diff options
Diffstat (limited to 'kernel/bpf/verifier.c')
-rw-r--r-- | kernel/bpf/verifier.c | 663 |
1 files changed, 468 insertions, 195 deletions
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 5dd1dcb902bf..92246117d2b0 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -22,6 +22,7 @@ #include <linux/stringify.h> #include <linux/bsearch.h> #include <linux/sort.h> +#include <linux/perf_event.h> #include "disasm.h" @@ -156,7 +157,29 @@ struct bpf_verifier_stack_elem { #define BPF_COMPLEXITY_LIMIT_INSNS 131072 #define BPF_COMPLEXITY_LIMIT_STACK 1024 -#define BPF_MAP_PTR_POISON ((void *)0xeB9F + POISON_POINTER_DELTA) +#define BPF_MAP_PTR_UNPRIV 1UL +#define BPF_MAP_PTR_POISON ((void *)((0xeB9FUL << 1) + \ + POISON_POINTER_DELTA)) +#define BPF_MAP_PTR(X) ((struct bpf_map *)((X) & ~BPF_MAP_PTR_UNPRIV)) + +static bool bpf_map_ptr_poisoned(const struct bpf_insn_aux_data *aux) +{ + return BPF_MAP_PTR(aux->map_state) == BPF_MAP_PTR_POISON; +} + +static bool bpf_map_ptr_unpriv(const struct bpf_insn_aux_data *aux) +{ + return aux->map_state & BPF_MAP_PTR_UNPRIV; +} + +static void bpf_map_ptr_store(struct bpf_insn_aux_data *aux, + const struct bpf_map *map, bool unpriv) +{ + BUILD_BUG_ON((unsigned long)BPF_MAP_PTR_POISON & BPF_MAP_PTR_UNPRIV); + unpriv |= bpf_map_ptr_unpriv(aux); + aux->map_state = (unsigned long)map | + (unpriv ? BPF_MAP_PTR_UNPRIV : 0UL); +} struct bpf_call_arg_meta { struct bpf_map *map_ptr; @@ -164,6 +187,8 @@ struct bpf_call_arg_meta { bool pkt_access; int regno; int access_size; + s64 msize_smax_value; + u64 msize_umax_value; }; static DEFINE_MUTEX(bpf_verifier_lock); @@ -738,18 +763,19 @@ enum reg_arg_type { static int cmp_subprogs(const void *a, const void *b) { - return *(int *)a - *(int *)b; + return ((struct bpf_subprog_info *)a)->start - + ((struct bpf_subprog_info *)b)->start; } static int find_subprog(struct bpf_verifier_env *env, int off) { - u32 *p; + struct bpf_subprog_info *p; - p = bsearch(&off, env->subprog_starts, env->subprog_cnt, - sizeof(env->subprog_starts[0]), cmp_subprogs); + p = bsearch(&off, env->subprog_info, env->subprog_cnt, + sizeof(env->subprog_info[0]), cmp_subprogs); if (!p) return -ENOENT; - return p - env->subprog_starts; + return p - env->subprog_info; } @@ -769,18 +795,24 @@ static int add_subprog(struct bpf_verifier_env *env, int off) verbose(env, "too many subprograms\n"); return -E2BIG; } - env->subprog_starts[env->subprog_cnt++] = off; - sort(env->subprog_starts, env->subprog_cnt, - sizeof(env->subprog_starts[0]), cmp_subprogs, NULL); + env->subprog_info[env->subprog_cnt++].start = off; + sort(env->subprog_info, env->subprog_cnt, + sizeof(env->subprog_info[0]), cmp_subprogs, NULL); return 0; } static int check_subprogs(struct bpf_verifier_env *env) { int i, ret, subprog_start, subprog_end, off, cur_subprog = 0; + struct bpf_subprog_info *subprog = env->subprog_info; struct bpf_insn *insn = env->prog->insnsi; int insn_cnt = env->prog->len; + /* Add entry function. */ + ret = add_subprog(env, 0); + if (ret < 0) + return ret; + /* determine subprog starts. The end is one before the next starts */ for (i = 0; i < insn_cnt; i++) { if (insn[i].code != (BPF_JMP | BPF_CALL)) @@ -800,16 +832,18 @@ static int check_subprogs(struct bpf_verifier_env *env) return ret; } + /* Add a fake 'exit' subprog which could simplify subprog iteration + * logic. 'subprog_cnt' should not be increased. + */ + subprog[env->subprog_cnt].start = insn_cnt; + if (env->log.level > 1) for (i = 0; i < env->subprog_cnt; i++) - verbose(env, "func#%d @%d\n", i, env->subprog_starts[i]); + verbose(env, "func#%d @%d\n", i, subprog[i].start); /* now check that all jumps are within the same subprog */ - subprog_start = 0; - if (env->subprog_cnt == cur_subprog) - subprog_end = insn_cnt; - else - subprog_end = env->subprog_starts[cur_subprog++]; + subprog_start = subprog[cur_subprog].start; + subprog_end = subprog[cur_subprog + 1].start; for (i = 0; i < insn_cnt; i++) { u8 code = insn[i].code; @@ -834,10 +868,9 @@ next: return -EINVAL; } subprog_start = subprog_end; - if (env->subprog_cnt == cur_subprog) - subprog_end = insn_cnt; - else - subprog_end = env->subprog_starts[cur_subprog++]; + cur_subprog++; + if (cur_subprog < env->subprog_cnt) + subprog_end = subprog[cur_subprog + 1].start; } } return 0; @@ -978,7 +1011,7 @@ static bool register_is_null(struct bpf_reg_state *reg) */ static int check_stack_write(struct bpf_verifier_env *env, struct bpf_func_state *state, /* func where register points to */ - int off, int size, int value_regno) + int off, int size, int value_regno, int insn_idx) { struct bpf_func_state *cur; /* state of the current function */ int i, slot = -off - 1, spi = slot / BPF_REG_SIZE, err; @@ -1017,8 +1050,33 @@ static int check_stack_write(struct bpf_verifier_env *env, state->stack[spi].spilled_ptr = cur->regs[value_regno]; state->stack[spi].spilled_ptr.live |= REG_LIVE_WRITTEN; - for (i = 0; i < BPF_REG_SIZE; i++) + for (i = 0; i < BPF_REG_SIZE; i++) { + if (state->stack[spi].slot_type[i] == STACK_MISC && + !env->allow_ptr_leaks) { + int *poff = &env->insn_aux_data[insn_idx].sanitize_stack_off; + int soff = (-spi - 1) * BPF_REG_SIZE; + + /* detected reuse of integer stack slot with a pointer + * which means either llvm is reusing stack slot or + * an attacker is trying to exploit CVE-2018-3639 + * (speculative store bypass) + * Have to sanitize that slot with preemptive + * store of zero. + */ + if (*poff && *poff != soff) { + /* disallow programs where single insn stores + * into two different stack slots, since verifier + * cannot sanitize them + */ + verbose(env, + "insn %d cannot access two stack slots fp%d and fp%d", + insn_idx, *poff, soff); + return -EINVAL; + } + *poff = soff; + } state->stack[spi].slot_type[i] = STACK_SPILL; + } } else { u8 type = STACK_MISC; @@ -1251,6 +1309,8 @@ static bool may_access_direct_pkt_data(struct bpf_verifier_env *env, switch (env->prog->type) { case BPF_PROG_TYPE_LWT_IN: case BPF_PROG_TYPE_LWT_OUT: + case BPF_PROG_TYPE_LWT_SEG6LOCAL: + case BPF_PROG_TYPE_SK_REUSEPORT: /* dst_input() and dst_output() can't write for now */ if (t == BPF_WRITE) return false; @@ -1470,13 +1530,13 @@ static int update_stack_depth(struct bpf_verifier_env *env, const struct bpf_func_state *func, int off) { - u16 stack = env->subprog_stack_depth[func->subprogno]; + u16 stack = env->subprog_info[func->subprogno].stack_depth; if (stack >= -off) return 0; /* update known max for given subprogram */ - env->subprog_stack_depth[func->subprogno] = -off; + env->subprog_info[func->subprogno].stack_depth = -off; return 0; } @@ -1488,9 +1548,9 @@ static int update_stack_depth(struct bpf_verifier_env *env, */ static int check_max_stack_depth(struct bpf_verifier_env *env) { - int depth = 0, frame = 0, subprog = 0, i = 0, subprog_end; + int depth = 0, frame = 0, idx = 0, i = 0, subprog_end; + struct bpf_subprog_info *subprog = env->subprog_info; struct bpf_insn *insn = env->prog->insnsi; - int insn_cnt = env->prog->len; int ret_insn[MAX_CALL_FRAMES]; int ret_prog[MAX_CALL_FRAMES]; @@ -1498,17 +1558,14 @@ process_func: /* round up to 32-bytes, since this is granularity * of interpreter stack size */ - depth += round_up(max_t(u32, env->subprog_stack_depth[subprog], 1), 32); + depth += round_up(max_t(u32, subprog[idx].stack_depth, 1), 32); if (depth > MAX_BPF_STACK) { verbose(env, "combined stack size of %d calls is %d. Too large\n", frame + 1, depth); return -EACCES; } continue_func: - if (env->subprog_cnt == subprog) - subprog_end = insn_cnt; - else - subprog_end = env->subprog_starts[subprog]; + subprog_end = subprog[idx + 1].start; for (; i < subprog_end; i++) { if (insn[i].code != (BPF_JMP | BPF_CALL)) continue; @@ -1516,17 +1573,16 @@ continue_func: continue; /* remember insn and function to return to */ ret_insn[frame] = i + 1; - ret_prog[frame] = subprog; + ret_prog[frame] = idx; /* find the callee */ i = i + insn[i].imm + 1; - subprog = find_subprog(env, i); - if (subprog < 0) { + idx = find_subprog(env, i); + if (idx < 0) { WARN_ONCE(1, "verifier bug. No program starts at insn %d\n", i); return -EFAULT; } - subprog++; frame++; if (frame >= MAX_CALL_FRAMES) { WARN_ONCE(1, "verifier bug. Call stack is too deep\n"); @@ -1539,10 +1595,10 @@ continue_func: */ if (frame == 0) return 0; - depth -= round_up(max_t(u32, env->subprog_stack_depth[subprog], 1), 32); + depth -= round_up(max_t(u32, subprog[idx].stack_depth, 1), 32); frame--; i = ret_insn[frame]; - subprog = ret_prog[frame]; + idx = ret_prog[frame]; goto continue_func; } @@ -1558,11 +1614,34 @@ static int get_callee_stack_depth(struct bpf_verifier_env *env, start); return -EFAULT; } - subprog++; - return env->subprog_stack_depth[subprog]; + return env->subprog_info[subprog].stack_depth; } #endif +static int check_ctx_reg(struct bpf_verifier_env *env, + const struct bpf_reg_state *reg, int regno) +{ + /* Access to ctx or passing it to a helper is only allowed in + * its original, unmodified form. + */ + + if (reg->off) { + verbose(env, "dereference of modified ctx ptr R%d off=%d disallowed\n", + regno, reg->off); + return -EACCES; + } + + if (!tnum_is_const(reg->var_off) || reg->var_off.value) { + char tn_buf[48]; + + tnum_strn(tn_buf, sizeof(tn_buf), reg->var_off); + verbose(env, "variable ctx access var_off=%s disallowed\n", tn_buf); + return -EACCES; + } + + return 0; +} + /* truncate register to smaller size (in bytes) * must be called with size < BPF_REG_SIZE */ @@ -1632,24 +1711,11 @@ static int check_mem_access(struct bpf_verifier_env *env, int insn_idx, u32 regn verbose(env, "R%d leaks addr into ctx\n", value_regno); return -EACCES; } - /* ctx accesses must be at a fixed offset, so that we can - * determine what type of data were returned. - */ - if (reg->off) { - verbose(env, - "dereference of modified ctx ptr R%d off=%d+%d, ctx+const is allowed, ctx+const+const is not\n", - regno, reg->off, off - reg->off); - return -EACCES; - } - if (!tnum_is_const(reg->var_off) || reg->var_off.value) { - char tn_buf[48]; - tnum_strn(tn_buf, sizeof(tn_buf), reg->var_off); - verbose(env, - "variable ctx access var_off=%s off=%d size=%d", - tn_buf, off, size); - return -EACCES; - } + err = check_ctx_reg(env, reg, regno); + if (err < 0) + return err; + err = check_ctx_access(env, insn_idx, off, size, t, ®_type); if (!err && t == BPF_READ && value_regno >= 0) { /* ctx access returns either a scalar, or a @@ -1694,7 +1760,7 @@ static int check_mem_access(struct bpf_verifier_env *env, int insn_idx, u32 regn if (t == BPF_WRITE) err = check_stack_write(env, state, off, size, - value_regno); + value_regno, insn_idx); else err = check_stack_read(env, state, off, size, value_regno); @@ -1914,7 +1980,7 @@ static int check_func_arg(struct bpf_verifier_env *env, u32 regno, if (arg_type == ARG_PTR_TO_MAP_KEY || arg_type == ARG_PTR_TO_MAP_VALUE) { expected_type = PTR_TO_STACK; - if (!type_is_pkt_pointer(type) && + if (!type_is_pkt_pointer(type) && type != PTR_TO_MAP_VALUE && type != expected_type) goto err_type; } else if (arg_type == ARG_CONST_SIZE || @@ -1930,6 +1996,9 @@ static int check_func_arg(struct bpf_verifier_env *env, u32 regno, expected_type = PTR_TO_CTX; if (type != expected_type) goto err_type; + err = check_ctx_reg(env, reg, regno); + if (err < 0) + return err; } else if (arg_type_is_mem_ptr(arg_type)) { expected_type = PTR_TO_STACK; /* One exception here. In case function allows for NULL to be @@ -1966,14 +2035,9 @@ static int check_func_arg(struct bpf_verifier_env *env, u32 regno, verbose(env, "invalid map_ptr to access map->key\n"); return -EACCES; } - if (type_is_pkt_pointer(type)) - err = check_packet_access(env, regno, reg->off, - meta->map_ptr->key_size, - false); - else - err = check_stack_boundary(env, regno, - meta->map_ptr->key_size, - false, NULL); + err = check_helper_mem_access(env, regno, + meta->map_ptr->key_size, false, + NULL); } else if (arg_type == ARG_PTR_TO_MAP_VALUE) { /* bpf_map_xxx(..., map_ptr, ..., value) call: * check [value, value + map->value_size) validity @@ -1983,17 +2047,18 @@ static int check_func_arg(struct bpf_verifier_env *env, u32 regno, verbose(env, "invalid map_ptr to access map->value\n"); return -EACCES; } - if (type_is_pkt_pointer(type)) - err = check_packet_access(env, regno, reg->off, - meta->map_ptr->value_size, - false); - else - err = check_stack_boundary(env, regno, - meta->map_ptr->value_size, - false, NULL); + err = check_helper_mem_access(env, regno, + meta->map_ptr->value_size, false, + NULL); } else if (arg_type_is_mem_size(arg_type)) { bool zero_size_allowed = (arg_type == ARG_CONST_SIZE_OR_ZERO); + /* remember the mem_size which may be used later + * to refine return values. + */ + meta->msize_smax_value = reg->smax_value; + meta->msize_umax_value = reg->umax_value; + /* The register is SCALAR_VALUE; the access check * happens using its boundaries. */ @@ -2063,6 +2128,10 @@ static int check_map_func_compatibility(struct bpf_verifier_env *env, func_id != BPF_FUNC_current_task_under_cgroup) goto error; break; + case BPF_MAP_TYPE_CGROUP_STORAGE: + if (func_id != BPF_FUNC_get_local_storage) + goto error; + break; /* devmap returns a pointer to a live net_device ifindex that we cannot * allow to be modified from bpf side. So do not allow lookup elements * for now. @@ -2071,8 +2140,11 @@ static int check_map_func_compatibility(struct bpf_verifier_env *env, if (func_id != BPF_FUNC_redirect_map) goto error; break; - /* Restrict bpf side of cpumap, open when use-cases appear */ + /* Restrict bpf side of cpumap and xskmap, open when use-cases + * appear. + */ case BPF_MAP_TYPE_CPUMAP: + case BPF_MAP_TYPE_XSKMAP: if (func_id != BPF_FUNC_redirect_map) goto error; break; @@ -2088,6 +2160,17 @@ static int check_map_func_compatibility(struct bpf_verifier_env *env, func_id != BPF_FUNC_msg_redirect_map) goto error; break; + case BPF_MAP_TYPE_SOCKHASH: + if (func_id != BPF_FUNC_sk_redirect_hash && + func_id != BPF_FUNC_sock_hash_update && + func_id != BPF_FUNC_map_delete_elem && + func_id != BPF_FUNC_msg_redirect_hash) + goto error; + break; + case BPF_MAP_TYPE_REUSEPORT_SOCKARRAY: + if (func_id != BPF_FUNC_sk_select_reuseport) + goto error; + break; default: break; } @@ -2097,7 +2180,7 @@ static int check_map_func_compatibility(struct bpf_verifier_env *env, case BPF_FUNC_tail_call: if (map->map_type != BPF_MAP_TYPE_PROG_ARRAY) goto error; - if (env->subprog_cnt) { + if (env->subprog_cnt > 1) { verbose(env, "tail_calls are not allowed in programs with bpf-to-bpf calls\n"); return -EINVAL; } @@ -2119,16 +2202,28 @@ static int check_map_func_compatibility(struct bpf_verifier_env *env, break; case BPF_FUNC_redirect_map: if (map->map_type != BPF_MAP_TYPE_DEVMAP && - map->map_type != BPF_MAP_TYPE_CPUMAP) + map->map_type != BPF_MAP_TYPE_CPUMAP && + map->map_type != BPF_MAP_TYPE_XSKMAP) goto error; break; case BPF_FUNC_sk_redirect_map: case BPF_FUNC_msg_redirect_map: + case BPF_FUNC_sock_map_update: if (map->map_type != BPF_MAP_TYPE_SOCKMAP) goto error; break; - case BPF_FUNC_sock_map_update: - if (map->map_type != BPF_MAP_TYPE_SOCKMAP) + case BPF_FUNC_sk_redirect_hash: + case BPF_FUNC_msg_redirect_hash: + case BPF_FUNC_sock_hash_update: + if (map->map_type != BPF_MAP_TYPE_SOCKHASH) + goto error; + break; + case BPF_FUNC_get_local_storage: + if (map->map_type != BPF_MAP_TYPE_CGROUP_STORAGE) + goto error; + break; + case BPF_FUNC_sk_select_reuseport: + if (map->map_type != BPF_MAP_TYPE_REUSEPORT_SOCKARRAY) goto error; break; default: @@ -2269,7 +2364,7 @@ static int check_func_call(struct bpf_verifier_env *env, struct bpf_insn *insn, /* remember the callsite, it will be used by bpf_exit */ *insn_idx /* callsite */, state->curframe + 1 /* frameno within this callchain */, - subprog + 1 /* subprog number within this prog */); + subprog /* subprog number within this prog */); /* copy r1 - r5 args that callee can access */ for (i = BPF_REG_1; i <= BPF_REG_5; i++) @@ -2333,6 +2428,49 @@ static int prepare_func_exit(struct bpf_verifier_env *env, int *insn_idx) return 0; } +static void do_refine_retval_range(struct bpf_reg_state *regs, int ret_type, + int func_id, + struct bpf_call_arg_meta *meta) +{ + struct bpf_reg_state *ret_reg = ®s[BPF_REG_0]; + + if (ret_type != RET_INTEGER || + (func_id != BPF_FUNC_get_stack && + func_id != BPF_FUNC_probe_read_str)) + return; + + ret_reg->smax_value = meta->msize_smax_value; + ret_reg->umax_value = meta->msize_umax_value; + __reg_deduce_bounds(ret_reg); + __reg_bound_offset(ret_reg); +} + +static int +record_func_map(struct bpf_verifier_env *env, struct bpf_call_arg_meta *meta, + int func_id, int insn_idx) +{ + struct bpf_insn_aux_data *aux = &env->insn_aux_data[insn_idx]; + + if (func_id != BPF_FUNC_tail_call && + func_id != BPF_FUNC_map_lookup_elem && + func_id != BPF_FUNC_map_update_elem && + func_id != BPF_FUNC_map_delete_elem) + return 0; + + if (meta->map_ptr == NULL) { + verbose(env, "kernel subsystem misconfigured verifier\n"); + return -EINVAL; + } + + if (!BPF_MAP_PTR(aux->map_state)) + bpf_map_ptr_store(aux, meta->map_ptr, + meta->map_ptr->unpriv_array); + else if (BPF_MAP_PTR(aux->map_state) != meta->map_ptr) + bpf_map_ptr_store(aux, BPF_MAP_PTR_POISON, + meta->map_ptr->unpriv_array); + return 0; +} + static int check_helper_call(struct bpf_verifier_env *env, int func_id, int insn_idx) { const struct bpf_func_proto *fn = NULL; @@ -2358,7 +2496,7 @@ static int check_helper_call(struct bpf_verifier_env *env, int func_id, int insn /* eBPF programs must be GPL compatible to use GPL-ed functions */ if (!env->prog->gpl_compatible && fn->gpl_only) { - verbose(env, "cannot call GPL only function from proprietary program\n"); + verbose(env, "cannot call GPL-restricted function from non-GPL compatible program\n"); return -EINVAL; } @@ -2387,13 +2525,6 @@ static int check_helper_call(struct bpf_verifier_env *env, int func_id, int insn err = check_func_arg(env, BPF_REG_2, fn->arg2_type, &meta); if (err) return err; - if (func_id == BPF_FUNC_tail_call) { - if (meta.map_ptr == NULL) { - verbose(env, "verifier bug\n"); - return -EINVAL; - } - env->insn_aux_data[insn_idx].map_ptr = meta.map_ptr; - } err = check_func_arg(env, BPF_REG_3, fn->arg3_type, &meta); if (err) return err; @@ -2404,6 +2535,10 @@ static int check_helper_call(struct bpf_verifier_env *env, int func_id, int insn if (err) return err; + err = record_func_map(env, &meta, func_id, insn_idx); + if (err) + return err; + /* Mark slots with STACK_MISC in case of raw mode, stack offset * is inferred from register state. */ @@ -2415,6 +2550,16 @@ static int check_helper_call(struct bpf_verifier_env *env, int func_id, int insn } regs = cur_regs(env); + + /* check that flags argument in get_local_storage(map, flags) is 0, + * this is required because get_local_storage() can't return an error. + */ + if (func_id == BPF_FUNC_get_local_storage && + !register_is_null(®s[BPF_REG_2])) { + verbose(env, "get_local_storage() doesn't support non-zero flags\n"); + return -EINVAL; + } + /* reset caller saved regs */ for (i = 0; i < CALLER_SAVED_REGS; i++) { mark_reg_not_init(env, regs, caller_saved[i]); @@ -2427,10 +2572,12 @@ static int check_helper_call(struct bpf_verifier_env *env, int func_id, int insn mark_reg_unknown(env, regs, BPF_REG_0); } else if (fn->ret_type == RET_VOID) { regs[BPF_REG_0].type = NOT_INIT; - } else if (fn->ret_type == RET_PTR_TO_MAP_VALUE_OR_NULL) { - struct bpf_insn_aux_data *insn_aux; - - regs[BPF_REG_0].type = PTR_TO_MAP_VALUE_OR_NULL; + } else if (fn->ret_type == RET_PTR_TO_MAP_VALUE_OR_NULL || + fn->ret_type == RET_PTR_TO_MAP_VALUE) { + if (fn->ret_type == RET_PTR_TO_MAP_VALUE) + regs[BPF_REG_0].type = PTR_TO_MAP_VALUE; + else + regs[BPF_REG_0].type = PTR_TO_MAP_VALUE_OR_NULL; /* There is no offset yet applied, variable or fixed */ mark_reg_known_zero(env, regs, BPF_REG_0); regs[BPF_REG_0].off = 0; @@ -2445,21 +2592,36 @@ static int check_helper_call(struct bpf_verifier_env *env, int func_id, int insn } regs[BPF_REG_0].map_ptr = meta.map_ptr; regs[BPF_REG_0].id = ++env->id_gen; - insn_aux = &env->insn_aux_data[insn_idx]; - if (!insn_aux->map_ptr) - insn_aux->map_ptr = meta.map_ptr; - else if (insn_aux->map_ptr != meta.map_ptr) - insn_aux->map_ptr = BPF_MAP_PTR_POISON; } else { verbose(env, "unknown return type %d of func %s#%d\n", fn->ret_type, func_id_name(func_id), func_id); return -EINVAL; } + do_refine_retval_range(regs, fn->ret_type, func_id, &meta); + err = check_map_func_compatibility(env, meta.map_ptr, func_id); if (err) return err; + if (func_id == BPF_FUNC_get_stack && !env->prog->has_callchain_buf) { + const char *err_str; + +#ifdef CONFIG_PERF_EVENTS + err = get_callchain_buffers(sysctl_perf_event_max_stack); + err_str = "cannot get callchain buffer for func %s#%d\n"; +#else + err = -ENOTSUPP; + err_str = "func %s#%d not supported without CONFIG_PERF_EVENTS\n"; +#endif + if (err) { + verbose(env, err_str, func_id_name(func_id), func_id); + return err; + } + + env->prog->has_callchain_buf = true; + } + if (changes_data) clear_all_pkt_pointers(env); return 0; @@ -2904,10 +3066,7 @@ static int adjust_scalar_min_max_vals(struct bpf_verifier_env *env, dst_reg->umin_value <<= umin_val; dst_reg->umax_value <<= umax_val; } - if (src_known) - dst_reg->var_off = tnum_lshift(dst_reg->var_off, umin_val); - else - dst_reg->var_off = tnum_lshift(tnum_unknown, umin_val); + dst_reg->var_off = tnum_lshift(dst_reg->var_off, umin_val); /* We may learn something more from the var_off */ __update_reg_bounds(dst_reg); break; @@ -2935,16 +3094,35 @@ static int adjust_scalar_min_max_vals(struct bpf_verifier_env *env, */ dst_reg->smin_value = S64_MIN; dst_reg->smax_value = S64_MAX; - if (src_known) - dst_reg->var_off = tnum_rshift(dst_reg->var_off, - umin_val); - else - dst_reg->var_off = tnum_rshift(tnum_unknown, umin_val); + dst_reg->var_off = tnum_rshift(dst_reg->var_off, umin_val); dst_reg->umin_value >>= umax_val; dst_reg->umax_value >>= umin_val; /* We may learn something more from the var_off */ __update_reg_bounds(dst_reg); break; + case BPF_ARSH: + if (umax_val >= insn_bitness) { + /* Shifts greater than 31 or 63 are undefined. + * This includes shifts by a negative number. + */ + mark_reg_unknown(env, regs, insn->dst_reg); + break; + } + + /* Upon reaching here, src_known is true and + * umax_val is equal to umin_val. + */ + dst_reg->smin_value >>= umin_val; + dst_reg->smax_value >>= umin_val; + dst_reg->var_off = tnum_arshift(dst_reg->var_off, umin_val); + + /* blow away the dst_reg umin_value/umax_value and rely on + * dst_reg var_off to refine the result. + */ + dst_reg->umin_value = 0; + dst_reg->umax_value = U64_MAX; + __update_reg_bounds(dst_reg); + break; default: mark_reg_unknown(env, regs, insn->dst_reg); break; @@ -3091,8 +3269,8 @@ 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); + /* check dest operand, mark as required later */ + err = check_reg_arg(env, insn->dst_reg, DST_OP_NO_MARK); if (err) return err; @@ -3118,6 +3296,8 @@ static int check_alu_op(struct bpf_verifier_env *env, struct bpf_insn *insn) /* case: R = imm * remember the value we stored into this reg */ + /* clear any state __mark_reg_known doesn't set */ + mark_reg_unknown(env, regs, insn->dst_reg); regs[insn->dst_reg].type = SCALAR_VALUE; if (BPF_CLASS(insn->code) == BPF_ALU64) { __mark_reg_known(regs + insn->dst_reg, @@ -3828,7 +4008,12 @@ static int check_ld_abs(struct bpf_verifier_env *env, struct bpf_insn *insn) return -EINVAL; } - if (env->subprog_cnt) { + if (!env->ops->gen_ld_abs) { + verbose(env, "bpf verifier is misconfigured\n"); + return -EINVAL; + } + + if (env->subprog_cnt > 1) { /* when program has LD_ABS insn JITs and interpreter assume * that r1 == ctx == skb which is not the case for callees * that can have arbitrary arguments. It's problematic @@ -4859,15 +5044,15 @@ process_bpf_exit: verbose(env, "processed %d insns (limit %d), stack depth ", insn_processed, BPF_COMPLEXITY_LIMIT_INSNS); - for (i = 0; i < env->subprog_cnt + 1; i++) { - u32 depth = env->subprog_stack_depth[i]; + for (i = 0; i < env->subprog_cnt; i++) { + u32 depth = env->subprog_info[i].stack_depth; verbose(env, "%d", depth); - if (i + 1 < env->subprog_cnt + 1) + if (i + 1 < env->subprog_cnt) verbose(env, "+"); } verbose(env, "\n"); - env->prog->aux->stack_depth = env->subprog_stack_depth[0]; + env->prog->aux->stack_depth = env->subprog_info[0].stack_depth; return 0; } @@ -4902,7 +5087,7 @@ static int check_map_prog_compatibility(struct bpf_verifier_env *env, } if ((bpf_prog_is_dev_bound(prog->aux) || bpf_map_is_dev_bound(map)) && - !bpf_offload_dev_match(prog, map)) { + !bpf_offload_prog_map_match(prog, map)) { verbose(env, "offload device mismatch between prog and map\n"); return -EINVAL; } @@ -4991,7 +5176,7 @@ static int replace_map_fd_with_map_ptr(struct bpf_verifier_env *env) /* hold the map. If the program is rejected by verifier, * the map will be released by release_maps() or it * will be used by the valid program until it's unloaded - * and all maps are released in free_bpf_prog_info() + * and all maps are released in free_used_maps() */ map = bpf_map_inc(map, false); if (IS_ERR(map)) { @@ -5000,6 +5185,14 @@ static int replace_map_fd_with_map_ptr(struct bpf_verifier_env *env) } env->used_maps[env->used_map_cnt++] = map; + if (map->map_type == BPF_MAP_TYPE_CGROUP_STORAGE && + bpf_cgroup_storage_assign(env->prog, map)) { + verbose(env, + "only one cgroup storage is allowed\n"); + fdput(f); + return -EBUSY; + } + fdput(f); next_insn: insn++; @@ -5026,6 +5219,10 @@ static void release_maps(struct bpf_verifier_env *env) { int i; + if (env->prog->aux->cgroup_storage) + bpf_cgroup_storage_release(env->prog, + env->prog->aux->cgroup_storage); + for (i = 0; i < env->used_map_cnt; i++) bpf_map_put(env->used_maps[i]); } @@ -5054,7 +5251,8 @@ static int adjust_insn_aux_data(struct bpf_verifier_env *env, u32 prog_len, if (cnt == 1) return 0; - new_data = vzalloc(sizeof(struct bpf_insn_aux_data) * prog_len); + new_data = vzalloc(array_size(prog_len, + sizeof(struct bpf_insn_aux_data))); if (!new_data) return -ENOMEM; memcpy(new_data, old_data, sizeof(struct bpf_insn_aux_data) * off); @@ -5073,10 +5271,11 @@ static void adjust_subprog_starts(struct bpf_verifier_env *env, u32 off, u32 len if (len == 1) return; - for (i = 0; i < env->subprog_cnt; i++) { - if (env->subprog_starts[i] < off) + /* NOTE: fake 'exit' subprog should be updated as well. */ + for (i = 0; i <= env->subprog_cnt; i++) { + if (env->subprog_info[i].start < off) continue; - env->subprog_starts[i] += len - 1; + env->subprog_info[i].start += len - 1; } } @@ -5150,7 +5349,7 @@ static int convert_ctx_accesses(struct bpf_verifier_env *env) } } - if (!ops->convert_ctx_access) + if (!ops->convert_ctx_access || bpf_prog_is_dev_bound(env->prog->aux)) return 0; insn = env->prog->insnsi + delta; @@ -5169,6 +5368,34 @@ static int convert_ctx_accesses(struct bpf_verifier_env *env) else continue; + if (type == BPF_WRITE && + env->insn_aux_data[i + delta].sanitize_stack_off) { + struct bpf_insn patch[] = { + /* Sanitize suspicious stack slot with zero. + * There are no memory dependencies for this store, + * since it's only using frame pointer and immediate + * constant of zero + */ + BPF_ST_MEM(BPF_DW, BPF_REG_FP, + env->insn_aux_data[i + delta].sanitize_stack_off, + 0), + /* the original STX instruction will immediately + * overwrite the same stack slot with appropriate value + */ + *insn, + }; + + cnt = ARRAY_SIZE(patch); + new_prog = bpf_patch_insn_data(env, i + delta, patch, cnt); + if (!new_prog) + return -ENOMEM; + + delta += cnt - 1; + env->prog = new_prog; + insn = new_prog->insnsi + i + delta; + continue; + } + if (env->insn_aux_data[i + delta].ptr_type != PTR_TO_CTX) continue; @@ -5182,6 +5409,7 @@ static int convert_ctx_accesses(struct bpf_verifier_env *env) */ is_narrower_load = size < ctx_field_size; if (is_narrower_load) { + u32 size_default = bpf_ctx_off_adjust_machine(ctx_field_size); u32 off = insn->off; u8 size_code; @@ -5196,7 +5424,7 @@ static int convert_ctx_accesses(struct bpf_verifier_env *env) else if (ctx_field_size == 8) size_code = BPF_DW; - insn->off = off & ~(ctx_field_size - 1); + insn->off = off & ~(size_default - 1); insn->code = BPF_LDX | BPF_MEM | size_code; } @@ -5240,13 +5468,17 @@ static int jit_subprogs(struct bpf_verifier_env *env) void *old_bpf_func; int err = -ENOMEM; - if (env->subprog_cnt == 0) + if (env->subprog_cnt <= 1) return 0; for (i = 0, insn = prog->insnsi; i < prog->len; i++, insn++) { if (insn->code != (BPF_JMP | BPF_CALL) || insn->src_reg != BPF_PSEUDO_CALL) continue; + /* Upon error here we cannot fall back to interpreter but + * need a hard reject of the program. Thus -EFAULT is + * propagated in any case. + */ subprog = find_subprog(env, i + insn->imm + 1); if (subprog < 0) { WARN_ONCE(1, "verifier bug. No program starts at insn %d\n", @@ -5256,7 +5488,7 @@ static int jit_subprogs(struct bpf_verifier_env *env) /* temporarily remember subprog id inside insn instead of * aux_data, since next loop will split up all insns into funcs */ - insn->off = subprog + 1; + insn->off = subprog; /* remember original imm in case JIT fails and fallback * to interpreter will be needed */ @@ -5265,16 +5497,13 @@ static int jit_subprogs(struct bpf_verifier_env *env) insn->imm = 1; } - func = kzalloc(sizeof(prog) * (env->subprog_cnt + 1), GFP_KERNEL); + func = kcalloc(env->subprog_cnt, sizeof(prog), GFP_KERNEL); if (!func) - return -ENOMEM; + goto out_undo_insn; - for (i = 0; i <= env->subprog_cnt; i++) { + for (i = 0; i < env->subprog_cnt; i++) { subprog_start = subprog_end; - if (env->subprog_cnt == i) - subprog_end = prog->len; - else - subprog_end = env->subprog_starts[i]; + subprog_end = env->subprog_info[i + 1].start; len = subprog_end - subprog_start; func[i] = bpf_prog_alloc(bpf_prog_size(len), GFP_USER); @@ -5291,7 +5520,7 @@ static int jit_subprogs(struct bpf_verifier_env *env) * Long term would need debug info to populate names */ func[i]->aux->name[0] = 'F'; - func[i]->aux->stack_depth = env->subprog_stack_depth[i]; + func[i]->aux->stack_depth = env->subprog_info[i].stack_depth; func[i]->jit_requested = 1; func[i] = bpf_int_jit_compile(func[i]); if (!func[i]->jited) { @@ -5304,25 +5533,38 @@ static int jit_subprogs(struct bpf_verifier_env *env) * now populate all bpf_calls with correct addresses and * run last pass of JIT */ - for (i = 0; i <= env->subprog_cnt; i++) { + for (i = 0; i < env->subprog_cnt; i++) { insn = func[i]->insnsi; for (j = 0; j < func[i]->len; j++, insn++) { if (insn->code != (BPF_JMP | BPF_CALL) || insn->src_reg != BPF_PSEUDO_CALL) continue; subprog = insn->off; - insn->off = 0; insn->imm = (u64 (*)(u64, u64, u64, u64, u64)) func[subprog]->bpf_func - __bpf_call_base; } + + /* we use the aux data to keep a list of the start addresses + * of the JITed images for each function in the program + * + * for some architectures, such as powerpc64, the imm field + * might not be large enough to hold the offset of the start + * address of the callee's JITed image from __bpf_call_base + * + * in such cases, we can lookup the start address of a callee + * by using its subprog id, available from the off field of + * the call instruction, as an index for this list + */ + func[i]->aux->func = func; + func[i]->aux->func_cnt = env->subprog_cnt; } - for (i = 0; i <= env->subprog_cnt; i++) { + for (i = 0; i < env->subprog_cnt; i++) { old_bpf_func = func[i]->bpf_func; tmp = bpf_int_jit_compile(func[i]); if (tmp != func[i] || func[i]->bpf_func != old_bpf_func) { verbose(env, "JIT doesn't support bpf-to-bpf calls\n"); - err = -EFAULT; + err = -ENOTSUPP; goto out_free; } cond_resched(); @@ -5331,7 +5573,7 @@ static int jit_subprogs(struct bpf_verifier_env *env) /* finally lock prog and jit images for all functions and * populate kallsysm */ - for (i = 0; i <= env->subprog_cnt; i++) { + for (i = 0; i < env->subprog_cnt; i++) { bpf_prog_lock_ro(func[i]); bpf_prog_kallsyms_add(func[i]); } @@ -5341,29 +5583,25 @@ static int jit_subprogs(struct bpf_verifier_env *env) * later look the same as if they were interpreted only. */ for (i = 0, insn = prog->insnsi; i < prog->len; i++, insn++) { - unsigned long addr; - if (insn->code != (BPF_JMP | BPF_CALL) || insn->src_reg != BPF_PSEUDO_CALL) continue; insn->off = env->insn_aux_data[i].call_imm; subprog = find_subprog(env, i + insn->off + 1); - addr = (unsigned long)func[subprog + 1]->bpf_func; - addr &= PAGE_MASK; - insn->imm = (u64 (*)(u64, u64, u64, u64, u64)) - addr - __bpf_call_base; + insn->imm = subprog; } prog->jited = 1; prog->bpf_func = func[0]->bpf_func; prog->aux->func = func; - prog->aux->func_cnt = env->subprog_cnt + 1; + prog->aux->func_cnt = env->subprog_cnt; return 0; out_free: - for (i = 0; i <= env->subprog_cnt; i++) + for (i = 0; i < env->subprog_cnt; i++) if (func[i]) bpf_jit_free(func[i]); kfree(func); +out_undo_insn: /* cleanup main prog to be interpreted */ prog->jit_requested = 0; for (i = 0, insn = prog->insnsi; i < prog->len; i++, insn++) { @@ -5390,6 +5628,8 @@ static int fixup_call_args(struct bpf_verifier_env *env) err = jit_subprogs(env); if (err == 0) return 0; + if (err == -EFAULT) + return err; } #ifndef CONFIG_BPF_JIT_ALWAYS_ON for (i = 0; i < prog->len; i++, insn++) { @@ -5417,6 +5657,8 @@ static int fixup_bpf_calls(struct bpf_verifier_env *env) struct bpf_insn *insn = prog->insnsi; const struct bpf_func_proto *fn; const int insn_cnt = prog->len; + const struct bpf_map_ops *ops; + struct bpf_insn_aux_data *aux; struct bpf_insn insn_buf[16]; struct bpf_prog *new_prog; struct bpf_map *map_ptr; @@ -5463,6 +5705,25 @@ static int fixup_bpf_calls(struct bpf_verifier_env *env) continue; } + if (BPF_CLASS(insn->code) == BPF_LD && + (BPF_MODE(insn->code) == BPF_ABS || + BPF_MODE(insn->code) == BPF_IND)) { + cnt = env->ops->gen_ld_abs(insn, insn_buf); + if (cnt == 0 || cnt >= ARRAY_SIZE(insn_buf)) { + verbose(env, "bpf verifier is misconfigured\n"); + return -EINVAL; + } + + new_prog = bpf_patch_insn_data(env, i + delta, insn_buf, cnt); + if (!new_prog) + return -ENOMEM; + + delta += cnt - 1; + env->prog = prog = new_prog; + insn = new_prog->insnsi + i + delta; + continue; + } + if (insn->code != (BPF_JMP | BPF_CALL)) continue; if (insn->src_reg == BPF_PSEUDO_CALL) @@ -5491,19 +5752,22 @@ static int fixup_bpf_calls(struct bpf_verifier_env *env) insn->imm = 0; insn->code = BPF_JMP | BPF_TAIL_CALL; + aux = &env->insn_aux_data[i + delta]; + if (!bpf_map_ptr_unpriv(aux)) + continue; + /* instead of changing every JIT dealing with tail_call * emit two extra insns: * if (index >= max_entries) goto out; * index &= array->index_mask; * to avoid out-of-bounds cpu speculation */ - map_ptr = env->insn_aux_data[i + delta].map_ptr; - if (map_ptr == BPF_MAP_PTR_POISON) { + if (bpf_map_ptr_poisoned(aux)) { verbose(env, "tail_call abusing map_ptr\n"); return -EINVAL; } - if (!map_ptr->unpriv_array) - continue; + + map_ptr = BPF_MAP_PTR(aux->map_state); insn_buf[0] = BPF_JMP_IMM(BPF_JGE, BPF_REG_3, map_ptr->max_entries, 2); insn_buf[1] = BPF_ALU32_IMM(BPF_AND, BPF_REG_3, @@ -5523,55 +5787,63 @@ static int fixup_bpf_calls(struct bpf_verifier_env *env) } /* BPF_EMIT_CALL() assumptions in some of the map_gen_lookup - * handlers are currently limited to 64 bit only. + * and other inlining handlers are currently limited to 64 bit + * only. */ if (prog->jit_requested && BITS_PER_LONG == 64 && - insn->imm == BPF_FUNC_map_lookup_elem) { - map_ptr = env->insn_aux_data[i + delta].map_ptr; - if (map_ptr == BPF_MAP_PTR_POISON || - !map_ptr->ops->map_gen_lookup) + (insn->imm == BPF_FUNC_map_lookup_elem || + insn->imm == BPF_FUNC_map_update_elem || + insn->imm == BPF_FUNC_map_delete_elem)) { + aux = &env->insn_aux_data[i + delta]; + if (bpf_map_ptr_poisoned(aux)) goto patch_call_imm; - cnt = map_ptr->ops->map_gen_lookup(map_ptr, insn_buf); - if (cnt == 0 || cnt >= ARRAY_SIZE(insn_buf)) { - verbose(env, "bpf verifier is misconfigured\n"); - return -EINVAL; - } - - new_prog = bpf_patch_insn_data(env, i + delta, insn_buf, - cnt); - if (!new_prog) - return -ENOMEM; - - delta += cnt - 1; + map_ptr = BPF_MAP_PTR(aux->map_state); + ops = map_ptr->ops; + if (insn->imm == BPF_FUNC_map_lookup_elem && + ops->map_gen_lookup) { + cnt = ops->map_gen_lookup(map_ptr, insn_buf); + if (cnt == 0 || cnt >= ARRAY_SIZE(insn_buf)) { + verbose(env, "bpf verifier is misconfigured\n"); + return -EINVAL; + } - /* keep walking new program and skip insns we just inserted */ - env->prog = prog = new_prog; - insn = new_prog->insnsi + i + delta; - continue; - } + new_prog = bpf_patch_insn_data(env, i + delta, + insn_buf, cnt); + if (!new_prog) + return -ENOMEM; - if (insn->imm == BPF_FUNC_redirect_map) { - /* Note, we cannot use prog directly as imm as subsequent - * rewrites would still change the prog pointer. The only - * stable address we can use is aux, which also works with - * prog clones during blinding. - */ - u64 addr = (unsigned long)prog->aux; - struct bpf_insn r4_ld[] = { - BPF_LD_IMM64(BPF_REG_4, addr), - *insn, - }; - cnt = ARRAY_SIZE(r4_ld); + delta += cnt - 1; + env->prog = prog = new_prog; + insn = new_prog->insnsi + i + delta; + continue; + } - new_prog = bpf_patch_insn_data(env, i + delta, r4_ld, cnt); - if (!new_prog) - return -ENOMEM; + BUILD_BUG_ON(!__same_type(ops->map_lookup_elem, + (void *(*)(struct bpf_map *map, void *key))NULL)); + BUILD_BUG_ON(!__same_type(ops->map_delete_elem, + (int (*)(struct bpf_map *map, void *key))NULL)); + BUILD_BUG_ON(!__same_type(ops->map_update_elem, + (int (*)(struct bpf_map *map, void *key, void *value, + u64 flags))NULL)); + switch (insn->imm) { + case BPF_FUNC_map_lookup_elem: + insn->imm = BPF_CAST_CALL(ops->map_lookup_elem) - + __bpf_call_base; + continue; + case BPF_FUNC_map_update_elem: + insn->imm = BPF_CAST_CALL(ops->map_update_elem) - + __bpf_call_base; + continue; + case BPF_FUNC_map_delete_elem: + insn->imm = BPF_CAST_CALL(ops->map_delete_elem) - + __bpf_call_base; + continue; + } - delta += cnt - 1; - env->prog = prog = new_prog; - insn = new_prog->insnsi + i + delta; + goto patch_call_imm; } + patch_call_imm: fn = env->ops->get_func_proto(insn->imm, env->prog); /* all functions that have prototype and verifier allowed @@ -5630,8 +5902,9 @@ int bpf_check(struct bpf_prog **prog, union bpf_attr *attr) return -ENOMEM; log = &env->log; - env->insn_aux_data = vzalloc(sizeof(struct bpf_insn_aux_data) * - (*prog)->len); + env->insn_aux_data = + vzalloc(array_size(sizeof(struct bpf_insn_aux_data), + (*prog)->len)); ret = -ENOMEM; if (!env->insn_aux_data) goto err_free_env; @@ -5660,16 +5933,16 @@ int bpf_check(struct bpf_prog **prog, union bpf_attr *attr) if (!IS_ENABLED(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS)) env->strict_alignment = true; + ret = replace_map_fd_with_map_ptr(env); + if (ret < 0) + goto skip_full_check; + if (bpf_prog_is_dev_bound(env->prog->aux)) { ret = bpf_prog_offload_verifier_prep(env); if (ret) - goto err_unlock; + goto skip_full_check; } - ret = replace_map_fd_with_map_ptr(env); - if (ret < 0) - goto skip_full_check; - env->explored_states = kcalloc(env->prog->len, sizeof(struct bpf_verifier_state_list *), GFP_USER); @@ -5740,7 +6013,7 @@ skip_full_check: err_release_maps: if (!env->prog->aux->used_maps) /* if we didn't copy map pointers into bpf_prog_info, release - * them now. Otherwise free_bpf_prog_info() will release them. + * them now. Otherwise free_used_maps() will release them. */ release_maps(env); *prog = env->prog; |