diff options
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/bpf/btf.c | 68 | ||||
| -rw-r--r-- | kernel/bpf/verifier.c | 44 | ||||
| -rw-r--r-- | kernel/trace/bpf_trace.c | 4 |
3 files changed, 101 insertions, 15 deletions
diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c index 271d27cd427f..f7557af39756 100644 --- a/kernel/bpf/btf.c +++ b/kernel/bpf/btf.c @@ -3626,6 +3626,74 @@ again: return -EINVAL; } +u32 btf_resolve_helper_id(struct bpf_verifier_log *log, void *fn, int arg) +{ + char fnname[KSYM_SYMBOL_LEN + 4] = "btf_"; + const struct btf_param *args; + const struct btf_type *t; + const char *tname, *sym; + u32 btf_id, i; + + if (IS_ERR(btf_vmlinux)) { + bpf_log(log, "btf_vmlinux is malformed\n"); + return -EINVAL; + } + + sym = kallsyms_lookup((long)fn, NULL, NULL, NULL, fnname + 4); + if (!sym) { + bpf_log(log, "kernel doesn't have kallsyms\n"); + return -EFAULT; + } + + for (i = 1; i <= btf_vmlinux->nr_types; i++) { + t = btf_type_by_id(btf_vmlinux, i); + if (BTF_INFO_KIND(t->info) != BTF_KIND_TYPEDEF) + continue; + tname = __btf_name_by_offset(btf_vmlinux, t->name_off); + if (!strcmp(tname, fnname)) + break; + } + if (i > btf_vmlinux->nr_types) { + bpf_log(log, "helper %s type is not found\n", fnname); + return -ENOENT; + } + + t = btf_type_by_id(btf_vmlinux, t->type); + if (!btf_type_is_ptr(t)) + return -EFAULT; + t = btf_type_by_id(btf_vmlinux, t->type); + if (!btf_type_is_func_proto(t)) + return -EFAULT; + + args = (const struct btf_param *)(t + 1); + if (arg >= btf_type_vlen(t)) { + bpf_log(log, "bpf helper %s doesn't have %d-th argument\n", + fnname, arg); + return -EINVAL; + } + + t = btf_type_by_id(btf_vmlinux, args[arg].type); + if (!btf_type_is_ptr(t) || !t->type) { + /* anything but the pointer to struct is a helper config bug */ + bpf_log(log, "ARG_PTR_TO_BTF is misconfigured\n"); + return -EFAULT; + } + btf_id = t->type; + t = btf_type_by_id(btf_vmlinux, t->type); + /* skip modifiers */ + while (btf_type_is_modifier(t)) { + btf_id = t->type; + t = btf_type_by_id(btf_vmlinux, t->type); + } + if (!btf_type_is_struct(t)) { + bpf_log(log, "ARG_PTR_TO_BTF is not a struct\n"); + return -EFAULT; + } + bpf_log(log, "helper %s arg%d has btf_id %d struct %s\n", fnname + 4, + arg, btf_id, __btf_name_by_offset(btf_vmlinux, t->name_off)); + return btf_id; +} + void btf_type_seq_show(const struct btf *btf, u32 type_id, void *obj, struct seq_file *m) { diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index fba9ef6a831b..556e82f8869b 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -205,6 +205,7 @@ struct bpf_call_arg_meta { u64 msize_umax_value; int ref_obj_id; int func_id; + u32 btf_id; }; struct btf *btf_vmlinux; @@ -3439,6 +3440,22 @@ 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)) @@ -3586,6 +3603,7 @@ 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; @@ -3673,6 +3691,7 @@ 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; @@ -4127,21 +4146,16 @@ 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); - if (err) - return err; + for (i = 0; i < 5; i++) { + if (fn->arg_type[i] == ARG_PTR_TO_BTF_ID) { + if (!fn->btf_id[i]) + fn->btf_id[i] = btf_resolve_helper_id(&env->log, fn->func, i); + meta.btf_id = fn->btf_id[i]; + } + 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) diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c index 6221e8c6ecc3..52f7e9d8c29b 100644 --- a/kernel/trace/bpf_trace.c +++ b/kernel/trace/bpf_trace.c @@ -995,6 +995,8 @@ static const struct bpf_func_proto bpf_perf_event_output_proto_raw_tp = { .arg5_type = ARG_CONST_SIZE_OR_ZERO, }; +extern const struct bpf_func_proto bpf_skb_output_proto; + BPF_CALL_3(bpf_get_stackid_raw_tp, struct bpf_raw_tracepoint_args *, args, struct bpf_map *, map, u64, flags) { @@ -1053,6 +1055,8 @@ raw_tp_prog_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) switch (func_id) { case BPF_FUNC_perf_event_output: return &bpf_perf_event_output_proto_raw_tp; + case BPF_FUNC_skb_output: + return &bpf_skb_output_proto; case BPF_FUNC_get_stackid: return &bpf_get_stackid_proto_raw_tp; case BPF_FUNC_get_stack: |