Commit cd7c97f4 authored by Alexei Starovoitov's avatar Alexei Starovoitov
Browse files

Merge branch... 

Merge branch 'bpf-show-precise-rejected-function-when-attaching-to-__noreturn-and-deny-list-functions'

KaFai Wan says:

====================
bpf: Show precise rejected function when attaching to __noreturn and deny list functions

Show precise rejected function when attaching fexit/fmod_ret to __noreturn
functions.
Add log for attaching tracing programs to functions in deny list.
Add selftest for attaching tracing programs to functions in deny list.
Migrate fexit_noreturns case into tracing_failure test suite.

changes:
v4:
- change tracing_deny case attaching function (Yonghong Song)
- add Acked-by: Yafang Shao and Yonghong Song

v3:
- add tracing_deny case into existing files (Alexei)
- migrate fexit_noreturns into tracing_failure
- change SOB
  https://lore.kernel.org/bpf/20250722153434.20571-1-kafai.wan@linux.dev/

v2:
- change verifier log message (Alexei)
- add missing Suggested-by
  https://lore.kernel.org/bpf/20250714120408.1627128-1-mannkafai@gmail.com/

v1:
 https://lore.kernel.org/all/20250710162717.3808020-1-mannkafai@gmail.com/
---
====================

Link: https://patch.msgid.link/20250724151454.499040-1-kafai.wan@linux.dev


Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parents 5b4c54ac 51d3750a

kernel/bpf/verifier.c

+4 −1
Original line number Diff line number Diff line
@@ -23981,11 +23981,14 @@ static int check_attach_btf_id(struct bpf_verifier_env *env) 
			return ret;

	} else if (prog->type == BPF_PROG_TYPE_TRACING &&

		   btf_id_set_contains(&btf_id_deny, btf_id)) {

		verbose(env, "Attaching tracing programs to function '%s' is rejected.\n",

			tgt_info.tgt_name);

		return -EINVAL;

	} else if ((prog->expected_attach_type == BPF_TRACE_FEXIT ||

		   prog->expected_attach_type == BPF_MODIFY_RETURN) &&

		   btf_id_set_contains(&noreturn_deny, btf_id)) {

		verbose(env, "Attaching fexit/fmod_ret to __noreturn functions is rejected.\n");

		verbose(env, "Attaching fexit/fmod_ret to __noreturn function '%s' is rejected.\n",

			tgt_info.tgt_name);

		return -EINVAL;

	}

























tools/testing/selftests/bpf/prog_tests/fexit_noreturns.c
deleted100644 → 0



+0
−9






























Original line number
Diff line number
Diff line









// SPDX-License-Identifier: GPL-2.0



















#include <test_progs.h>









#include "fexit_noreturns.skel.h"



















void test_fexit_noreturns(void)









{









	RUN_TESTS(fexit_noreturns);









}
























tools/testing/selftests/bpf/prog_tests/tracing_failure.c



+52
−0






























Original line number
Diff line number
Diff line







@@ -28,10 +28,62 @@ static void test_bpf_spin_lock(bool is_spin_lock)







	tracing_failure__destroy(skel);









}



















static void test_tracing_fail_prog(const char *prog_name, const char *exp_msg)









{









	struct tracing_failure *skel;









	struct bpf_program *prog;









	char log_buf[256];









	int err;



















	skel = tracing_failure__open();









	if (!ASSERT_OK_PTR(skel, "tracing_failure__open"))









		return;



















	prog = bpf_object__find_program_by_name(skel->obj, prog_name);









	if (!ASSERT_OK_PTR(prog, "bpf_object__find_program_by_name"))









		goto out;



















	bpf_program__set_autoload(prog, true);









	bpf_program__set_log_buf(prog, log_buf, sizeof(log_buf));



















	err = tracing_failure__load(skel);









	if (!ASSERT_ERR(err, "tracing_failure__load"))









		goto out;



















	ASSERT_HAS_SUBSTR(log_buf, exp_msg, "log_buf");









out:









	tracing_failure__destroy(skel);









}



















static void test_tracing_deny(void)









{









	int btf_id;



















	/* __rcu_read_lock depends on CONFIG_PREEMPT_RCU */









	btf_id = libbpf_find_vmlinux_btf_id("__rcu_read_lock", BPF_TRACE_FENTRY);









	if (btf_id <= 0) {









		test__skip();









		return;









	}



















	test_tracing_fail_prog("tracing_deny",









			       "Attaching tracing programs to function '__rcu_read_lock' is rejected.");









}



















static void test_fexit_noreturns(void)









{









	test_tracing_fail_prog("fexit_noreturns",









			       "Attaching fexit/fmod_ret to __noreturn function 'do_exit' is rejected.");









}



















void test_tracing_failure(void)









{









	if (test__start_subtest("bpf_spin_lock"))









		test_bpf_spin_lock(true);









	if (test__start_subtest("bpf_spin_unlock"))









		test_bpf_spin_lock(false);









	if (test__start_subtest("tracing_deny"))









		test_tracing_deny();









	if (test__start_subtest("fexit_noreturns"))









		test_fexit_noreturns();









}
























tools/testing/selftests/bpf/progs/fexit_noreturns.c
deleted100644 → 0



+0
−15






























Original line number
Diff line number
Diff line









// SPDX-License-Identifier: GPL-2.0



















#include <linux/bpf.h>









#include <bpf/bpf_helpers.h>









#include <bpf/bpf_tracing.h>









#include "bpf_misc.h"



















char _license[] SEC("license") = "GPL";



















SEC("fexit/do_exit")









__failure __msg("Attaching fexit/fmod_ret to __noreturn functions is rejected.")









int BPF_PROG(noreturns)









{









	return 0;









}
























tools/testing/selftests/bpf/progs/tracing_failure.c



+12
−0






























Original line number
Diff line number
Diff line







@@ -18,3 +18,15 @@ int BPF_PROG(test_spin_unlock, struct bpf_spin_lock *lock)







{









	return 0;









}



















SEC("?fentry/__rcu_read_lock")









int BPF_PROG(tracing_deny)









{









	return 0;









}



















SEC("?fexit/do_exit")









int BPF_PROG(fexit_noreturns)









{









	return 0;









}