nptl: Fix abort in case of set*id failure [BZ #17135]

If a call to the set*id functions fails in a multi-threaded program,
the abort introduced in commit 13f7fe35ae2b0ea55dc4b9628763aafdc8bdc30c
was triggered.

We address by checking that all calls to set*id on all threads give
the same result, and only abort if we see success followed by failure
(or vice versa).

1 files changed, 104 insertions, 0 deletions

diff --git a/nptl/tst-setuid3.c b/nptl/tst-setuid3.c
new file mode 100644
index 0000000000..f78f485239
--- /dev/null
+++ b/nptl/tst-setuid3.c
@@ -0,0 +1,104 @@
+/* Copyright (C) 2014 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+#include <err.h>
+#include <errno.h>
+#include <pthread.h>
+#include <stdbool.h>
+#include <unistd.h>
+
+/* The test must run under a non-privileged user ID.  */
+static const uid_t test_uid = 1;
+
+static pthread_barrier_t barrier1;
+static pthread_barrier_t barrier2;
+
+static void *
+thread_func (void *ctx __attribute__ ((unused)))
+{
+  int ret = pthread_barrier_wait (&barrier1);
+  if (ret != PTHREAD_BARRIER_SERIAL_THREAD && ret != 0)
+    errx (1, "pthread_barrier_wait (barrier1) (on thread): %d", ret);
+  ret = pthread_barrier_wait (&barrier2);
+  if (ret != PTHREAD_BARRIER_SERIAL_THREAD && ret != 0)
+    errx (1, "pthread_barrier_wait (barrier2) (on thread): %d", ret);
+  return NULL;
+}
+
+static void
+setuid_failure (int phase)
+{
+  int ret = setuid (0);
+  switch (ret)
+    {
+    case 0:
+      errx (1, "setuid succeeded unexpectedly in phase %d", phase);
+    case -1:
+      if (errno != EPERM)
+	err (1, "setuid phase %d", phase);
+      break;
+    default:
+      errx (1, "invalid setuid return value in phase %d: %d", phase, ret);
+    }
+}
+
+static int
+do_test (void)
+{
+  if (getuid () == 0)
+    if (setuid (test_uid) != 0)
+      err (1, "setuid (%u)", (unsigned) test_uid);
+  if (setuid (getuid ()))
+    err (1, "setuid (getuid ())");
+  setuid_failure (1);
+
+  int ret = pthread_barrier_init (&barrier1, NULL, 2);
+  if (ret != 0)
+    errx (1, "pthread_barrier_init (barrier1): %d", ret);
+  ret = pthread_barrier_init (&barrier2, NULL, 2);
+  if (ret != 0)
+    errx (1, "pthread_barrier_init (barrier2): %d", ret);
+
+  pthread_t thread;
+  ret = pthread_create (&thread, NULL, thread_func, NULL);
+  if (ret != 0)
+    errx (1, "pthread_create: %d", ret);
+
+  /* Ensure that the thread is running properly.  */
+  ret = pthread_barrier_wait (&barrier1);
+  if (ret != 0)
+    errx (1, "pthread_barrier_wait (barrier1): %d", ret);
+
+  setuid_failure (2);
+
+  /* Check success case. */
+  if (setuid (getuid ()) != 0)
+    err (1, "setuid (getuid ())");
+
+  /* Shutdown.  */
+  ret = pthread_barrier_wait (&barrier2);
+  if (ret != PTHREAD_BARRIER_SERIAL_THREAD && ret != 0)
+    errx (1, "pthread_barrier_wait (barrier2): %d", ret);
+
+  if (ret != PTHREAD_BARRIER_SERIAL_THREAD && ret != 0)
+    errx (1, "pthread_join: %d", ret);
+
+  return 0;
+}
+
+#define TEST_FUNCTION do_test ()
+#include "../test-skeleton.c"