[PATCH 2/3] selftests/seccomp: Change the syscall used in KILL_THREAD test

From: Terry Tritton
Date: Wed Jan 24 2024 - 09:15:43 EST


The Bionic version of pthread_create used on Android calls the prctl
function to give the stack and thread local storage a useful name. This
will cause the KILL_THREAD test to fail as it will kill the thread as
soon as it is created.

change the test to use getpid instead of prctl.

Signed-off-by: Terry Tritton <terry.tritton@xxxxxxxxxx>
---
tools/testing/selftests/seccomp/seccomp_bpf.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/tools/testing/selftests/seccomp/seccomp_bpf.c b/tools/testing/selftests/seccomp/seccomp_bpf.c
index 5e705674b706..da11b95b8872 100644
--- a/tools/testing/selftests/seccomp/seccomp_bpf.c
+++ b/tools/testing/selftests/seccomp/seccomp_bpf.c
@@ -784,7 +784,7 @@ void *kill_thread(void *data)
bool die = (bool)data;

if (die) {
- prctl(PR_GET_SECCOMP, 0, 0, 0, 0);
+ syscall(__NR_getpid);
return (void *)SIBLING_EXIT_FAILURE;
}

@@ -803,11 +803,11 @@ void kill_thread_or_group(struct __test_metadata *_metadata,
{
pthread_t thread;
void *status;
- /* Kill only when calling __NR_prctl. */
+ /* Kill only when calling __NR_getpid. */
struct sock_filter filter_thread[] = {
BPF_STMT(BPF_LD|BPF_W|BPF_ABS,
offsetof(struct seccomp_data, nr)),
- BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, __NR_prctl, 0, 1),
+ BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, __NR_getpid, 0, 1),
BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_KILL_THREAD),
BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW),
};
@@ -819,7 +819,7 @@ void kill_thread_or_group(struct __test_metadata *_metadata,
struct sock_filter filter_process[] = {
BPF_STMT(BPF_LD|BPF_W|BPF_ABS,
offsetof(struct seccomp_data, nr)),
- BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, __NR_prctl, 0, 1),
+ BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, __NR_getpid, 0, 1),
BPF_STMT(BPF_RET|BPF_K, kill),
BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW),
};
--
2.43.0.429.g432eaa2c6b-goog