diff options
Diffstat (limited to 'kernel/bpf/verifier.c')
| -rw-r--r-- | kernel/bpf/verifier.c | 543 |
1 files changed, 506 insertions, 37 deletions
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index ffc3e53f5300..a0482e1c4a77 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -23,7 +23,7 @@ #include "disasm.h" static const struct bpf_verifier_ops * const bpf_verifier_ops[] = { -#define BPF_PROG_TYPE(_id, _name) \ +#define BPF_PROG_TYPE(_id, _name, prog_ctx_type, kern_ctx_type) \ [_id] = & _name ## _verifier_ops, #define BPF_MAP_TYPE(_id, _ops) #include <linux/bpf_types.h> @@ -171,6 +171,9 @@ struct bpf_verifier_stack_elem { #define BPF_COMPLEXITY_LIMIT_JMP_SEQ 8192 #define BPF_COMPLEXITY_LIMIT_STATES 64 +#define BPF_MAP_KEY_POISON (1ULL << 63) +#define BPF_MAP_KEY_SEEN (1ULL << 62) + #define BPF_MAP_PTR_UNPRIV 1UL #define BPF_MAP_PTR_POISON ((void *)((0xeB9FUL << 1) + \ POISON_POINTER_DELTA)) @@ -178,12 +181,12 @@ struct bpf_verifier_stack_elem { static bool bpf_map_ptr_poisoned(const struct bpf_insn_aux_data *aux) { - return BPF_MAP_PTR(aux->map_state) == BPF_MAP_PTR_POISON; + return BPF_MAP_PTR(aux->map_ptr_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; + return aux->map_ptr_state & BPF_MAP_PTR_UNPRIV; } static void bpf_map_ptr_store(struct bpf_insn_aux_data *aux, @@ -191,8 +194,31 @@ static void bpf_map_ptr_store(struct bpf_insn_aux_data *aux, { 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); + aux->map_ptr_state = (unsigned long)map | + (unpriv ? BPF_MAP_PTR_UNPRIV : 0UL); +} + +static bool bpf_map_key_poisoned(const struct bpf_insn_aux_data *aux) +{ + return aux->map_key_state & BPF_MAP_KEY_POISON; +} + +static bool bpf_map_key_unseen(const struct bpf_insn_aux_data *aux) +{ + return !(aux->map_key_state & BPF_MAP_KEY_SEEN); +} + +static u64 bpf_map_key_immediate(const struct bpf_insn_aux_data *aux) +{ + return aux->map_key_state & ~(BPF_MAP_KEY_SEEN | BPF_MAP_KEY_POISON); +} + +static void bpf_map_key_store(struct bpf_insn_aux_data *aux, u64 state) +{ + bool poisoned = bpf_map_key_poisoned(aux); + + aux->map_key_state = state | BPF_MAP_KEY_SEEN | + (poisoned ? BPF_MAP_KEY_POISON : 0ULL); } struct bpf_call_arg_meta { @@ -205,8 +231,11 @@ struct bpf_call_arg_meta { u64 msize_umax_value; int ref_obj_id; int func_id; + u32 btf_id; }; +struct btf *btf_vmlinux; + static DEFINE_MUTEX(bpf_verifier_lock); static const struct bpf_line_info * @@ -243,6 +272,10 @@ void bpf_verifier_vlog(struct bpf_verifier_log *log, const char *fmt, n = min(log->len_total - log->len_used - 1, n); log->kbuf[n] = '\0'; + if (log->level == BPF_LOG_KERNEL) { + pr_err("BPF:%s\n", log->kbuf); + return; + } if (!copy_to_user(log->ubuf + log->len_used, log->kbuf, n + 1)) log->len_used += n; else @@ -280,6 +313,19 @@ __printf(2, 3) static void verbose(void *private_data, const char *fmt, ...) va_end(args); } +__printf(2, 3) void bpf_log(struct bpf_verifier_log *log, + const char *fmt, ...) +{ + va_list args; + + if (!bpf_verifier_log_needed(log)) + return; + + va_start(args, fmt); + bpf_verifier_vlog(log, fmt, args); + va_end(args); +} + static const char *ltrim(const char *s) { while (isspace(*s)) @@ -400,6 +446,7 @@ static const char * const reg_type_str[] = { [PTR_TO_TCP_SOCK_OR_NULL] = "tcp_sock_or_null", [PTR_TO_TP_BUFFER] = "tp_buffer", [PTR_TO_XDP_SOCK] = "xdp_sock", + [PTR_TO_BTF_ID] = "ptr_", }; static char slot_type_char[] = { @@ -430,6 +477,12 @@ static struct bpf_func_state *func(struct bpf_verifier_env *env, return cur->frame[reg->frameno]; } +const char *kernel_type_name(u32 id) +{ + return btf_name_by_offset(btf_vmlinux, + btf_type_by_id(btf_vmlinux, id)->name_off); +} + static void print_verifier_state(struct bpf_verifier_env *env, const struct bpf_func_state *state) { @@ -454,6 +507,8 @@ static void print_verifier_state(struct bpf_verifier_env *env, /* reg->off should be 0 for SCALAR_VALUE */ verbose(env, "%lld", reg->var_off.value + reg->off); } else { + if (t == PTR_TO_BTF_ID) + verbose(env, "%s", kernel_type_name(reg->btf_id)); verbose(env, "(id=%d", reg->id); if (reg_type_may_be_refcounted_or_null(t)) verbose(env, ",ref_obj_id=%d", reg->ref_obj_id); @@ -978,6 +1033,17 @@ static void __reg_bound_offset(struct bpf_reg_state *reg) reg->umax_value)); } +static void __reg_bound_offset32(struct bpf_reg_state *reg) +{ + u64 mask = 0xffffFFFF; + struct tnum range = tnum_range(reg->umin_value & mask, + reg->umax_value & mask); + struct tnum lo32 = tnum_cast(reg->var_off, 4); + struct tnum hi32 = tnum_lshift(tnum_rshift(reg->var_off, 32), 32); + + reg->var_off = tnum_or(hi32, tnum_intersect(lo32, range)); +} + /* Reset the min/max bounds of a register */ static void __mark_reg_unbounded(struct bpf_reg_state *reg) { @@ -2331,10 +2397,12 @@ static int check_packet_access(struct bpf_verifier_env *env, u32 regno, int off, /* check access to 'struct bpf_context' fields. Supports fixed offsets only */ static int check_ctx_access(struct bpf_verifier_env *env, int insn_idx, int off, int size, - enum bpf_access_type t, enum bpf_reg_type *reg_type) + enum bpf_access_type t, enum bpf_reg_type *reg_type, + u32 *btf_id) { struct bpf_insn_access_aux info = { .reg_type = *reg_type, + .log = &env->log, }; if (env->ops->is_valid_access && @@ -2348,7 +2416,10 @@ static int check_ctx_access(struct bpf_verifier_env *env, int insn_idx, int off, */ *reg_type = info.reg_type; - env->insn_aux_data[insn_idx].ctx_field_size = info.ctx_field_size; + if (*reg_type == PTR_TO_BTF_ID) + *btf_id = info.btf_id; + else + env->insn_aux_data[insn_idx].ctx_field_size = info.ctx_field_size; /* remember the offset of last byte accessed in ctx */ if (env->prog->aux->max_ctx_offset < off + size) env->prog->aux->max_ctx_offset = off + size; @@ -2739,6 +2810,88 @@ static void coerce_reg_to_size(struct bpf_reg_state *reg, int size) reg->smax_value = reg->umax_value; } +static bool bpf_map_is_rdonly(const struct bpf_map *map) +{ + return (map->map_flags & BPF_F_RDONLY_PROG) && map->frozen; +} + +static int bpf_map_direct_read(struct bpf_map *map, int off, int size, u64 *val) +{ + void *ptr; + u64 addr; + int err; + + err = map->ops->map_direct_value_addr(map, &addr, off); + if (err) + return err; + ptr = (void *)(long)addr + off; + + switch (size) { + case sizeof(u8): + *val = (u64)*(u8 *)ptr; + break; + case sizeof(u16): + *val = (u64)*(u16 *)ptr; + break; + case sizeof(u32): + *val = (u64)*(u32 *)ptr; + break; + case sizeof(u64): + *val = *(u64 *)ptr; + break; + default: + return -EINVAL; + } + return 0; +} + +static int check_ptr_to_btf_access(struct bpf_verifier_env *env, + struct bpf_reg_state *regs, + int regno, int off, int size, + enum bpf_access_type atype, + int value_regno) +{ + struct bpf_reg_state *reg = regs + regno; + const struct btf_type *t = btf_type_by_id(btf_vmlinux, reg->btf_id); + const char *tname = btf_name_by_offset(btf_vmlinux, t->name_off); + u32 btf_id; + int ret; + + if (atype != BPF_READ) { + verbose(env, "only read is supported\n"); + return -EACCES; + } + + if (off < 0) { + verbose(env, + "R%d is ptr_%s invalid negative access: off=%d\n", + regno, tname, 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, + "R%d is ptr_%s invalid variable offset: off=%d, var_off=%s\n", + regno, tname, off, tn_buf); + return -EACCES; + } + + ret = btf_struct_access(&env->log, t, off, size, atype, &btf_id); + if (ret < 0) + return ret; + + if (ret == SCALAR_VALUE) { + mark_reg_unknown(env, regs, value_regno); + return 0; + } + mark_reg_known_zero(env, regs, value_regno); + regs[value_regno].type = PTR_TO_BTF_ID; + regs[value_regno].btf_id = btf_id; + return 0; +} + /* check whether memory at (regno + off) is accessible for t = (read | write) * if t==write, value_regno is a register which value is stored into memory * if t==read, value_regno is a register which will receive the value from memory @@ -2776,11 +2929,30 @@ static int check_mem_access(struct bpf_verifier_env *env, int insn_idx, u32 regn if (err) return err; err = check_map_access(env, regno, off, size, false); - if (!err && t == BPF_READ && value_regno >= 0) - mark_reg_unknown(env, regs, value_regno); + if (!err && t == BPF_READ && value_regno >= 0) { + struct bpf_map *map = reg->map_ptr; + + /* if map is read-only, track its contents as scalars */ + if (tnum_is_const(reg->var_off) && + bpf_map_is_rdonly(map) && + map->ops->map_direct_value_addr) { + int map_off = off + reg->var_off.value; + u64 val = 0; + + err = bpf_map_direct_read(map, map_off, size, + &val); + if (err) + return err; + regs[value_regno].type = SCALAR_VALUE; + __mark_reg_known(®s[value_regno], val); + } else { + mark_reg_unknown(env, regs, value_regno); + } + } } else if (reg->type == PTR_TO_CTX) { enum bpf_reg_type reg_type = SCALAR_VALUE; + u32 btf_id = 0; if (t == BPF_WRITE && value_regno >= 0 && is_pointer_value(env, value_regno)) { @@ -2792,7 +2964,9 @@ static int check_mem_access(struct bpf_verifier_env *env, int insn_idx, u32 regn if (err < 0) return err; - err = check_ctx_access(env, insn_idx, off, size, t, ®_type); + err = check_ctx_access(env, insn_idx, off, size, t, ®_type, &btf_id); + if (err) + verbose_linfo(env, insn_idx, "; "); if (!err && t == BPF_READ && value_regno >= 0) { /* ctx access returns either a scalar, or a * PTR_TO_PACKET[_META,_END]. In the latter @@ -2811,6 +2985,8 @@ static int check_mem_access(struct bpf_verifier_env *env, int insn_idx, u32 regn * a sub-register. */ regs[value_regno].subreg_def = DEF_NOT_SUBREG; + if (reg_type == PTR_TO_BTF_ID) + regs[value_regno].btf_id = btf_id; } regs[value_regno].type = reg_type; } @@ -2870,6 +3046,9 @@ static int check_mem_access(struct bpf_verifier_env *env, int insn_idx, u32 regn err = check_tp_buffer_access(env, reg, regno, off, size); if (!err && t == BPF_READ && value_regno >= 0) mark_reg_unknown(env, regs, value_regno); + } else if (reg->type == PTR_TO_BTF_ID) { + err = check_ptr_to_btf_access(env, regs, regno, off, size, t, + value_regno); } else { verbose(env, "R%d invalid mem access '%s'\n", regno, reg_type_str[reg->type]); @@ -3298,6 +3477,22 @@ static int check_func_arg(struct bpf_verifier_env *env, u32 regno, expected_type = PTR_TO_SOCKET; if (type != expected_type) goto err_type; + } else if (arg_type == ARG_PTR_TO_BTF_ID) { + expected_type = PTR_TO_BTF_ID; + if (type != expected_type) + goto err_type; + if (reg->btf_id != meta->btf_id) { + verbose(env, "Helper has type %s got %s in R%d\n", + kernel_type_name(meta->btf_id), + kernel_type_name(reg->btf_id), regno); + + return -EACCES; + } + if (!tnum_is_const(reg->var_off) || reg->var_off.value || reg->off) { + verbose(env, "R%d is a pointer to in-kernel struct with non-zero offset\n", + regno); + return -EACCES; + } } else if (arg_type == ARG_PTR_TO_SPIN_LOCK) { if (meta->func_id == BPF_FUNC_spin_lock) { if (process_spin_lock(env, regno, true)) @@ -3445,6 +3640,7 @@ static int check_map_func_compatibility(struct bpf_verifier_env *env, case BPF_MAP_TYPE_PERF_EVENT_ARRAY: if (func_id != BPF_FUNC_perf_event_read && func_id != BPF_FUNC_perf_event_output && + func_id != BPF_FUNC_skb_output && func_id != BPF_FUNC_perf_event_read_value) goto error; break; @@ -3532,6 +3728,7 @@ static int check_map_func_compatibility(struct bpf_verifier_env *env, case BPF_FUNC_perf_event_read: case BPF_FUNC_perf_event_output: case BPF_FUNC_perf_event_read_value: + case BPF_FUNC_skb_output: if (map->map_type != BPF_MAP_TYPE_PERF_EVENT_ARRAY) goto error; break; @@ -3810,6 +4007,9 @@ static int check_func_call(struct bpf_verifier_env *env, struct bpf_insn *insn, /* only increment it after check_reg_arg() finished */ state->curframe++; + if (btf_check_func_arg_match(env, subprog)) + return -EINVAL; + /* and go analyze first insn of the callee */ *insn_idx = target_insn; @@ -3916,15 +4116,49 @@ record_func_map(struct bpf_verifier_env *env, struct bpf_call_arg_meta *meta, return -EACCES; } - if (!BPF_MAP_PTR(aux->map_state)) + if (!BPF_MAP_PTR(aux->map_ptr_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) + else if (BPF_MAP_PTR(aux->map_ptr_state) != meta->map_ptr) bpf_map_ptr_store(aux, BPF_MAP_PTR_POISON, meta->map_ptr->unpriv_array); return 0; } +static int +record_func_key(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]; + struct bpf_reg_state *regs = cur_regs(env), *reg; + struct bpf_map *map = meta->map_ptr; + struct tnum range; + u64 val; + + 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"); + return -EINVAL; + } + + range = tnum_range(0, map->max_entries - 1); + reg = ®s[BPF_REG_3]; + + if (!register_is_const(reg) || !tnum_in(range, reg->var_off)) { + bpf_map_key_store(aux, BPF_MAP_KEY_POISON); + return 0; + } + + val = reg->var_off.value; + if (bpf_map_key_unseen(aux)) + bpf_map_key_store(aux, val); + else if (!bpf_map_key_poisoned(aux) && + bpf_map_key_immediate(aux) != val) + bpf_map_key_store(aux, BPF_MAP_KEY_POISON); + return 0; +} + static int check_reference_leak(struct bpf_verifier_env *env) { struct bpf_func_state *state = cur_func(env); @@ -3986,23 +4220,20 @@ static int check_helper_call(struct bpf_verifier_env *env, int func_id, int insn meta.func_id = func_id; /* check args */ - err = check_func_arg(env, BPF_REG_1, fn->arg1_type, &meta); - if (err) - return err; - err = check_func_arg(env, BPF_REG_2, fn->arg2_type, &meta); - if (err) - return err; - err = check_func_arg(env, BPF_REG_3, fn->arg3_type, &meta); - if (err) - return err; - err = check_func_arg(env, BPF_REG_4, fn->arg4_type, &meta); - if (err) - return err; - err = check_func_arg(env, BPF_REG_5, fn->arg5_type, &meta); + for (i = 0; i < 5; i++) { + err = btf_resolve_helper_id(&env->log, fn, i); + if (err > 0) + meta.btf_id = err; + err = check_func_arg(env, BPF_REG_1 + i, fn->arg_type[i], &meta); + if (err) + return err; + } + + err = record_func_map(env, &meta, func_id, insn_idx); if (err) return err; - err = record_func_map(env, &meta, func_id, insn_idx); + err = record_func_key(env, &meta, func_id, insn_idx); if (err) return err; @@ -5433,6 +5664,10 @@ static void reg_set_min_max(struct bpf_reg_state *true_reg, /* We might have learned some bits from the bounds. */ __reg_bound_offset(false_reg); __reg_bound_offset(true_reg); + if (is_jmp32) { + __reg_bound_offset32(false_reg); + __reg_bound_offset32(true_reg); + } /* Intersecting with the old var_off might have improved our bounds * slightly. e.g. if umax was 0x7f...f and var_off was (0; 0xf...fc), * then new var_off is (0; 0x7f...fc) which improves our umax. @@ -5542,6 +5777,10 @@ static void reg_set_min_max_inv(struct bpf_reg_state *true_reg, /* We might have learned some bits from the bounds. */ __reg_bound_offset(false_reg); __reg_bound_offset(true_reg); + if (is_jmp32) { + __reg_bound_offset32(false_reg); + __reg_bound_offset32(true_reg); + } /* Intersecting with the old var_off might have improved our bounds * slightly. e.g. if umax was 0x7f...f and var_off was (0; 0xf...fc), * then new var_off is (0; 0x7f...fc) which improves our umax. @@ -6124,6 +6363,11 @@ static int check_return_code(struct bpf_verifier_env *env) case BPF_PROG_TYPE_CGROUP_SYSCTL: case BPF_PROG_TYPE_CGROUP_SOCKOPT: break; + case BPF_PROG_TYPE_RAW_TRACEPOINT: + if (!env->prog->aux->attach_btf_id) + return 0; + range = tnum_const(0); + break; default: return 0; } @@ -6406,6 +6650,7 @@ static int check_btf_func(struct bpf_verifier_env *env, u32 i, nfuncs, urec_size, min_size; u32 krec_size = sizeof(struct bpf_func_info); struct bpf_func_info *krecord; + struct bpf_func_info_aux *info_aux = NULL; const struct btf_type *type; struct bpf_prog *prog; const struct btf *btf; @@ -6439,6 +6684,9 @@ static int check_btf_func(struct bpf_verifier_env *env, krecord = kvcalloc(nfuncs, krec_size, GFP_KERNEL | __GFP_NOWARN); if (!krecord) return -ENOMEM; + info_aux = kcalloc(nfuncs, sizeof(*info_aux), GFP_KERNEL | __GFP_NOWARN); + if (!info_aux) + goto err_free; for (i = 0; i < nfuncs; i++) { ret = bpf_check_uarg_tail_zero(urecord, krec_size, urec_size); @@ -6490,29 +6738,31 @@ static int check_btf_func(struct bpf_verifier_env *env, ret = -EINVAL; goto err_free; } - prev_offset = krecord[i].insn_off; urecord += urec_size; } prog->aux->func_info = krecord; prog->aux->func_info_cnt = nfuncs; + prog->aux->func_info_aux = info_aux; return 0; err_free: kvfree(krecord); + kfree(info_aux); return ret; } static void adjust_btf_func(struct bpf_verifier_env *env) { + struct bpf_prog_aux *aux = env->prog->aux; int i; - if (!env->prog->aux->func_info) + if (!aux->func_info) return; for (i = 0; i < env->subprog_cnt; i++) - env->prog->aux->func_info[i].insn_off = env->subprog_info[i].start; + aux->func_info[i].insn_off = env->subprog_info[i].start; } #define MIN_BPF_LINEINFO_SIZE (offsetof(struct bpf_line_info, line_col) + \ @@ -7440,6 +7690,7 @@ static bool reg_type_mismatch_ok(enum bpf_reg_type type) case PTR_TO_TCP_SOCK: case PTR_TO_TCP_SOCK_OR_NULL: case PTR_TO_XDP_SOCK: + case PTR_TO_BTF_ID: return false; default: return true; @@ -7492,6 +7743,9 @@ static int do_check(struct bpf_verifier_env *env) 0 /* frameno */, 0 /* subprogno, zero == main subprog */); + if (btf_check_func_arg_match(env, 0)) + return -EINVAL; + for (;;) { struct bpf_insn *insn; u8 class; @@ -8008,11 +8262,7 @@ static int replace_map_fd_with_map_ptr(struct bpf_verifier_env *env) * will be used by the valid program until it's unloaded * and all maps are released in free_used_maps() */ - map = bpf_map_inc(map, false); - if (IS_ERR(map)) { - fdput(f); - return PTR_ERR(map); - } + bpf_map_inc(map); aux->map_index = env->used_map_cnt; env->used_maps[env->used_map_cnt++] = map; @@ -8581,6 +8831,14 @@ static int convert_ctx_accesses(struct bpf_verifier_env *env) case PTR_TO_XDP_SOCK: convert_ctx_access = bpf_xdp_sock_convert_ctx_access; break; + case PTR_TO_BTF_ID: + if (type == BPF_WRITE) { + verbose(env, "Writes through BTF pointers are not allowed\n"); + return -EINVAL; + } + insn->code = BPF_LDX | BPF_PROBE_MEM | BPF_SIZE((insn)->code); + env->prog->aux->num_exentries++; + continue; default: continue; } @@ -8871,6 +9129,7 @@ static int fixup_call_args(struct bpf_verifier_env *env) static int fixup_bpf_calls(struct bpf_verifier_env *env) { struct bpf_prog *prog = env->prog; + bool expect_blinding = bpf_jit_blinding_enabled(prog); struct bpf_insn *insn = prog->insnsi; const struct bpf_func_proto *fn; const int insn_cnt = prog->len; @@ -8879,7 +9138,7 @@ static int fixup_bpf_calls(struct bpf_verifier_env *env) struct bpf_insn insn_buf[16]; struct bpf_prog *new_prog; struct bpf_map *map_ptr; - int i, cnt, delta = 0; + int i, ret, cnt, delta = 0; for (i = 0; i < insn_cnt; i++, insn++) { if (insn->code == (BPF_ALU64 | BPF_MOD | BPF_X) || @@ -9023,6 +9282,26 @@ static int fixup_bpf_calls(struct bpf_verifier_env *env) insn->code = BPF_JMP | BPF_TAIL_CALL; aux = &env->insn_aux_data[i + delta]; + if (prog->jit_requested && !expect_blinding && + !bpf_map_key_poisoned(aux) && + !bpf_map_ptr_poisoned(aux) && + !bpf_map_ptr_unpriv(aux)) { + struct bpf_jit_poke_descriptor desc = { + .reason = BPF_POKE_REASON_TAIL_CALL, + .tail_call.map = BPF_MAP_PTR(aux->map_ptr_state), + .tail_call.key = bpf_map_key_immediate(aux), + }; + + ret = bpf_jit_add_poke_descriptor(prog, &desc); + if (ret < 0) { + verbose(env, "adding tail call poke descriptor failed\n"); + return ret; + } + + insn->imm = ret + 1; + continue; + } + if (!bpf_map_ptr_unpriv(aux)) continue; @@ -9037,7 +9316,7 @@ static int fixup_bpf_calls(struct bpf_verifier_env *env) return -EINVAL; } - map_ptr = BPF_MAP_PTR(aux->map_state); + map_ptr = BPF_MAP_PTR(aux->map_ptr_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, @@ -9071,7 +9350,7 @@ static int fixup_bpf_calls(struct bpf_verifier_env *env) if (bpf_map_ptr_poisoned(aux)) goto patch_call_imm; - map_ptr = BPF_MAP_PTR(aux->map_state); + map_ptr = BPF_MAP_PTR(aux->map_ptr_state); ops = map_ptr->ops; if (insn->imm == BPF_FUNC_map_lookup_elem && ops->map_gen_lookup) { @@ -9151,6 +9430,23 @@ patch_call_imm: insn->imm = fn->func - __bpf_call_base; } + /* Since poke tab is now finalized, publish aux to tracker. */ + for (i = 0; i < prog->aux->size_poke_tab; i++) { + map_ptr = prog->aux->poke_tab[i].tail_call.map; + 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; + } + + ret = map_ptr->ops->map_poke_track(map_ptr, prog->aux); + if (ret < 0) { + verbose(env, "tracking tail call prog failed\n"); + return ret; + } + } + return 0; } @@ -9208,6 +9504,161 @@ static void print_verification_stats(struct bpf_verifier_env *env) env->peak_states, env->longest_mark_read_walk); } +static int check_attach_btf_id(struct bpf_verifier_env *env) +{ + struct bpf_prog *prog = env->prog; + struct bpf_prog *tgt_prog = prog->aux->linked_prog; + u32 btf_id = prog->aux->attach_btf_id; + const char prefix[] = "btf_trace_"; + int ret = 0, subprog = -1, i; + struct bpf_trampoline *tr; + const struct btf_type *t; + bool conservative = true; + const char *tname; + struct btf *btf; + long addr; + u64 key; + + if (prog->type != BPF_PROG_TYPE_TRACING) + return 0; + + if (!btf_id) { + verbose(env, "Tracing programs must provide btf_id\n"); + return -EINVAL; + } + btf = bpf_prog_get_target_btf(prog); + if (!btf) { + verbose(env, + "FENTRY/FEXIT program can only be attached to another program annotated with BTF\n"); + return -EINVAL; + } + t = btf_type_by_id(btf, btf_id); + if (!t) { + verbose(env, "attach_btf_id %u is invalid\n", btf_id); + return -EINVAL; + } + tname = btf_name_by_offset(btf, t->name_off); + if (!tname) { + verbose(env, "attach_btf_id %u doesn't have a name\n", btf_id); + return -EINVAL; + } + if (tgt_prog) { + struct bpf_prog_aux *aux = tgt_prog->aux; + + for (i = 0; i < aux->func_info_cnt; i++) + if (aux->func_info[i].type_id == btf_id) { + subprog = i; + break; + } + if (subprog == -1) { + verbose(env, "Subprog %s doesn't exist\n", tname); + return -EINVAL; + } + conservative = aux->func_info_aux[subprog].unreliable; + key = ((u64)aux->id) << 32 | btf_id; + } else { + key = btf_id; + } + + switch (prog->expected_attach_type) { + case BPF_TRACE_RAW_TP: + if (tgt_prog) { + verbose(env, + "Only FENTRY/FEXIT progs are attachable to another BPF prog\n"); + return -EINVAL; + } + if (!btf_type_is_typedef(t)) { + verbose(env, "attach_btf_id %u is not a typedef\n", + btf_id); + return -EINVAL; + } + if (strncmp(prefix, tname, sizeof(prefix) - 1)) { + verbose(env, "attach_btf_id %u points to wrong type name %s\n", + btf_id, tname); + return -EINVAL; + } + tname += sizeof(prefix) - 1; + t = btf_type_by_id(btf, t->type); + if (!btf_type_is_ptr(t)) + /* should never happen in valid vmlinux build */ + return -EINVAL; + t = btf_type_by_id(btf, t->type); + if (!btf_type_is_func_proto(t)) + /* should never happen in valid vmlinux build */ + return -EINVAL; + + /* remember two read only pointers that are valid for + * the life time of the kernel + */ + prog->aux->attach_func_name = tname; + prog->aux->attach_func_proto = t; + prog->aux->attach_btf_trace = true; + return 0; + case BPF_TRACE_FENTRY: + case BPF_TRACE_FEXIT: + if (!btf_type_is_func(t)) { + verbose(env, "attach_btf_id %u is not a function\n", + btf_id); + return -EINVAL; + } + t = btf_type_by_id(btf, t->type); + if (!btf_type_is_func_proto(t)) + return -EINVAL; + tr = bpf_trampoline_lookup(key); + if (!tr) + return -ENOMEM; + prog->aux->attach_func_name = tname; + /* t is either vmlinux type or another program's type */ + prog->aux->attach_func_proto = t; + mutex_lock(&tr->mutex); + if (tr->func.addr) { + prog->aux->trampoline = tr; + goto out; + } + if (tgt_prog && conservative) { + prog->aux->attach_func_proto = NULL; + t = NULL; + } + ret = btf_distill_func_proto(&env->log, btf, t, + tname, &tr->func.model); + if (ret < 0) + goto out; + if (tgt_prog) { + if (!tgt_prog->jited) { + /* for now */ + verbose(env, "Can trace only JITed BPF progs\n"); + ret = -EINVAL; + goto out; + } + if (tgt_prog->type == BPF_PROG_TYPE_TRACING) { + /* prevent cycles */ + verbose(env, "Cannot recursively attach\n"); + ret = -EINVAL; + goto out; + } + addr = (long) tgt_prog->aux->func[subprog]->bpf_func; + } else { + addr = kallsyms_lookup_name(tname); + if (!addr) { + verbose(env, + "The address of function %s cannot be found\n", + tname); + ret = -ENOENT; + goto out; + } + } + tr->func.addr = (void *)addr; + prog->aux->trampoline = tr; +out: + mutex_unlock(&tr->mutex); + if (ret) + bpf_trampoline_put(tr); + return ret; + default: + return -EINVAL; + } +} + int bpf_check(struct bpf_prog **prog, union bpf_attr *attr, union bpf_attr __user *uattr) { @@ -9241,6 +9692,13 @@ int bpf_check(struct bpf_prog **prog, union bpf_attr *attr, env->ops = bpf_verifier_ops[env->prog->type]; is_priv = capable(CAP_SYS_ADMIN); + if (!btf_vmlinux && IS_ENABLED(CONFIG_DEBUG_INFO_BTF)) { + mutex_lock(&bpf_verifier_lock); + if (!btf_vmlinux) + btf_vmlinux = btf_parse_vmlinux(); + mutex_unlock(&bpf_verifier_lock); + } + /* grab the mutex to protect few globals used by verifier */ if (!is_priv) mutex_lock(&bpf_verifier_lock); @@ -9260,6 +9718,17 @@ int bpf_check(struct bpf_prog **prog, union bpf_attr *attr, goto err_unlock; } + if (IS_ERR(btf_vmlinux)) { + /* Either gcc or pahole or kernel are broken. */ + verbose(env, "in-kernel BTF is malformed\n"); + ret = PTR_ERR(btf_vmlinux); + goto skip_full_check; + } + + ret = check_attach_btf_id(env); + if (ret) + goto skip_full_check; + env->strict_alignment = !!(attr->prog_flags & BPF_F_STRICT_ALIGNMENT); if (!IS_ENABLED(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS)) env->strict_alignment = true; |