[PATCH bpf-next v2 5/9] bpf: verifier: add btf to the function args of bpf_check_attach_target

Menglong Dong
2024-03-11T09:35:07Z

Add target btf to the function args of bpf_check_attach_target(), then
the caller can specify the btf to check.

Signed-off-by: Menglong Dong <dongmenglong.8@bytedance.com>
---
include/linux/bpf_verifier.h | 1 +
kernel/bpf/syscall.c | 6 ++++--
kernel/bpf/trampoline.c | 1 +
kernel/bpf/verifier.c | 8 +++++---
4 files changed, 11 insertions(+), 5 deletions(-)

diff --git a/include/linux/bpf_verifier.h b/include/linux/bpf_verifier.h
index 4b0f6600e499..6cb20efcfac3 100644
--- a/include/linux/bpf_verifier.h
+++ b/include/linux/bpf_verifier.h
@@ -811,6 +811,7 @@ static inline void bpf_trampoline_unpack_key(u64 key, u32 *obj_id, u32 *btf_id)
int bpf_check_attach_target(struct bpf_verifier_log *log,
const struct bpf_prog *prog,
const struct bpf_prog *tgt_prog,
+ struct btf *btf,
u32 btf_id,
struct bpf_attach_target_info *tgt_info);
void bpf_free_kfunc_btf_tab(struct bpf_kfunc_btf_tab *tab);
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index d1cd645ef9ac..6128c3131141 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -3401,9 +3401,11 @@ static int bpf_tracing_prog_attach(struct bpf_prog *prog,
* need a new trampoline and a check for compatibility
*/
struct bpf_attach_target_info tgt_info = {};
+ struct btf *btf;

- err = bpf_check_attach_target(NULL, prog, tgt_prog, btf_id,
- &tgt_info);
+ btf = tgt_prog ? tgt_prog->aux->btf : prog->aux->attach_btf;
+ err = bpf_check_attach_target(NULL, prog, tgt_prog, btf,
+ btf_id, &tgt_info);
if (err)
goto out_unlock;

diff --git a/kernel/bpf/trampoline.c b/kernel/bpf/trampoline.c
index 2167aa3fe583..b00d53af8fcb 100644
--- a/kernel/bpf/trampoline.c
+++ b/kernel/bpf/trampoline.c
@@ -747,6 +747,7 @@ int bpf_trampoline_link_cgroup_shim(struct bpf_prog *prog,
int err;

err = bpf_check_attach_target(NULL, prog, NULL,
+ prog->aux->attach_btf,
prog->aux->attach_btf_id,
&tgt_info);
if (err)
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index bf084c693507..4493ecc23597 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -20613,6 +20613,7 @@ static int check_non_sleepable_error_inject(u32 btf_id)
int bpf_check_attach_target(struct bpf_verifier_log *log,
const struct bpf_prog *prog,
const struct bpf_prog *tgt_prog,
+ struct btf *btf,
u32 btf_id,
struct bpf_attach_target_info *tgt_info)
{
@@ -20623,7 +20624,6 @@ int bpf_check_attach_target(struct bpf_verifier_log *log,
const struct btf_type *t;
bool conservative = true;
const char *tname;
- struct btf *btf;
long addr = 0;
struct module *mod = NULL;

@@ -20631,7 +20631,6 @@ int bpf_check_attach_target(struct bpf_verifier_log *log,
bpf_log(log, "Tracing programs must provide btf_id\n");
return -EINVAL;
}
- btf = tgt_prog ? tgt_prog->aux->btf : prog->aux->attach_btf;
if (!btf) {
bpf_log(log,
"FENTRY/FEXIT program can only be attached to another program annotated with BTF\n");
@@ -20940,6 +20939,7 @@ static int check_attach_btf_id(struct bpf_verifier_env *env)
struct bpf_attach_target_info tgt_info = {};
u32 btf_id = prog->aux->attach_btf_id;
struct bpf_trampoline *tr;
+ struct btf *btf;
int ret;
u64 key;

@@ -20964,7 +20964,9 @@ static int check_attach_btf_id(struct bpf_verifier_env *env)
prog->type != BPF_PROG_TYPE_EXT)
return 0;

- ret = bpf_check_attach_target(&env->log, prog, tgt_prog, btf_id, &tgt_info);
+ btf = tgt_prog ? tgt_prog->aux->btf : prog->aux->attach_btf;
+ ret = bpf_check_attach_target(&env->log, prog, tgt_prog, btf,
+ btf_id, &tgt_info);
if (ret)
return ret;

--
2.39.2