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From: Siddhesh Poyarekar <siddhesh@sourceware.org> To: glibc-cvs@sourceware.org Subject: [glibc/release/2.28/master] tst-env-setuid: Use support_capture_subprogram_self_sgid Date: Wed, 14 Apr 2021 06:22:19 +0000 (GMT) [thread overview] Message-ID: <20210414062219.982F63972039@sourceware.org> (raw) https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=c43e69db62d7621503aa8e878b2ad58772fd00c5 commit c43e69db62d7621503aa8e878b2ad58772fd00c5 Author: Siddhesh Poyarekar <siddhesh@sourceware.org> Date: Tue Mar 16 12:37:53 2021 +0530 tst-env-setuid: Use support_capture_subprogram_self_sgid Use the support_capture_subprogram_self_sgid to spawn an sgid child. Reviewed-by: Carlos O'Donell <carlos@redhat.com> (cherry picked from commit ca335281068a1ed549a75ee64f90a8310755956f) Diff: --- elf/tst-env-setuid.c | 197 ++++----------------------------------------------- 1 file changed, 14 insertions(+), 183 deletions(-) diff --git a/elf/tst-env-setuid.c b/elf/tst-env-setuid.c index 183a6dd133..eda87f9dda 100644 --- a/elf/tst-env-setuid.c +++ b/elf/tst-env-setuid.c @@ -29,173 +29,12 @@ #include <sys/wait.h> #include <unistd.h> +#include <support/check.h> #include <support/support.h> #include <support/test-driver.h> +#include <support/capture_subprocess.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 @@ -256,40 +95,32 @@ do_test (int argc, char **argv) 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); - } + /* This can happen if the file system is mounted nosuid. */ + FAIL_UNSUPPORTED ("SGID failed: GID and EGID match (%jd)\n", + (intmax_t) getgid ()); int ret = test_child (); if (ret != 0) exit (1); - exit (CHILD_STATUS); + exit (EXIT_SUCCESS); } 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); - } + int status = support_capture_subprogram_self_sgid (SETGID_CHILD); - return run_executable_sgid (target); - } + if (WEXITSTATUS (status) == EXIT_UNSUPPORTED) + return EXIT_UNSUPPORTED; + + if (!WIFEXITED (status)) + FAIL_EXIT1 ("Unexpected exit status %d from child process\n", status); - /* Something went wrong and our argv was corrupted. */ - _exit (1); + return 0; + } } #define TEST_FUNCTION_ARGV do_test
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