| /* 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> |