summaryrefslogtreecommitdiff
path: root/elf/tst-env-setuid.c
diff options
context:
space:
mode:
Diffstat (limited to 'elf/tst-env-setuid.c')
-rw-r--r--elf/tst-env-setuid.c296
1 files changed, 296 insertions, 0 deletions
diff --git a/elf/tst-env-setuid.c b/elf/tst-env-setuid.c
new file mode 100644
index 0000000000..183a6dd133
--- /dev/null
+++ b/elf/tst-env-setuid.c
@@ -0,0 +1,296 @@
+/* Copyright (C) 2012-2018 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/>. */
+
+/* Verify that tunables correctly filter out unsafe environment variables like
+ MALLOC_CHECK_ and MALLOC_MMAP_THRESHOLD_ but also retain
+ MALLOC_MMAP_THRESHOLD_ in an unprivileged child. */
+
+#include <errno.h>
+#include <fcntl.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <string.h>
+#include <sys/stat.h>
+#include <sys/wait.h>
+#include <unistd.h>
+
+#include <support/support.h>
+#include <support/test-driver.h>
+
+static char SETGID_CHILD[] = "setgid-child";
+#define CHILD_STATUS 42
+
+/* Return a GID which is not our current GID, but is present in the
+ supplementary group list. */
+static gid_t
+choose_gid (void)
+{
+ const int count = 64;
+ gid_t groups[count];
+ int ret = getgroups (count, groups);
+ if (ret < 0)
+ {
+ printf ("getgroups: %m\n");
+ exit (1);
+ }
+ gid_t current = getgid ();
+ for (int i = 0; i < ret; ++i)
+ {
+ if (groups[i] != current)
+ return groups[i];
+ }
+ return 0;
+}
+
+/* Spawn and execute a program and verify that it returns the CHILD_STATUS. */
+static pid_t
+do_execve (char **args)
+{
+ pid_t kid = vfork ();
+
+ if (kid < 0)
+ {
+ printf ("vfork: %m\n");
+ return -1;
+ }
+
+ if (kid == 0)
+ {
+ /* Child process. */
+ execve (args[0], args, environ);
+ _exit (-errno);
+ }
+
+ if (kid < 0)
+ return 1;
+
+ int status;
+
+ if (waitpid (kid, &status, 0) < 0)
+ {
+ printf ("waitpid: %m\n");
+ return 1;
+ }
+
+ if (WEXITSTATUS (status) == EXIT_UNSUPPORTED)
+ return EXIT_UNSUPPORTED;
+
+ if (!WIFEXITED (status) || WEXITSTATUS (status) != CHILD_STATUS)
+ {
+ printf ("Unexpected exit status %d from child process\n",
+ WEXITSTATUS (status));
+ return 1;
+ }
+ return 0;
+}
+
+/* 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/tst-tunables-setuid.%jd",
+ test_dir, (intmax_t) getpid ());
+ char *execname = xasprintf ("%s/bin", dirname);
+ int infd = -1;
+ int outfd = -1;
+ int ret = 0;
+ 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;
+ }
+
+ char *args[] = {execname, SETGID_CHILD, NULL};
+
+ ret = do_execve (args);
+
+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;
+}
+
+#ifndef test_child
+static int
+test_child (void)
+{
+ if (getenv ("MALLOC_CHECK_") != NULL)
+ {
+ printf ("MALLOC_CHECK_ is still set\n");
+ return 1;
+ }
+
+ if (getenv ("MALLOC_MMAP_THRESHOLD_") == NULL)
+ {
+ printf ("MALLOC_MMAP_THRESHOLD_ lost\n");
+ return 1;
+ }
+
+ if (getenv ("LD_HWCAP_MASK") != NULL)
+ {
+ printf ("LD_HWCAP_MASK still set\n");
+ return 1;
+ }
+
+ return 0;
+}
+#endif
+
+#ifndef test_parent
+static int
+test_parent (void)
+{
+ if (getenv ("MALLOC_CHECK_") == NULL)
+ {
+ printf ("MALLOC_CHECK_ lost\n");
+ return 1;
+ }
+
+ if (getenv ("MALLOC_MMAP_THRESHOLD_") == NULL)
+ {
+ printf ("MALLOC_MMAP_THRESHOLD_ lost\n");
+ return 1;
+ }
+
+ if (getenv ("LD_HWCAP_MASK") == NULL)
+ {
+ printf ("LD_HWCAP_MASK lost\n");
+ return 1;
+ }
+
+ return 0;
+}
+#endif
+
+static int
+do_test (int argc, char **argv)
+{
+ /* Setgid child process. */
+ if (argc == 2 && strcmp (argv[1], SETGID_CHILD) == 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 (EXIT_UNSUPPORTED);
+ }
+
+ int ret = test_child ();
+
+ if (ret != 0)
+ exit (1);
+
+ exit (CHILD_STATUS);
+ }
+ else
+ {
+ if (test_parent () != 0)
+ exit (1);
+
+ /* Try running a setgid program. */
+ 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);
+ }
+
+ /* Something went wrong and our argv was corrupted. */
+ _exit (1);
+}
+
+#define TEST_FUNCTION_ARGV do_test
+#include <support/test-driver.c>