diff options
Diffstat (limited to 'kernel/bpf/verifier.c')
| -rw-r--r-- | kernel/bpf/verifier.c | 406 |
1 files changed, 339 insertions, 67 deletions
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index a834068a400e..339c8a1371de 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -140,9 +140,11 @@ struct bpf_verifier_stack_elem { struct bpf_verifier_stack_elem *next; }; -#define BPF_COMPLEXITY_LIMIT_INSNS 65536 +#define BPF_COMPLEXITY_LIMIT_INSNS 98304 #define BPF_COMPLEXITY_LIMIT_STACK 1024 +#define BPF_MAP_PTR_POISON ((void *)0xeB9F + POISON_POINTER_DELTA) + struct bpf_call_arg_meta { struct bpf_map *map_ptr; bool raw_mode; @@ -239,6 +241,12 @@ static void print_verifier_state(struct bpf_verifier_state *state) if (reg->max_value != BPF_REGISTER_MAX_RANGE) verbose(",max_value=%llu", (unsigned long long)reg->max_value); + if (reg->min_align) + verbose(",min_align=%u", reg->min_align); + if (reg->aux_off) + verbose(",aux_off=%u", reg->aux_off); + if (reg->aux_off_align) + verbose(",aux_off_align=%u", reg->aux_off_align); } for (i = 0; i < MAX_BPF_STACK; i += BPF_REG_SIZE) { if (state->stack_slot_type[i] == STACK_SPILL) @@ -296,7 +304,8 @@ static const char *const bpf_jmp_string[16] = { [BPF_EXIT >> 4] = "exit", }; -static void print_bpf_insn(struct bpf_insn *insn) +static void print_bpf_insn(const struct bpf_verifier_env *env, + const struct bpf_insn *insn) { u8 class = BPF_CLASS(insn->code); @@ -360,9 +369,19 @@ static void print_bpf_insn(struct bpf_insn *insn) insn->code, bpf_ldst_string[BPF_SIZE(insn->code) >> 3], insn->src_reg, insn->imm); - } else if (BPF_MODE(insn->code) == BPF_IMM) { - verbose("(%02x) r%d = 0x%x\n", - insn->code, insn->dst_reg, insn->imm); + } else if (BPF_MODE(insn->code) == BPF_IMM && + BPF_SIZE(insn->code) == BPF_DW) { + /* At this point, we already made sure that the second + * part of the ldimm64 insn is accessible. + */ + u64 imm = ((u64)(insn + 1)->imm << 32) | (u32)insn->imm; + bool map_ptr = insn->src_reg == BPF_PSEUDO_MAP_FD; + + if (map_ptr && !env->allow_ptr_leaks) + imm = 0; + + verbose("(%02x) r%d = 0x%llx\n", insn->code, + insn->dst_reg, (unsigned long long)imm); } else { verbose("BUG_ld_%02x\n", insn->code); return; @@ -444,16 +463,22 @@ static const int caller_saved[CALLER_SAVED_REGS] = { BPF_REG_0, BPF_REG_1, BPF_REG_2, BPF_REG_3, BPF_REG_4, BPF_REG_5 }; +static void mark_reg_not_init(struct bpf_reg_state *regs, u32 regno) +{ + BUG_ON(regno >= MAX_BPF_REG); + + memset(®s[regno], 0, sizeof(regs[regno])); + regs[regno].type = NOT_INIT; + regs[regno].min_value = BPF_REGISTER_MIN_RANGE; + regs[regno].max_value = BPF_REGISTER_MAX_RANGE; +} + static void init_reg_state(struct bpf_reg_state *regs) { int i; - for (i = 0; i < MAX_BPF_REG; i++) { - regs[i].type = NOT_INIT; - regs[i].imm = 0; - regs[i].min_value = BPF_REGISTER_MIN_RANGE; - regs[i].max_value = BPF_REGISTER_MAX_RANGE; - } + for (i = 0; i < MAX_BPF_REG; i++) + mark_reg_not_init(regs, i); /* frame pointer */ regs[BPF_REG_FP].type = FRAME_PTR; @@ -479,6 +504,7 @@ static void reset_reg_range_values(struct bpf_reg_state *regs, u32 regno) { regs[regno].min_value = BPF_REGISTER_MIN_RANGE; regs[regno].max_value = BPF_REGISTER_MAX_RANGE; + regs[regno].min_align = 0; } static void mark_reg_unknown_value_and_range(struct bpf_reg_state *regs, @@ -766,17 +792,37 @@ static bool is_pointer_value(struct bpf_verifier_env *env, int regno) } static int check_pkt_ptr_alignment(const struct bpf_reg_state *reg, - int off, int size) + int off, int size, bool strict) { - if (reg->id && size != 1) { - verbose("Unknown alignment. Only byte-sized access allowed in packet access.\n"); - return -EACCES; + int ip_align; + int reg_off; + + /* Byte size accesses are always allowed. */ + if (!strict || size == 1) + return 0; + + reg_off = reg->off; + if (reg->id) { + if (reg->aux_off_align % size) { + verbose("Packet access is only %u byte aligned, %d byte access not allowed\n", + reg->aux_off_align, size); + return -EACCES; + } + reg_off += reg->aux_off; } - /* skb->data is NET_IP_ALIGN-ed */ - if ((NET_IP_ALIGN + reg->off + off) % size != 0) { + /* For platforms that do not have a Kconfig enabling + * CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS the value of + * NET_IP_ALIGN is universally set to '2'. And on platforms + * that do set CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS, we get + * to this code only in strict mode where we want to emulate + * the NET_IP_ALIGN==2 checking. Therefore use an + * unconditional IP align value of '2'. + */ + ip_align = 2; + if ((ip_align + reg_off + off) % size != 0) { verbose("misaligned packet access off %d+%d+%d size %d\n", - NET_IP_ALIGN, reg->off, off, size); + ip_align, reg_off, off, size); return -EACCES; } @@ -784,9 +830,9 @@ static int check_pkt_ptr_alignment(const struct bpf_reg_state *reg, } static int check_val_ptr_alignment(const struct bpf_reg_state *reg, - int size) + int size, bool strict) { - if (size != 1) { + if (strict && size != 1) { verbose("Unknown alignment. Only byte-sized access allowed in value access.\n"); return -EACCES; } @@ -794,16 +840,17 @@ static int check_val_ptr_alignment(const struct bpf_reg_state *reg, return 0; } -static int check_ptr_alignment(const struct bpf_reg_state *reg, +static int check_ptr_alignment(struct bpf_verifier_env *env, + const struct bpf_reg_state *reg, int off, int size) { + bool strict = env->strict_alignment; + switch (reg->type) { case PTR_TO_PACKET: - return IS_ENABLED(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) ? 0 : - check_pkt_ptr_alignment(reg, off, size); + return check_pkt_ptr_alignment(reg, off, size, strict); case PTR_TO_MAP_VALUE_ADJ: - return IS_ENABLED(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) ? 0 : - check_val_ptr_alignment(reg, size); + return check_val_ptr_alignment(reg, size, strict); default: if (off % size != 0) { verbose("misaligned access off %d size %d\n", @@ -836,7 +883,7 @@ static int check_mem_access(struct bpf_verifier_env *env, u32 regno, int off, if (size < 0) return size; - err = check_ptr_alignment(reg, off, size); + err = check_ptr_alignment(env, reg, off, size); if (err) return err; @@ -870,6 +917,8 @@ static int check_mem_access(struct bpf_verifier_env *env, u32 regno, int off, value_regno); /* note that reg.[id|off|range] == 0 */ state->regs[value_regno].type = reg_type; + state->regs[value_regno].aux_off = 0; + state->regs[value_regno].aux_off_align = 0; } } else if (reg->type == FRAME_PTR || reg->type == PTR_TO_STACK) { @@ -1215,6 +1264,10 @@ static int check_map_func_compatibility(struct bpf_map *map, int func_id) func_id != BPF_FUNC_current_task_under_cgroup) goto error; break; + case BPF_MAP_TYPE_ARRAY_OF_MAPS: + case BPF_MAP_TYPE_HASH_OF_MAPS: + if (func_id != BPF_FUNC_map_lookup_elem) + goto error; default: break; } @@ -1291,12 +1344,11 @@ static void clear_all_pkt_pointers(struct bpf_verifier_env *env) } } -static int check_call(struct bpf_verifier_env *env, int func_id) +static int check_call(struct bpf_verifier_env *env, int func_id, int insn_idx) { struct bpf_verifier_state *state = &env->cur_state; const struct bpf_func_proto *fn = NULL; struct bpf_reg_state *regs = state->regs; - struct bpf_reg_state *reg; struct bpf_call_arg_meta meta; bool changes_data; int i, err; @@ -1363,11 +1415,8 @@ static int check_call(struct bpf_verifier_env *env, int func_id) } /* reset caller saved regs */ - for (i = 0; i < CALLER_SAVED_REGS; i++) { - reg = regs + caller_saved[i]; - reg->type = NOT_INIT; - reg->imm = 0; - } + for (i = 0; i < CALLER_SAVED_REGS; i++) + mark_reg_not_init(regs, caller_saved[i]); /* update return register */ if (fn->ret_type == RET_INTEGER) { @@ -1375,6 +1424,8 @@ static int check_call(struct bpf_verifier_env *env, int func_id) } 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; regs[BPF_REG_0].max_value = regs[BPF_REG_0].min_value = 0; /* remember map_ptr, so that check_map_access() @@ -1387,6 +1438,11 @@ static int check_call(struct bpf_verifier_env *env, int func_id) } 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("unknown return type %d of func %s#%d\n", fn->ret_type, func_id_name(func_id), func_id); @@ -1431,6 +1487,8 @@ add_imm: */ dst_reg->off += imm; } else { + bool had_id; + if (src_reg->type == PTR_TO_PACKET) { /* R6=pkt(id=0,off=0,r=62) R7=imm22; r7 += r6 */ tmp_reg = *dst_reg; /* save r7 state */ @@ -1464,14 +1522,23 @@ add_imm: src_reg->imm); return -EACCES; } + + had_id = (dst_reg->id != 0); + /* dst_reg stays as pkt_ptr type and since some positive * integer value was added to the pointer, increment its 'id' */ dst_reg->id = ++env->id_gen; - /* something was added to pkt_ptr, set range and off to zero */ + /* something was added to pkt_ptr, set range to zero */ + dst_reg->aux_off += dst_reg->off; dst_reg->off = 0; dst_reg->range = 0; + if (had_id) + dst_reg->aux_off_align = min(dst_reg->aux_off_align, + src_reg->min_align); + else + dst_reg->aux_off_align = src_reg->min_align; } return 0; } @@ -1645,6 +1712,13 @@ static void check_reg_overflow(struct bpf_reg_state *reg) reg->min_value = BPF_REGISTER_MIN_RANGE; } +static u32 calc_align(u32 imm) +{ + if (!imm) + return 1U << 31; + return imm - ((imm - 1) & imm); +} + static void adjust_reg_min_max_vals(struct bpf_verifier_env *env, struct bpf_insn *insn) { @@ -1652,8 +1726,10 @@ static void adjust_reg_min_max_vals(struct bpf_verifier_env *env, s64 min_val = BPF_REGISTER_MIN_RANGE; u64 max_val = BPF_REGISTER_MAX_RANGE; u8 opcode = BPF_OP(insn->code); + u32 dst_align, src_align; dst_reg = ®s[insn->dst_reg]; + src_align = 0; if (BPF_SRC(insn->code) == BPF_X) { check_reg_overflow(®s[insn->src_reg]); min_val = regs[insn->src_reg].min_value; @@ -1669,12 +1745,18 @@ static void adjust_reg_min_max_vals(struct bpf_verifier_env *env, regs[insn->src_reg].type != UNKNOWN_VALUE) { min_val = BPF_REGISTER_MIN_RANGE; max_val = BPF_REGISTER_MAX_RANGE; + src_align = 0; + } else { + src_align = regs[insn->src_reg].min_align; } } else if (insn->imm < BPF_REGISTER_MAX_RANGE && (s64)insn->imm > BPF_REGISTER_MIN_RANGE) { min_val = max_val = insn->imm; + src_align = calc_align(insn->imm); } + dst_align = dst_reg->min_align; + /* We don't know anything about what was done to this register, mark it * as unknown. */ @@ -1699,18 +1781,21 @@ static void adjust_reg_min_max_vals(struct bpf_verifier_env *env, dst_reg->min_value += min_val; if (dst_reg->max_value != BPF_REGISTER_MAX_RANGE) dst_reg->max_value += max_val; + dst_reg->min_align = min(src_align, dst_align); break; case BPF_SUB: if (dst_reg->min_value != BPF_REGISTER_MIN_RANGE) dst_reg->min_value -= min_val; if (dst_reg->max_value != BPF_REGISTER_MAX_RANGE) dst_reg->max_value -= max_val; + dst_reg->min_align = min(src_align, dst_align); break; case BPF_MUL: if (dst_reg->min_value != BPF_REGISTER_MIN_RANGE) dst_reg->min_value *= min_val; if (dst_reg->max_value != BPF_REGISTER_MAX_RANGE) dst_reg->max_value *= max_val; + dst_reg->min_align = max(src_align, dst_align); break; case BPF_AND: /* Disallow AND'ing of negative numbers, ain't nobody got time @@ -1722,17 +1807,23 @@ static void adjust_reg_min_max_vals(struct bpf_verifier_env *env, else dst_reg->min_value = 0; dst_reg->max_value = max_val; + dst_reg->min_align = max(src_align, dst_align); break; case BPF_LSH: /* Gotta have special overflow logic here, if we're shifting * more than MAX_RANGE then just assume we have an invalid * range. */ - if (min_val > ilog2(BPF_REGISTER_MAX_RANGE)) + if (min_val > ilog2(BPF_REGISTER_MAX_RANGE)) { dst_reg->min_value = BPF_REGISTER_MIN_RANGE; - else if (dst_reg->min_value != BPF_REGISTER_MIN_RANGE) - dst_reg->min_value <<= min_val; - + dst_reg->min_align = 1; + } else { + if (dst_reg->min_value != BPF_REGISTER_MIN_RANGE) + dst_reg->min_value <<= min_val; + if (!dst_reg->min_align) + dst_reg->min_align = 1; + dst_reg->min_align <<= min_val; + } if (max_val > ilog2(BPF_REGISTER_MAX_RANGE)) dst_reg->max_value = BPF_REGISTER_MAX_RANGE; else if (dst_reg->max_value != BPF_REGISTER_MAX_RANGE) @@ -1742,11 +1833,19 @@ static void adjust_reg_min_max_vals(struct bpf_verifier_env *env, /* RSH by a negative number is undefined, and the BPF_RSH is an * unsigned shift, so make the appropriate casts. */ - if (min_val < 0 || dst_reg->min_value < 0) + if (min_val < 0 || dst_reg->min_value < 0) { dst_reg->min_value = BPF_REGISTER_MIN_RANGE; - else + } else { dst_reg->min_value = (u64)(dst_reg->min_value) >> min_val; + } + if (min_val < 0) { + dst_reg->min_align = 1; + } else { + dst_reg->min_align >>= (u64) min_val; + if (!dst_reg->min_align) + dst_reg->min_align = 1; + } if (dst_reg->max_value != BPF_REGISTER_MAX_RANGE) dst_reg->max_value >>= max_val; break; @@ -1848,6 +1947,7 @@ static int check_alu_op(struct bpf_verifier_env *env, struct bpf_insn *insn) regs[insn->dst_reg].imm = insn->imm; regs[insn->dst_reg].max_value = insn->imm; regs[insn->dst_reg].min_value = insn->imm; + regs[insn->dst_reg].min_align = calc_align(insn->imm); } } else if (opcode > BPF_END) { @@ -1911,6 +2011,17 @@ static int check_alu_op(struct bpf_verifier_env *env, struct bpf_insn *insn) return 0; } else if (opcode == BPF_ADD && BPF_CLASS(insn->code) == BPF_ALU64 && + dst_reg->type == PTR_TO_STACK && + ((BPF_SRC(insn->code) == BPF_X && + regs[insn->src_reg].type == CONST_IMM) || + BPF_SRC(insn->code) == BPF_K)) { + if (BPF_SRC(insn->code) == BPF_X) + dst_reg->imm += regs[insn->src_reg].imm; + else + dst_reg->imm += insn->imm; + return 0; + } else if (opcode == BPF_ADD && + BPF_CLASS(insn->code) == BPF_ALU64 && (dst_reg->type == PTR_TO_PACKET || (BPF_SRC(insn->code) == BPF_X && regs[insn->src_reg].type == PTR_TO_PACKET))) { @@ -2112,14 +2223,19 @@ static void mark_map_reg(struct bpf_reg_state *regs, u32 regno, u32 id, struct bpf_reg_state *reg = ®s[regno]; if (reg->type == PTR_TO_MAP_VALUE_OR_NULL && reg->id == id) { - reg->type = type; + if (type == UNKNOWN_VALUE) { + __mark_reg_unknown_value(regs, regno); + } else if (reg->map_ptr->inner_map_meta) { + reg->type = CONST_PTR_TO_MAP; + reg->map_ptr = reg->map_ptr->inner_map_meta; + } else { + reg->type = type; + } /* We don't need id from this point onwards anymore, thus we * should better reset it, so that state pruning has chances * to take effect. */ reg->id = 0; - if (type == UNKNOWN_VALUE) - __mark_reg_unknown_value(regs, regno); } } @@ -2328,7 +2444,6 @@ static int check_ld_abs(struct bpf_verifier_env *env, struct bpf_insn *insn) { struct bpf_reg_state *regs = env->cur_state.regs; u8 mode = BPF_MODE(insn->code); - struct bpf_reg_state *reg; int i, err; if (!may_access_skb(env->prog->type)) { @@ -2361,11 +2476,8 @@ static int check_ld_abs(struct bpf_verifier_env *env, struct bpf_insn *insn) } /* reset caller saved regs to unreadable */ - for (i = 0; i < CALLER_SAVED_REGS; i++) { - reg = regs + caller_saved[i]; - reg->type = NOT_INIT; - reg->imm = 0; - } + for (i = 0; i < CALLER_SAVED_REGS; i++) + mark_reg_not_init(regs, caller_saved[i]); /* mark destination R0 register as readable, since it contains * the value fetched from the packet @@ -2524,6 +2636,7 @@ peek_stack: env->explored_states[t + 1] = STATE_LIST_MARK; } else { /* conditional jump with two edges */ + env->explored_states[t] = STATE_LIST_MARK; ret = push_insn(t, t + 1, FALLTHROUGH, env); if (ret == 1) goto peek_stack; @@ -2575,7 +2688,8 @@ err_free: /* the following conditions reduce the number of explored insns * from ~140k to ~80k for ultra large programs that use a lot of ptr_to_packet */ -static bool compare_ptrs_to_packet(struct bpf_reg_state *old, +static bool compare_ptrs_to_packet(struct bpf_verifier_env *env, + struct bpf_reg_state *old, struct bpf_reg_state *cur) { if (old->id != cur->id) @@ -2618,7 +2732,7 @@ static bool compare_ptrs_to_packet(struct bpf_reg_state *old, * 'if (R4 > data_end)' and all further insn were already good with r=20, * so they will be good with r=30 and we can prune the search. */ - if (old->off <= cur->off && + if (!env->strict_alignment && old->off <= cur->off && old->off >= old->range && cur->off >= cur->range) return true; @@ -2682,8 +2796,14 @@ static bool states_equal(struct bpf_verifier_env *env, rcur->type != NOT_INIT)) continue; + /* Don't care about the reg->id in this case. */ + if (rold->type == PTR_TO_MAP_VALUE_OR_NULL && + rcur->type == PTR_TO_MAP_VALUE_OR_NULL && + rold->map_ptr == rcur->map_ptr) + continue; + if (rold->type == PTR_TO_PACKET && rcur->type == PTR_TO_PACKET && - compare_ptrs_to_packet(rold, rcur)) + compare_ptrs_to_packet(env, rold, rcur)) continue; return false; @@ -2816,15 +2936,22 @@ static int do_check(struct bpf_verifier_env *env) goto process_bpf_exit; } - if (log_level && do_print_state) { - verbose("\nfrom %d to %d:", prev_insn_idx, insn_idx); + if (need_resched()) + cond_resched(); + + if (log_level > 1 || (log_level && do_print_state)) { + if (log_level > 1) + verbose("%d:", insn_idx); + else + verbose("\nfrom %d to %d:", + prev_insn_idx, insn_idx); print_verifier_state(&env->cur_state); do_print_state = false; } if (log_level) { verbose("%d: ", insn_idx); - print_bpf_insn(insn); + print_bpf_insn(env, insn); } err = ext_analyzer_insn_hook(env, insn_idx, prev_insn_idx); @@ -2960,7 +3087,7 @@ static int do_check(struct bpf_verifier_env *env) return -EINVAL; } - err = check_call(env, insn->imm); + err = check_call(env, insn->imm, insn_idx); if (err) return err; @@ -3044,16 +3171,33 @@ process_bpf_exit: return 0; } +static int check_map_prealloc(struct bpf_map *map) +{ + return (map->map_type != BPF_MAP_TYPE_HASH && + map->map_type != BPF_MAP_TYPE_PERCPU_HASH && + map->map_type != BPF_MAP_TYPE_HASH_OF_MAPS) || + !(map->map_flags & BPF_F_NO_PREALLOC); +} + static int check_map_prog_compatibility(struct bpf_map *map, struct bpf_prog *prog) { - if (prog->type == BPF_PROG_TYPE_PERF_EVENT && - (map->map_type == BPF_MAP_TYPE_HASH || - map->map_type == BPF_MAP_TYPE_PERCPU_HASH) && - (map->map_flags & BPF_F_NO_PREALLOC)) { - verbose("perf_event programs can only use preallocated hash map\n"); - return -EINVAL; + /* Make sure that BPF_PROG_TYPE_PERF_EVENT programs only use + * preallocated hash maps, since doing memory allocation + * in overflow_handler can crash depending on where nmi got + * triggered. + */ + if (prog->type == BPF_PROG_TYPE_PERF_EVENT) { + if (!check_map_prealloc(map)) { + verbose("perf_event programs can only use preallocated hash map\n"); + return -EINVAL; + } + if (map->inner_map_meta && + !check_map_prealloc(map->inner_map_meta)) { + verbose("perf_event programs can only use preallocated inner hash map\n"); + return -EINVAL; + } } return 0; } @@ -3182,6 +3326,41 @@ static void convert_pseudo_ld_imm64(struct bpf_verifier_env *env) insn->src_reg = 0; } +/* single env->prog->insni[off] instruction was replaced with the range + * insni[off, off + cnt). Adjust corresponding insn_aux_data by copying + * [0, off) and [off, end) to new locations, so the patched range stays zero + */ +static int adjust_insn_aux_data(struct bpf_verifier_env *env, u32 prog_len, + u32 off, u32 cnt) +{ + struct bpf_insn_aux_data *new_data, *old_data = env->insn_aux_data; + + if (cnt == 1) + return 0; + new_data = vzalloc(sizeof(struct bpf_insn_aux_data) * prog_len); + if (!new_data) + return -ENOMEM; + memcpy(new_data, old_data, sizeof(struct bpf_insn_aux_data) * off); + memcpy(new_data + off + cnt - 1, old_data + off, + sizeof(struct bpf_insn_aux_data) * (prog_len - off - cnt + 1)); + env->insn_aux_data = new_data; + vfree(old_data); + return 0; +} + +static struct bpf_prog *bpf_patch_insn_data(struct bpf_verifier_env *env, u32 off, + const struct bpf_insn *patch, u32 len) +{ + struct bpf_prog *new_prog; + + new_prog = bpf_patch_insn_single(env->prog, off, patch, len); + if (!new_prog) + return NULL; + if (adjust_insn_aux_data(env, new_prog->len, off, len)) + return NULL; + return new_prog; +} + /* convert load instructions that access fields of 'struct __sk_buff' * into sequence of instructions that access fields of 'struct sk_buff' */ @@ -3201,10 +3380,10 @@ static int convert_ctx_accesses(struct bpf_verifier_env *env) verbose("bpf verifier is misconfigured\n"); return -EINVAL; } else if (cnt) { - new_prog = bpf_patch_insn_single(env->prog, 0, - insn_buf, cnt); + new_prog = bpf_patch_insn_data(env, 0, insn_buf, cnt); if (!new_prog) return -ENOMEM; + env->prog = new_prog; delta += cnt - 1; } @@ -3229,7 +3408,7 @@ static int convert_ctx_accesses(struct bpf_verifier_env *env) else continue; - if (env->insn_aux_data[i].ptr_type != PTR_TO_CTX) + if (env->insn_aux_data[i + delta].ptr_type != PTR_TO_CTX) continue; cnt = ops->convert_ctx_access(type, insn, insn_buf, env->prog); @@ -3238,8 +3417,7 @@ static int convert_ctx_accesses(struct bpf_verifier_env *env) return -EINVAL; } - new_prog = bpf_patch_insn_single(env->prog, i + delta, insn_buf, - cnt); + new_prog = bpf_patch_insn_data(env, i + delta, insn_buf, cnt); if (!new_prog) return -ENOMEM; @@ -3253,6 +3431,89 @@ static int convert_ctx_accesses(struct bpf_verifier_env *env) return 0; } +/* fixup insn->imm field of bpf_call instructions + * and inline eligible helpers as explicit sequence of BPF instructions + * + * this function is called after eBPF program passed verification + */ +static int fixup_bpf_calls(struct bpf_verifier_env *env) +{ + struct bpf_prog *prog = env->prog; + struct bpf_insn *insn = prog->insnsi; + const struct bpf_func_proto *fn; + const int insn_cnt = prog->len; + struct bpf_insn insn_buf[16]; + struct bpf_prog *new_prog; + struct bpf_map *map_ptr; + int i, cnt, delta = 0; + + for (i = 0; i < insn_cnt; i++, insn++) { + if (insn->code != (BPF_JMP | BPF_CALL)) + continue; + + if (insn->imm == BPF_FUNC_get_route_realm) + prog->dst_needed = 1; + if (insn->imm == BPF_FUNC_get_prandom_u32) + bpf_user_rnd_init_once(); + if (insn->imm == BPF_FUNC_tail_call) { + /* If we tail call into other programs, we + * cannot make any assumptions since they can + * be replaced dynamically during runtime in + * the program array. + */ + prog->cb_access = 1; + + /* mark bpf_tail_call as different opcode to avoid + * conditional branch in the interpeter for every normal + * call and to prevent accidental JITing by JIT compiler + * that doesn't support bpf_tail_call yet + */ + insn->imm = 0; + insn->code |= BPF_X; + continue; + } + + if (ebpf_jit_enabled() && 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) + goto patch_call_imm; + + cnt = map_ptr->ops->map_gen_lookup(map_ptr, insn_buf); + if (cnt == 0 || cnt >= ARRAY_SIZE(insn_buf)) { + verbose("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; + + /* keep walking new program and skip insns we just inserted */ + env->prog = prog = new_prog; + insn = new_prog->insnsi + i + delta; + continue; + } + +patch_call_imm: + fn = prog->aux->ops->get_func_proto(insn->imm); + /* all functions that have prototype and verifier allowed + * programs to call them, must be real in-kernel functions + */ + if (!fn->func) { + verbose("kernel subsystem misconfigured func %s#%d\n", + func_id_name(insn->imm), insn->imm); + return -EFAULT; + } + insn->imm = fn->func - __bpf_call_base; + } + + return 0; +} + static void free_states(struct bpf_verifier_env *env) { struct bpf_verifier_state_list *sl, *sln; @@ -3321,6 +3582,10 @@ int bpf_check(struct bpf_prog **prog, union bpf_attr *attr) log_level = 0; } + env->strict_alignment = !!(attr->prog_flags & BPF_F_STRICT_ALIGNMENT); + 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; @@ -3348,6 +3613,9 @@ skip_full_check: /* program is valid, convert *(u32*)(ctx + off) accesses */ ret = convert_ctx_accesses(env); + if (ret == 0) + ret = fixup_bpf_calls(env); + if (log_level && log_len >= log_size - 1) { BUG_ON(log_len >= log_size); /* verifier log exceeded user supplied buffer */ @@ -3423,6 +3691,10 @@ int bpf_analyzer(struct bpf_prog *prog, const struct bpf_ext_analyzer_ops *ops, log_level = 0; + env->strict_alignment = false; + if (!IS_ENABLED(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS)) + env->strict_alignment = true; + env->explored_states = kcalloc(env->prog->len, sizeof(struct bpf_verifier_state_list *), GFP_KERNEL); |