diff options
Diffstat (limited to 'stdlib/tst-secure-getenv.c')
| -rw-r--r-- | stdlib/tst-secure-getenv.c | 250 |
1 files changed, 250 insertions, 0 deletions
diff --git a/stdlib/tst-secure-getenv.c b/stdlib/tst-secure-getenv.c new file mode 100644 index 0000000..76d8de6 --- /dev/null +++ b/stdlib/tst-secure-getenv.c @@ -0,0 +1,250 @@ +/* Copyright (C) 2012 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/>. */ + +/* Test that secure_getenv works by invoking the test as a SGID + program with a group ID from the supplementary group list. This + test can fail spuriously if the user is not a member of a suitable + supplementary group. */ + +#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> + +static char MAGIC_ARGUMENT[] = "run-actual-test"; +#define MAGIC_STATUS 19 + +static const char *test_dir; + +/* 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) + { + perror ("getgroups"); + exit (1); + } + gid_t current = getgid (); + for (int i = 0; i < ret; ++i) + { + if (groups[i] != current) + return groups[i]; + } + 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 = 0; + char *execname = 0; + int infd = -1; + int outfd = -1; + int ret = -1; + if (asprintf (&dirname, "%s/secure-getenv.%jd", + test_dir, (intmax_t) getpid ()) < 0) + { + perror ("asprintf"); + goto err; + } + if (mkdir (dirname, 0700) < 0) + { + perror ("mkdir"); + goto err; + } + if (asprintf (&execname, "%s/bin", dirname) < 0) + { + perror ("asprintf"); + goto err; + } + infd = open ("/proc/self/exe", O_RDONLY); + if (infd < 0) + { + perror ("open"); + goto err; + } + outfd = open (execname, O_WRONLY | O_CREAT | O_EXCL, 0700); + if (outfd < 0) + { + perror ("open"); + goto err; + } + char buf[4096]; + for (;;) + { + ssize_t rdcount = read (infd, buf, sizeof (buf)); + if (rdcount < 0) + { + perror ("read"); + 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) + { + perror ("write"); + goto err; + } + p += wrcount; + } + } + if (fchown (outfd, getuid (), target) < 0) + { + perror ("fchown"); + goto err; + } + if (fchmod (outfd, 02750) < 0) + { + perror ("fchmod"); + goto err; + } + if (close (outfd) < 0) + { + perror ("close"); + goto err; + } + if (close (infd) < 0) + { + perror ("close"); + goto err; + } + + int kid = fork (); + if (kid < 0) + { + perror ("fork"); + goto err; + } + if (kid == 0) + { + /* Child process. */ + char *args[] = { execname, MAGIC_ARGUMENT, NULL }; + execve (execname, args, environ); + perror ("execve"); + _exit (1); + } + int status; + if (waitpid (kid, &status, 0) < 0) + { + perror ("waitpid"); + goto err; + } + if (!WIFEXITED (status) || WEXITSTATUS (status) != MAGIC_STATUS) + { + fprintf (stderr, "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) +{ + if (getenv ("PATH") == NULL) + { + fprintf (stderr, "PATH not set\n"); + exit (1); + } + if (secure_getenv ("PATH") == NULL) + { + fprintf (stderr, "PATH not set according to secure_getenv\n"); + exit (1); + } + if (strcmp (getenv ("PATH"), secure_getenv ("PATH")) != 0) + { + fprintf (stderr, "PATH mismatch (%s, %s)\n", + getenv ("PATH"), secure_getenv ("PATH")); + exit (1); + } + + gid_t target = choose_gid (); + if (target == 0) + { + fprintf (stderr, "Could not find a suitable GID user %jd\n", + (intmax_t) getuid ()); + exit (1); + } + return run_executable_sgid (target); +} + +static void +alternative_main (int argc, char **argv) +{ + if (argc == 2 && strcmp (argv[1], MAGIC_ARGUMENT) == 0) + { + if (getgid () == getegid ()) + { + fprintf (stderr, "SGID failed: GID and EGID match (%jd)\n", + (intmax_t) getgid ()); + exit (2); + } + if (getenv ("PATH") == NULL) + { + fprintf (stderr, "PATH variable not present\n"); + exit (3); + } + if (secure_getenv ("PATH") != NULL) + { + fprintf (stderr, "PATH variable not filtered out\n"); + exit (4); + } + exit (MAGIC_STATUS); + } +} + +#define PREPARE(argc, argv) alternative_main(argc, argv) +#define TEST_FUNCTION do_test () +#include "../test-skeleton.c" |