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Subject[PATCH RESEND 3/5] selftests/seccomp: Add test for wait killable notifier
Date
This adds a test for the positive case of the wait killable notifier,
in testing that when the feature is activated the process acts as
expected -- in not terminating on a non-fatal signal, and instead
queueing it up. There is already a test case for normal handlers
and preemption.

Signed-off-by: Sargun Dhillon <sargun@sargun.me>
---
tools/testing/selftests/seccomp/seccomp_bpf.c | 64 +++++++++++++++++++
1 file changed, 64 insertions(+)

diff --git a/tools/testing/selftests/seccomp/seccomp_bpf.c b/tools/testing/selftests/seccomp/seccomp_bpf.c
index 98c3b647f54d..34140ce2ab21 100644
--- a/tools/testing/selftests/seccomp/seccomp_bpf.c
+++ b/tools/testing/selftests/seccomp/seccomp_bpf.c
@@ -235,6 +235,10 @@ struct seccomp_notif_addfd {
};
#endif

+#ifndef SECCOMP_USER_NOTIF_FLAG_WAIT_KILLABLE
+#define SECCOMP_USER_NOTIF_FLAG_WAIT_KILLABLE (1UL << 0) /* Prevent task from being interrupted */
+#endif
+
struct seccomp_notif_addfd_small {
__u64 id;
char weird[4];
@@ -4135,6 +4139,66 @@ TEST(user_notification_addfd_rlimit)
close(memfd);
}

+TEST(user_notification_signal_wait_killable)
+{
+ pid_t pid;
+ long ret;
+ int status, listener, sk_pair[2];
+ struct seccomp_notif req = {
+ .flags = SECCOMP_USER_NOTIF_FLAG_WAIT_KILLABLE,
+ };
+ struct seccomp_notif_resp resp = {};
+ char c;
+
+ ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0);
+ ASSERT_EQ(0, ret) {
+ TH_LOG("Kernel does not support PR_SET_NO_NEW_PRIVS!");
+ }
+
+ ASSERT_EQ(socketpair(PF_LOCAL, SOCK_SEQPACKET, 0, sk_pair), 0);
+ ASSERT_EQ(fcntl(sk_pair[0], F_SETFL, O_NONBLOCK), 0);
+
+ listener = user_notif_syscall(__NR_gettid,
+ SECCOMP_FILTER_FLAG_NEW_LISTENER);
+ ASSERT_GE(listener, 0);
+
+ pid = fork();
+ ASSERT_GE(pid, 0);
+
+ if (pid == 0) {
+ close(sk_pair[0]);
+ handled = sk_pair[1];
+ if (signal(SIGUSR1, signal_handler) == SIG_ERR) {
+ perror("signal");
+ exit(1);
+ }
+
+ ret = syscall(__NR_gettid);
+ exit(!(ret == 42));
+ }
+ close(sk_pair[1]);
+
+ EXPECT_EQ(ioctl(listener, SECCOMP_IOCTL_NOTIF_RECV, &req), 0);
+ EXPECT_EQ(kill(pid, SIGUSR1), 0);
+ /* Make sure we didn't get a signal */
+ EXPECT_EQ(read(sk_pair[0], &c, 1), -1);
+ /* Make sure the notification is still alive */
+ EXPECT_EQ(ioctl(listener, SECCOMP_IOCTL_NOTIF_ID_VALID, &req.id), 0);
+
+ resp.id = req.id;
+ resp.error = 0;
+ resp.val = 42;
+
+ EXPECT_EQ(ioctl(listener, SECCOMP_IOCTL_NOTIF_SEND, &resp), 0);
+
+ EXPECT_EQ(waitpid(pid, &status, 0), pid);
+ EXPECT_EQ(true, WIFEXITED(status));
+ EXPECT_EQ(0, WEXITSTATUS(status));
+ /* Check we eventually received the signal */
+ EXPECT_EQ(read(sk_pair[0], &c, 1), 1);
+}
+
+
/*
* TODO:
* - expand NNP testing
--
2.25.1
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