Commit 503e4def authored May 27, 2023 by Daniel T. Lee Committed by Andrii Nakryiko Jun 05, 2023

bpf: Replace open code with for allocated object check



>From commit 282de143 ("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 d8939cb0 ("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 <danieltimlee@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20230527122706.59315-1-danieltimlee@gmail.com

parent 41148662

kernel/bpf/verifier.c

+2 −2

Original line number	Diff line number	Diff line
		@@ -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++) {