5 files changed, 168 insertions, 181 deletions

diff --git a/stdlib/tst-secure-getenv.c b/stdlib/tst-secure-getenv.c
index c9ec03866f..5567c9ae21 100644
--- a/stdlib/tst-secure-getenv.c
+++ b/stdlib/tst-secure-getenv.c
@@ -30,167 +30,12 @@
 #include <sys/wait.h>
 #include <unistd.h>
 
+#include <support/check.h>
 #include <support/support.h>
+#include <support/capture_subprocess.h>
 #include <support/test-driver.h>
 
 static char MAGIC_ARGUMENT[] = "run-actual-test";
-#define MAGIC_STATUS 19
-
-/* Return a GID which is not our current GID, but is present in the
-   supplementary group list.  */
-static gid_t
-choose_gid (void)
-{
-  int count = getgroups (0, NULL);
-  if (count < 0)
-    {
-      printf ("getgroups: %m\n");
-      exit (1);
-    }
-  gid_t *groups;
-  groups = xcalloc (count, sizeof (*groups));
-  int ret = getgroups (count, groups);
-  if (ret < 0)
-    {
-      printf ("getgroups: %m\n");
-      exit (1);
-    }
-  gid_t current = getgid ();
-  gid_t not_current = 0;
-  for (int i = 0; i < ret; ++i)
-    {
-      if (groups[i] != current)
-        {
-          not_current = groups[i];
-          break;
-        }
-    }
-  free (groups);
-  return not_current;
-}
-
-
-/* Copies the executable into a restricted directory, so that we can
-   safely make it SGID with the TARGET group ID.  Then runs the
-   executable.  */
-static int
-run_executable_sgid (gid_t target)
-{
-  char *dirname = xasprintf ("%s/secure-getenv.%jd",
-			     test_dir, (intmax_t) getpid ());
-  char *execname = xasprintf ("%s/bin", dirname);
-  int infd = -1;
-  int outfd = -1;
-  int ret = -1;
-  if (mkdir (dirname, 0700) < 0)
-    {
-      printf ("mkdir: %m\n");
-      goto err;
-    }
-  infd = open ("/proc/self/exe", O_RDONLY);
-  if (infd < 0)
-    {
-      printf ("open (/proc/self/exe): %m\n");
-      goto err;
-    }
-  outfd = open (execname, O_WRONLY | O_CREAT | O_EXCL, 0700);
-  if (outfd < 0)
-    {
-      printf ("open (%s): %m\n", execname);
-      goto err;
-    }
-  char buf[4096];
-  for (;;)
-    {
-      ssize_t rdcount = read (infd, buf, sizeof (buf));
-      if (rdcount < 0)
-	{
-	  printf ("read: %m\n");
-	  goto err;
-	}
-      if (rdcount == 0)
-	break;
-      char *p = buf;
-      char *end = buf + rdcount;
-      while (p != end)
-	{
-	  ssize_t wrcount = write (outfd, buf, end - p);
-	  if (wrcount == 0)
-	    errno = ENOSPC;
-	  if (wrcount <= 0)
-	    {
-	      printf ("write: %m\n");
-	      goto err;
-	    }
-	  p += wrcount;
-	}
-    }
-  if (fchown (outfd, getuid (), target) < 0)
-    {
-      printf ("fchown (%s): %m\n", execname);
-      goto err;
-    }
-  if (fchmod (outfd, 02750) < 0)
-    {
-      printf ("fchmod (%s): %m\n", execname);
-      goto err;
-    }
-  if (close (outfd) < 0)
-    {
-      printf ("close (outfd): %m\n");
-      goto err;
-    }
-  if (close (infd) < 0)
-    {
-      printf ("close (infd): %m\n");
-      goto err;
-    }
-
-  int kid = fork ();
-  if (kid < 0)
-    {
-      printf ("fork: %m\n");
-      goto err;
-    }
-  if (kid == 0)
-    {
-      /* Child process.  */
-      char *args[] = { execname, MAGIC_ARGUMENT, NULL };
-      execve (execname, args, environ);
-      printf ("execve (%s): %m\n", execname);
-      _exit (1);
-    }
-  int status;
-  if (waitpid (kid, &status, 0) < 0)
-    {
-      printf ("waitpid: %m\n");
-      goto err;
-    }
-  if (!WIFEXITED (status) || WEXITSTATUS (status) != MAGIC_STATUS)
-    {
-      printf ("Unexpected exit status %d from child process\n",
-	      status);
-      goto err;
-    }
-  ret = 0;
-
-err:
-  if (outfd >= 0)
-    close (outfd);
-  if (infd >= 0)
-    close (infd);
-  if (execname)
-    {
-      unlink (execname);
-      free (execname);
-    }
-  if (dirname)
-    {
-      rmdir (dirname);
-      free (dirname);
-    }
-  return ret;
-}
 
 static int
 do_test (void)
@@ -212,15 +57,15 @@ do_test (void)
       exit (1);
     }
 
-  gid_t target = choose_gid ();
-  if (target == 0)
-    {
-      fprintf (stderr,
-	       "Could not find a suitable GID for user %jd, skipping test\n",
-	       (intmax_t) getuid ());
-      exit (0);
-    }
-  return run_executable_sgid (target);
+  int status = support_capture_subprogram_self_sgid (MAGIC_ARGUMENT);
+
+  if (WEXITSTATUS (status) == EXIT_UNSUPPORTED)
+    return EXIT_UNSUPPORTED;
+
+  if (!WIFEXITED (status))
+    FAIL_EXIT1 ("Unexpected exit status %d from child process\n", status);
+
+  return 0;
 }
 
 static void
@@ -229,23 +74,15 @@ alternative_main (int argc, char **argv)
   if (argc == 2 && strcmp (argv[1], MAGIC_ARGUMENT) == 0)
     {
       if (getgid () == getegid ())
-	{
-	  /* This can happen if the file system is mounted nosuid.  */
-	  fprintf (stderr, "SGID failed: GID and EGID match (%jd)\n",
-		  (intmax_t) getgid ());
-	  exit (MAGIC_STATUS);
-	}
+	/* This can happen if the file system is mounted nosuid.  */
+	FAIL_UNSUPPORTED ("SGID failed: GID and EGID match (%jd)\n",
+		   (intmax_t) getgid ());
       if (getenv ("PATH") == NULL)
-	{
-	  printf ("PATH variable not present\n");
-	  exit (3);
-	}
+	FAIL_EXIT (3, "PATH variable not present\n");
       if (secure_getenv ("PATH") != NULL)
-	{
-	  printf ("PATH variable not filtered out\n");
-	  exit (4);
-	}
-      exit (MAGIC_STATUS);
+	FAIL_EXIT (4, "PATH variable not filtered out\n");
+
+      exit (EXIT_SUCCESS);
     }
 }
 
diff --git a/support/capture_subprocess.h b/support/capture_subprocess.h
index 8969d4a99a..4be430f099 100644
--- a/support/capture_subprocess.h
+++ b/support/capture_subprocess.h
@@ -41,6 +41,12 @@ struct support_capture_subprocess support_capture_subprocess
 struct support_capture_subprocess support_capture_subprogram
   (const char *file, char *const argv[]);
 
+/* Copy the running program into a setgid binary and run it with CHILD_ID
+   argument.  If execution is successful, return the exit status of the child
+   program, otherwise return a non-zero failure exit code.  */
+int support_capture_subprogram_self_sgid
+  (char *child_id);
+
 /* Deallocate the subprocess data captured by
    support_capture_subprocess.  */
 void support_capture_subprocess_free (struct support_capture_subprocess *);
diff --git a/support/subprocess.h b/support/subprocess.h
index 11cfc6a07f..40d82c7e4d 100644
--- a/support/subprocess.h
+++ b/support/subprocess.h
@@ -38,6 +38,11 @@ struct support_subprocess support_subprocess
 struct support_subprocess support_subprogram
   (const char *file, char *const argv[]);
 
+/* Invoke program FILE with ARGV arguments by using posix_spawn and wait for it
+   to complete.  Return program exit status.  */
+int support_subprogram_wait
+  (const char *file, char *const argv[]);
+
 /* Wait for the subprocess indicated by PROC::PID.  Return the status
    indicate by waitpid call.  */
 int support_process_wait (struct support_subprocess *proc);
diff --git a/support/support_capture_subprocess.c b/support/support_capture_subprocess.c
index 3eb825b9af..27bfd19c93 100644
--- a/support/support_capture_subprocess.c
+++ b/support/support_capture_subprocess.c
@@ -20,11 +20,14 @@
 #include <support/capture_subprocess.h>
 
 #include <errno.h>
+#include <fcntl.h>
 #include <stdlib.h>
 #include <support/check.h>
 #include <support/xunistd.h>
 #include <support/xsocket.h>
 #include <support/xspawn.h>
+#include <support/support.h>
+#include <support/test-driver.h>
 
 static void
 transfer (const char *what, struct pollfd *pfd, struct xmemstream *stream)
@@ -102,6 +105,129 @@ support_capture_subprogram (const char *file, char *const argv[])
   return result;
 }
 
+/* Copies the executable into a restricted directory, so that we can
+   safely make it SGID with the TARGET group ID.  Then runs the
+   executable.  */
+static int
+copy_and_spawn_sgid (char *child_id, gid_t gid)
+{
+  char *dirname = xasprintf ("%s/tst-tunables-setuid.%jd",
+			     test_dir, (intmax_t) getpid ());
+  char *execname = xasprintf ("%s/bin", dirname);
+  int infd = -1;
+  int outfd = -1;
+  int ret = 1, status = 1;
+
+  TEST_VERIFY (mkdir (dirname, 0700) == 0);
+  if (support_record_failure_is_failed ())
+    goto err;
+
+  infd = open ("/proc/self/exe", O_RDONLY);
+  if (infd < 0)
+    FAIL_UNSUPPORTED ("unsupported: Cannot read binary from procfs\n");
+
+  outfd = open (execname, O_WRONLY | O_CREAT | O_EXCL, 0700);
+  TEST_VERIFY (outfd >= 0);
+  if (support_record_failure_is_failed ())
+    goto err;
+
+  char buf[4096];
+  for (;;)
+    {
+      ssize_t rdcount = read (infd, buf, sizeof (buf));
+      TEST_VERIFY (rdcount >= 0);
+      if (support_record_failure_is_failed ())
+	goto err;
+      if (rdcount == 0)
+	break;
+      char *p = buf;
+      char *end = buf + rdcount;
+      while (p != end)
+	{
+	  ssize_t wrcount = write (outfd, buf, end - p);
+	  if (wrcount == 0)
+	    errno = ENOSPC;
+	  TEST_VERIFY (wrcount > 0);
+	  if (support_record_failure_is_failed ())
+	    goto err;
+	  p += wrcount;
+	}
+    }
+  TEST_VERIFY (fchown (outfd, getuid (), gid) == 0);
+  if (support_record_failure_is_failed ())
+    goto err;
+  TEST_VERIFY (fchmod (outfd, 02750) == 0);
+  if (support_record_failure_is_failed ())
+    goto err;
+  TEST_VERIFY (close (outfd) == 0);
+  if (support_record_failure_is_failed ())
+    goto err;
+  TEST_VERIFY (close (infd) == 0);
+  if (support_record_failure_is_failed ())
+    goto err;
+
+  /* We have the binary, now spawn the subprocess.  Avoid using
+     support_subprogram because we only want the program exit status, not the
+     contents.  */
+  ret = 0;
+
+  char * const args[] = {execname, child_id, NULL};
+
+  status = support_subprogram_wait (args[0], args);
+
+err:
+  if (outfd >= 0)
+    close (outfd);
+  if (infd >= 0)
+    close (infd);
+  if (execname != NULL)
+    {
+      unlink (execname);
+      free (execname);
+    }
+  if (dirname != NULL)
+    {
+      rmdir (dirname);
+      free (dirname);
+    }
+
+  if (ret != 0)
+    FAIL_EXIT1("Failed to make sgid executable for test\n");
+
+  return status;
+}
+
+int
+support_capture_subprogram_self_sgid (char *child_id)
+{
+  gid_t target = 0;
+  const int count = 64;
+  gid_t groups[count];
+
+  /* Get a GID which is not our current GID, but is present in the
+     supplementary group list.  */
+  int ret = getgroups (count, groups);
+  if (ret < 0)
+    FAIL_UNSUPPORTED("Could not get group list for user %jd\n",
+		     (intmax_t) getuid ());
+
+  gid_t current = getgid ();
+  for (int i = 0; i < ret; ++i)
+    {
+      if (groups[i] != current)
+	{
+	  target = groups[i];
+	  break;
+	}
+    }
+
+  if (target == 0)
+    FAIL_UNSUPPORTED("Could not find a suitable GID for user %jd\n",
+		     (intmax_t) getuid ());
+
+  return copy_and_spawn_sgid (child_id, target);
+}
+
 void
 support_capture_subprocess_free (struct support_capture_subprocess *p)
 {
diff --git a/support/support_subprocess.c b/support/support_subprocess.c
index 2acfc57b7e..89e767ae47 100644
--- a/support/support_subprocess.c
+++ b/support/support_subprocess.c
@@ -93,6 +93,19 @@ support_subprogram (const char *file, char *const argv[])
 }
 
 int
+support_subprogram_wait (const char *file, char *const argv[])
+{
+  posix_spawn_file_actions_t fa;
+
+  posix_spawn_file_actions_init (&fa);
+  struct support_subprocess res = support_subprocess_init ();
+
+  res.pid = xposix_spawn (file, &fa, NULL, argv, environ);
+
+  return support_process_wait (&res);
+}
+
+int
 support_process_wait (struct support_subprocess *proc)
 {
   xclose (proc->stdout_pipe[0]);