diff options
| -rw-r--r-- | tools/testing/selftests/seccomp/seccomp_bpf.c | 131 |
1 files changed, 131 insertions, 0 deletions
diff --git a/tools/testing/selftests/seccomp/seccomp_bpf.c b/tools/testing/selftests/seccomp/seccomp_bpf.c index 61acbd45ffaa..fc4910d35342 100644 --- a/tools/testing/selftests/seccomp/seccomp_bpf.c +++ b/tools/testing/selftests/seccomp/seccomp_bpf.c @@ -24,6 +24,7 @@ #include <linux/filter.h> #include <sys/prctl.h> #include <sys/ptrace.h> +#include <sys/time.h> #include <sys/user.h> #include <linux/prctl.h> #include <linux/ptrace.h> @@ -3547,6 +3548,10 @@ static void signal_handler(int signal) perror("write from signal"); } +static void signal_handler_nop(int signal) +{ +} + TEST(user_notification_signal) { pid_t pid; @@ -4819,6 +4824,132 @@ TEST(user_notification_wait_killable_fatal) EXPECT_EQ(SIGTERM, WTERMSIG(status)); } +/* Ensure signals after the reply do not interrupt */ +TEST(user_notification_wait_killable_after_reply) +{ + int i, max_iter = 100000; + int listener, status; + int pipe_fds[2]; + pid_t pid; + long ret; + + 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!"); + } + + listener = user_notif_syscall( + __NR_dup, SECCOMP_FILTER_FLAG_NEW_LISTENER | + SECCOMP_FILTER_FLAG_WAIT_KILLABLE_RECV); + ASSERT_GE(listener, 0); + + /* + * Used to count invocations. One token is transferred from the child + * to the parent per syscall invocation, the parent tries to take + * one token per successful RECV. If the syscall is restarted after + * RECV the parent will try to get two tokens while the child only + * provided one. + */ + ASSERT_EQ(pipe(pipe_fds), 0); + + pid = fork(); + ASSERT_GE(pid, 0); + + if (pid == 0) { + struct sigaction new_action = { + .sa_handler = signal_handler_nop, + .sa_flags = SA_RESTART, + }; + struct itimerval timer = { + .it_value = { .tv_usec = 1000 }, + .it_interval = { .tv_usec = 1000 }, + }; + char c = 'a'; + + close(pipe_fds[0]); + + /* Setup the sigaction with SA_RESTART */ + if (sigaction(SIGALRM, &new_action, NULL)) { + perror("sigaction"); + exit(1); + } + + /* + * Kill with SIGALRM repeatedly, to try to hit the race when + * handling the syscall. + */ + if (setitimer(ITIMER_REAL, &timer, NULL) < 0) + perror("setitimer"); + + for (i = 0; i < max_iter; ++i) { + int fd; + + /* Send one token per iteration to catch repeats. */ + if (write(pipe_fds[1], &c, sizeof(c)) != 1) { + perror("write"); + exit(1); + } + + fd = syscall(__NR_dup, 0); + if (fd < 0) { + perror("dup"); + exit(1); + } + close(fd); + } + + exit(0); + } + + close(pipe_fds[1]); + + for (i = 0; i < max_iter; ++i) { + struct seccomp_notif req = {}; + struct seccomp_notif_addfd addfd = {}; + struct pollfd pfd = { + .fd = pipe_fds[0], + .events = POLLIN, + }; + char c; + + /* + * Try to receive one token. If it failed, one child syscall + * was restarted after RECV and needed to be handled twice. + */ + ASSERT_EQ(poll(&pfd, 1, 1000), 1) + kill(pid, SIGKILL); + + ASSERT_EQ(read(pipe_fds[0], &c, sizeof(c)), 1) + kill(pid, SIGKILL); + + /* + * Get the notification, reply to it as fast as possible to test + * whether the child wrongly skips going into the non-preemptible + * (TASK_KILLABLE) state. + */ + do + ret = ioctl(listener, SECCOMP_IOCTL_NOTIF_RECV, &req); + while (ret < 0 && errno == ENOENT); /* Accept interruptions before RECV */ + ASSERT_EQ(ret, 0) + kill(pid, SIGKILL); + + addfd.id = req.id; + addfd.flags = SECCOMP_ADDFD_FLAG_SEND; + addfd.srcfd = 0; + ASSERT_GE(ioctl(listener, SECCOMP_IOCTL_NOTIF_ADDFD, &addfd), 0) + kill(pid, SIGKILL); + } + + /* + * Wait for the process to exit, and make sure the process terminated + * with a zero exit code.. + */ + EXPECT_EQ(waitpid(pid, &status, 0), pid); + EXPECT_EQ(true, WIFEXITED(status)); + EXPECT_EQ(0, WEXITSTATUS(status)); +} + struct tsync_vs_thread_leader_args { pthread_t leader; }; |