diff options
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/bpf/btf.c | 31 | ||||
| -rw-r--r-- | kernel/bpf/verifier.c | 17 |
2 files changed, 42 insertions, 6 deletions
diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c index d8d64201c4e0..df966acaaeb1 100644 --- a/kernel/bpf/btf.c +++ b/kernel/bpf/btf.c @@ -4160,6 +4160,37 @@ int btf_struct_access(struct bpf_verifier_log *log, return -EINVAL; } +bool btf_struct_ids_match(struct bpf_verifier_log *log, + int off, u32 id, u32 need_type_id) +{ + const struct btf_type *type; + int err; + + /* Are we already done? */ + if (need_type_id == id && off == 0) + return true; + +again: + type = btf_type_by_id(btf_vmlinux, id); + if (!type) + return false; + err = btf_struct_walk(log, type, off, 1, &id); + if (err != WALK_STRUCT) + return false; + + /* We found nested struct object. If it matches + * the requested ID, we're done. Otherwise let's + * continue the search with offset 0 in the new + * type. + */ + if (need_type_id != id) { + off = 0; + goto again; + } + + return true; +} + int btf_resolve_helper_id(struct bpf_verifier_log *log, const struct bpf_func_proto *fn, int arg) { diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 38748794518e..f003cee75d22 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -3995,16 +3995,21 @@ static int check_func_arg(struct bpf_verifier_env *env, u32 arg, goto err_type; } } else if (arg_type == ARG_PTR_TO_BTF_ID) { + bool ids_match = false; + expected_type = PTR_TO_BTF_ID; if (type != expected_type) goto err_type; if (!fn->check_btf_id) { 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; + ids_match = btf_struct_ids_match(&env->log, reg->off, reg->btf_id, + meta->btf_id); + if (!ids_match) { + 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; + } } } else if (!fn->check_btf_id(reg->btf_id, arg)) { verbose(env, "Helper does not support %s in R%d\n", @@ -4012,7 +4017,7 @@ static int check_func_arg(struct bpf_verifier_env *env, u32 arg, return -EACCES; } - if (!tnum_is_const(reg->var_off) || reg->var_off.value || reg->off) { + if ((reg->off && !ids_match) || !tnum_is_const(reg->var_off) || reg->var_off.value) { verbose(env, "R%d is a pointer to in-kernel struct with non-zero offset\n", regno); return -EACCES; |