end = src->insn_hist_end; dst_state->dfs_depth = src->dfs_depth; dst_state->callback_unroll_depth = src->callback_unroll_depth; - dst_state->used_as_loop_entry = src->used_as_loop_entry; dst_state->may_goto_depth = src->may_goto_depth; - dst_state->loop_entry = src->loop_entry; + dst_state->equal_state = src->equal_state; for (i = 0; i <= src->curframe; i++) { dst = dst_state->frame[i]; if (!dst) { - dst = kzalloc(sizeof(*dst), GFP_KERNEL); + dst = kzalloc(sizeof(*dst), GFP_KERNEL_ACCOUNT); if (!dst) return -ENOMEM; dst_state->frame[i] = dst; @@ -1799,181 +1805,241 @@ static bool same_callsites(struct bpf_verifier_state *a, struct bpf_verifier_sta return true; } -/* Open coded iterators allow back-edges in the state graph in order to - * check unbounded loops that iterators. - * - * In is_state_visited() it is necessary to know if explored states are - * part of some loops in order to decide whether non-exact states - * comparison could be used: - * - non-exact states comparison establishes sub-state relation and uses - * read and precision marks to do so, these marks are propagated from - * children states and thus are not guaranteed to be final in a loop; - * - exact states comparison just checks if current and explored states - * are identical (and thus form a back-edge). - * - * Paper "A New Algorithm for Identifying Loops in Decompilation" - * by Tao Wei, Jian Mao, Wei Zou and Yu Chen [1] presents a convenient - * algorithm for loop structure detection and gives an overview of - * relevant terminology. It also has helpful illustrations. - * - * [1] https://api.semanticscholar.org/CorpusID:15784067 - * - * We use a similar algorithm but because loop nested structure is - * irrelevant for verifier ours is significantly simpler and resembles - * strongly connected components algorithm from Sedgewick's textbook. - * - * Define topmost loop entry as a first node of the loop traversed in a - * depth first search starting from initial state. The goal of the loop - * tracking algorithm is to associate topmost loop entries with states - * derived from these entries. - * - * For each step in the DFS states traversal algorithm needs to identify - * the following situations: - * - * initial initial initial - * | | | - * V V V - * ... ... .---------> hdr - * | | | | - * V V | V - * cur .-> succ | .------... - * | | | | | | - * V | V | V V - * succ '-- cur | ... ... - * | | | - * | V V - * | succ <- cur - * | | - * | V - * | ... - * | | - * '----' - * - * (A) successor state of cur (B) successor state of cur or it's entry - * not yet traversed are in current DFS path, thus cur and succ - * are members of the same outermost loop - * - * initial initial - * | | - * V V - * ... ... - * | | - * V V - * .------... .------... - * | | | | - * V V V V - * .-> hdr ... ... ... - * | | | | | - * | V V V V - * | succ <- cur succ <- cur - * | | | - * | V V - * | ... ... - * | | | - * '----' exit - * - * (C) successor state of cur is a part of some loop but this loop - * does not include cur or successor state is not in a loop at all. - * - * Algorithm could be described as the following python code: - * - * traversed = set() # Set of traversed nodes - * entries = {} # Mapping from node to loop entry - * depths = {} # Depth level assigned to graph node - * path = set() # Current DFS path - * - * # Find outermost loop entry known for n - * def get_loop_entry(n): - * h = entries.get(n, None) - * while h in entries: - * h = entries[h] - * return h - * - * # Update n's loop entry if h comes before n in current DFS path. - * def update_loop_entry(n, h): - * if h in path and depths[entries.get(n, n)] < depths[n]: - * entries[n] = h1 +/* Return IP for a given frame in a call stack */ +static u32 frame_insn_idx(struct bpf_verifier_state *st, u32 frame) +{ + return frame == st->curframe + ? st->insn_idx + : st->frame[frame + 1]->callsite; +} + +/* For state @st look for a topmost frame with frame_insn_idx() in some SCC, + * if such frame exists form a corresponding @callchain as an array of + * call sites leading to this frame and SCC id. + * E.g.: * - * def dfs(n, depth): - * traversed.add(n) - * path.add(n) - * depths[n] = depth - * for succ in G.successors(n): - * if succ not in traversed: - * # Case A: explore succ and update cur's loop entry - * # only if succ's entry is in current DFS path. - * dfs(succ, depth + 1) - * h = entries.get(succ, None) - * update_loop_entry(n, h) - * else: - * # Case B or C depending on `h1 in path` check in update_loop_entry(). - * update_loop_entry(n, succ) - * path.remove(n) + * void foo() { A: loop {... SCC#1 ...}; } + * void bar() { B: loop { C: foo(); ... SCC#2 ... } + * D: loop { E: foo(); ... SCC#3 ... } } + * void main() { F: bar(); } * - * To adapt this algorithm for use with verifier: - * - use st->branch == 0 as a signal that DFS of succ had been finished - * and cur's loop entry has to be updated (case A), handle this in - * update_branch_counts(); - * - use st->branch > 0 as a signal that st is in the current DFS path; - * - handle cases B and C in is_state_visited(). + * @callchain at (A) would be either (F,SCC#2) or (F,SCC#3) depending + * on @st frame call sites being (F,C,A) or (F,E,A). */ -static struct bpf_verifier_state *get_loop_entry(struct bpf_verifier_env *env, - struct bpf_verifier_state *st) +static bool compute_scc_callchain(struct bpf_verifier_env *env, + struct bpf_verifier_state *st, + struct bpf_scc_callchain *callchain) { - struct bpf_verifier_state *topmost = st->loop_entry; - u32 steps = 0; + u32 i, scc, insn_idx; - while (topmost && topmost->loop_entry) { - if (verifier_bug_if(steps++ > st->dfs_depth, env, "infinite loop")) - return ERR_PTR(-EFAULT); - topmost = topmost->loop_entry; + memset(callchain, 0, sizeof(*callchain)); + for (i = 0; i <= st->curframe; i++) { + insn_idx = frame_insn_idx(st, i); + scc = env->insn_aux_data[insn_idx].scc; + if (scc) { + callchain->scc = scc; + break; + } else if (i < st->curframe) { + callchain->callsites[i] = insn_idx; + } else { + return false; + } } - return topmost; + return true; } -static void update_loop_entry(struct bpf_verifier_env *env, - struct bpf_verifier_state *cur, struct bpf_verifier_state *hdr) +/* Check if bpf_scc_visit instance for @callchain exists. */ +static struct bpf_scc_visit *scc_visit_lookup(struct bpf_verifier_env *env, + struct bpf_scc_callchain *callchain) { - /* The hdr->branches check decides between cases B and C in - * comment for get_loop_entry(). If hdr->branches == 0 then - * head's topmost loop entry is not in current DFS path, - * hence 'cur' and 'hdr' are not in the same loop and there is - * no need to update cur->loop_entry. - */ - if (hdr->branches && hdr->dfs_depth < (cur->loop_entry ?: cur)->dfs_depth) { - if (cur->loop_entry) { - cur->loop_entry->used_as_loop_entry--; - maybe_free_verifier_state(env, state_loop_entry_as_list(cur)); - } - cur->loop_entry = hdr; - hdr->used_as_loop_entry++; + struct bpf_scc_info *info = env->scc_info[callchain->scc]; + struct bpf_scc_visit *visits = info->visits; + u32 i; + + if (!info) + return NULL; + for (i = 0; i < info->num_visits; i++) + if (memcmp(callchain, &visits[i].callchain, sizeof(*callchain)) == 0) + return &visits[i]; + return NULL; +} + +/* Allocate a new bpf_scc_visit instance corresponding to @callchain. + * Allocated instances are alive for a duration of the do_check_common() + * call and are freed by free_states(). + */ +static struct bpf_scc_visit *scc_visit_alloc(struct bpf_verifier_env *env, + struct bpf_scc_callchain *callchain) +{ + struct bpf_scc_visit *visit; + struct bpf_scc_info *info; + u32 scc, num_visits; + u64 new_sz; + + scc = callchain->scc; + info = env->scc_info[scc]; + num_visits = info ? info->num_visits : 0; + new_sz = sizeof(*info) + sizeof(struct bpf_scc_visit) * (num_visits + 1); + info = kvrealloc(env->scc_info[scc], new_sz, GFP_KERNEL_ACCOUNT); + if (!info) + return NULL; + env->scc_info[scc] = info; + info->num_visits = num_visits + 1; + visit = &info->visits[num_visits]; + memset(visit, 0, sizeof(*visit)); + memcpy(&visit->callchain, callchain, sizeof(*callchain)); + return visit; +} + +/* Form a string '(callsite#1,callsite#2,...,scc)' in env->tmp_str_buf */ +static char *format_callchain(struct bpf_verifier_env *env, struct bpf_scc_callchain *callchain) +{ + char *buf = env->tmp_str_buf; + int i, delta = 0; + + delta += snprintf(buf + delta, TMP_STR_BUF_LEN - delta, "("); + for (i = 0; i < ARRAY_SIZE(callchain->callsites); i++) { + if (!callchain->callsites[i]) + break; + delta += snprintf(buf + delta, TMP_STR_BUF_LEN - delta, "%u,", + callchain->callsites[i]); + } + delta += snprintf(buf + delta, TMP_STR_BUF_LEN - delta, "%u)", callchain->scc); + return env->tmp_str_buf; +} + +/* If callchain for @st exists (@st is in some SCC), ensure that + * bpf_scc_visit instance for this callchain exists. + * If instance does not exist or is empty, assign visit->entry_state to @st. + */ +static int maybe_enter_scc(struct bpf_verifier_env *env, struct bpf_verifier_state *st) +{ + struct bpf_scc_callchain *callchain = &env->callchain_buf; + struct bpf_scc_visit *visit; + + if (!compute_scc_callchain(env, st, callchain)) + return 0; + visit = scc_visit_lookup(env, callchain); + visit = visit ?: scc_visit_alloc(env, callchain); + if (!visit) + return -ENOMEM; + if (!visit->entry_state) { + visit->entry_state = st; + if (env->log.level & BPF_LOG_LEVEL2) + verbose(env, "SCC enter %s\n", format_callchain(env, callchain)); + } + return 0; +} + +static int propagate_backedges(struct bpf_verifier_env *env, struct bpf_scc_visit *visit); + +/* If callchain for @st exists (@st is in some SCC), make it empty: + * - set visit->entry_state to NULL; + * - flush accumulated backedges. + */ +static int maybe_exit_scc(struct bpf_verifier_env *env, struct bpf_verifier_state *st) +{ + struct bpf_scc_callchain *callchain = &env->callchain_buf; + struct bpf_scc_visit *visit; + + if (!compute_scc_callchain(env, st, callchain)) + return 0; + visit = scc_visit_lookup(env, callchain); + if (!visit) { + verifier_bug(env, "scc exit: no visit info for call chain %s", + format_callchain(env, callchain)); + return -EFAULT; + } + if (visit->entry_state != st) + return 0; + if (env->log.level & BPF_LOG_LEVEL2) + verbose(env, "SCC exit %s\n", format_callchain(env, callchain)); + visit->entry_state = NULL; + env->num_backedges -= visit->num_backedges; + visit->num_backedges = 0; + update_peak_states(env); + return propagate_backedges(env, visit); +} + +/* Lookup an bpf_scc_visit instance corresponding to @st callchain + * and add @backedge to visit->backedges. @st callchain must exist. + */ +static int add_scc_backedge(struct bpf_verifier_env *env, + struct bpf_verifier_state *st, + struct bpf_scc_backedge *backedge) +{ + struct bpf_scc_callchain *callchain = &env->callchain_buf; + struct bpf_scc_visit *visit; + + if (!compute_scc_callchain(env, st, callchain)) { + verifier_bug(env, "add backedge: no SCC in verification path, insn_idx %d", + st->insn_idx); + return -EFAULT; + } + visit = scc_visit_lookup(env, callchain); + if (!visit) { + verifier_bug(env, "add backedge: no visit info for call chain %s", + format_callchain(env, callchain)); + return -EFAULT; } + if (env->log.level & BPF_LOG_LEVEL2) + verbose(env, "SCC backedge %s\n", format_callchain(env, callchain)); + backedge->next = visit->backedges; + visit->backedges = backedge; + visit->num_backedges++; + env->num_backedges++; + update_peak_states(env); + return 0; } -static void update_branch_counts(struct bpf_verifier_env *env, struct bpf_verifier_state *st) +/* bpf_reg_state->live marks for registers in a state @st are incomplete, + * if state @st is in some SCC and not all execution paths starting at this + * SCC are fully explored. + */ +static bool incomplete_read_marks(struct bpf_verifier_env *env, + struct bpf_verifier_state *st) +{ + struct bpf_scc_callchain *callchain = &env->callchain_buf; + struct bpf_scc_visit *visit; + + if (!compute_scc_callchain(env, st, callchain)) + return false; + visit = scc_visit_lookup(env, callchain); + if (!visit) + return false; + return !!visit->backedges; +} + +static void free_backedges(struct bpf_scc_visit *visit) +{ + struct bpf_scc_backedge *backedge, *next; + + for (backedge = visit->backedges; backedge; backedge = next) { + free_verifier_state(&backedge->state, false); + next = backedge->next; + kvfree(backedge); + } + visit->backedges = NULL; +} + +static int update_branch_counts(struct bpf_verifier_env *env, struct bpf_verifier_state *st) { struct bpf_verifier_state_list *sl = NULL, *parent_sl; struct bpf_verifier_state *parent; + int err; while (st) { u32 br = --st->branches; - /* br == 0 signals that DFS exploration for 'st' is finished, - * thus it is necessary to update parent's loop entry if it - * turned out that st is a part of some loop. - * This is a part of 'case A' in get_loop_entry() comment. - */ - if (br == 0 && st->parent && st->loop_entry) - update_loop_entry(env, st->parent, st->loop_entry); - - /* WARN_ON(br > 1) technically makes sense here, + /* verifier_bug_if(br > 1, ...) technically makes sense here, * but see comment in push_stack(), hence: */ - WARN_ONCE((int)br < 0, - "BUG update_branch_counts:branches_to_explore=%d\n", - br); + verifier_bug_if((int)br < 0, env, "%s:branches_to_explore=%d", __func__, br); if (br) break; + err = maybe_exit_scc(env, st); + if (err) + return err; parent = st->parent; parent_sl = state_parent_as_list(st); if (sl) @@ -1981,6 +2047,7 @@ static void update_branch_counts(struct bpf_verifier_env *env, struct bpf_verifi st = parent; sl = parent_sl; } + return 0; } static int pop_stack(struct bpf_verifier_env *env, int *prev_insn_idx, @@ -2012,6 +2079,18 @@ static int pop_stack(struct bpf_verifier_env *env, int *prev_insn_idx, return 0; } +static bool error_recoverable_with_nospec(int err) +{ + /* Should only return true for non-fatal errors that are allowed to + * occur during speculative verification. For these we can insert a + * nospec and the program might still be accepted. Do not include + * something like ENOMEM because it is likely to re-occur for the next + * architectural path once it has been recovered-from in all speculative + * paths. + */ + return err == -EPERM || err == -EACCES || err == -EINVAL; +} + static struct bpf_verifier_state *push_stack(struct bpf_verifier_env *env, int insn_idx, int prev_insn_idx, bool speculative) @@ -2020,9 +2099,9 @@ static struct bpf_verifier_state *push_stack(struct bpf_verifier_env *env, struct bpf_verifier_stack_elem *elem; int err; - elem = kzalloc(sizeof(struct bpf_verifier_stack_elem), GFP_KERNEL); + elem = kzalloc(sizeof(struct bpf_verifier_stack_elem), GFP_KERNEL_ACCOUNT); if (!elem) - goto err; + return NULL; elem->insn_idx = insn_idx; elem->prev_insn_idx = prev_insn_idx; @@ -2032,12 +2111,12 @@ static struct bpf_verifier_state *push_stack(struct bpf_verifier_env *env, env->stack_size++; err = copy_verifier_state(&elem->st, cur); if (err) - goto err; + return NULL; elem->st.speculative |= speculative; if (env->stack_size > BPF_COMPLEXITY_LIMIT_JMP_SEQ) { verbose(env, "The sequence of %d jumps is too complex.\n", env->stack_size); - goto err; + return NULL; } if (elem->st.parent) { ++elem->st.parent->branches; @@ -2052,12 +2131,6 @@ static struct bpf_verifier_state *push_stack(struct bpf_verifier_env *env, */ } return &elem->st; -err: - free_verifier_state(env->cur_state, true); - env->cur_state = NULL; - /* pop all elements and return */ - while (!pop_stack(env, NULL, NULL, false)); - return NULL; } #define CALLER_SAVED_REGS 6 @@ -2450,6 +2523,58 @@ static void __reg64_deduce_bounds(struct bpf_reg_state *reg) if ((u64)reg->smin_value <= (u64)reg->smax_value) { reg->umin_value = max_t(u64, reg->smin_value, reg->umin_value); reg->umax_value = min_t(u64, reg->smax_value, reg->umax_value); + } else { + /* If the s64 range crosses the sign boundary, then it's split + * between the beginning and end of the U64 domain. In that + * case, we can derive new bounds if the u64 range overlaps + * with only one end of the s64 range. + * + * In the following example, the u64 range overlaps only with + * positive portion of the s64 range. + * + * 0 U64_MAX + * | [xxxxxxxxxxxxxx u64 range xxxxxxxxxxxxxx] | + * |----------------------------|----------------------------| + * |xxxxx s64 range xxxxxxxxx] [xxxxxxx| + * 0 S64_MAX S64_MIN -1 + * + * We can thus derive the following new s64 and u64 ranges. + * + * 0 U64_MAX + * | [xxxxxx u64 range xxxxx] | + * |----------------------------|----------------------------| + * | [xxxxxx s64 range xxxxx] | + * 0 S64_MAX S64_MIN -1 + * + * If they overlap in two places, we can't derive anything + * because reg_state can't represent two ranges per numeric + * domain. + * + * 0 U64_MAX + * | [xxxxxxxxxxxxxxxxx u64 range xxxxxxxxxxxxxxxxx] | + * |----------------------------|----------------------------| + * |xxxxx s64 range xxxxxxxxx] [xxxxxxxxxx| + * 0 S64_MAX S64_MIN -1 + * + * The first condition below corresponds to the first diagram + * above. + */ + if (reg->umax_value < (u64)reg->smin_value) { + reg->smin_value = (s64)reg->umin_value; + reg->umax_value = min_t(u64, reg->umax_value, reg->smax_value); + } else if ((u64)reg->smax_value < reg->umin_value) { + /* This second condition considers the case where the u64 range + * overlaps with the negative portion of the s64 range: + * + * 0 U64_MAX + * | [xxxxxxxxxxxxxx u64 range xxxxxxxxxxxxxx] | + * |----------------------------|----------------------------| + * |xxxxxxxxx] [xxxxxxxxxxxx s64 range | + * 0 S64_MAX S64_MIN -1 + */ + reg->smax_value = (s64)reg->umax_value; + reg->umin_value = max_t(u64, reg->umin_value, reg->smin_value); + } } } @@ -2481,20 +2606,6 @@ static void __reg_deduce_mixed_bounds(struct bpf_reg_state *reg) reg->smin_value = max_t(s64, reg->smin_value, new_smin); reg->smax_value = min_t(s64, reg->smax_value, new_smax); - /* if s32 can be treated as valid u32 range, we can use it as well */ - if ((u32)reg->s32_min_value <= (u32)reg->s32_max_value) { - /* s32 -> u64 tightening */ - new_umin = (reg->umin_value & ~0xffffffffULL) | (u32)reg->s32_min_value; - new_umax = (reg->umax_value & ~0xffffffffULL) | (u32)reg->s32_max_value; - reg->umin_value = max_t(u64, reg->umin_value, new_umin); - reg->umax_value = min_t(u64, reg->umax_value, new_umax); - /* s32 -> s64 tightening */ - new_smin = (reg->smin_value & ~0xffffffffULL) | (u32)reg->s32_min_value; - new_smax = (reg->smax_value & ~0xffffffffULL) | (u32)reg->s32_max_value; - reg->smin_value = max_t(s64, reg->smin_value, new_smin); - reg->smax_value = min_t(s64, reg->smax_value, new_smax); - } - /* Here we would like to handle a special case after sign extending load, * when upper bits for a 64-bit range are all 1s or all 0s. * @@ -2561,6 +2672,7 @@ static void reg_bounds_sync(struct bpf_reg_state *reg) /* We might have learned something about the sign bit. */ __reg_deduce_bounds(reg); __reg_deduce_bounds(reg); + __reg_deduce_bounds(reg); /* We might have learned some bits from the bounds. */ __reg_bound_offset(reg); /* Intersecting with the old var_off might have improved our bounds @@ -2607,13 +2719,13 @@ static int reg_bounds_sanity_check(struct bpf_verifier_env *env, return 0; out: - verbose(env, "REG INVARIANTS VIOLATION (%s): %s u64=[%#llx, %#llx] " - "s64=[%#llx, %#llx] u32=[%#x, %#x] s32=[%#x, %#x] var_off=(%#llx, %#llx)\n", - ctx, msg, reg->umin_value, reg->umax_value, - reg->smin_value, reg->smax_value, - reg->u32_min_value, reg->u32_max_value, - reg->s32_min_value, reg->s32_max_value, - reg->var_off.value, reg->var_off.mask); + verifier_bug(env, "REG INVARIANTS VIOLATION (%s): %s u64=[%#llx, %#llx] " + "s64=[%#llx, %#llx] u32=[%#x, %#x] s32=[%#x, %#x] var_off=(%#llx, %#llx)", + ctx, msg, reg->umin_value, reg->umax_value, + reg->smin_value, reg->smax_value, + reg->u32_min_value, reg->u32_max_value, + reg->s32_min_value, reg->s32_max_value, + reg->var_off.value, reg->var_off.mask); if (env->test_reg_invariants) return -EFAULT; __mark_reg_unbounded(reg); @@ -2723,22 +2835,33 @@ static void mark_reg_not_init(struct bpf_verifier_env *env, __mark_reg_not_init(env, regs + regno); } -static void mark_btf_ld_reg(struct bpf_verifier_env *env, - struct bpf_reg_state *regs, u32 regno, - enum bpf_reg_type reg_type, - struct btf *btf, u32 btf_id, - enum bpf_type_flag flag) +static int mark_btf_ld_reg(struct bpf_verifier_env *env, + struct bpf_reg_state *regs, u32 regno, + enum bpf_reg_type reg_type, + struct btf *btf, u32 btf_id, + enum bpf_type_flag flag) { - if (reg_type == SCALAR_VALUE) { + switch (reg_type) { + case SCALAR_VALUE: mark_reg_unknown(env, regs, regno); - return; + return 0; + case PTR_TO_BTF_ID: + mark_reg_known_zero(env, regs, regno); + regs[regno].type = PTR_TO_BTF_ID | flag; + regs[regno].btf = btf; + regs[regno].btf_id = btf_id; + if (type_may_be_null(flag)) + regs[regno].id = ++env->id_gen; + return 0; + case PTR_TO_MEM: + mark_reg_known_zero(env, regs, regno); + regs[regno].type = PTR_TO_MEM | flag; + regs[regno].mem_size = 0; + return 0; + default: + verifier_bug(env, "unexpected reg_type %d in %s\n", reg_type, __func__); + return -EFAULT; } - mark_reg_known_zero(env, regs, regno); - regs[regno].type = PTR_TO_BTF_ID | flag; - regs[regno].btf = btf; - regs[regno].btf_id = btf_id; - if (type_may_be_null(flag)) - regs[regno].id = ++env->id_gen; } #define DEF_NOT_SUBREG (0) @@ -2787,9 +2910,9 @@ static struct bpf_verifier_state *push_async_cb(struct bpf_verifier_env *env, struct bpf_verifier_stack_elem *elem; struct bpf_func_state *frame; - elem = kzalloc(sizeof(struct bpf_verifier_stack_elem), GFP_KERNEL); + elem = kzalloc(sizeof(struct bpf_verifier_stack_elem), GFP_KERNEL_ACCOUNT); if (!elem) - goto err; + return NULL; elem->insn_idx = insn_idx; elem->prev_insn_idx = prev_insn_idx; @@ -2801,35 +2924,24 @@ static struct bpf_verifier_state *push_async_cb(struct bpf_verifier_env *env, verbose(env, "The sequence of %d jumps is too complex for async cb.\n", env->stack_size); - goto err; + return NULL; } /* Unlike push_stack() do not copy_verifier_state(). * The caller state doesn't matter. * This is async callback. It starts in a fresh stack. * Initialize it similar to do_check_common(). - * But we do need to make sure to not clobber insn_hist, so we keep - * chaining insn_hist_start/insn_hist_end indices as for a normal - * child state. */ elem->st.branches = 1; elem->st.in_sleepable = is_sleepable; - elem->st.insn_hist_start = env->cur_state->insn_hist_end; - elem->st.insn_hist_end = elem->st.insn_hist_start; - frame = kzalloc(sizeof(*frame), GFP_KERNEL); + frame = kzalloc(sizeof(*frame), GFP_KERNEL_ACCOUNT); if (!frame) - goto err; + return NULL; init_func_state(env, frame, BPF_MAIN_FUNC /* callsite */, 0 /* frameno within this callchain */, subprog /* subprog number within this prog */); elem->st.frame[0] = frame; return &elem->st; -err: - free_verifier_state(env->cur_state, true); - env->cur_state = NULL; - /* pop all elements and return */ - while (!pop_stack(env, NULL, NULL, false)); - return NULL; } @@ -3167,7 +3279,7 @@ static int add_kfunc_call(struct bpf_verifier_env *env, u32 func_id, s16 offset) return -EINVAL; } - tab = kzalloc(sizeof(*tab), GFP_KERNEL); + tab = kzalloc(sizeof(*tab), GFP_KERNEL_ACCOUNT); if (!tab) return -ENOMEM; prog_aux->kfunc_tab = tab; @@ -3183,7 +3295,7 @@ static int add_kfunc_call(struct bpf_verifier_env *env, u32 func_id, s16 offset) return 0; if (!btf_tab && offset) { - btf_tab = kzalloc(sizeof(*btf_tab), GFP_KERNEL); + btf_tab = kzalloc(sizeof(*btf_tab), GFP_KERNEL_ACCOUNT); if (!btf_tab) return -ENOMEM; prog_aux->kfunc_btf_tab = btf_tab; @@ -3843,10 +3955,11 @@ static void linked_regs_unpack(u64 val, struct linked_regs *s) } /* for any branch, call, exit record the history of jmps in the given state */ -static int push_insn_history(struct bpf_verifier_env *env, struct bpf_verifier_state *cur, - int insn_flags, u64 linked_regs) +static int push_jmp_history(struct bpf_verifier_env *env, struct bpf_verifier_state *cur, + int insn_flags, u64 linked_regs) { - struct bpf_insn_hist_entry *p; + u32 cnt = cur->jmp_history_cnt; + struct bpf_jmp_history_entry *p; size_t alloc_size; /* combine instruction flags if we already recorded this instruction */ @@ -3866,32 +3979,29 @@ static int push_insn_history(struct bpf_verifier_env *env, struct bpf_verifier_s return 0; } - if (cur->insn_hist_end + 1 > env->insn_hist_cap) { - alloc_size = size_mul(cur->insn_hist_end + 1, sizeof(*p)); - p = kvrealloc(env->insn_hist, alloc_size, GFP_USER); - if (!p) - return -ENOMEM; - env->insn_hist = p; - env->insn_hist_cap = alloc_size / sizeof(*p); - } + cnt++; + alloc_size = kmalloc_size_roundup(size_mul(cnt, sizeof(*p))); + p = krealloc(cur->jmp_history, alloc_size, GFP_KERNEL_ACCOUNT); + if (!p) + return -ENOMEM; + cur->jmp_history = p; - p = &env->insn_hist[cur->insn_hist_end]; + p = &cur->jmp_history[cnt - 1]; p->idx = env->insn_idx; p->prev_idx = env->prev_insn_idx; p->flags = insn_flags; p->linked_regs = linked_regs; - - cur->insn_hist_end++; + cur->jmp_history_cnt = cnt; env->cur_hist_ent = p; return 0; } -static struct bpf_insn_hist_entry *get_insn_hist_entry(struct bpf_verifier_env *env, - u32 hist_start, u32 hist_end, int insn_idx) +static struct bpf_jmp_history_entry *get_jmp_hist_entry(struct bpf_verifier_state *st, + u32 hist_end, int insn_idx) { - if (hist_end > hist_start && env->insn_hist[hist_end - 1].idx == insn_idx) - return &env->insn_hist[hist_end - 1]; + if (hist_end > 0 && st->jmp_history[hist_end - 1].idx == insn_idx) + return &st->jmp_history[hist_end - 1]; return NULL; } @@ -3908,26 +4018,25 @@ static struct bpf_insn_hist_entry *get_insn_hist_entry(struct bpf_verifier_env * * history entry recording a jump from last instruction of parent state and * first instruction of given state. */ -static int get_prev_insn_idx(const struct bpf_verifier_env *env, - struct bpf_verifier_state *st, - int insn_idx, u32 hist_start, u32 *hist_endp) +static int get_prev_insn_idx(struct bpf_verifier_state *st, int i, + u32 *history) { - u32 hist_end = *hist_endp; - u32 cnt = hist_end - hist_start; + u32 cnt = *history; - if (insn_idx == st->first_insn_idx) { + if (i == st->first_insn_idx) { if (cnt == 0) return -ENOENT; - if (cnt == 1 && env->insn_hist[hist_start].idx == insn_idx) + if (cnt == 1 && st->jmp_history[0].idx == i) return -ENOENT; } - if (cnt && env->insn_hist[hist_end - 1].idx == insn_idx) { - (*hist_endp)--; - return env->insn_hist[hist_end - 1].prev_idx; + if (cnt && st->jmp_history[cnt - 1].idx == i) { + i = st->jmp_history[cnt - 1].prev_idx; + (*history)--; } else { - return insn_idx - 1; + i--; } + return i; } static const char *disasm_kfunc_name(void *data, const struct bpf_insn *insn) @@ -4108,7 +4217,7 @@ static void fmt_stack_mask(char *buf, ssize_t buf_sz, u64 stack_mask) /* If any register R in hist->linked_regs is marked as precise in bt, * do bt_set_frame_{reg,slot}(bt, R) for all registers in hist->linked_regs. */ -static void bt_sync_linked_regs(struct backtrack_state *bt, struct bpf_insn_hist_entry *hist) +static void bt_sync_linked_regs(struct backtrack_state *bt, struct bpf_jmp_history_entry *hist) { struct linked_regs linked_regs; bool some_precise = false; @@ -4153,7 +4262,7 @@ static bool calls_callback(struct bpf_verifier_env *env, int insn_idx); * - *was* processed previously during backtracking. */ static int backtrack_insn(struct bpf_verifier_env *env, int idx, int subseq_idx, - struct bpf_insn_hist_entry *hist, struct backtrack_state *bt) + struct bpf_jmp_history_entry *hist, struct backtrack_state *bt) { struct bpf_insn *insn = env->prog->insnsi + idx; u8 class = BPF_CLASS(insn->code); @@ -4448,7 +4557,7 @@ static int backtrack_insn(struct bpf_verifier_env *env, int idx, int subseq_idx, * . if (scalar cond K|scalar) * . helper_call(.., scalar, ...) where ARG_CONST is expected * backtrack through the verifier states and mark all registers and - * stack slots with spilled constants that these scalar regisers + * stack slots with spilled constants that these scalar registers * should be precise. * . during state pruning two registers (or spilled stack slots) * are equivalent if both are not precise. @@ -4571,7 +4680,7 @@ static void mark_all_scalars_imprecise(struct bpf_verifier_env *env, struct bpf_ * SCALARS, as well as any other registers and slots that contribute to * a tracked state of given registers/stack slots, depending on specific BPF * assembly instructions (see backtrack_insns() for exact instruction handling - * logic). This backtracking relies on recorded insn_hist and is able to + * logic). This backtracking relies on recorded jmp_history and is able to * traverse entire chain of parent states. This process ends only when all the * necessary registers/slots and their transitive dependencies are marked as * precise. @@ -4651,23 +4760,27 @@ static void mark_all_scalars_imprecise(struct bpf_verifier_env *env, struct bpf_ * mark_all_scalars_imprecise() to hopefully get more permissive and generic * finalized states which help in short circuiting more future states. */ -static int __mark_chain_precision(struct bpf_verifier_env *env, int regno) +static int __mark_chain_precision(struct bpf_verifier_env *env, + struct bpf_verifier_state *starting_state, + int regno, + bool *changed) { + struct bpf_verifier_state *st = starting_state; struct backtrack_state *bt = &env->bt; - struct bpf_verifier_state *st = env->cur_state; int first_idx = st->first_insn_idx; - int last_idx = env->insn_idx; + int last_idx = starting_state->insn_idx; int subseq_idx = -1; struct bpf_func_state *func; + bool tmp, skip_first = true; struct bpf_reg_state *reg; - bool skip_first = true; int i, fr, err; if (!env->bpf_capable) return 0; + changed = changed ?: &tmp; /* set frame number from which we are starting to backtrack */ - bt_init(bt, env->cur_state->curframe); + bt_init(bt, starting_state->curframe); /* Do sanity checks against current state of register and/or stack * slot, but don't set precise flag in current state, as precision @@ -4677,7 +4790,7 @@ static int __mark_chain_precision(struct bpf_verifier_env *env, int regno) if (regno >= 0) { reg = &func->regs[regno]; if (reg->type != SCALAR_VALUE) { - WARN_ONCE(1, "backtracing misuse"); + verifier_bug(env, "backtracking misuse"); return -EFAULT; } bt_set_reg(bt, regno); @@ -4688,9 +4801,8 @@ static int __mark_chain_precision(struct bpf_verifier_env *env, int regno) for (;;) { DECLARE_BITMAP(mask, 64); - u32 hist_start = st->insn_hist_start; - u32 hist_end = st->insn_hist_end; - struct bpf_insn_hist_entry *hist; + u32 history = st->jmp_history_cnt; + struct bpf_jmp_history_entry *hist; if (env->log.level & BPF_LOG_LEVEL2) { verbose(env, "mark_precise: frame%d: last_idx %d first_idx %d subseq_idx %d \n", @@ -4712,8 +4824,10 @@ static int __mark_chain_precision(struct bpf_verifier_env *env, int regno) for_each_set_bit(i, mask, 32) { reg = &st->frame[0]->regs[i]; bt_clear_reg(bt, i); - if (reg->type == SCALAR_VALUE) + if (reg->type == SCALAR_VALUE) { reg->precise = true; + *changed = true; + } } return 0; } @@ -4728,11 +4842,11 @@ static int __mark_chain_precision(struct bpf_verifier_env *env, int regno) err = 0; skip_first = false; } else { - hist = get_insn_hist_entry(env, hist_start, hist_end, i); + hist = get_jmp_hist_entry(st, history, i); err = backtrack_insn(env, i, subseq_idx, hist, bt); } if (err == -ENOTSUPP) { - mark_all_scalars_precise(env, env->cur_state); + mark_all_scalars_precise(env, starting_state); bt_reset(bt); return 0; } else if (err) { @@ -4745,7 +4859,7 @@ static int __mark_chain_precision(struct bpf_verifier_env *env, int regno) */ return 0; subseq_idx = i; - i = get_prev_insn_idx(env, st, i, hist_start, &hist_end); + i = get_prev_insn_idx(st, i, &history); if (i == -ENOENT) break; if (i >= env->prog->len) { @@ -4772,10 +4886,12 @@ static int __mark_chain_precision(struct bpf_verifier_env *env, int regno) bt_clear_frame_reg(bt, fr, i); continue; } - if (reg->precise) + if (reg->precise) { bt_clear_frame_reg(bt, fr, i); - else + } else { reg->precise = true; + *changed = true; + } } bitmap_from_u64(mask, bt_frame_stack_mask(bt, fr)); @@ -4790,10 +4906,12 @@ static int __mark_chain_precision(struct bpf_verifier_env *env, int regno) continue; } reg = &func->stack[i].spilled_ptr; - if (reg->precise) + if (reg->precise) { bt_clear_frame_slot(bt, fr, i); - else + } else { reg->precise = true; + *changed = true; + } } if (env->log.level & BPF_LOG_LEVEL2) { fmt_reg_mask(env->tmp_str_buf, TMP_STR_BUF_LEN, @@ -4820,7 +4938,7 @@ static int __mark_chain_precision(struct bpf_verifier_env *env, int regno) * fallback to marking all precise */ if (!bt_empty(bt)) { - mark_all_scalars_precise(env, env->cur_state); + mark_all_scalars_precise(env, starting_state); bt_reset(bt); } @@ -4829,15 +4947,16 @@ static int __mark_chain_precision(struct bpf_verifier_env *env, int regno) int mark_chain_precision(struct bpf_verifier_env *env, int regno) { - return __mark_chain_precision(env, regno); + return __mark_chain_precision(env, env->cur_state, regno, NULL); } /* mark_chain_precision_batch() assumes that env->bt is set in the caller to * desired reg and stack masks across all relevant frames */ -static int mark_chain_precision_batch(struct bpf_verifier_env *env) +static int mark_chain_precision_batch(struct bpf_verifier_env *env, + struct bpf_verifier_state *starting_state) { - return __mark_chain_precision(env, -1); + return __mark_chain_precision(env, starting_state, -1, NULL); } static bool is_spillable_regtype(enum bpf_reg_type type) @@ -5026,7 +5145,7 @@ static int check_stack_write_fixed_off(struct bpf_verifier_env *env, } if (sanitize) - env->insn_aux_data[insn_idx].sanitize_stack_spill = true; + env->insn_aux_data[insn_idx].nospec_result = true; } err = destroy_if_dynptr_stack_slot(env, state, spi); @@ -5109,7 +5228,7 @@ static int check_stack_write_fixed_off(struct bpf_verifier_env *env, } if (insn_flags) - return push_insn_history(env, env->cur_state, insn_flags, 0); + return push_jmp_history(env, env->cur_state, insn_flags, 0); return 0; } @@ -5416,7 +5535,7 @@ static int check_stack_read_fixed_off(struct bpf_verifier_env *env, insn_flags = 0; /* we are not restoring spilled register */ } if (insn_flags) - return push_insn_history(env, env->cur_state, insn_flags, 0); + return push_jmp_history(env, env->cur_state, insn_flags, 0); return 0; } @@ -5896,6 +6015,7 @@ static int check_map_kptr_access(struct bpf_verifier_env *env, u32 regno, struct bpf_insn *insn = &env->prog->insnsi[insn_idx]; int class = BPF_CLASS(insn->code); struct bpf_reg_state *val_reg; + int ret; /* Things we already checked for in check_map_access and caller: * - Reject cases where variable offset may touch kptr @@ -5929,8 +6049,11 @@ static int check_map_kptr_access(struct bpf_verifier_env *env, u32 regno, /* We can simply mark the value_regno receiving the pointer * value from map as PTR_TO_BTF_ID, with the correct type. */ - mark_btf_ld_reg(env, cur_regs(env), value_regno, PTR_TO_BTF_ID, kptr_field->kptr.btf, - kptr_field->kptr.btf_id, btf_ld_kptr_type(env, kptr_field)); + ret = mark_btf_ld_reg(env, cur_regs(env), value_regno, PTR_TO_BTF_ID, + kptr_field->kptr.btf, kptr_field->kptr.btf_id, + btf_ld_kptr_type(env, kptr_field)); + if (ret < 0) + return ret; } else if (class == BPF_STX) { val_reg = reg_state(env, value_regno); if (!register_is_null(val_reg) && @@ -6993,6 +7116,10 @@ BTF_TYPE_SAFE_RCU(struct css_set) { struct cgroup *dfl_cgrp; }; +BTF_TYPE_SAFE_RCU(struct cgroup_subsys_state) { + struct cgroup *cgroup; +}; + /* RCU trusted: these fields are trusted in RCU CS and can be NULL */ BTF_TYPE_SAFE_RCU_OR_NULL(struct mm_struct) { struct file __rcu *exe_file; @@ -7027,8 +7154,7 @@ BTF_TYPE_SAFE_TRUSTED(struct file) { struct inode *f_inode; }; -BTF_TYPE_SAFE_TRUSTED(struct dentry) { - /* no negative dentry-s in places where bpf can see it */ +BTF_TYPE_SAFE_TRUSTED_OR_NULL(struct dentry) { struct inode *d_inode; }; @@ -7043,6 +7169,7 @@ static bool type_is_rcu(struct bpf_verifier_env *env, BTF_TYPE_EMIT(BTF_TYPE_SAFE_RCU(struct task_struct)); BTF_TYPE_EMIT(BTF_TYPE_SAFE_RCU(struct cgroup)); BTF_TYPE_EMIT(BTF_TYPE_SAFE_RCU(struct css_set)); + BTF_TYPE_EMIT(BTF_TYPE_SAFE_RCU(struct cgroup_subsys_state)); return btf_nested_type_is_trusted(&env->log, reg, field_name, btf_id, "__safe_rcu"); } @@ -7066,7 +7193,6 @@ static bool type_is_trusted(struct bpf_verifier_env *env, BTF_TYPE_EMIT(BTF_TYPE_SAFE_TRUSTED(struct bpf_iter__task)); BTF_TYPE_EMIT(BTF_TYPE_SAFE_TRUSTED(struct linux_binprm)); BTF_TYPE_EMIT(BTF_TYPE_SAFE_TRUSTED(struct file)); - BTF_TYPE_EMIT(BTF_TYPE_SAFE_TRUSTED(struct dentry)); return btf_nested_type_is_trusted(&env->log, reg, field_name, btf_id, "__safe_trusted"); } @@ -7076,6 +7202,7 @@ static bool type_is_trusted_or_null(struct bpf_verifier_env *env, const char *field_name, u32 btf_id) { BTF_TYPE_EMIT(BTF_TYPE_SAFE_TRUSTED_OR_NULL(struct socket)); + BTF_TYPE_EMIT(BTF_TYPE_SAFE_TRUSTED_OR_NULL(struct dentry)); return btf_nested_type_is_trusted(&env->log, reg, field_name, btf_id, "__safe_trusted_or_null"); @@ -7139,7 +7266,7 @@ static int check_ptr_to_btf_access(struct bpf_verifier_env *env, if (env->ops->btf_struct_access && !type_is_alloc(reg->type) && atype == BPF_WRITE) { if (!btf_is_kernel(reg->btf)) { - verbose(env, "verifier internal error: reg->btf must be kernel btf\n"); + verifier_bug(env, "reg->btf must be kernel btf"); return -EFAULT; } ret = env->ops->btf_struct_access(&env->log, reg, off, size); @@ -7155,7 +7282,7 @@ static int check_ptr_to_btf_access(struct bpf_verifier_env *env, if (type_is_alloc(reg->type) && !type_is_non_owning_ref(reg->type) && !(reg->type & MEM_RCU) && !reg->ref_obj_id) { - verbose(env, "verifier internal error: ref_obj_id for allocated object must be non-zero\n"); + verifier_bug(env, "ref_obj_id for allocated object must be non-zero"); return -EFAULT; } @@ -7225,8 +7352,11 @@ static int check_ptr_to_btf_access(struct bpf_verifier_env *env, clear_trusted_flags(&flag); } - if (atype == BPF_READ && value_regno >= 0) - mark_btf_ld_reg(env, regs, value_regno, ret, reg->btf, btf_id, flag); + if (atype == BPF_READ && value_regno >= 0) { + ret = mark_btf_ld_reg(env, regs, value_regno, ret, reg->btf, btf_id, flag); + if (ret < 0) + return ret; + } return 0; } @@ -7280,13 +7410,19 @@ static int check_ptr_to_map_access(struct bpf_verifier_env *env, /* Simulate access to a PTR_TO_BTF_ID */ memset(&map_reg, 0, sizeof(map_reg)); - mark_btf_ld_reg(env, &map_reg, 0, PTR_TO_BTF_ID, btf_vmlinux, *map->ops->map_btf_id, 0); + ret = mark_btf_ld_reg(env, &map_reg, 0, PTR_TO_BTF_ID, + btf_vmlinux, *map->ops->map_btf_id, 0); + if (ret < 0) + return ret; ret = btf_struct_access(&env->log, &map_reg, off, size, atype, &btf_id, &flag, NULL); if (ret < 0) return ret; - if (value_regno >= 0) - mark_btf_ld_reg(env, regs, value_regno, ret, btf_vmlinux, btf_id, flag); + if (value_regno >= 0) { + ret = mark_btf_ld_reg(env, regs, value_regno, ret, btf_vmlinux, btf_id, flag); + if (ret < 0) + return ret; + } return 0; } @@ -7470,6 +7606,7 @@ static int check_mem_access(struct bpf_verifier_env *env, int insn_idx, u32 regn } } else if (base_type(reg->type) == PTR_TO_MEM) { bool rdonly_mem = type_is_rdonly_mem(reg->type); + bool rdonly_untrusted = rdonly_mem && (reg->type & PTR_UNTRUSTED); if (type_may_be_null(reg->type)) { verbose(env, "R%d invalid mem access '%s'\n", regno, @@ -7489,8 +7626,13 @@ static int check_mem_access(struct bpf_verifier_env *env, int insn_idx, u32 regn return -EACCES; } - err = check_mem_region_access(env, regno, off, size, - reg->mem_size, false); + /* + * Accesses to untrusted PTR_TO_MEM are done through probe + * instructions, hence no need to check bounds in that case. + */ + if (!rdonly_untrusted) + err = check_mem_region_access(env, regno, off, size, + reg->mem_size, false); if (!err && value_regno >= 0 && (t == BPF_READ || rdonly_mem)) mark_reg_unknown(env, regs, value_regno); } else if (reg->type == PTR_TO_CTX) { @@ -8517,7 +8659,7 @@ static int process_dynptr_func(struct bpf_verifier_env *env, int regno, int insn * ARG_PTR_TO_DYNPTR (or ARG_PTR_TO_DYNPTR | DYNPTR_TYPE_*): */ if ((arg_type & (MEM_UNINIT | MEM_RDONLY)) == (MEM_UNINIT | MEM_RDONLY)) { - verbose(env, "verifier internal error: misconfigured dynptr helper type flags\n"); + verifier_bug(env, "misconfigured dynptr helper type flags"); return -EFAULT; } @@ -8883,8 +9025,8 @@ static int process_iter_next_call(struct bpf_verifier_env *env, int insn_idx, if (cur_iter->iter.state != BPF_ITER_STATE_ACTIVE && cur_iter->iter.state != BPF_ITER_STATE_DRAINED) { - verbose(env, "verifier internal error: unexpected iterator state %d (%s)\n", - cur_iter->iter.state, iter_state_str(cur_iter->iter.state)); + verifier_bug(env, "unexpected iterator state %d (%s)", + cur_iter->iter.state, iter_state_str(cur_iter->iter.state)); return -EFAULT; } @@ -8894,7 +9036,7 @@ static int process_iter_next_call(struct bpf_verifier_env *env, int insn_idx, */ if (!cur_st->parent || cur_st->parent->insn_idx != insn_idx || !same_callsites(cur_st->parent, cur_st)) { - verbose(env, "bug: bad parent state for iter next call"); + verifier_bug(env, "bad parent state for iter next call"); return -EFAULT; } /* Note cur_st->parent in the call below, it is necessary to skip @@ -8953,8 +9095,8 @@ static int resolve_map_arg_type(struct bpf_verifier_env *env, { if (!meta->map_ptr) { /* kernel subsystem misconfigured verifier */ - verbose(env, "invalid map_ptr to access map->type\n"); - return -EACCES; + verifier_bug(env, "invalid map_ptr to access map->type"); + return -EFAULT; } switch (meta->map_ptr->map_type) { @@ -9100,7 +9242,7 @@ static int check_reg_type(struct bpf_verifier_env *env, u32 regno, compatible = compatible_reg_types[base_type(arg_type)]; if (!compatible) { - verbose(env, "verifier internal error: unsupported arg type %d\n", arg_type); + verifier_bug(env, "unsupported arg type %d", arg_type); return -EFAULT; } @@ -9182,7 +9324,7 @@ found: if (!arg_btf_id) { if (!compatible->btf_id) { - verbose(env, "verifier internal error: missing arg compatible BTF ID\n"); + verifier_bug(env, "missing arg compatible BTF ID"); return -EFAULT; } arg_btf_id = compatible->btf_id; @@ -9214,7 +9356,7 @@ found: case PTR_TO_BTF_ID | MEM_PERCPU | MEM_ALLOC: if (meta->func_id != BPF_FUNC_spin_lock && meta->func_id != BPF_FUNC_spin_unlock && meta->func_id != BPF_FUNC_kptr_xchg) { - verbose(env, "verifier internal error: unimplemented handling of MEM_ALLOC\n"); + verifier_bug(env, "unimplemented handling of MEM_ALLOC"); return -EFAULT; } /* Check if local kptr in src arg matches kptr in dst arg */ @@ -9229,7 +9371,7 @@ found: /* Handled by helper specific checks */ break; default: - verbose(env, "verifier internal error: invalid PTR_TO_BTF_ID register for type match\n"); + verifier_bug(env, "invalid PTR_TO_BTF_ID register for type match"); return -EFAULT; } return 0; @@ -9490,7 +9632,7 @@ static int get_constant_map_key(struct bpf_verifier_env *env, * to prevent pruning on it. */ bt_set_frame_slot(&env->bt, key->frameno, spi); - err = mark_chain_precision_batch(env); + err = mark_chain_precision_batch(env, env->cur_state); if (err < 0) return err; @@ -9587,7 +9729,7 @@ skip_type_check: return -EINVAL; } if (meta->release_regno) { - verbose(env, "verifier internal error: more than one release argument\n"); + verifier_bug(env, "more than one release argument"); return -EFAULT; } meta->release_regno = regno; @@ -9595,10 +9737,10 @@ skip_type_check: if (reg->ref_obj_id && base_type(arg_type) != ARG_KPTR_XCHG_DEST) { if (meta->ref_obj_id) { - verbose(env, "verifier internal error: more than one arg with ref_obj_id R%d %u %u\n", + verbose(env, "more than one arg with ref_obj_id R%d %u %u", regno, reg->ref_obj_id, meta->ref_obj_id); - return -EFAULT; + return -EACCES; } meta->ref_obj_id = reg->ref_obj_id; } @@ -9641,8 +9783,8 @@ skip_type_check: * we have to check map_key here. Otherwise it means * that kernel subsystem misconfigured verifier */ - verbose(env, "invalid map_ptr to access map->key\n"); - return -EACCES; + verifier_bug(env, "invalid map_ptr to access map->key"); + return -EFAULT; } key_size = meta->map_ptr->key_size; err = check_helper_mem_access(env, regno, key_size, BPF_READ, false, NULL); @@ -9668,8 +9810,8 @@ skip_type_check: */ if (!meta->map_ptr) { /* kernel subsystem misconfigured verifier */ - verbose(env, "invalid map_ptr to access map->value\n"); - return -EACCES; + verifier_bug(env, "invalid map_ptr to access map->value"); + return -EFAULT; } meta->raw_mode = arg_type & MEM_UNINIT; err = check_helper_mem_access(env, regno, meta->map_ptr->value_size, @@ -9698,7 +9840,7 @@ skip_type_check: if (err) return err; } else { - verbose(env, "verifier internal error\n"); + verifier_bug(env, "spin lock arg on unexpected helper"); return -EFAULT; } break; @@ -10279,7 +10421,7 @@ static int setup_func_entry(struct bpf_verifier_env *env, int subprog, int calls } caller = state->frame[state->curframe]; - callee = kzalloc(sizeof(*callee), GFP_KERNEL); + callee = kzalloc(sizeof(*callee), GFP_KERNEL_ACCOUNT); if (!callee) return -ENOMEM; state->frame[state->curframe + 1] = callee; @@ -10334,6 +10476,12 @@ static int btf_check_func_arg_match(struct bpf_verifier_env *env, int subprog, bpf_log(log, "R%d is not a scalar\n", regno); return -EINVAL; } + } else if (arg->arg_type & PTR_UNTRUSTED) { + /* + * Anything is allowed for untrusted arguments, as these are + * read-only and probe read instructions would protect against + * invalid memory access. + */ } else if (arg->arg_type == ARG_PTR_TO_CTX) { ret = check_func_arg_reg_off(env, reg, regno, ARG_DONTCARE); if (ret < 0) @@ -10856,8 +11004,8 @@ static int prepare_func_exit(struct bpf_verifier_env *env, int *insn_idx) return -EINVAL; } if (!calls_callback(env, callee->callsite)) { - verbose(env, "BUG: in callback at %d, callsite %d !calls_callback\n", - *insn_idx, callee->callsite); + verifier_bug(env, "in callback at %d, callsite %d !calls_callback", + *insn_idx, callee->callsite); return -EFAULT; } } else { @@ -10964,8 +11112,8 @@ record_func_map(struct bpf_verifier_env *env, struct bpf_call_arg_meta *meta, return 0; if (map == NULL) { - verbose(env, "kernel subsystem misconfigured verifier\n"); - return -EINVAL; + verifier_bug(env, "expected map for helper call"); + return -EFAULT; } /* In case of read-only, some additional restrictions @@ -11003,7 +11151,7 @@ record_func_key(struct bpf_verifier_env *env, struct bpf_call_arg_meta *meta, if (func_id != BPF_FUNC_tail_call) return 0; if (!map || map->map_type != BPF_MAP_TYPE_PROG_ARRAY) { - verbose(env, "kernel subsystem misconfigured verifier\n"); + verbose(env, "expected prog array map for tail call"); return -EINVAL; } @@ -11146,7 +11294,7 @@ static int check_get_func_ip(struct bpf_verifier_env *env) return -ENOTSUPP; } -static struct bpf_insn_aux_data *cur_aux(struct bpf_verifier_env *env) +static struct bpf_insn_aux_data *cur_aux(const struct bpf_verifier_env *env) { return &env->insn_aux_data[env->insn_idx]; } @@ -11256,9 +11404,8 @@ static int check_helper_call(struct bpf_verifier_env *env, struct bpf_insn *insn /* With LD_ABS/IND some JITs save/restore skb from r1. */ changes_data = bpf_helper_changes_pkt_data(func_id); if (changes_data && fn->arg1_type != ARG_PTR_TO_CTX) { - verbose(env, "kernel subsystem misconfigured func %s#%d: r1 != ctx\n", - func_id_name(func_id), func_id); - return -EINVAL; + verifier_bug(env, "func %s#%d: r1 != ctx", func_id_name(func_id), func_id); + return -EFAULT; } memset(&meta, 0, sizeof(meta)); @@ -11266,8 +11413,7 @@ static int check_helper_call(struct bpf_verifier_env *env, struct bpf_insn *insn err = check_func_proto(fn, func_id); if (err) { - verbose(env, "kernel subsystem misconfigured func %s#%d\n", - func_id_name(func_id), func_id); + verifier_bug(env, "incorrect func proto %s#%d", func_id_name(func_id), func_id); return err; } @@ -11340,7 +11486,7 @@ static int check_helper_call(struct bpf_verifier_env *env, struct bpf_insn *insn */ if (arg_type_is_dynptr(fn->arg_type[meta.release_regno - BPF_REG_1])) { if (regs[meta.release_regno].type == CONST_PTR_TO_DYNPTR) { - verbose(env, "verifier internal error: CONST_PTR_TO_DYNPTR cannot be released\n"); + verifier_bug(env, "CONST_PTR_TO_DYNPTR cannot be released"); return -EFAULT; } err = unmark_stack_slots_dynptr(env, ®s[meta.release_regno]); @@ -11457,23 +11603,23 @@ static int check_helper_call(struct bpf_verifier_env *env, struct bpf_insn *insn if (meta.dynptr_id) { - verbose(env, "verifier internal error: meta.dynptr_id already set\n"); + verifier_bug(env, "meta.dynptr_id already set"); return -EFAULT; } if (meta.ref_obj_id) { - verbose(env, "verifier internal error: meta.ref_obj_id already set\n"); + verifier_bug(env, "meta.ref_obj_id already set"); return -EFAULT; } id = dynptr_id(env, reg); if (id < 0) { - verbose(env, "verifier internal error: failed to obtain dynptr id\n"); + verifier_bug(env, "failed to obtain dynptr id"); return id; } ref_obj_id = dynptr_ref_obj_id(env, reg); if (ref_obj_id < 0) { - verbose(env, "verifier internal error: failed to obtain dynptr ref_obj_id\n"); + verifier_bug(env, "failed to obtain dynptr ref_obj_id"); return ref_obj_id; } @@ -11558,9 +11704,8 @@ static int check_helper_call(struct bpf_verifier_env *env, struct bpf_insn *insn * to map element returned from bpf_map_lookup_elem() */ if (meta.map_ptr == NULL) { - verbose(env, - "kernel subsystem misconfigured verifier\n"); - return -EINVAL; + verifier_bug(env, "unexpected null map_ptr"); + return -EFAULT; } if (func_id == BPF_FUNC_map_lookup_elem && @@ -11650,10 +11795,9 @@ static int check_helper_call(struct bpf_verifier_env *env, struct bpf_insn *insn } } else { if (fn->ret_btf_id == BPF_PTR_POISON) { - verbose(env, "verifier internal error:"); - verbose(env, "func %s has non-overwritten BPF_PTR_POISON return type\n", - func_id_name(func_id)); - return -EINVAL; + verifier_bug(env, "func %s has non-overwritten BPF_PTR_POISON return type", + func_id_name(func_id)); + return -EFAULT; } ret_btf = btf_vmlinux; ret_btf_id = *fn->ret_btf_id; @@ -11678,8 +11822,8 @@ static int check_helper_call(struct bpf_verifier_env *env, struct bpf_insn *insn regs[BPF_REG_0].id = ++env->id_gen; if (helper_multiple_ref_obj_use(func_id, meta.map_ptr)) { - verbose(env, "verifier internal error: func %s#%d sets ref_obj_id more than once\n", - func_id_name(func_id), func_id); + verifier_bug(env, "func %s#%d sets ref_obj_id more than once", + func_id_name(func_id), func_id); return -EFAULT; } @@ -12391,7 +12535,7 @@ static int process_irq_flag(struct bpf_verifier_env *env, int regno, if (meta->func_id == special_kfunc_list[KF_bpf_res_spin_unlock_irqrestore]) kfunc_class = IRQ_LOCK_KFUNC; } else { - verbose(env, "verifier internal error: unknown irq flags kfunc\n"); + verifier_bug(env, "unknown irq flags kfunc"); return -EFAULT; } @@ -12432,12 +12576,12 @@ static int ref_set_non_owning(struct bpf_verifier_env *env, struct bpf_reg_state struct btf_record *rec = reg_btf_record(reg); if (!env->cur_state->active_locks) { - verbose(env, "verifier internal error: ref_set_non_owning w/o active lock\n"); + verifier_bug(env, "%s w/o active lock", __func__); return -EFAULT; } if (type_flag(reg->type) & NON_OWN_REF) { - verbose(env, "verifier internal error: NON_OWN_REF already set\n"); + verifier_bug(env, "NON_OWN_REF already set"); return -EFAULT; } @@ -12456,8 +12600,7 @@ static int ref_convert_owning_non_owning(struct bpf_verifier_env *env, u32 ref_o int i; if (!ref_obj_id) { - verbose(env, "verifier internal error: ref_obj_id is zero for " - "owning -> non-owning conversion\n"); + verifier_bug(env, "ref_obj_id is zero for owning -> non-owning conversion"); return -EFAULT; } @@ -12477,7 +12620,7 @@ static int ref_convert_owning_non_owning(struct bpf_verifier_env *env, u32 ref_o return 0; } - verbose(env, "verifier internal error: ref state missing for ref_obj_id\n"); + verifier_bug(env, "ref state missing for ref_obj_id"); return -EFAULT; } @@ -12539,7 +12682,7 @@ static int check_reg_allocation_locked(struct bpf_verifier_env *env, struct bpf_ ptr = reg->btf; break; default: - verbose(env, "verifier internal error: unknown reg type for lock check\n"); + verifier_bug(env, "unknown reg type for lock check"); return -EFAULT; } id = reg->id; @@ -12700,7 +12843,7 @@ __process_kf_arg_ptr_to_graph_root(struct bpf_verifier_env *env, u32 head_off; if (meta->btf != btf_vmlinux) { - verbose(env, "verifier internal error: unexpected btf mismatch in kfunc call\n"); + verifier_bug(env, "unexpected btf mismatch in kfunc call"); return -EFAULT; } @@ -12731,7 +12874,7 @@ __process_kf_arg_ptr_to_graph_root(struct bpf_verifier_env *env, } if (*head_field) { - verbose(env, "verifier internal error: repeating %s arg\n", head_type_name); + verifier_bug(env, "repeating %s arg", head_type_name); return -EFAULT; } *head_field = field; @@ -12768,7 +12911,7 @@ __process_kf_arg_ptr_to_graph_node(struct bpf_verifier_env *env, u32 node_off; if (meta->btf != btf_vmlinux) { - verbose(env, "verifier internal error: unexpected btf mismatch in kfunc call\n"); + verifier_bug(env, "unexpected btf mismatch in kfunc call"); return -EFAULT; } @@ -12896,7 +13039,7 @@ static int check_kfunc_args(struct bpf_verifier_env *env, struct bpf_kfunc_call_ if (is_kfunc_arg_prog(btf, &args[i])) { /* Used to reject repeated use of __prog. */ if (meta->arg_prog) { - verbose(env, "Only 1 prog->aux argument supported per-kfunc\n"); + verifier_bug(env, "Only 1 prog->aux argument supported per-kfunc"); return -EFAULT; } meta->arg_prog = true; @@ -12912,7 +13055,7 @@ static int check_kfunc_args(struct bpf_verifier_env *env, struct bpf_kfunc_call_ if (is_kfunc_arg_constant(meta->btf, &args[i])) { if (meta->arg_constant.found) { - verbose(env, "verifier internal error: only one constant argument permitted\n"); + verifier_bug(env, "only one constant argument permitted"); return -EFAULT; } if (!tnum_is_const(reg->var_off)) { @@ -12964,9 +13107,9 @@ static int check_kfunc_args(struct bpf_verifier_env *env, struct bpf_kfunc_call_ if (reg->ref_obj_id) { if (is_kfunc_release(meta) && meta->ref_obj_id) { - verbose(env, "verifier internal error: more than one arg with ref_obj_id R%d %u %u\n", - regno, reg->ref_obj_id, - meta->ref_obj_id); + verifier_bug(env, "more than one arg with ref_obj_id R%d %u %u", + regno, reg->ref_obj_id, + meta->ref_obj_id); return -EFAULT; } meta->ref_obj_id = reg->ref_obj_id; @@ -13046,7 +13189,7 @@ static int check_kfunc_args(struct bpf_verifier_env *env, struct bpf_kfunc_call_ case KF_ARG_PTR_TO_RES_SPIN_LOCK: break; default: - WARN_ON_ONCE(1); + verifier_bug(env, "unknown kfunc arg type %d", kf_arg_type); return -EFAULT; } @@ -13115,14 +13258,14 @@ static int check_kfunc_args(struct bpf_verifier_env *env, struct bpf_kfunc_call_ enum bpf_dynptr_type parent_type = meta->initialized_dynptr.type; if (parent_type == BPF_DYNPTR_TYPE_INVALID) { - verbose(env, "verifier internal error: no dynptr type for parent of clone\n"); + verifier_bug(env, "no dynptr type for parent of clone"); return -EFAULT; } dynptr_arg_type |= (unsigned int)get_dynptr_type_flag(parent_type); clone_ref_obj_id = meta->initialized_dynptr.ref_obj_id; if (dynptr_type_refcounted(parent_type) && !clone_ref_obj_id) { - verbose(env, "verifier internal error: missing ref obj id for parent of clone\n"); + verifier_bug(env, "missing ref obj id for parent of clone"); return -EFAULT; } } @@ -13135,7 +13278,7 @@ static int check_kfunc_args(struct bpf_verifier_env *env, struct bpf_kfunc_call_ int id = dynptr_id(env, reg); if (id < 0) { - verbose(env, "verifier internal error: failed to obtain dynptr id\n"); + verifier_bug(env, "failed to obtain dynptr id"); return id; } meta->initialized_dynptr.id = id; @@ -13271,7 +13414,7 @@ static int check_kfunc_args(struct bpf_verifier_env *env, struct bpf_kfunc_call_ if (is_kfunc_arg_const_mem_size(meta->btf, size_arg, size_reg)) { if (meta->arg_constant.found) { - verbose(env, "verifier internal error: only one constant argument permitted\n"); + verifier_bug(env, "only one constant argument permitted"); return -EFAULT; } if (!tnum_is_const(size_reg->var_off)) { @@ -13303,7 +13446,7 @@ static int check_kfunc_args(struct bpf_verifier_env *env, struct bpf_kfunc_call_ rec = reg_btf_record(reg); if (!rec) { - verbose(env, "verifier internal error: Couldn't find btf_record\n"); + verifier_bug(env, "Couldn't find btf_record"); return -EFAULT; } @@ -13537,16 +13680,24 @@ static int check_special_kfunc(struct bpf_verifier_env *env, struct bpf_kfunc_ca regs[BPF_REG_0].btf_id = meta->ret_btf_id; } else if (meta->func_id == special_kfunc_list[KF_bpf_rdonly_cast]) { ret_t = btf_type_by_id(desc_btf, meta->arg_constant.value); - if (!ret_t || !btf_type_is_struct(ret_t)) { + if (!ret_t) { + verbose(env, "Unknown type ID %lld passed to kfunc bpf_rdonly_cast\n", + meta->arg_constant.value); + return -EINVAL; + } else if (btf_type_is_struct(ret_t)) { + mark_reg_known_zero(env, regs, BPF_REG_0); + regs[BPF_REG_0].type = PTR_TO_BTF_ID | PTR_UNTRUSTED; + regs[BPF_REG_0].btf = desc_btf; + regs[BPF_REG_0].btf_id = meta->arg_constant.value; + } else if (btf_type_is_void(ret_t)) { + mark_reg_known_zero(env, regs, BPF_REG_0); + regs[BPF_REG_0].type = PTR_TO_MEM | MEM_RDONLY | PTR_UNTRUSTED; + regs[BPF_REG_0].mem_size = 0; + } else { verbose(env, - "kfunc bpf_rdonly_cast type ID argument must be of a struct\n"); + "kfunc bpf_rdonly_cast type ID argument must be of a struct or void\n"); return -EINVAL; } - - mark_reg_known_zero(env, regs, BPF_REG_0); - regs[BPF_REG_0].type = PTR_TO_BTF_ID | PTR_UNTRUSTED; - regs[BPF_REG_0].btf = desc_btf; - regs[BPF_REG_0].btf_id = meta->arg_constant.value; } else if (meta->func_id == special_kfunc_list[KF_bpf_dynptr_slice] || meta->func_id == special_kfunc_list[KF_bpf_dynptr_slice_rdwr]) { enum bpf_type_flag type_flag = get_dynptr_type_flag(meta->initialized_dynptr.type); @@ -13554,7 +13705,7 @@ static int check_special_kfunc(struct bpf_verifier_env *env, struct bpf_kfunc_ca mark_reg_known_zero(env, regs, BPF_REG_0); if (!meta->arg_constant.found) { - verbose(env, "verifier internal error: bpf_dynptr_slice(_rdwr) no constant size\n"); + verifier_bug(env, "bpf_dynptr_slice(_rdwr) no constant size"); return -EFAULT; } @@ -13574,7 +13725,7 @@ static int check_special_kfunc(struct bpf_verifier_env *env, struct bpf_kfunc_ca } if (!meta->initialized_dynptr.id) { - verbose(env, "verifier internal error: no dynptr id\n"); + verifier_bug(env, "no dynptr id"); return -EFAULT; } regs[BPF_REG_0].dynptr_id = meta->initialized_dynptr.id; @@ -14014,7 +14165,9 @@ static int retrieve_ptr_limit(const struct bpf_reg_state *ptr_reg, static bool can_skip_alu_sanitation(const struct bpf_verifier_env *env, const struct bpf_insn *insn) { - return env->bypass_spec_v1 || BPF_SRC(insn->code) == BPF_K; + return env->bypass_spec_v1 || + BPF_SRC(insn->code) == BPF_K || + cur_aux(env)->nospec; } static int update_alu_sanitation_state(struct bpf_insn_aux_data *aux, @@ -14214,10 +14367,9 @@ static int sanitize_err(struct bpf_verifier_env *env, case REASON_STACK: verbose(env, "R%d could not be pushed for speculative verification, %s\n", dst, err); - break; + return -ENOMEM; default: - verbose(env, "verifier internal error: unknown reason (%d)\n", - reason); + verifier_bug(env, "unknown reason (%d)", reason); break; } @@ -14284,7 +14436,7 @@ static int sanitize_check_bounds(struct bpf_verifier_env *env, } break; default: - break; + return -EOPNOTSUPP; } return 0; @@ -14311,7 +14463,7 @@ static int adjust_ptr_min_max_vals(struct bpf_verifier_env *env, struct bpf_sanitize_info info = {}; u8 opcode = BPF_OP(insn->code); u32 dst = insn->dst_reg; - int ret; + int ret, bounds_ret; dst_reg = ®s[dst]; @@ -14343,6 +14495,13 @@ static int adjust_ptr_min_max_vals(struct bpf_verifier_env *env, return -EACCES; } + /* + * Accesses to untrusted PTR_TO_MEM are done through probe + * instructions, hence no need to track offsets. + */ + if (base_type(ptr_reg->type) == PTR_TO_MEM && (ptr_reg->type & PTR_UNTRUSTED)) + return 0; + switch (base_type(ptr_reg->type)) { case PTR_TO_CTX: case PTR_TO_MAP_VALUE: @@ -14511,11 +14670,19 @@ static int adjust_ptr_min_max_vals(struct bpf_verifier_env *env, if (!check_reg_sane_offset(env, dst_reg, ptr_reg->type)) return -EINVAL; reg_bounds_sync(dst_reg); - if (sanitize_check_bounds(env, insn, dst_reg) < 0) - return -EACCES; + bounds_ret = sanitize_check_bounds(env, insn, dst_reg); + if (bounds_ret == -EACCES) + return bounds_ret; if (sanitize_needed(opcode)) { ret = sanitize_ptr_alu(env, insn, dst_reg, off_reg, dst_reg, &info, true); + if (verifier_bug_if(!can_skip_alu_sanitation(env, insn) + && !env->cur_state->speculative + && bounds_ret + && !ret, + env, "Pointer type unsupported by sanitize_check_bounds() not rejected by retrieve_ptr_limit() as required")) { + return -EFAULT; + } if (ret < 0) return sanitize_err(env, insn, ret, off_reg, dst_reg); } @@ -14530,14 +14697,25 @@ static void scalar32_min_max_add(struct bpf_reg_state *dst_reg, s32 *dst_smax = &dst_reg->s32_max_value; u32 *dst_umin = &dst_reg->u32_min_value; u32 *dst_umax = &dst_reg->u32_max_value; + u32 umin_val = src_reg->u32_min_value; + u32 umax_val = src_reg->u32_max_value; + bool min_overflow, max_overflow; if (check_add_overflow(*dst_smin, src_reg->s32_min_value, dst_smin) || check_add_overflow(*dst_smax, src_reg->s32_max_value, dst_smax)) { *dst_smin = S32_MIN; *dst_smax = S32_MAX; } - if (check_add_overflow(*dst_umin, src_reg->u32_min_value, dst_umin) || - check_add_overflow(*dst_umax, src_reg->u32_max_value, dst_umax)) { + + /* If either all additions overflow or no additions overflow, then + * it is okay to set: dst_umin = dst_umin + src_umin, dst_umax = + * dst_umax + src_umax. Otherwise (some additions overflow), set + * the output bounds to unbounded. + */ + min_overflow = check_add_overflow(*dst_umin, umin_val, dst_umin); + max_overflow = check_add_overflow(*dst_umax, umax_val, dst_umax); + + if (!min_overflow && max_overflow) { *dst_umin = 0; *dst_umax = U32_MAX; } @@ -14550,14 +14728,25 @@ static void scalar_min_max_add(struct bpf_reg_state *dst_reg, s64 *dst_smax = &dst_reg->smax_value; u64 *dst_umin = &dst_reg->umin_value; u64 *dst_umax = &dst_reg->umax_value; + u64 umin_val = src_reg->umin_value; + u64 umax_val = src_reg->umax_value; + bool min_overflow, max_overflow; if (check_add_overflow(*dst_smin, src_reg->smin_value, dst_smin) || check_add_overflow(*dst_smax, src_reg->smax_value, dst_smax)) { *dst_smin = S64_MIN; *dst_smax = S64_MAX; } - if (check_add_overflow(*dst_umin, src_reg->umin_value, dst_umin) || - check_add_overflow(*dst_umax, src_reg->umax_value, dst_umax)) { + + /* If either all additions overflow or no additions overflow, then + * it is okay to set: dst_umin = dst_umin + src_umin, dst_umax = + * dst_umax + src_umax. Otherwise (some additions overflow), set + * the output bounds to unbounded. + */ + min_overflow = check_add_overflow(*dst_umin, umin_val, dst_umin); + max_overflow = check_add_overflow(*dst_umax, umax_val, dst_umax); + + if (!min_overflow && max_overflow) { *dst_umin = 0; *dst_umax = U64_MAX; } @@ -14568,8 +14757,11 @@ static void scalar32_min_max_sub(struct bpf_reg_state *dst_reg, { s32 *dst_smin = &dst_reg->s32_min_value; s32 *dst_smax = &dst_reg->s32_max_value; + u32 *dst_umin = &dst_reg->u32_min_value; + u32 *dst_umax = &dst_reg->u32_max_value; u32 umin_val = src_reg->u32_min_value; u32 umax_val = src_reg->u32_max_value; + bool min_underflow, max_underflow; if (check_sub_overflow(*dst_smin, src_reg->s32_max_value, dst_smin) || check_sub_overflow(*dst_smax, src_reg->s32_min_value, dst_smax)) { @@ -14577,14 +14769,18 @@ static void scalar32_min_max_sub(struct bpf_reg_state *dst_reg, *dst_smin = S32_MIN; *dst_smax = S32_MAX; } - if (dst_reg->u32_min_value < umax_val) { - /* Overflow possible, we know nothing */ - dst_reg->u32_min_value = 0; - dst_reg->u32_max_value = U32_MAX; - } else { - /* Cannot overflow (as long as bounds are consistent) */ - dst_reg->u32_min_value -= umax_val; - dst_reg->u32_max_value -= umin_val; + + /* If either all subtractions underflow or no subtractions + * underflow, it is okay to set: dst_umin = dst_umin - src_umax, + * dst_umax = dst_umax - src_umin. Otherwise (some subtractions + * underflow), set the output bounds to unbounded. + */ + min_underflow = check_sub_overflow(*dst_umin, umax_val, dst_umin); + max_underflow = check_sub_overflow(*dst_umax, umin_val, dst_umax); + + if (min_underflow && !max_underflow) { + *dst_umin = 0; + *dst_umax = U32_MAX; } } @@ -14593,8 +14789,11 @@ static void scalar_min_max_sub(struct bpf_reg_state *dst_reg, { s64 *dst_smin = &dst_reg->smin_value; s64 *dst_smax = &dst_reg->smax_value; + u64 *dst_umin = &dst_reg->umin_value; + u64 *dst_umax = &dst_reg->umax_value; u64 umin_val = src_reg->umin_value; u64 umax_val = src_reg->umax_value; + bool min_underflow, max_underflow; if (check_sub_overflow(*dst_smin, src_reg->smax_value, dst_smin) || check_sub_overflow(*dst_smax, src_reg->smin_value, dst_smax)) { @@ -14602,14 +14801,18 @@ static void scalar_min_max_sub(struct bpf_reg_state *dst_reg, *dst_smin = S64_MIN; *dst_smax = S64_MAX; } - if (dst_reg->umin_value < umax_val) { - /* Overflow possible, we know nothing */ - dst_reg->umin_value = 0; - dst_reg->umax_value = U64_MAX; - } else { - /* Cannot overflow (as long as bounds are consistent) */ - dst_reg->umin_value -= umax_val; - dst_reg->umax_value -= umin_val; + + /* If either all subtractions underflow or no subtractions + * underflow, it is okay to set: dst_umin = dst_umin - src_umax, + * dst_umax = dst_umax - src_umin. Otherwise (some subtractions + * underflow), set the output bounds to unbounded. + */ + min_underflow = check_sub_overflow(*dst_umin, umax_val, dst_umin); + max_underflow = check_sub_overflow(*dst_umax, umin_val, dst_umax); + + if (min_underflow && !max_underflow) { + *dst_umin = 0; + *dst_umax = U64_MAX; } } @@ -15071,6 +15274,7 @@ static bool is_safe_to_compute_dst_reg_range(struct bpf_insn *insn, switch (BPF_OP(insn->code)) { case BPF_ADD: case BPF_SUB: + case BPF_NEG: case BPF_AND: case BPF_XOR: case BPF_OR: @@ -15139,6 +15343,13 @@ static int adjust_scalar_min_max_vals(struct bpf_verifier_env *env, scalar_min_max_sub(dst_reg, &src_reg); dst_reg->var_off = tnum_sub(dst_reg->var_off, src_reg.var_off); break; + case BPF_NEG: + env->fake_reg[0] = *dst_reg; + __mark_reg_known(dst_reg, 0); + scalar32_min_max_sub(dst_reg, &env->fake_reg[0]); + scalar_min_max_sub(dst_reg, &env->fake_reg[0]); + dst_reg->var_off = tnum_neg(env->fake_reg[0].var_off); + break; case BPF_MUL: dst_reg->var_off = tnum_mul(dst_reg->var_off, src_reg.var_off); scalar32_min_max_mul(dst_reg, &src_reg); @@ -15278,12 +15489,12 @@ static int adjust_reg_min_max_vals(struct bpf_verifier_env *env, if (WARN_ON_ONCE(ptr_reg)) { print_verifier_state(env, vstate, vstate->curframe, true); verbose(env, "verifier internal error: unexpected ptr_reg\n"); - return -EINVAL; + return -EFAULT; } if (WARN_ON(!src_reg)) { print_verifier_state(env, vstate, vstate->curframe, true); verbose(env, "verifier internal error: no src_reg\n"); - return -EINVAL; + return -EFAULT; } err = adjust_scalar_min_max_vals(env, insn, dst_reg, *src_reg); if (err) @@ -15362,7 +15573,14 @@ static int check_alu_op(struct bpf_verifier_env *env, struct bpf_insn *insn) } /* check dest operand */ - err = check_reg_arg(env, insn->dst_reg, DST_OP); + if (opcode == BPF_NEG) { + err = check_reg_arg(env, insn->dst_reg, DST_OP_NO_MARK); + err = err ?: adjust_scalar_min_max_vals(env, insn, + ®s[insn->dst_reg], + regs[insn->dst_reg]); + } else { + err = check_reg_arg(env, insn->dst_reg, DST_OP); + } if (err) return err; @@ -16029,6 +16247,10 @@ static void regs_refine_cond_op(struct bpf_reg_state *reg1, struct bpf_reg_state if (!is_reg_const(reg2, is_jmp32)) break; val = reg_const_value(reg2, is_jmp32); + /* Forget the ranges before narrowing tnums, to avoid invariant + * violations if we're on a dead branch. + */ + __mark_reg_unbounded(reg1); if (is_jmp32) { t = tnum_and(tnum_subreg(reg1->var_off), tnum_const(~val)); reg1->var_off = tnum_with_subreg(reg1->var_off, t); @@ -16473,7 +16695,7 @@ static int check_cond_jmp_op(struct bpf_verifier_env *env, } if (insn_flags) { - err = push_insn_history(env, this_branch, insn_flags, 0); + err = push_jmp_history(env, this_branch, insn_flags, 0); if (err) return err; } @@ -16531,7 +16753,7 @@ static int check_cond_jmp_op(struct bpf_verifier_env *env, if (dst_reg->type == SCALAR_VALUE && dst_reg->id) collect_linked_regs(this_branch, dst_reg->id, &linked_regs); if (linked_regs.cnt > 1) { - err = push_insn_history(env, this_branch, 0, linked_regs_pack(&linked_regs)); + err = push_jmp_history(env, this_branch, 0, linked_regs_pack(&linked_regs)); if (err) return err; } @@ -16686,7 +16908,7 @@ static int check_ld_imm(struct bpf_verifier_env *env, struct bpf_insn *insn) dst_reg->btf_id = aux->btf_var.btf_id; break; default: - verbose(env, "bpf verifier is misconfigured\n"); + verifier_bug(env, "pseudo btf id: unexpected dst reg type"); return -EFAULT; } return 0; @@ -16728,8 +16950,8 @@ static int check_ld_imm(struct bpf_verifier_env *env, struct bpf_insn *insn) insn->src_reg == BPF_PSEUDO_MAP_IDX) { dst_reg->type = CONST_PTR_TO_MAP; } else { - verbose(env, "bpf verifier is misconfigured\n"); - return -EINVAL; + verifier_bug(env, "unexpected src reg value for ldimm64"); + return -EFAULT; } return 0; @@ -16775,8 +16997,8 @@ static int check_ld_abs(struct bpf_verifier_env *env, struct bpf_insn *insn) } if (!env->ops->gen_ld_abs) { - verbose(env, "bpf verifier is misconfigured\n"); - return -EINVAL; + verifier_bug(env, "gen_ld_abs is null"); + return -EFAULT; } if (insn->dst_reg != BPF_REG_0 || insn->off != 0 || @@ -17186,7 +17408,7 @@ static int push_insn(int t, int w, int e, struct bpf_verifier_env *env) /* forward- or cross-edge */ insn_state[t] = DISCOVERED | e; } else { - verbose(env, "insn state internal bug\n"); + verifier_bug(env, "insn state internal bug"); return -EFAULT; } return DONE_EXPLORING; @@ -17606,17 +17828,18 @@ static int check_cfg(struct bpf_verifier_env *env) int *insn_stack, *insn_state, *insn_postorder; int ex_insn_beg, i, ret = 0; - insn_state = env->cfg.insn_state = kvcalloc(insn_cnt, sizeof(int), GFP_KERNEL); + insn_state = env->cfg.insn_state = kvcalloc(insn_cnt, sizeof(int), GFP_KERNEL_ACCOUNT); if (!insn_state) return -ENOMEM; - insn_stack = env->cfg.insn_stack = kvcalloc(insn_cnt, sizeof(int), GFP_KERNEL); + insn_stack = env->cfg.insn_stack = kvcalloc(insn_cnt, sizeof(int), GFP_KERNEL_ACCOUNT); if (!insn_stack) { kvfree(insn_state); return -ENOMEM; } - insn_postorder = env->cfg.insn_postorder = kvcalloc(insn_cnt, sizeof(int), GFP_KERNEL); + insn_postorder = env->cfg.insn_postorder = + kvcalloc(insn_cnt, sizeof(int), GFP_KERNEL_ACCOUNT); if (!insn_postorder) { kvfree(insn_state); kvfree(insn_stack); @@ -17646,7 +17869,7 @@ walk_cfg: break; default: if (ret > 0) { - verbose(env, "visit_insn internal bug\n"); + verifier_bug(env, "visit_insn internal bug"); ret = -EFAULT; } goto err_free; @@ -17654,7 +17877,7 @@ walk_cfg: } if (env->cfg.cur_stack < 0) { - verbose(env, "pop stack internal bug\n"); + verifier_bug(env, "pop stack internal bug"); ret = -EFAULT; goto err_free; } @@ -17750,7 +17973,7 @@ static int check_btf_func_early(struct bpf_verifier_env *env, urecord = make_bpfptr(attr->func_info, uattr.is_kernel); min_size = min_t(u32, krec_size, urec_size); - krecord = kvcalloc(nfuncs, krec_size, GFP_KERNEL | __GFP_NOWARN); + krecord = kvcalloc(nfuncs, krec_size, GFP_KERNEL_ACCOUNT | __GFP_NOWARN); if (!krecord) return -ENOMEM; @@ -17850,7 +18073,7 @@ static int check_btf_func(struct bpf_verifier_env *env, urecord = make_bpfptr(attr->func_info, uattr.is_kernel); krecord = prog->aux->func_info; - info_aux = kcalloc(nfuncs, sizeof(*info_aux), GFP_KERNEL | __GFP_NOWARN); + info_aux = kcalloc(nfuncs, sizeof(*info_aux), GFP_KERNEL_ACCOUNT | __GFP_NOWARN); if (!info_aux) return -ENOMEM; @@ -17936,7 +18159,7 @@ static int check_btf_line(struct bpf_verifier_env *env, * pass in a smaller bpf_line_info object. */ linfo = kvcalloc(nr_linfo, sizeof(struct bpf_line_info), - GFP_KERNEL | __GFP_NOWARN); + GFP_KERNEL_ACCOUNT | __GFP_NOWARN); if (!linfo) return -ENOMEM; @@ -18259,10 +18482,6 @@ static void clean_verifier_state(struct bpf_verifier_env *env, { int i; - if (st->frame[0]->regs[0].live & REG_LIVE_DONE) - /* all regs in this state in all frames were already marked */ - return; - for (i = 0; i <= st->curframe; i++) clean_func_state(env, st->frame[i]); } @@ -18270,7 +18489,7 @@ static void clean_verifier_state(struct bpf_verifier_env *env, /* the parentage chains form a tree. * the verifier states are added to state lists at given insn and * pushed into state stack for future exploration. - * when the verifier reaches bpf_exit insn some of the verifer states + * when the verifier reaches bpf_exit insn some of the verifier states * stored in the state lists have their final liveness state already, * but a lot of states will get revised from liveness point of view when * the verifier explores other branches. @@ -18302,7 +18521,6 @@ static void clean_verifier_state(struct bpf_verifier_env *env, static void clean_live_states(struct bpf_verifier_env *env, int insn, struct bpf_verifier_state *cur) { - struct bpf_verifier_state *loop_entry; struct bpf_verifier_state_list *sl; struct list_head *pos, *head; @@ -18311,12 +18529,14 @@ static void clean_live_states(struct bpf_verifier_env *env, int insn, sl = container_of(pos, struct bpf_verifier_state_list, node); if (sl->state.branches) continue; - loop_entry = get_loop_entry(env, &sl->state); - if (!IS_ERR_OR_NULL(loop_entry) && loop_entry->branches) - continue; if (sl->state.insn_idx != insn || !same_callsites(&sl->state, cur)) continue; + if (sl->state.frame[0]->regs[0].live & REG_LIVE_DONE) + /* all regs in this state in all frames were already marked */ + continue; + if (incomplete_read_marks(env, &sl->state)) + continue; clean_verifier_state(env, &sl->state); } } @@ -18763,9 +18983,7 @@ static bool states_equal(struct bpf_verifier_env *env, * and all frame states need to be equivalent */ for (i = 0; i <= old->curframe; i++) { - insn_idx = i == old->curframe - ? env->insn_idx - : old->frame[i + 1]->callsite; + insn_idx = frame_insn_idx(old, i); if (old->frame[i]->callsite != cur->frame[i]->callsite) return false; if (!func_states_equal(env, old->frame[i], cur->frame[i], insn_idx, exact)) @@ -18812,12 +19030,15 @@ static int propagate_liveness_reg(struct bpf_verifier_env *env, */ static int propagate_liveness(struct bpf_verifier_env *env, const struct bpf_verifier_state *vstate, - struct bpf_verifier_state *vparent) + struct bpf_verifier_state *vparent, + bool *changed) { struct bpf_reg_state *state_reg, *parent_reg; struct bpf_func_state *state, *parent; int i, frame, err = 0; + bool tmp = false; + changed = changed ?: &tmp; if (vparent->curframe != vstate->curframe) { WARN(1, "propagate_live: parent frame %d current frame %d\n", vparent->curframe, vstate->curframe); @@ -18836,6 +19057,7 @@ static int propagate_liveness(struct bpf_verifier_env *env, &parent_reg[i]); if (err < 0) return err; + *changed |= err > 0; if (err == REG_LIVE_READ64) mark_insn_zext(env, &parent_reg[i]); } @@ -18847,6 +19069,7 @@ static int propagate_liveness(struct bpf_verifier_env *env, state_reg = &state->stack[i].spilled_ptr; err = propagate_liveness_reg(env, state_reg, parent_reg); + *changed |= err > 0; if (err < 0) return err; } @@ -18858,7 +19081,9 @@ static int propagate_liveness(struct bpf_verifier_env *env, * propagate them into the current state */ static int propagate_precision(struct bpf_verifier_env *env, - const struct bpf_verifier_state *old) + const struct bpf_verifier_state *old, + struct bpf_verifier_state *cur, + bool *changed) { struct bpf_reg_state *state_reg; struct bpf_func_state *state; @@ -18906,13 +19131,53 @@ static int propagate_precision(struct bpf_verifier_env *env, verbose(env, "\n"); } - err = mark_chain_precision_batch(env); + err = __mark_chain_precision(env, cur, -1, changed); if (err < 0) return err; return 0; } +#define MAX_BACKEDGE_ITERS 64 + +/* Propagate read and precision marks from visit->backedges[*].state->equal_state + * to corresponding parent states of visit->backedges[*].state until fixed point is reached, + * then free visit->backedges. + * After execution of this function incomplete_read_marks() will return false + * for all states corresponding to @visit->callchain. + */ +static int propagate_backedges(struct bpf_verifier_env *env, struct bpf_scc_visit *visit) +{ + struct bpf_scc_backedge *backedge; + struct bpf_verifier_state *st; + bool changed; + int i, err; + + i = 0; + do { + if (i++ > MAX_BACKEDGE_ITERS) { + if (env->log.level & BPF_LOG_LEVEL2) + verbose(env, "%s: too many iterations\n", __func__); + for (backedge = visit->backedges; backedge; backedge = backedge->next) + mark_all_scalars_precise(env, &backedge->state); + break; + } + changed = false; + for (backedge = visit->backedges; backedge; backedge = backedge->next) { + st = &backedge->state; + err = propagate_liveness(env, st->equal_state, st, &changed); + if (err) + return err; + err = propagate_precision(env, st->equal_state, st, &changed); + if (err) + return err; + } + } while (changed); + + free_backedges(visit); + return 0; +} + static bool states_maybe_looping(struct bpf_verifier_state *old, struct bpf_verifier_state *cur) { @@ -18940,7 +19205,7 @@ static bool is_iter_next_insn(struct bpf_verifier_env *env, int insn_idx) * terminology) calls specially: as opposed to bounded BPF loops, it *expects* * states to match, which otherwise would look like an infinite loop. So while * iter_next() calls are taken care of, we still need to be careful and - * prevent erroneous and too eager declaration of "ininite loop", when + * prevent erroneous and too eager declaration of "infinite loop", when * iterators are involved. * * Here's a situation in pseudo-BPF assembly form: @@ -18982,7 +19247,7 @@ static bool is_iter_next_insn(struct bpf_verifier_env *env, int insn_idx) * * This approach allows to keep infinite loop heuristic even in the face of * active iterator. E.g., C snippet below is and will be detected as - * inifintely looping: + * infinitely looping: * * struct bpf_iter_num it; * int *p, x; @@ -19022,14 +19287,14 @@ static int is_state_visited(struct bpf_verifier_env *env, int insn_idx) { struct bpf_verifier_state_list *new_sl; struct bpf_verifier_state_list *sl; - struct bpf_verifier_state *cur = env->cur_state, *new, *loop_entry; + struct bpf_verifier_state *cur = env->cur_state, *new; + bool force_new_state, add_new_state, loop; int i, j, n, err, states_cnt = 0; - bool force_new_state, add_new_state, force_exact; struct list_head *pos, *tmp, *head; force_new_state = env->test_state_freq || is_force_checkpoint(env, insn_idx) || /* Avoid accumulating infinitely long jmp history */ - cur->insn_hist_end - cur->insn_hist_start > 40; + cur->jmp_history_cnt > 40; /* bpf progs typically have pruning point every 4 instructions * http://vger.kernel.org/bpfconf2019.html#session-1 @@ -19046,6 +19311,7 @@ static int is_state_visited(struct bpf_verifier_env *env, int insn_idx) clean_live_states(env, insn_idx, cur); + loop = false; head = explored_state(env, insn_idx); list_for_each_safe(pos, tmp, head) { sl = container_of(pos, struct bpf_verifier_state_list, node); @@ -19125,7 +19391,7 @@ static int is_state_visited(struct bpf_verifier_env *env, int insn_idx) spi = __get_spi(iter_reg->off + iter_reg->var_off.value); iter_state = &func(env, iter_reg)->stack[spi].spilled_ptr; if (iter_state->iter.state == BPF_ITER_STATE_ACTIVE) { - update_loop_entry(env, cur, &sl->state); + loop = true; goto hit; } } @@ -19134,7 +19400,7 @@ static int is_state_visited(struct bpf_verifier_env *env, int insn_idx) if (is_may_goto_insn_at(env, insn_idx)) { if (sl->state.may_goto_depth != cur->may_goto_depth && states_equal(env, &sl->state, cur, RANGE_WITHIN)) { - update_loop_entry(env, cur, &sl->state); + loop = true; goto hit; } } @@ -19176,38 +19442,9 @@ skip_inf_loop_check: add_new_state = false; goto miss; } - /* If sl->state is a part of a loop and this loop's entry is a part of - * current verification path then states have to be compared exactly. - * 'force_exact' is needed to catch the following case: - * - * initial Here state 'succ' was processed first, - * | it was eventually tracked to produce a - * V state identical to 'hdr'. - * .---------> hdr All branches from 'succ' had been explored - * | | and thus 'succ' has its .branches == 0. - * | V - * | .------... Suppose states 'cur' and 'succ' correspond - * | | | to the same instruction + callsites. - * | V V In such case it is necessary to check - * | ... ... if 'succ' and 'cur' are states_equal(). - * | | | If 'succ' and 'cur' are a part of the - * | V V same loop exact flag has to be set. - * | succ <- cur To check if that is the case, verify - * | | if loop entry of 'succ' is in current - * | V DFS path. - * | ... - * | | - * '----' - * - * Additional details are in the comment before get_loop_entry(). - */ - loop_entry = get_loop_entry(env, &sl->state); - if (IS_ERR(loop_entry)) - return PTR_ERR(loop_entry); - force_exact = loop_entry && loop_entry->branches > 0; - if (states_equal(env, &sl->state, cur, force_exact ? RANGE_WITHIN : NOT_EXACT)) { - if (force_exact) - update_loop_entry(env, cur, loop_entry); + /* See comments for mark_all_regs_read_and_precise() */ + loop = incomplete_read_marks(env, &sl->state); + if (states_equal(env, &sl->state, cur, loop ? RANGE_WITHIN : NOT_EXACT)) { hit: sl->hit_cnt++; /* reached equivalent register/stack state, @@ -19220,7 +19457,7 @@ hit: * they'll be immediately forgotten as we're pruning * this state and will pop a new one. */ - err = propagate_liveness(env, &sl->state, cur); + err = propagate_liveness(env, &sl->state, cur, NULL); /* if previous state reached the exit with precision and * current state is equivalent to it (except precision marks) @@ -19228,10 +19465,98 @@ hit: * the current state. */ if (is_jmp_point(env, env->insn_idx)) - err = err ? : push_insn_history(env, cur, 0, 0); - err = err ? : propagate_precision(env, &sl->state); + err = err ? : push_jmp_history(env, cur, 0, 0); + err = err ? : propagate_precision(env, &sl->state, cur, NULL); if (err) return err; + /* When processing iterator based loops above propagate_liveness and + * propagate_precision calls are not sufficient to transfer all relevant + * read and precision marks. E.g. consider the following case: + * + * .-> A --. Assume the states are visited in the order A, B, C. + * | | | Assume that state B reaches a state equivalent to state A. + * | v v At this point, state C is not processed yet, so state A + * '-- B C has not received any read or precision marks from C. + * Thus, marks propagated from A to B are incomplete. + * + * The verifier mitigates this by performing the following steps: + * + * - Prior to the main verification pass, strongly connected components + * (SCCs) are computed over the program's control flow graph, + * intraprocedurally. + * + * - During the main verification pass, `maybe_enter_scc()` checks + * whether the current verifier state is entering an SCC. If so, an + * instance of a `bpf_scc_visit` object is created, and the state + * entering the SCC is recorded as the entry state. + * + * - This instance is associated not with the SCC itself, but with a + * `bpf_scc_callchain`: a tuple consisting of the call sites leading to + * the SCC and the SCC id. See `compute_scc_callchain()`. + * + * - When a verification path encounters a `states_equal(..., + * RANGE_WITHIN)` condition, there exists a call chain describing the + * current state and a corresponding `bpf_scc_visit` instance. A copy + * of the current state is created and added to + * `bpf_scc_visit->backedges`. + * + * - When a verification path terminates, `maybe_exit_scc()` is called + * from `update_branch_counts()`. For states with `branches == 0`, it + * checks whether the state is the entry state of any `bpf_scc_visit` + * instance. If it is, this indicates that all paths originating from + * this SCC visit have been explored. `propagate_backedges()` is then + * called, which propagates read and precision marks through the + * backedges until a fixed point is reached. + * (In the earlier example, this would propagate marks from A to B, + * from C to A, and then again from A to B.) + * + * A note on callchains + * -------------------- + * + * Consider the following example: + * + * void foo() { loop { ... SCC#1 ... } } + * void main() { + * A: foo(); + * B: ... + * C: foo(); + * } + * + * Here, there are two distinct callchains leading to SCC#1: + * - (A, SCC#1) + * - (C, SCC#1) + * + * Each callchain identifies a separate `bpf_scc_visit` instance that + * accumulates backedge states. The `propagate_{liveness,precision}()` + * functions traverse the parent state of each backedge state, which + * means these parent states must remain valid (i.e., not freed) while + * the corresponding `bpf_scc_visit` instance exists. + * + * Associating `bpf_scc_visit` instances directly with SCCs instead of + * callchains would break this invariant: + * - States explored during `C: foo()` would contribute backedges to + * SCC#1, but SCC#1 would only be exited once the exploration of + * `A: foo()` completes. + * - By that time, the states explored between `A: foo()` and `C: foo()` + * (i.e., `B: ...`) may have already been freed, causing the parent + * links for states from `C: foo()` to become invalid. + */ + if (loop) { + struct bpf_scc_backedge *backedge; + + backedge = kzalloc(sizeof(*backedge), GFP_KERNEL_ACCOUNT); + if (!backedge) + return -ENOMEM; + err = copy_verifier_state(&backedge->state, cur); + backedge->state.equal_state = &sl->state; + backedge->state.insn_idx = insn_idx; + err = err ?: add_scc_backedge(env, &sl->state, backedge); + if (err) { + free_verifier_state(&backedge->state, false); + kvfree(backedge); + return err; + } + } return 1; } miss: @@ -19283,7 +19608,7 @@ miss: * When looping the sl->state.branches will be > 0 and this state * will not be considered for equivalence until branches == 0. */ - new_sl = kzalloc(sizeof(struct bpf_verifier_state_list), GFP_KERNEL); + new_sl = kzalloc(sizeof(struct bpf_verifier_state_list), GFP_KERNEL_ACCOUNT); if (!new_sl) return -ENOMEM; env->total_states++; @@ -19305,13 +19630,20 @@ miss: return err; } new->insn_idx = insn_idx; - WARN_ONCE(new->branches != 1, - "BUG is_state_visited:branches_to_explore=%d insn %d\n", new->branches, insn_idx); + verifier_bug_if(new->branches != 1, env, + "%s:branches_to_explore=%d insn %d", + __func__, new->branches, insn_idx); + err = maybe_enter_scc(env, new); + if (err) { + free_verifier_state(new, false); + kvfree(new_sl); + return err; + } cur->parent = new; cur->first_insn_idx = insn_idx; - cur->insn_hist_start = cur->insn_hist_end; cur->dfs_depth = new->dfs_depth + 1; + clear_jmp_history(cur); list_add(&new_sl->node, head); /* connect new state to parentage chain. Current frame needs all @@ -19383,10 +19715,27 @@ static bool reg_type_mismatch(enum bpf_reg_type src, enum bpf_reg_type prev) !reg_type_mismatch_ok(prev)); } +static bool is_ptr_to_mem_or_btf_id(enum bpf_reg_type type) +{ + switch (base_type(type)) { + case PTR_TO_MEM: + case PTR_TO_BTF_ID: + return true; + default: + return false; + } +} + +static bool is_ptr_to_mem(enum bpf_reg_type type) +{ + return base_type(type) == PTR_TO_MEM; +} + static int save_aux_ptr_type(struct bpf_verifier_env *env, enum bpf_reg_type type, bool allow_trust_mismatch) { enum bpf_reg_type *prev_type = &env->insn_aux_data[env->insn_idx].ptr_type; + enum bpf_reg_type merged_type; if (*prev_type == NOT_INIT) { /* Saw a valid insn @@ -19403,15 +19752,24 @@ static int save_aux_ptr_type(struct bpf_verifier_env *env, enum bpf_reg_type typ * Reject it. */ if (allow_trust_mismatch && - base_type(type) == PTR_TO_BTF_ID && - base_type(*prev_type) == PTR_TO_BTF_ID) { + is_ptr_to_mem_or_btf_id(type) && + is_ptr_to_mem_or_btf_id(*prev_type)) { /* * Have to support a use case when one path through * the program yields TRUSTED pointer while another * is UNTRUSTED. Fallback to UNTRUSTED to generate * BPF_PROBE_MEM/BPF_PROBE_MEMSX. + * Same behavior of MEM_RDONLY flag. */ - *prev_type = PTR_TO_BTF_ID | PTR_UNTRUSTED; + if (is_ptr_to_mem(type) || is_ptr_to_mem(*prev_type)) + merged_type = PTR_TO_MEM; + else + merged_type = PTR_TO_BTF_ID; + if ((type & PTR_UNTRUSTED) || (*prev_type & PTR_UNTRUSTED)) + merged_type |= PTR_UNTRUSTED; + if ((type & MEM_RDONLY) || (*prev_type & MEM_RDONLY)) + merged_type |= MEM_RDONLY; + *prev_type = merged_type; } else { verbose(env, "same insn cannot be used with different pointers\n"); return -EINVAL; @@ -19421,20 +19779,224 @@ static int save_aux_ptr_type(struct bpf_verifier_env *env, enum bpf_reg_type typ return 0; } +enum { + PROCESS_BPF_EXIT = 1 +}; + +static int process_bpf_exit_full(struct bpf_verifier_env *env, + bool *do_print_state, + bool exception_exit) +{ + /* We must do check_reference_leak here before + * prepare_func_exit to handle the case when + * state->curframe > 0, it may be a callback function, + * for which reference_state must match caller reference + * state when it exits. + */ + int err = check_resource_leak(env, exception_exit, + !env->cur_state->curframe, + "BPF_EXIT instruction in main prog"); + if (err) + return err; + + /* The side effect of the prepare_func_exit which is + * being skipped is that it frees bpf_func_state. + * Typically, process_bpf_exit will only be hit with + * outermost exit. copy_verifier_state in pop_stack will + * handle freeing of any extra bpf_func_state left over + * from not processing all nested function exits. We + * also skip return code checks as they are not needed + * for exceptional exits. + */ + if (exception_exit) + return PROCESS_BPF_EXIT; + + if (env->cur_state->curframe) { + /* exit from nested function */ + err = prepare_func_exit(env, &env->insn_idx); + if (err) + return err; + *do_print_state = true; + return 0; + } + + err = check_return_code(env, BPF_REG_0, "R0"); + if (err) + return err; + return PROCESS_BPF_EXIT; +} + +static int do_check_insn(struct bpf_verifier_env *env, bool *do_print_state) +{ + int err; + struct bpf_insn *insn = &env->prog->insnsi[env->insn_idx]; + u8 class = BPF_CLASS(insn->code); + + if (class == BPF_ALU || class == BPF_ALU64) { + err = check_alu_op(env, insn); + if (err) + return err; + + } else if (class == BPF_LDX) { + bool is_ldsx = BPF_MODE(insn->code) == BPF_MEMSX; + + /* Check for reserved fields is already done in + * resolve_pseudo_ldimm64(). + */ + err = check_load_mem(env, insn, false, is_ldsx, true, "ldx"); + if (err) + return err; + } else if (class == BPF_STX) { + if (BPF_MODE(insn->code) == BPF_ATOMIC) { + err = check_atomic(env, insn); + if (err) + return err; + env->insn_idx++; + return 0; + } + + if (BPF_MODE(insn->code) != BPF_MEM || insn->imm != 0) { + verbose(env, "BPF_STX uses reserved fields\n"); + return -EINVAL; + } + + err = check_store_reg(env, insn, false); + if (err) + return err; + } else if (class == BPF_ST) { + enum bpf_reg_type dst_reg_type; + + if (BPF_MODE(insn->code) != BPF_MEM || + insn->src_reg != BPF_REG_0) { + verbose(env, "BPF_ST uses reserved fields\n"); + return -EINVAL; + } + /* check src operand */ + err = check_reg_arg(env, insn->dst_reg, SRC_OP); + if (err) + return err; + + dst_reg_type = cur_regs(env)[insn->dst_reg].type; + + /* check that memory (dst_reg + off) is writeable */ + err = check_mem_access(env, env->insn_idx, insn->dst_reg, + insn->off, BPF_SIZE(insn->code), + BPF_WRITE, -1, false, false); + if (err) + return err; + + err = save_aux_ptr_type(env, dst_reg_type, false); + if (err) + return err; + } else if (class == BPF_JMP || class == BPF_JMP32) { + u8 opcode = BPF_OP(insn->code); + + env->jmps_processed++; + if (opcode == BPF_CALL) { + if (BPF_SRC(insn->code) != BPF_K || + (insn->src_reg != BPF_PSEUDO_KFUNC_CALL && + insn->off != 0) || + (insn->src_reg != BPF_REG_0 && + insn->src_reg != BPF_PSEUDO_CALL && + insn->src_reg != BPF_PSEUDO_KFUNC_CALL) || + insn->dst_reg != BPF_REG_0 || class == BPF_JMP32) { + verbose(env, "BPF_CALL uses reserved fields\n"); + return -EINVAL; + } + + if (env->cur_state->active_locks) { + if ((insn->src_reg == BPF_REG_0 && + insn->imm != BPF_FUNC_spin_unlock) || + (insn->src_reg == BPF_PSEUDO_KFUNC_CALL && + (insn->off != 0 || !kfunc_spin_allowed(insn->imm)))) { + verbose(env, + "function calls are not allowed while holding a lock\n"); + return -EINVAL; + } + } + if (insn->src_reg == BPF_PSEUDO_CALL) { + err = check_func_call(env, insn, &env->insn_idx); + } else if (insn->src_reg == BPF_PSEUDO_KFUNC_CALL) { + err = check_kfunc_call(env, insn, &env->insn_idx); + if (!err && is_bpf_throw_kfunc(insn)) + return process_bpf_exit_full(env, do_print_state, true); + } else { + err = check_helper_call(env, insn, &env->insn_idx); + } + if (err) + return err; + + mark_reg_scratched(env, BPF_REG_0); + } else if (opcode == BPF_JA) { + if (BPF_SRC(insn->code) != BPF_K || + insn->src_reg != BPF_REG_0 || + insn->dst_reg != BPF_REG_0 || + (class == BPF_JMP && insn->imm != 0) || + (class == BPF_JMP32 && insn->off != 0)) { + verbose(env, "BPF_JA uses reserved fields\n"); + return -EINVAL; + } + + if (class == BPF_JMP) + env->insn_idx += insn->off + 1; + else + env->insn_idx += insn->imm + 1; + return 0; + } else if (opcode == BPF_EXIT) { + if (BPF_SRC(insn->code) != BPF_K || + insn->imm != 0 || + insn->src_reg != BPF_REG_0 || + insn->dst_reg != BPF_REG_0 || + class == BPF_JMP32) { + verbose(env, "BPF_EXIT uses reserved fields\n"); + return -EINVAL; + } + return process_bpf_exit_full(env, do_print_state, false); + } else { + err = check_cond_jmp_op(env, insn, &env->insn_idx); + if (err) + return err; + } + } else if (class == BPF_LD) { + u8 mode = BPF_MODE(insn->code); + + if (mode == BPF_ABS || mode == BPF_IND) { + err = check_ld_abs(env, insn); + if (err) + return err; + + } else if (mode == BPF_IMM) { + err = check_ld_imm(env, insn); + if (err) + return err; + + env->insn_idx++; + sanitize_mark_insn_seen(env); + } else { + verbose(env, "invalid BPF_LD mode\n"); + return -EINVAL; + } + } else { + verbose(env, "unknown insn class %d\n", class); + return -EINVAL; + } + + env->insn_idx++; + return 0; +} + static int do_check(struct bpf_verifier_env *env) { bool pop_log = !(env->log.level & BPF_LOG_LEVEL2); struct bpf_verifier_state *state = env->cur_state; struct bpf_insn *insns = env->prog->insnsi; - struct bpf_reg_state *regs; int insn_cnt = env->prog->len; bool do_print_state = false; int prev_insn_idx = -1; for (;;) { - bool exception_exit = false; struct bpf_insn *insn; - u8 class; + struct bpf_insn_aux_data *insn_aux; int err; /* reset current history entry on each new instruction */ @@ -19448,7 +20010,7 @@ static int do_check(struct bpf_verifier_env *env) } insn = &insns[env->insn_idx]; - class = BPF_CLASS(insn->code); + insn_aux = &env->insn_aux_data[env->insn_idx]; if (++env->insn_processed > BPF_COMPLEXITY_LIMIT_INSNS) { verbose(env, @@ -19458,6 +20020,7 @@ static int do_check(struct bpf_verifier_env *env) } state->last_insn_idx = env->prev_insn_idx; + state->insn_idx = env->insn_idx; if (is_prune_point(env, env->insn_idx)) { err = is_state_visited(env, env->insn_idx); @@ -19479,7 +20042,7 @@ static int do_check(struct bpf_verifier_env *env) } if (is_jmp_point(env, env->insn_idx)) { - err = push_insn_history(env, state, 0, 0); + err = push_jmp_history(env, state, 0, 0); if (err) return err; } @@ -19518,215 +20081,67 @@ static int do_check(struct bpf_verifier_env *env) return err; } - regs = cur_regs(env); sanitize_mark_insn_seen(env); prev_insn_idx = env->insn_idx; - if (class == BPF_ALU || class == BPF_ALU64) { - err = check_alu_op(env, insn); - if (err) - return err; - - } else if (class == BPF_LDX) { - bool is_ldsx = BPF_MODE(insn->code) == BPF_MEMSX; + /* Reduce verification complexity by stopping speculative path + * verification when a nospec is encountered. + */ + if (state->speculative && insn_aux->nospec) + goto process_bpf_exit; - /* Check for reserved fields is already done in - * resolve_pseudo_ldimm64(). + err = do_check_insn(env, &do_print_state); + if (error_recoverable_with_nospec(err) && state->speculative) { + /* Prevent this speculative path from ever reaching the + * insn that would have been unsafe to execute. */ - err = check_load_mem(env, insn, false, is_ldsx, true, - "ldx"); - if (err) - return err; - } else if (class == BPF_STX) { - if (BPF_MODE(insn->code) == BPF_ATOMIC) { - err = check_atomic(env, insn); - if (err) - return err; - env->insn_idx++; - continue; - } - - if (BPF_MODE(insn->code) != BPF_MEM || insn->imm != 0) { - verbose(env, "BPF_STX uses reserved fields\n"); - return -EINVAL; - } - - err = check_store_reg(env, insn, false); - if (err) - return err; - } else if (class == BPF_ST) { - enum bpf_reg_type dst_reg_type; - - if (BPF_MODE(insn->code) != BPF_MEM || - insn->src_reg != BPF_REG_0) { - verbose(env, "BPF_ST uses reserved fields\n"); - return -EINVAL; - } - /* check src operand */ - err = check_reg_arg(env, insn->dst_reg, SRC_OP); - if (err) - return err; - - dst_reg_type = regs[insn->dst_reg].type; - - /* check that memory (dst_reg + off) is writeable */ - err = check_mem_access(env, env->insn_idx, insn->dst_reg, - insn->off, BPF_SIZE(insn->code), - BPF_WRITE, -1, false, false); - if (err) - return err; - - err = save_aux_ptr_type(env, dst_reg_type, false); + insn_aux->nospec = true; + /* If it was an ADD/SUB insn, potentially remove any + * markings for alu sanitization. + */ + insn_aux->alu_state = 0; + goto process_bpf_exit; + } else if (err < 0) { + return err; + } else if (err == PROCESS_BPF_EXIT) { + goto process_bpf_exit; + } + WARN_ON_ONCE(err); + + if (state->speculative && insn_aux->nospec_result) { + /* If we are on a path that performed a jump-op, this + * may skip a nospec patched-in after the jump. This can + * currently never happen because nospec_result is only + * used for the write-ops + * `*(size*)(dst_reg+off)=src_reg|imm32` which must + * never skip the following insn. Still, add a warning + * to document this in case nospec_result is used + * elsewhere in the future. + * + * All non-branch instructions have a single + * fall-through edge. For these, nospec_result should + * already work. + */ + if (verifier_bug_if(BPF_CLASS(insn->code) == BPF_JMP || + BPF_CLASS(insn->code) == BPF_JMP32, env, + "speculation barrier after jump instruction may not have the desired effect")) + return -EFAULT; +process_bpf_exit: + mark_verifier_state_scratched(env); + err = update_branch_counts(env, env->cur_state); if (err) return err; - } else if (class == BPF_JMP || class == BPF_JMP32) { - u8 opcode = BPF_OP(insn->code); - - env->jmps_processed++; - if (opcode == BPF_CALL) { - if (BPF_SRC(insn->code) != BPF_K || - (insn->src_reg != BPF_PSEUDO_KFUNC_CALL - && insn->off != 0) || - (insn->src_reg != BPF_REG_0 && - insn->src_reg != BPF_PSEUDO_CALL && - insn->src_reg != BPF_PSEUDO_KFUNC_CALL) || - insn->dst_reg != BPF_REG_0 || - class == BPF_JMP32) { - verbose(env, "BPF_CALL uses reserved fields\n"); - return -EINVAL; - } - - if (env->cur_state->active_locks) { - if ((insn->src_reg == BPF_REG_0 && insn->imm != BPF_FUNC_spin_unlock) || - (insn->src_reg == BPF_PSEUDO_KFUNC_CALL && - (insn->off != 0 || !kfunc_spin_allowed(insn->imm)))) { - verbose(env, "function calls are not allowed while holding a lock\n"); - return -EINVAL; - } - } - if (insn->src_reg == BPF_PSEUDO_CALL) { - err = check_func_call(env, insn, &env->insn_idx); - } else if (insn->src_reg == BPF_PSEUDO_KFUNC_CALL) { - err = check_kfunc_call(env, insn, &env->insn_idx); - if (!err && is_bpf_throw_kfunc(insn)) { - exception_exit = true; - goto process_bpf_exit_full; - } - } else { - err = check_helper_call(env, insn, &env->insn_idx); - } - if (err) - return err; - - mark_reg_scratched(env, BPF_REG_0); - } else if (opcode == BPF_JA) { - if (BPF_SRC(insn->code) != BPF_K || - insn->src_reg != BPF_REG_0 || - insn->dst_reg != BPF_REG_0 || - (class == BPF_JMP && insn->imm != 0) || - (class == BPF_JMP32 && insn->off != 0)) { - verbose(env, "BPF_JA uses reserved fields\n"); - return -EINVAL; - } - - if (class == BPF_JMP) - env->insn_idx += insn->off + 1; - else - env->insn_idx += insn->imm + 1; - continue; - - } else if (opcode == BPF_EXIT) { - if (BPF_SRC(insn->code) != BPF_K || - insn->imm != 0 || - insn->src_reg != BPF_REG_0 || - insn->dst_reg != BPF_REG_0 || - class == BPF_JMP32) { - verbose(env, "BPF_EXIT uses reserved fields\n"); - return -EINVAL; - } -process_bpf_exit_full: - /* We must do check_reference_leak here before - * prepare_func_exit to handle the case when - * state->curframe > 0, it may be a callback - * function, for which reference_state must - * match caller reference state when it exits. - */ - err = check_resource_leak(env, exception_exit, !env->cur_state->curframe, - "BPF_EXIT instruction in main prog"); - if (err) - return err; - - /* The side effect of the prepare_func_exit - * which is being skipped is that it frees - * bpf_func_state. Typically, process_bpf_exit - * will only be hit with outermost exit. - * copy_verifier_state in pop_stack will handle - * freeing of any extra bpf_func_state left over - * from not processing all nested function - * exits. We also skip return code checks as - * they are not needed for exceptional exits. - */ - if (exception_exit) - goto process_bpf_exit; - - if (state->curframe) { - /* exit from nested function */ - err = prepare_func_exit(env, &env->insn_idx); - if (err) - return err; - do_print_state = true; - continue; - } - - err = check_return_code(env, BPF_REG_0, "R0"); - if (err) - return err; -process_bpf_exit: - mark_verifier_state_scratched(env); - update_branch_counts(env, env->cur_state); - err = pop_stack(env, &prev_insn_idx, - &env->insn_idx, pop_log); - if (err < 0) { - if (err != -ENOENT) - return err; - break; - } else { - if (verifier_bug_if(env->cur_state->loop_entry, env, - "broken loop detection")) - return -EFAULT; - do_print_state = true; - continue; - } - } else { - err = check_cond_jmp_op(env, insn, &env->insn_idx); - if (err) - return err; - } - } else if (class == BPF_LD) { - u8 mode = BPF_MODE(insn->code); - - if (mode == BPF_ABS || mode == BPF_IND) { - err = check_ld_abs(env, insn); - if (err) - return err; - - } else if (mode == BPF_IMM) { - err = check_ld_imm(env, insn); - if (err) + err = pop_stack(env, &prev_insn_idx, &env->insn_idx, + pop_log); + if (err < 0) { + if (err != -ENOENT) return err; - - env->insn_idx++; - sanitize_mark_insn_seen(env); + break; } else { - verbose(env, "invalid BPF_LD mode\n"); - return -EINVAL; + do_print_state = true; + continue; } - } else { - verbose(env, "unknown insn class %d\n", class); - return -EINVAL; } - - env->insn_idx++; } return 0; @@ -20678,7 +21093,10 @@ static int opt_remove_nops(struct bpf_verifier_env *env) static int opt_subreg_zext_lo32_rnd_hi32(struct bpf_verifier_env *env, const union bpf_attr *attr) { - struct bpf_insn *patch, zext_patch[2], rnd_hi32_patch[4]; + struct bpf_insn *patch; + /* use env->insn_buf as two independent buffers */ + struct bpf_insn *zext_patch = env->insn_buf; + struct bpf_insn *rnd_hi32_patch = &env->insn_buf[2]; struct bpf_insn_aux_data *aux = env->insn_aux_data; int i, patch_len, delta = 0, len = env->prog->len; struct bpf_insn *insns = env->prog->insnsi; @@ -20797,8 +21215,8 @@ static int convert_ctx_accesses(struct bpf_verifier_env *env) epilogue_cnt = ops->gen_epilogue(epilogue_buf, env->prog, -(subprogs[0].stack_depth + 8)); if (epilogue_cnt >= INSN_BUF_SIZE) { - verbose(env, "bpf verifier is misconfigured\n"); - return -EINVAL; + verifier_bug(env, "epilogue is too long"); + return -EFAULT; } else if (epilogue_cnt) { /* Save the ARG_PTR_TO_CTX for the epilogue to use */ cnt = 0; @@ -20820,14 +21238,14 @@ static int convert_ctx_accesses(struct bpf_verifier_env *env) if (ops->gen_prologue || env->seen_direct_write) { if (!ops->gen_prologue) { - verbose(env, "bpf verifier is misconfigured\n"); - return -EINVAL; + verifier_bug(env, "gen_prologue is null"); + return -EFAULT; } cnt = ops->gen_prologue(insn_buf, env->seen_direct_write, env->prog); if (cnt >= INSN_BUF_SIZE) { - verbose(env, "bpf verifier is misconfigured\n"); - return -EINVAL; + verifier_bug(env, "prologue is too long"); + return -EFAULT; } else if (cnt) { new_prog = bpf_patch_insn_data(env, 0, insn_buf, cnt); if (!new_prog) @@ -20854,6 +21272,28 @@ static int convert_ctx_accesses(struct bpf_verifier_env *env) bpf_convert_ctx_access_t convert_ctx_access; u8 mode; + if (env->insn_aux_data[i + delta].nospec) { + WARN_ON_ONCE(env->insn_aux_data[i + delta].alu_state); + struct bpf_insn *patch = insn_buf; + + *patch++ = BPF_ST_NOSPEC(); + *patch++ = *insn; + cnt = patch - insn_buf; + new_prog = bpf_patch_insn_data(env, i + delta, insn_buf, cnt); + if (!new_prog) + return -ENOMEM; + + delta += cnt - 1; + env->prog = new_prog; + insn = new_prog->insnsi + i + delta; + /* This can not be easily merged with the + * nospec_result-case, because an insn may require a + * nospec before and after itself. Therefore also do not + * 'continue' here but potentially apply further + * patching to insn. *insn should equal patch[1] now. + */ + } + if (insn->code == (BPF_LDX | BPF_MEM | BPF_B) || insn->code == (BPF_LDX | BPF_MEM | BPF_H) || insn->code == (BPF_LDX | BPF_MEM | BPF_W) || @@ -20903,14 +21343,16 @@ static int convert_ctx_accesses(struct bpf_verifier_env *env) } if (type == BPF_WRITE && - env->insn_aux_data[i + delta].sanitize_stack_spill) { - struct bpf_insn patch[] = { - *insn, - BPF_ST_NOSPEC(), - }; + env->insn_aux_data[i + delta].nospec_result) { + /* nospec_result is only used to mitigate Spectre v4 and + * to limit verification-time for Spectre v1. + */ + struct bpf_insn *patch = insn_buf; - cnt = ARRAY_SIZE(patch); - new_prog = bpf_patch_insn_data(env, i + delta, patch, cnt); + *patch++ = *insn; + *patch++ = BPF_ST_NOSPEC(); + cnt = patch - insn_buf; + new_prog = bpf_patch_insn_data(env, i + delta, insn_buf, cnt); if (!new_prog) return -ENOMEM; @@ -20945,6 +21387,7 @@ static int convert_ctx_accesses(struct bpf_verifier_env *env) * for this case. */ case PTR_TO_BTF_ID | MEM_ALLOC | PTR_UNTRUSTED: + case PTR_TO_MEM | MEM_RDONLY | PTR_UNTRUSTED: if (type == BPF_READ) { if (BPF_MODE(insn->code) == BPF_MEM) insn->code = BPF_LDX | BPF_PROBE_MEM | @@ -20983,8 +21426,8 @@ static int convert_ctx_accesses(struct bpf_verifier_env *env) u8 size_code; if (type == BPF_WRITE) { - verbose(env, "bpf verifier narrow ctx access misconfigured\n"); - return -EINVAL; + verifier_bug(env, "narrow ctx access misconfigured"); + return -EFAULT; } size_code = BPF_H; @@ -21002,16 +21445,16 @@ static int convert_ctx_accesses(struct bpf_verifier_env *env) &target_size); if (cnt == 0 || cnt >= INSN_BUF_SIZE || (ctx_field_size && !target_size)) { - verbose(env, "bpf verifier is misconfigured\n"); - return -EINVAL; + verifier_bug(env, "error during ctx access conversion"); + return -EFAULT; } if (is_narrower_load && size < target_size) { u8 shift = bpf_ctx_narrow_access_offset( off, size, size_default) * 8; if (shift && cnt + 1 >= INSN_BUF_SIZE) { - verbose(env, "bpf verifier narrow ctx load misconfigured\n"); - return -EINVAL; + verifier_bug(env, "narrow ctx load misconfigured"); + return -EFAULT; } if (ctx_field_size <= 4) { if (shift) @@ -21441,8 +21884,8 @@ static int fixup_kfunc_call(struct bpf_verifier_env *env, struct bpf_insn *insn, */ desc = find_kfunc_desc(env->prog, insn->imm, insn->off); if (!desc) { - verbose(env, "verifier internal error: kernel function descriptor not found for func_id %u\n", - insn->imm); + verifier_bug(env, "kernel function descriptor not found for func_id %u", + insn->imm); return -EFAULT; } @@ -21457,8 +21900,8 @@ static int fixup_kfunc_call(struct bpf_verifier_env *env, struct bpf_insn *insn, u64 obj_new_size = env->insn_aux_data[insn_idx].obj_new_size; if (desc->func_id == special_kfunc_list[KF_bpf_percpu_obj_new_impl] && kptr_struct_meta) { - verbose(env, "verifier internal error: NULL kptr_struct_meta expected at insn_idx %d\n", - insn_idx); + verifier_bug(env, "NULL kptr_struct_meta expected at insn_idx %d", + insn_idx); return -EFAULT; } @@ -21474,15 +21917,15 @@ static int fixup_kfunc_call(struct bpf_verifier_env *env, struct bpf_insn *insn, struct bpf_insn addr[2] = { BPF_LD_IMM64(BPF_REG_2, (long)kptr_struct_meta) }; if (desc->func_id == special_kfunc_list[KF_bpf_percpu_obj_drop_impl] && kptr_struct_meta) { - verbose(env, "verifier internal error: NULL kptr_struct_meta expected at insn_idx %d\n", - insn_idx); + verifier_bug(env, "NULL kptr_struct_meta expected at insn_idx %d", + insn_idx); return -EFAULT; } if (desc->func_id == special_kfunc_list[KF_bpf_refcount_acquire_impl] && !kptr_struct_meta) { - verbose(env, "verifier internal error: kptr_struct_meta expected at insn_idx %d\n", - insn_idx); + verifier_bug(env, "kptr_struct_meta expected at insn_idx %d", + insn_idx); return -EFAULT; } @@ -21504,8 +21947,8 @@ static int fixup_kfunc_call(struct bpf_verifier_env *env, struct bpf_insn *insn, } if (!kptr_struct_meta) { - verbose(env, "verifier internal error: kptr_struct_meta expected at insn_idx %d\n", - insn_idx); + verifier_bug(env, "kptr_struct_meta expected at insn_idx %d", + insn_idx); return -EFAULT; } @@ -21539,7 +21982,7 @@ static int add_hidden_subprog(struct bpf_verifier_env *env, struct bpf_insn *pat /* We only reserve one slot for hidden subprogs in subprog_info. */ if (env->hidden_subprog_cnt) { - verbose(env, "verifier internal error: only one hidden subprog supported\n"); + verifier_bug(env, "only one hidden subprog supported"); return -EFAULT; } /* We're not patching any existing instruction, just appending the new @@ -21579,13 +22022,12 @@ static int do_misc_fixups(struct bpf_verifier_env *env) u16 stack_depth_extra = 0; if (env->seen_exception && !env->exception_callback_subprog) { - struct bpf_insn patch[] = { - env->prog->insnsi[insn_cnt - 1], - BPF_MOV64_REG(BPF_REG_0, BPF_REG_1), - BPF_EXIT_INSN(), - }; + struct bpf_insn *patch = insn_buf; - ret = add_hidden_subprog(env, patch, ARRAY_SIZE(patch)); + *patch++ = env->prog->insnsi[insn_cnt - 1]; + *patch++ = BPF_MOV64_REG(BPF_REG_0, BPF_REG_1); + *patch++ = BPF_EXIT_INSN(); + ret = add_hidden_subprog(env, insn_buf, patch - insn_buf); if (ret < 0) return ret; prog = env->prog; @@ -21621,20 +22063,18 @@ static int do_misc_fixups(struct bpf_verifier_env *env) insn->off == 1 && insn->imm == -1) { bool is64 = BPF_CLASS(insn->code) == BPF_ALU64; bool isdiv = BPF_OP(insn->code) == BPF_DIV; - struct bpf_insn *patchlet; - struct bpf_insn chk_and_sdiv[] = { - BPF_RAW_INSN((is64 ? BPF_ALU64 : BPF_ALU) | - BPF_NEG | BPF_K, insn->dst_reg, - 0, 0, 0), - }; - struct bpf_insn chk_and_smod[] = { - BPF_MOV32_IMM(insn->dst_reg, 0), - }; + struct bpf_insn *patch = insn_buf; - patchlet = isdiv ? chk_and_sdiv : chk_and_smod; - cnt = isdiv ? ARRAY_SIZE(chk_and_sdiv) : ARRAY_SIZE(chk_and_smod); + if (isdiv) + *patch++ = BPF_RAW_INSN((is64 ? BPF_ALU64 : BPF_ALU) | + BPF_NEG | BPF_K, insn->dst_reg, + 0, 0, 0); + else + *patch++ = BPF_MOV32_IMM(insn->dst_reg, 0); - new_prog = bpf_patch_insn_data(env, i + delta, patchlet, cnt); + cnt = patch - insn_buf; + + new_prog = bpf_patch_insn_data(env, i + delta, insn_buf, cnt); if (!new_prog) return -ENOMEM; @@ -21653,83 +22093,79 @@ static int do_misc_fixups(struct bpf_verifier_env *env) bool isdiv = BPF_OP(insn->code) == BPF_DIV; bool is_sdiv = isdiv && insn->off == 1; bool is_smod = !isdiv && insn->off == 1; - struct bpf_insn *patchlet; - struct bpf_insn chk_and_div[] = { - /* [R,W]x div 0 -> 0 */ - BPF_RAW_INSN((is64 ? BPF_JMP : BPF_JMP32) | - BPF_JNE | BPF_K, insn->src_reg, - 0, 2, 0), - BPF_ALU32_REG(BPF_XOR, insn->dst_reg, insn->dst_reg), - BPF_JMP_IMM(BPF_JA, 0, 0, 1), - *insn, - }; - struct bpf_insn chk_and_mod[] = { - /* [R,W]x mod 0 -> [R,W]x */ - BPF_RAW_INSN((is64 ? BPF_JMP : BPF_JMP32) | - BPF_JEQ | BPF_K, insn->src_reg, - 0, 1 + (is64 ? 0 : 1), 0), - *insn, - BPF_JMP_IMM(BPF_JA, 0, 0, 1), - BPF_MOV32_REG(insn->dst_reg, insn->dst_reg), - }; - struct bpf_insn chk_and_sdiv[] = { + struct bpf_insn *patch = insn_buf; + + if (is_sdiv) { /* [R,W]x sdiv 0 -> 0 * LLONG_MIN sdiv -1 -> LLONG_MIN * INT_MIN sdiv -1 -> INT_MIN */ - BPF_MOV64_REG(BPF_REG_AX, insn->src_reg), - BPF_RAW_INSN((is64 ? BPF_ALU64 : BPF_ALU) | - BPF_ADD | BPF_K, BPF_REG_AX, - 0, 0, 1), - BPF_RAW_INSN((is64 ? BPF_JMP : BPF_JMP32) | - BPF_JGT | BPF_K, BPF_REG_AX, - 0, 4, 1), - BPF_RAW_INSN((is64 ? BPF_JMP : BPF_JMP32) | - BPF_JEQ | BPF_K, BPF_REG_AX, - 0, 1, 0), - BPF_RAW_INSN((is64 ? BPF_ALU64 : BPF_ALU) | - BPF_MOV | BPF_K, insn->dst_reg, - 0, 0, 0), + *patch++ = BPF_MOV64_REG(BPF_REG_AX, insn->src_reg); + *patch++ = BPF_RAW_INSN((is64 ? BPF_ALU64 : BPF_ALU) | + BPF_ADD | BPF_K, BPF_REG_AX, + 0, 0, 1); + *patch++ = BPF_RAW_INSN((is64 ? BPF_JMP : BPF_JMP32) | + BPF_JGT | BPF_K, BPF_REG_AX, + 0, 4, 1); + *patch++ = BPF_RAW_INSN((is64 ? BPF_JMP : BPF_JMP32) | + BPF_JEQ | BPF_K, BPF_REG_AX, + 0, 1, 0); + *patch++ = BPF_RAW_INSN((is64 ? BPF_ALU64 : BPF_ALU) | + BPF_MOV | BPF_K, insn->dst_reg, + 0, 0, 0); /* BPF_NEG(LLONG_MIN) == -LLONG_MIN == LLONG_MIN */ - BPF_RAW_INSN((is64 ? BPF_ALU64 : BPF_ALU) | - BPF_NEG | BPF_K, insn->dst_reg, - 0, 0, 0), - BPF_JMP_IMM(BPF_JA, 0, 0, 1), - *insn, - }; - struct bpf_insn chk_and_smod[] = { + *patch++ = BPF_RAW_INSN((is64 ? BPF_ALU64 : BPF_ALU) | + BPF_NEG | BPF_K, insn->dst_reg, + 0, 0, 0); + *patch++ = BPF_JMP_IMM(BPF_JA, 0, 0, 1); + *patch++ = *insn; + cnt = patch - insn_buf; + } else if (is_smod) { /* [R,W]x mod 0 -> [R,W]x */ /* [R,W]x mod -1 -> 0 */ - BPF_MOV64_REG(BPF_REG_AX, insn->src_reg), - BPF_RAW_INSN((is64 ? BPF_ALU64 : BPF_ALU) | - BPF_ADD | BPF_K, BPF_REG_AX, - 0, 0, 1), - BPF_RAW_INSN((is64 ? BPF_JMP : BPF_JMP32) | - BPF_JGT | BPF_K, BPF_REG_AX, - 0, 3, 1), - BPF_RAW_INSN((is64 ? BPF_JMP : BPF_JMP32) | - BPF_JEQ | BPF_K, BPF_REG_AX, - 0, 3 + (is64 ? 0 : 1), 1), - BPF_MOV32_IMM(insn->dst_reg, 0), - BPF_JMP_IMM(BPF_JA, 0, 0, 1), - *insn, - BPF_JMP_IMM(BPF_JA, 0, 0, 1), - BPF_MOV32_REG(insn->dst_reg, insn->dst_reg), - }; - - if (is_sdiv) { - patchlet = chk_and_sdiv; - cnt = ARRAY_SIZE(chk_and_sdiv); - } else if (is_smod) { - patchlet = chk_and_smod; - cnt = ARRAY_SIZE(chk_and_smod) - (is64 ? 2 : 0); + *patch++ = BPF_MOV64_REG(BPF_REG_AX, insn->src_reg); + *patch++ = BPF_RAW_INSN((is64 ? BPF_ALU64 : BPF_ALU) | + BPF_ADD | BPF_K, BPF_REG_AX, + 0, 0, 1); + *patch++ = BPF_RAW_INSN((is64 ? BPF_JMP : BPF_JMP32) | + BPF_JGT | BPF_K, BPF_REG_AX, + 0, 3, 1); + *patch++ = BPF_RAW_INSN((is64 ? BPF_JMP : BPF_JMP32) | + BPF_JEQ | BPF_K, BPF_REG_AX, + 0, 3 + (is64 ? 0 : 1), 1); + *patch++ = BPF_MOV32_IMM(insn->dst_reg, 0); + *patch++ = BPF_JMP_IMM(BPF_JA, 0, 0, 1); + *patch++ = *insn; + + if (!is64) { + *patch++ = BPF_JMP_IMM(BPF_JA, 0, 0, 1); + *patch++ = BPF_MOV32_REG(insn->dst_reg, insn->dst_reg); + } + cnt = patch - insn_buf; + } else if (isdiv) { + /* [R,W]x div 0 -> 0 */ + *patch++ = BPF_RAW_INSN((is64 ? BPF_JMP : BPF_JMP32) | + BPF_JNE | BPF_K, insn->src_reg, + 0, 2, 0); + *patch++ = BPF_ALU32_REG(BPF_XOR, insn->dst_reg, insn->dst_reg); + *patch++ = BPF_JMP_IMM(BPF_JA, 0, 0, 1); + *patch++ = *insn; + cnt = patch - insn_buf; } else { - patchlet = isdiv ? chk_and_div : chk_and_mod; - cnt = isdiv ? ARRAY_SIZE(chk_and_div) : - ARRAY_SIZE(chk_and_mod) - (is64 ? 2 : 0); + /* [R,W]x mod 0 -> [R,W]x */ + *patch++ = BPF_RAW_INSN((is64 ? BPF_JMP : BPF_JMP32) | + BPF_JEQ | BPF_K, insn->src_reg, + 0, 1 + (is64 ? 0 : 1), 0); + *patch++ = *insn; + + if (!is64) { + *patch++ = BPF_JMP_IMM(BPF_JA, 0, 0, 1); + *patch++ = BPF_MOV32_REG(insn->dst_reg, insn->dst_reg); + } + cnt = patch - insn_buf; } - new_prog = bpf_patch_insn_data(env, i + delta, patchlet, cnt); + new_prog = bpf_patch_insn_data(env, i + delta, insn_buf, cnt); if (!new_prog) return -ENOMEM; @@ -21743,7 +22179,7 @@ static int do_misc_fixups(struct bpf_verifier_env *env) if (BPF_CLASS(insn->code) == BPF_LDX && (BPF_MODE(insn->code) == BPF_PROBE_MEM || BPF_MODE(insn->code) == BPF_PROBE_MEMSX)) { - struct bpf_insn *patch = &insn_buf[0]; + struct bpf_insn *patch = insn_buf; u64 uaddress_limit = bpf_arch_uaddress_limit(); if (!uaddress_limit) @@ -21775,8 +22211,8 @@ static int do_misc_fixups(struct bpf_verifier_env *env) BPF_MODE(insn->code) == BPF_IND)) { cnt = env->ops->gen_ld_abs(insn, insn_buf); if (cnt == 0 || cnt >= INSN_BUF_SIZE) { - verbose(env, "bpf verifier is misconfigured\n"); - return -EINVAL; + verifier_bug(env, "%d insns generated for ld_abs", cnt); + return -EFAULT; } new_prog = bpf_patch_insn_data(env, i + delta, insn_buf, cnt); @@ -21794,7 +22230,7 @@ static int do_misc_fixups(struct bpf_verifier_env *env) insn->code == (BPF_ALU64 | BPF_SUB | BPF_X)) { const u8 code_add = BPF_ALU64 | BPF_ADD | BPF_X; const u8 code_sub = BPF_ALU64 | BPF_SUB | BPF_X; - struct bpf_insn *patch = &insn_buf[0]; + struct bpf_insn *patch = insn_buf; bool issrc, isneg, isimm; u32 off_reg; @@ -22111,8 +22547,8 @@ static int do_misc_fixups(struct bpf_verifier_env *env) if (cnt == -EOPNOTSUPP) goto patch_map_ops_generic; if (cnt <= 0 || cnt >= INSN_BUF_SIZE) { - verbose(env, "bpf verifier is misconfigured\n"); - return -EINVAL; + verifier_bug(env, "%d insns generated for map lookup", cnt); + return -EFAULT; } new_prog = bpf_patch_insn_data(env, i + delta, @@ -22399,9 +22835,9 @@ patch_call_imm: * programs to call them, must be real in-kernel functions */ if (!fn->func) { - verbose(env, - "kernel subsystem misconfigured func %s#%d\n", - func_id_name(insn->imm), insn->imm); + verifier_bug(env, + "not inlined functions %s#%d is missing func", + func_id_name(insn->imm), insn->imm); return -EFAULT; } insn->imm = fn->func - __bpf_call_base; @@ -22471,8 +22907,8 @@ next_insn: if (!map_ptr->ops->map_poke_track || !map_ptr->ops->map_poke_untrack || !map_ptr->ops->map_poke_run) { - verbose(env, "bpf verifier is misconfigured\n"); - return -EINVAL; + verifier_bug(env, "poke tab is misconfigured"); + return -EFAULT; } ret = map_ptr->ops->map_poke_track(map_ptr, prog->aux); @@ -22662,7 +23098,12 @@ static void free_states(struct bpf_verifier_env *env) { struct bpf_verifier_state_list *sl; struct list_head *head, *pos, *tmp; - int i; + struct bpf_scc_info *info; + int i, j; + + free_verifier_state(env->cur_state, true); + env->cur_state = NULL; + while (!pop_stack(env, NULL, NULL, false)); list_for_each_safe(pos, tmp, &env->free_list) { sl = container_of(pos, struct bpf_verifier_state_list, node); @@ -22671,6 +23112,14 @@ static void free_states(struct bpf_verifier_env *env) } INIT_LIST_HEAD(&env->free_list); + for (i = 0; i < env->scc_cnt; ++i) { + info = env->scc_info[i]; + for (j = 0; j < info->num_visits; j++) + free_backedges(&info->visits[j]); + kvfree(info); + env->scc_info[i] = NULL; + } + if (!env->explored_states) return; @@ -22698,13 +23147,13 @@ static int do_check_common(struct bpf_verifier_env *env, int subprog) env->prev_linfo = NULL; env->pass_cnt++; - state = kzalloc(sizeof(struct bpf_verifier_state), GFP_KERNEL); + state = kzalloc(sizeof(struct bpf_verifier_state), GFP_KERNEL_ACCOUNT); if (!state) return -ENOMEM; state->curframe = 0; state->speculative = false; state->branches = 1; - state->frame[0] = kzalloc(sizeof(struct bpf_func_state), GFP_KERNEL); + state->frame[0] = kzalloc(sizeof(struct bpf_func_state), GFP_KERNEL_ACCOUNT); if (!state->frame[0]) { kfree(state); return -ENOMEM; @@ -22755,11 +23204,12 @@ static int do_check_common(struct bpf_verifier_env *env, int subprog) __mark_dynptr_reg(reg, BPF_DYNPTR_TYPE_LOCAL, true, ++env->id_gen); } else if (base_type(arg->arg_type) == ARG_PTR_TO_MEM) { reg->type = PTR_TO_MEM; - if (arg->arg_type & PTR_MAYBE_NULL) - reg->type |= PTR_MAYBE_NULL; + reg->type |= arg->arg_type & + (PTR_MAYBE_NULL | PTR_UNTRUSTED | MEM_RDONLY); mark_reg_known_zero(env, regs, i); reg->mem_size = arg->mem_size; - reg->id = ++env->id_gen; + if (arg->arg_type & PTR_MAYBE_NULL) + reg->id = ++env->id_gen; } else if (base_type(arg->arg_type) == ARG_PTR_TO_BTF_ID) { reg->type = PTR_TO_BTF_ID; if (arg->arg_type & PTR_MAYBE_NULL) @@ -22776,8 +23226,8 @@ static int do_check_common(struct bpf_verifier_env *env, int subprog) /* caller can pass either PTR_TO_ARENA or SCALAR */ mark_reg_unknown(env, regs, i); } else { - WARN_ONCE(1, "BUG: unhandled arg#%d type %d\n", - i - BPF_REG_1, arg->arg_type); + verifier_bug(env, "unhandled arg#%d type %d", + i - BPF_REG_1, arg->arg_type); ret = -EFAULT; goto out; } @@ -22807,14 +23257,6 @@ static int do_check_common(struct bpf_verifier_env *env, int subprog) ret = do_check(env); out: - /* check for NULL is necessary, since cur_state can be freed inside - * do_check() under memory pressure. - */ - if (env->cur_state) { - free_verifier_state(env->cur_state, true); - env->cur_state = NULL; - } - while (!pop_stack(env, NULL, NULL, false)); if (!ret && pop_log) bpf_vlog_reset(&env->log, 0); free_states(env); @@ -22930,7 +23372,7 @@ static void print_verification_stats(struct bpf_verifier_env *env) int bpf_prog_ctx_arg_info_init(struct bpf_prog *prog, const struct bpf_ctx_arg_aux *info, u32 cnt) { - prog->aux->ctx_arg_info = kmemdup_array(info, cnt, sizeof(*info), GFP_KERNEL); + prog->aux->ctx_arg_info = kmemdup_array(info, cnt, sizeof(*info), GFP_KERNEL_ACCOUNT); prog->aux->ctx_arg_info_size = cnt; return prog->aux->ctx_arg_info ? 0 : -ENOMEM; @@ -23539,11 +23981,14 @@ static int check_attach_btf_id(struct bpf_verifier_env *env) return ret; } else if (prog->type == BPF_PROG_TYPE_TRACING && btf_id_set_contains(&btf_id_deny, btf_id)) { + verbose(env, "Attaching tracing programs to function '%s' is rejected.\n", + tgt_info.tgt_name); return -EINVAL; } else if ((prog->expected_attach_type == BPF_TRACE_FEXIT || prog->expected_attach_type == BPF_MODIFY_RETURN) && btf_id_set_contains(&noreturn_deny, btf_id)) { - verbose(env, "Attaching fexit/fmod_ret to __noreturn functions is rejected.\n"); + verbose(env, "Attaching fexit/fmod_ret to __noreturn function '%s' is rejected.\n", + tgt_info.tgt_name); return -EINVAL; } @@ -23672,6 +24117,7 @@ static bool can_jump(struct bpf_insn *insn) case BPF_JSLT: case BPF_JSLE: case BPF_JCOND: + case BPF_JSET: return true; } @@ -23874,7 +24320,7 @@ static int compute_live_registers(struct bpf_verifier_env *env) * - repeat the computation while {in,out} fields changes for * any instruction. */ - state = kvcalloc(insn_cnt, sizeof(*state), GFP_KERNEL); + state = kvcalloc(insn_cnt, sizeof(*state), GFP_KERNEL_ACCOUNT); if (!state) { err = -ENOMEM; goto out; @@ -23912,6 +24358,10 @@ static int compute_live_registers(struct bpf_verifier_env *env) if (env->log.level & BPF_LOG_LEVEL2) { verbose(env, "Live regs before insn:\n"); for (i = 0; i < insn_cnt; ++i) { + if (env->insn_aux_data[i].scc) + verbose(env, "%3d ", env->insn_aux_data[i].scc); + else + verbose(env, " "); verbose(env, "%3d: ", i); for (j = BPF_REG_0; j < BPF_REG_10; ++j) if (insn_aux[i].live_regs_before & BIT(j)) @@ -23933,6 +24383,185 @@ out: return err; } +/* + * Compute strongly connected components (SCCs) on the CFG. + * Assign an SCC number to each instruction, recorded in env->insn_aux[*].scc. + * If instruction is a sole member of its SCC and there are no self edges, + * assign it SCC number of zero. + * Uses a non-recursive adaptation of Tarjan's algorithm for SCC computation. + */ +static int compute_scc(struct bpf_verifier_env *env) +{ + const u32 NOT_ON_STACK = U32_MAX; + + struct bpf_insn_aux_data *aux = env->insn_aux_data; + const u32 insn_cnt = env->prog->len; + int stack_sz, dfs_sz, err = 0; + u32 *stack, *pre, *low, *dfs; + u32 succ_cnt, i, j, t, w; + u32 next_preorder_num; + u32 next_scc_id; + bool assign_scc; + u32 succ[2]; + + next_preorder_num = 1; + next_scc_id = 1; + /* + * - 'stack' accumulates vertices in DFS order, see invariant comment below; + * - 'pre[t] == p' => preorder number of vertex 't' is 'p'; + * - 'low[t] == n' => smallest preorder number of the vertex reachable from 't' is 'n'; + * - 'dfs' DFS traversal stack, used to emulate explicit recursion. + */ + stack = kvcalloc(insn_cnt, sizeof(int), GFP_KERNEL_ACCOUNT); + pre = kvcalloc(insn_cnt, sizeof(int), GFP_KERNEL_ACCOUNT); + low = kvcalloc(insn_cnt, sizeof(int), GFP_KERNEL_ACCOUNT); + dfs = kvcalloc(insn_cnt, sizeof(*dfs), GFP_KERNEL_ACCOUNT); + if (!stack || !pre || !low || !dfs) { + err = -ENOMEM; + goto exit; + } + /* + * References: + * [1] R. Tarjan "Depth-First Search and Linear Graph Algorithms" + * [2] D. J. Pearce "A Space-Efficient Algorithm for Finding Strongly Connected Components" + * + * The algorithm maintains the following invariant: + * - suppose there is a path 'u' ~> 'v', such that 'pre[v] < pre[u]'; + * - then, vertex 'u' remains on stack while vertex 'v' is on stack. + * + * Consequently: + * - If 'low[v] < pre[v]', there is a path from 'v' to some vertex 'u', + * such that 'pre[u] == low[v]'; vertex 'u' is currently on the stack, + * and thus there is an SCC (loop) containing both 'u' and 'v'. + * - If 'low[v] == pre[v]', loops containing 'v' have been explored, + * and 'v' can be considered the root of some SCC. + * + * Here is a pseudo-code for an explicitly recursive version of the algorithm: + * + * NOT_ON_STACK = insn_cnt + 1 + * pre = [0] * insn_cnt + * low = [0] * insn_cnt + * scc = [0] * insn_cnt + * stack = [] + * + * next_preorder_num = 1 + * next_scc_id = 1 + * + * def recur(w): + * nonlocal next_preorder_num + * nonlocal next_scc_id + * + * pre[w] = next_preorder_num + * low[w] = next_preorder_num + * next_preorder_num += 1 + * stack.append(w) + * for s in successors(w): + * # Note: for classic algorithm the block below should look as: + * # + * # if pre[s] == 0: + * # recur(s) + * # low[w] = min(low[w], low[s]) + * # elif low[s] != NOT_ON_STACK: + * # low[w] = min(low[w], pre[s]) + * # + * # But replacing both 'min' instructions with 'low[w] = min(low[w], low[s])' + * # does not break the invariant and makes itartive version of the algorithm + * # simpler. See 'Algorithm #3' from [2]. + * + * # 's' not yet visited + * if pre[s] == 0: + * recur(s) + * # if 's' is on stack, pick lowest reachable preorder number from it; + * # if 's' is not on stack 'low[s] == NOT_ON_STACK > low[w]', + * # so 'min' would be a noop. + * low[w] = min(low[w], low[s]) + * + * if low[w] == pre[w]: + * # 'w' is the root of an SCC, pop all vertices + * # below 'w' on stack and assign same SCC to them. + * while True: + * t = stack.pop() + * low[t] = NOT_ON_STACK + * scc[t] = next_scc_id + * if t == w: + * break + * next_scc_id += 1 + * + * for i in range(0, insn_cnt): + * if pre[i] == 0: + * recur(i) + * + * Below implementation replaces explicit recursion with array 'dfs'. + */ + for (i = 0; i < insn_cnt; i++) { + if (pre[i]) + continue; + stack_sz = 0; + dfs_sz = 1; + dfs[0] = i; +dfs_continue: + while (dfs_sz) { + w = dfs[dfs_sz - 1]; + if (pre[w] == 0) { + low[w] = next_preorder_num; + pre[w] = next_preorder_num; + next_preorder_num++; + stack[stack_sz++] = w; + } + /* Visit 'w' successors */ + succ_cnt = insn_successors(env->prog, w, succ); + for (j = 0; j < succ_cnt; ++j) { + if (pre[succ[j]]) { + low[w] = min(low[w], low[succ[j]]); + } else { + dfs[dfs_sz++] = succ[j]; + goto dfs_continue; + } + } + /* + * Preserve the invariant: if some vertex above in the stack + * is reachable from 'w', keep 'w' on the stack. + */ + if (low[w] < pre[w]) { + dfs_sz--; + goto dfs_continue; + } + /* + * Assign SCC number only if component has two or more elements, + * or if component has a self reference. + */ + assign_scc = stack[stack_sz - 1] != w; + for (j = 0; j < succ_cnt; ++j) { + if (succ[j] == w) { + assign_scc = true; + break; + } + } + /* Pop component elements from stack */ + do { + t = stack[--stack_sz]; + low[t] = NOT_ON_STACK; + if (assign_scc) + aux[t].scc = next_scc_id; + } while (t != w); + if (assign_scc) + next_scc_id++; + dfs_sz--; + } + } + env->scc_info = kvcalloc(next_scc_id, sizeof(*env->scc_info), GFP_KERNEL_ACCOUNT); + if (!env->scc_info) { + err = -ENOMEM; + goto exit; + } +exit: + kvfree(stack); + kvfree(pre); + kvfree(low); + kvfree(dfs); + return err; +} + int bpf_check(struct bpf_prog **prog, union bpf_attr *attr, bpfptr_t uattr, __u32 uattr_size) { u64 start_time = ktime_get_ns(); @@ -23941,6 +24570,8 @@ int bpf_check(struct bpf_prog **prog, union bpf_attr *attr, bpfptr_t uattr, __u3 u32 log_true_size; bool is_priv; + BTF_TYPE_EMIT(enum bpf_features); + /* no program is valid */ if (ARRAY_SIZE(bpf_verifier_ops) == 0) return -EINVAL; @@ -23948,7 +24579,7 @@ int bpf_check(struct bpf_prog **prog, union bpf_attr *attr, bpfptr_t uattr, __u3 /* 'struct bpf_verifier_env' can be global, but since it's not small, * allocate/free it every time bpf_check() is called */ - env = kvzalloc(sizeof(struct bpf_verifier_env), GFP_KERNEL); + env = kvzalloc(sizeof(struct bpf_verifier_env), GFP_KERNEL_ACCOUNT); if (!env) return -ENOMEM; @@ -24011,7 +24642,7 @@ int bpf_check(struct bpf_prog **prog, union bpf_attr *attr, bpfptr_t uattr, __u3 env->explored_states = kvcalloc(state_htab_size(env), sizeof(struct list_head), - GFP_USER); + GFP_KERNEL_ACCOUNT); ret = -ENOMEM; if (!env->explored_states) goto skip_full_check; @@ -24054,6 +24685,10 @@ int bpf_check(struct bpf_prog **prog, union bpf_attr *attr, bpfptr_t uattr, __u3 if (ret) goto skip_full_check; + ret = compute_scc(env); + if (ret < 0) + goto skip_full_check; + ret = compute_live_registers(env); if (ret < 0) goto skip_full_check; @@ -24138,7 +24773,7 @@ skip_full_check: /* if program passed verifier, update used_maps in bpf_prog_info */ env->prog->aux->used_maps = kmalloc_array(env->used_map_cnt, sizeof(env->used_maps[0]), - GFP_KERNEL); + GFP_KERNEL_ACCOUNT); if (!env->prog->aux->used_maps) { ret = -ENOMEM; @@ -24153,7 +24788,7 @@ skip_full_check: /* if program passed verifier, update used_btfs in bpf_prog_aux */ env->prog->aux->used_btfs = kmalloc_array(env->used_btf_cnt, sizeof(env->used_btfs[0]), - GFP_KERNEL); + GFP_KERNEL_ACCOUNT); if (!env->prog->aux->used_btfs) { ret = -ENOMEM; goto err_release_maps; @@ -24194,9 +24829,9 @@ err_unlock: if (!is_priv) mutex_unlock(&bpf_verifier_lock); vfree(env->insn_aux_data); - kvfree(env->insn_hist); err_free_env: kvfree(env->cfg.insn_postorder); + kvfree(env->scc_info); kvfree(env); return ret; } |