bpf: Replace open code with for allocated object check

>From commit 282de14 ("bpf: Introduce allocated objects support"), With this allocated object with BPF program, (PTR_TO_BTF_ID | MEM_ALLOC) has been a way of indicating to check the type is the allocated object. commit d8939cb ("bpf: Loosen alloc obj test in verifier's reg_btf_record") >From the commit, there has been helper function for checking this, named type_is_ptr_alloc_obj(). But still, some of the code use open code to retrieve this info. This commit replaces the open code with the type_is_alloc(), and the type_is_ptr_alloc_obj() function. Signed-off-by: Daniel T. Lee <[email protected]> Signed-off-by: Andrii Nakryiko <[email protected]> Link: https://lore.kernel.org/bpf/[email protected]
niw · Jun 5, 2023 · 503e4de · 503e4de
1 parent 4114866
commit 503e4de
Showing 1 changed file with 2 additions and 2 deletions.
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
@@ -5894,7 +5894,7 @@ static int check_ptr_to_btf_access(struct bpf_verifier_env *env,
 		 * program allocated objects (which always have ref_obj_id > 0),
 		 * but not for untrusted PTR_TO_BTF_ID | MEM_ALLOC.
 		 */
-		if (atype != BPF_READ && reg->type != (PTR_TO_BTF_ID | MEM_ALLOC)) {
+		if (atype != BPF_READ && !type_is_ptr_alloc_obj(reg->type)) {
 			verbose(env, "only read is supported\n");
 			return -EACCES;
 		}
@@ -7514,7 +7514,7 @@ static int check_reg_type(struct bpf_verifier_env *env, u32 regno,
 	if (base_type(arg_type) == ARG_PTR_TO_MEM)
 		type &= ~DYNPTR_TYPE_FLAG_MASK;
 
-	if (meta->func_id == BPF_FUNC_kptr_xchg && type & MEM_ALLOC)
+	if (meta->func_id == BPF_FUNC_kptr_xchg && type_is_alloc(type))
 		type &= ~MEM_ALLOC;
 
 	for (i = 0; i < ARRAY_SIZE(compatible->types); i++) {