selftests/timens: add a test for vfork+exit

* check that a child process is in parent's time namespace after vfork.
* check that a child process is in the target namespace after exec.

Output on success:
 1..4
 ok 1 parent before vfork
 ok 2 child after exec
 ok 3 wait for child
 ok 4 parent after vfork
 # Totals: pass:4 fail:0 xfail:0 xpass:0 skip:0 error:0

Signed-off-by: Andrei Vagin <avagin@gmail.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20221013173154.291597-1-avagin@google.com

diff --git a/tools/testing/selftests/timens/.gitignore b/tools/testing/selftests/timens/.gitignore
index fe1eb82..cae8dca 100644 (file)
--- a/tools/testing/selftests/timens/.gitignore
+++ b/tools/testing/selftests/timens/.gitignore
@@ -8,3 +8,4 @@ procfs
 timens
 timer
 timerfd
+vfork_exec

diff --git a/tools/testing/selftests/timens/Makefile b/tools/testing/selftests/timens/Makefile
index 3a5936c..f0d51d4 100644 (file)
--- a/tools/testing/selftests/timens/Makefile
+++ b/tools/testing/selftests/timens/Makefile
@@ -1,4 +1,4 @@
-TEST_GEN_PROGS := timens timerfd timer clock_nanosleep procfs exec futex
+TEST_GEN_PROGS := timens timerfd timer clock_nanosleep procfs exec futex vfork_exec
 TEST_GEN_PROGS_EXTENDED := gettime_perf
 
 CFLAGS := -Wall -Werror -pthread

diff --git a/tools/testing/selftests/timens/vfork_exec.c b/tools/testing/selftests/timens/vfork_exec.c
new file mode 100644 (file)
index 0000000..beb7614
--- /dev/null
+++ b/tools/testing/selftests/timens/vfork_exec.c
@@ -0,0 +1,139 @@
+// SPDX-License-Identifier: GPL-2.0
+#define _GNU_SOURCE
+#include <errno.h>
+#include <fcntl.h>
+#include <sched.h>
+#include <stdio.h>
+#include <stdbool.h>
+#include <sys/stat.h>
+#include <sys/syscall.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <time.h>
+#include <unistd.h>
+#include <string.h>
+#include <pthread.h>
+
+#include "log.h"
+#include "timens.h"
+
+#define OFFSET (36000)
+
+struct thread_args {
+       char *tst_name;
+       struct timespec *now;
+};
+
+static void *tcheck(void *_args)
+{
+       struct thread_args *args = _args;
+       struct timespec *now = args->now, tst;
+       int i;
+
+       for (i = 0; i < 2; i++) {
+               _gettime(CLOCK_MONOTONIC, &tst, i);
+               if (abs(tst.tv_sec - now->tv_sec) > 5) {
+                       pr_fail("%s: in-thread: unexpected value: %ld (%ld)\n",
+                               args->tst_name, tst.tv_sec, now->tv_sec);
+                       return (void *)1UL;
+               }
+       }
+       return NULL;
+}
+
+static int check_in_thread(char *tst_name, struct timespec *now)
+{
+       struct thread_args args = {
+               .tst_name = tst_name,
+               .now = now,
+       };
+       pthread_t th;
+       void *retval;
+
+       if (pthread_create(&th, NULL, tcheck, &args))
+               return pr_perror("thread");
+       if (pthread_join(th, &retval))
+               return pr_perror("pthread_join");
+       return !(retval == NULL);
+}
+
+static int check(char *tst_name, struct timespec *now)
+{
+       struct timespec tst;
+       int i;
+
+       for (i = 0; i < 2; i++) {
+               _gettime(CLOCK_MONOTONIC, &tst, i);
+               if (abs(tst.tv_sec - now->tv_sec) > 5)
+                       return pr_fail("%s: unexpected value: %ld (%ld)\n",
+                                       tst_name, tst.tv_sec, now->tv_sec);
+       }
+       if (check_in_thread(tst_name, now))
+               return 1;
+       ksft_test_result_pass("%s\n", tst_name);
+       return 0;
+}
+
+int main(int argc, char *argv[])
+{
+       struct timespec now;
+       int status;
+       pid_t pid;
+
+       if (argc > 1) {
+               char *endptr;
+
+               ksft_cnt.ksft_pass = 1;
+               now.tv_sec = strtoul(argv[1], &endptr, 0);
+               if (*endptr != 0)
+                       return pr_perror("strtoul");
+
+               return check("child after exec", &now);
+       }
+
+       nscheck();
+
+       ksft_set_plan(4);
+
+       clock_gettime(CLOCK_MONOTONIC, &now);
+
+       if (unshare_timens())
+               return 1;
+
+       if (_settime(CLOCK_MONOTONIC, OFFSET))
+               return 1;
+
+       if (check("parent before vfork", &now))
+               return 1;
+
+       pid = vfork();
+       if (pid < 0)
+               return pr_perror("fork");
+
+       if (pid == 0) {
+               char now_str[64];
+               char *cargv[] = {"exec", now_str, NULL};
+               char *cenv[] = {NULL};
+
+               /* Check for proper vvar offsets after execve. */
+               snprintf(now_str, sizeof(now_str), "%ld", now.tv_sec + OFFSET);
+               execve("/proc/self/exe", cargv, cenv);
+               pr_perror("execve");
+               _exit(1);
+       }
+
+       if (waitpid(pid, &status, 0) != pid)
+               return pr_perror("waitpid");
+
+       if (status)
+               ksft_exit_fail();
+       ksft_inc_pass_cnt();
+       ksft_test_result_pass("wait for child\n");
+
+       /* Check that we are still in the source timens. */
+       if (check("parent after vfork", &now))
+               return 1;
+
+       ksft_exit_pass();
+       return 0;
+}