Commit 51a52a29 authored by David Vernet's avatar David Vernet Committed by Alexei Starovoitov
Browse files

bpf: Pass const struct bpf_prog * to .check_member 



The .check_member field of struct bpf_struct_ops is currently passed the
member's btf_type via const struct btf_type *t, and a const struct
btf_member *member. This allows the struct_ops implementation to check
whether e.g. an ops is supported, but it would be useful to also enforce
that the struct_ops prog being loaded for that member has other
qualities, like being sleepable (or not). This patch therefore updates
the .check_member() callback to also take a const struct bpf_prog *prog
argument.

Signed-off-by: default avatarDavid Vernet <void@manifault.com>
Link: https://lore.kernel.org/r/20230125164735.785732-4-void@manifault.com


Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent 913b2255

include/linux/bpf.h

+2 −1
Original line number Diff line number Diff line
@@ -1422,7 +1422,8 @@ struct bpf_struct_ops { 
	const struct bpf_verifier_ops *verifier_ops;

	int (*init)(struct btf *btf);

	int (*check_member)(const struct btf_type *t,

			    const struct btf_member *member);

			    const struct btf_member *member,

			    const struct bpf_prog *prog);

	int (*init_member)(const struct btf_type *t,

			   const struct btf_member *member,

			   void *kdata, const void *udata);

kernel/bpf/verifier.c

+1 −1
Original line number Diff line number Diff line
@@ -16792,7 +16792,7 @@ static int check_struct_ops_btf_id(struct bpf_verifier_env *env) 
	}



	if (st_ops->check_member) {

		int err = st_ops->check_member(t, member);

		int err = st_ops->check_member(t, member, prog);



		if (err) {

			verbose(env, "attach to unsupported member %s of struct %s\n",

net/ipv4/bpf_tcp_ca.c

+2 −1
Original line number Diff line number Diff line
@@ -248,7 +248,8 @@ static int bpf_tcp_ca_init_member(const struct btf_type *t, 
}



static int bpf_tcp_ca_check_member(const struct btf_type *t,

				   const struct btf_member *member)

				   const struct btf_member *member,

				   const struct bpf_prog *prog)

{

	if (is_unsupported(__btf_member_bit_offset(t, member) / 8))

		return -ENOTSUPP;