461 lines
13 KiB
C
461 lines
13 KiB
C
// SPDX-License-Identifier: GPL-2.0
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#define _GNU_SOURCE
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#include <cap-ng.h>
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#include <linux/capability.h>
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#include <stdbool.h>
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#include <string.h>
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#include <stdio.h>
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#include <fcntl.h>
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#include <errno.h>
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#include <stdarg.h>
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#include <sched.h>
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#include <sys/mount.h>
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#include <limits.h>
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#include <libgen.h>
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#include <malloc.h>
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#include <sys/wait.h>
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#include <sys/prctl.h>
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#include <sys/stat.h>
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#include "../kselftest.h"
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#ifndef PR_CAP_AMBIENT
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#define PR_CAP_AMBIENT 47
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# define PR_CAP_AMBIENT_IS_SET 1
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# define PR_CAP_AMBIENT_RAISE 2
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# define PR_CAP_AMBIENT_LOWER 3
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# define PR_CAP_AMBIENT_CLEAR_ALL 4
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#endif
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static int nerrs;
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static pid_t mpid; /* main() pid is used to avoid duplicate test counts */
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static void vmaybe_write_file(bool enoent_ok, char *filename, char *fmt, va_list ap)
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{
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char buf[4096];
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int fd;
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ssize_t written;
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int buf_len;
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buf_len = vsnprintf(buf, sizeof(buf), fmt, ap);
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if (buf_len < 0)
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ksft_exit_fail_msg("vsnprintf failed - %s\n", strerror(errno));
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if (buf_len >= sizeof(buf))
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ksft_exit_fail_msg("vsnprintf output truncated\n");
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fd = open(filename, O_WRONLY);
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if (fd < 0) {
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if ((errno == ENOENT) && enoent_ok)
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return;
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ksft_exit_fail_msg("open of %s failed - %s\n",
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filename, strerror(errno));
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}
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written = write(fd, buf, buf_len);
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if (written != buf_len) {
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if (written >= 0) {
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ksft_exit_fail_msg("short write to %s\n", filename);
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} else {
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ksft_exit_fail_msg("write to %s failed - %s\n",
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filename, strerror(errno));
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}
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}
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if (close(fd) != 0) {
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ksft_exit_fail_msg("close of %s failed - %s\n",
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filename, strerror(errno));
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}
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}
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static void maybe_write_file(char *filename, char *fmt, ...)
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{
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va_list ap;
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va_start(ap, fmt);
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vmaybe_write_file(true, filename, fmt, ap);
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va_end(ap);
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}
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static void write_file(char *filename, char *fmt, ...)
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{
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va_list ap;
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va_start(ap, fmt);
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vmaybe_write_file(false, filename, fmt, ap);
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va_end(ap);
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}
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static bool create_and_enter_ns(uid_t inner_uid)
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{
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uid_t outer_uid;
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gid_t outer_gid;
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int i;
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bool have_outer_privilege;
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outer_uid = getuid();
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outer_gid = getgid();
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/*
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* TODO: If we're already root, we could skip creating the userns.
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*/
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if (unshare(CLONE_NEWNS) == 0) {
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ksft_print_msg("[NOTE]\tUsing global UIDs for tests\n");
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if (prctl(PR_SET_KEEPCAPS, 1, 0, 0, 0) != 0)
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ksft_exit_fail_msg("PR_SET_KEEPCAPS - %s\n",
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strerror(errno));
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if (setresuid(inner_uid, inner_uid, -1) != 0)
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ksft_exit_fail_msg("setresuid - %s\n", strerror(errno));
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// Re-enable effective caps
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capng_get_caps_process();
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for (i = 0; i < CAP_LAST_CAP; i++)
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if (capng_have_capability(CAPNG_PERMITTED, i))
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capng_update(CAPNG_ADD, CAPNG_EFFECTIVE, i);
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if (capng_apply(CAPNG_SELECT_CAPS) != 0)
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ksft_exit_fail_msg(
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"capng_apply - %s\n", strerror(errno));
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have_outer_privilege = true;
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} else if (unshare(CLONE_NEWUSER | CLONE_NEWNS) == 0) {
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ksft_print_msg("[NOTE]\tUsing a user namespace for tests\n");
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maybe_write_file("/proc/self/setgroups", "deny");
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write_file("/proc/self/uid_map", "%d %d 1", inner_uid, outer_uid);
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write_file("/proc/self/gid_map", "0 %d 1", outer_gid);
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have_outer_privilege = false;
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} else {
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ksft_exit_skip("must be root or be able to create a userns\n");
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}
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if (mount("none", "/", NULL, MS_REC | MS_PRIVATE, NULL) != 0)
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ksft_exit_fail_msg("remount everything private - %s\n",
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strerror(errno));
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return have_outer_privilege;
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}
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static void chdir_to_tmpfs(void)
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{
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char cwd[PATH_MAX];
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if (getcwd(cwd, sizeof(cwd)) != cwd)
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ksft_exit_fail_msg("getcwd - %s\n", strerror(errno));
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if (mount("private_tmp", ".", "tmpfs", 0, "mode=0777") != 0)
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ksft_exit_fail_msg("mount private tmpfs - %s\n",
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strerror(errno));
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if (chdir(cwd) != 0)
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ksft_exit_fail_msg("chdir to private tmpfs - %s\n",
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strerror(errno));
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}
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static void copy_fromat_to(int fromfd, const char *fromname, const char *toname)
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{
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int from = openat(fromfd, fromname, O_RDONLY);
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if (from == -1)
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ksft_exit_fail_msg("open copy source - %s\n", strerror(errno));
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int to = open(toname, O_CREAT | O_WRONLY | O_EXCL, 0700);
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while (true) {
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char buf[4096];
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ssize_t sz = read(from, buf, sizeof(buf));
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if (sz == 0)
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break;
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if (sz < 0)
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ksft_exit_fail_msg("read - %s\n", strerror(errno));
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if (write(to, buf, sz) != sz)
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/* no short writes on tmpfs */
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ksft_exit_fail_msg("write - %s\n", strerror(errno));
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}
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close(from);
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close(to);
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}
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static bool fork_wait(void)
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{
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pid_t child = fork();
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if (child == 0) {
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nerrs = 0;
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return true;
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} else if (child > 0) {
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int status;
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if (waitpid(child, &status, 0) != child ||
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!WIFEXITED(status)) {
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ksft_print_msg("Child died\n");
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nerrs++;
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} else if (WEXITSTATUS(status) != 0) {
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ksft_print_msg("Child failed\n");
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nerrs++;
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} else {
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/* don't print this message for mpid */
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if (getpid() != mpid)
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ksft_test_result_pass("Passed\n");
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}
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return false;
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} else {
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ksft_exit_fail_msg("fork - %s\n", strerror(errno));
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return false;
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}
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}
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static void exec_other_validate_cap(const char *name,
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bool eff, bool perm, bool inh, bool ambient)
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{
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execl(name, name, (eff ? "1" : "0"),
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(perm ? "1" : "0"), (inh ? "1" : "0"), (ambient ? "1" : "0"),
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NULL);
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ksft_exit_fail_msg("execl - %s\n", strerror(errno));
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}
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static void exec_validate_cap(bool eff, bool perm, bool inh, bool ambient)
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{
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exec_other_validate_cap("./validate_cap", eff, perm, inh, ambient);
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}
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static int do_tests(int uid, const char *our_path)
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{
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bool have_outer_privilege = create_and_enter_ns(uid);
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int ourpath_fd = open(our_path, O_RDONLY | O_DIRECTORY);
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if (ourpath_fd == -1)
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ksft_exit_fail_msg("open '%s' - %s\n",
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our_path, strerror(errno));
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chdir_to_tmpfs();
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copy_fromat_to(ourpath_fd, "validate_cap", "validate_cap");
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if (have_outer_privilege) {
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uid_t gid = getegid();
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copy_fromat_to(ourpath_fd, "validate_cap",
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"validate_cap_suidroot");
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if (chown("validate_cap_suidroot", 0, -1) != 0)
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ksft_exit_fail_msg("chown - %s\n", strerror(errno));
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if (chmod("validate_cap_suidroot", S_ISUID | 0700) != 0)
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ksft_exit_fail_msg("chmod - %s\n", strerror(errno));
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copy_fromat_to(ourpath_fd, "validate_cap",
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"validate_cap_suidnonroot");
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if (chown("validate_cap_suidnonroot", uid + 1, -1) != 0)
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ksft_exit_fail_msg("chown - %s\n", strerror(errno));
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if (chmod("validate_cap_suidnonroot", S_ISUID | 0700) != 0)
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ksft_exit_fail_msg("chmod - %s\n", strerror(errno));
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copy_fromat_to(ourpath_fd, "validate_cap",
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"validate_cap_sgidroot");
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if (chown("validate_cap_sgidroot", -1, 0) != 0)
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ksft_exit_fail_msg("chown - %s\n", strerror(errno));
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if (chmod("validate_cap_sgidroot", S_ISGID | 0710) != 0)
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ksft_exit_fail_msg("chmod - %s\n", strerror(errno));
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copy_fromat_to(ourpath_fd, "validate_cap",
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"validate_cap_sgidnonroot");
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if (chown("validate_cap_sgidnonroot", -1, gid + 1) != 0)
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ksft_exit_fail_msg("chown - %s\n", strerror(errno));
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if (chmod("validate_cap_sgidnonroot", S_ISGID | 0710) != 0)
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ksft_exit_fail_msg("chmod - %s\n", strerror(errno));
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}
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capng_get_caps_process();
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/* Make sure that i starts out clear */
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capng_update(CAPNG_DROP, CAPNG_INHERITABLE, CAP_NET_BIND_SERVICE);
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if (capng_apply(CAPNG_SELECT_CAPS) != 0)
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ksft_exit_fail_msg("capng_apply - %s\n", strerror(errno));
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if (uid == 0) {
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ksft_print_msg("[RUN]\tRoot => ep\n");
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if (fork_wait())
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exec_validate_cap(true, true, false, false);
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} else {
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ksft_print_msg("[RUN]\tNon-root => no caps\n");
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if (fork_wait())
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exec_validate_cap(false, false, false, false);
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}
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ksft_print_msg("Check cap_ambient manipulation rules\n");
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/* We should not be able to add ambient caps yet. */
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if (prctl(PR_CAP_AMBIENT, PR_CAP_AMBIENT_RAISE, CAP_NET_BIND_SERVICE, 0, 0, 0) != -1 || errno != EPERM) {
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if (errno == EINVAL)
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ksft_test_result_fail(
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"PR_CAP_AMBIENT_RAISE isn't supported\n");
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else
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ksft_test_result_fail(
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"PR_CAP_AMBIENT_RAISE should have failed eith EPERM on a non-inheritable cap\n");
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return 1;
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}
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ksft_test_result_pass(
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"PR_CAP_AMBIENT_RAISE failed on non-inheritable cap\n");
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capng_update(CAPNG_ADD, CAPNG_INHERITABLE, CAP_NET_RAW);
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capng_update(CAPNG_DROP, CAPNG_PERMITTED, CAP_NET_RAW);
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capng_update(CAPNG_DROP, CAPNG_EFFECTIVE, CAP_NET_RAW);
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if (capng_apply(CAPNG_SELECT_CAPS) != 0)
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ksft_exit_fail_msg("capng_apply - %s\n", strerror(errno));
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if (prctl(PR_CAP_AMBIENT, PR_CAP_AMBIENT_RAISE, CAP_NET_RAW, 0, 0, 0) != -1 || errno != EPERM) {
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ksft_test_result_fail(
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"PR_CAP_AMBIENT_RAISE should have failed on a non-permitted cap\n");
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return 1;
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}
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ksft_test_result_pass(
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"PR_CAP_AMBIENT_RAISE failed on non-permitted cap\n");
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capng_update(CAPNG_ADD, CAPNG_INHERITABLE, CAP_NET_BIND_SERVICE);
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if (capng_apply(CAPNG_SELECT_CAPS) != 0)
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ksft_exit_fail_msg("capng_apply - %s\n", strerror(errno));
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if (prctl(PR_CAP_AMBIENT, PR_CAP_AMBIENT_RAISE, CAP_NET_BIND_SERVICE, 0, 0, 0) != 0) {
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ksft_test_result_fail(
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"PR_CAP_AMBIENT_RAISE should have succeeded\n");
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return 1;
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}
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ksft_test_result_pass("PR_CAP_AMBIENT_RAISE worked\n");
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if (prctl(PR_CAP_AMBIENT, PR_CAP_AMBIENT_IS_SET, CAP_NET_BIND_SERVICE, 0, 0, 0) != 1) {
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ksft_test_result_fail("PR_CAP_AMBIENT_IS_SET is broken\n");
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return 1;
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}
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if (prctl(PR_CAP_AMBIENT, PR_CAP_AMBIENT_CLEAR_ALL, 0, 0, 0, 0) != 0)
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ksft_exit_fail_msg("PR_CAP_AMBIENT_CLEAR_ALL - %s\n",
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strerror(errno));
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if (prctl(PR_CAP_AMBIENT, PR_CAP_AMBIENT_IS_SET, CAP_NET_BIND_SERVICE, 0, 0, 0) != 0) {
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ksft_test_result_fail(
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"PR_CAP_AMBIENT_CLEAR_ALL didn't work\n");
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return 1;
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}
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if (prctl(PR_CAP_AMBIENT, PR_CAP_AMBIENT_RAISE, CAP_NET_BIND_SERVICE, 0, 0, 0) != 0)
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ksft_exit_fail_msg("PR_CAP_AMBIENT_RAISE - %s\n",
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strerror(errno));
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capng_update(CAPNG_DROP, CAPNG_INHERITABLE, CAP_NET_BIND_SERVICE);
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if (capng_apply(CAPNG_SELECT_CAPS) != 0)
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ksft_exit_fail_msg("capng_apply - %s\n", strerror(errno));
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if (prctl(PR_CAP_AMBIENT, PR_CAP_AMBIENT_IS_SET, CAP_NET_BIND_SERVICE, 0, 0, 0) != 0) {
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ksft_test_result_fail("Dropping I should have dropped A\n");
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return 1;
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}
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ksft_test_result_pass("Basic manipulation appears to work\n");
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capng_update(CAPNG_ADD, CAPNG_INHERITABLE, CAP_NET_BIND_SERVICE);
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if (capng_apply(CAPNG_SELECT_CAPS) != 0)
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ksft_exit_fail_msg("capng_apply - %s\n", strerror(errno));
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if (uid == 0) {
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ksft_print_msg("[RUN]\tRoot +i => eip\n");
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if (fork_wait())
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exec_validate_cap(true, true, true, false);
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} else {
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ksft_print_msg("[RUN]\tNon-root +i => i\n");
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if (fork_wait())
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exec_validate_cap(false, false, true, false);
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}
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if (prctl(PR_CAP_AMBIENT, PR_CAP_AMBIENT_RAISE, CAP_NET_BIND_SERVICE, 0, 0, 0) != 0)
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ksft_exit_fail_msg("PR_CAP_AMBIENT_RAISE - %s\n",
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strerror(errno));
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ksft_print_msg("[RUN]\tUID %d +ia => eipa\n", uid);
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if (fork_wait())
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exec_validate_cap(true, true, true, true);
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/* The remaining tests need real privilege */
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if (!have_outer_privilege) {
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ksft_test_result_skip("SUID/SGID tests (needs privilege)\n");
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goto done;
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}
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if (uid == 0) {
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ksft_print_msg("[RUN]\tRoot +ia, suidroot => eipa\n");
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if (fork_wait())
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exec_other_validate_cap("./validate_cap_suidroot",
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true, true, true, true);
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ksft_print_msg("[RUN]\tRoot +ia, suidnonroot => ip\n");
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if (fork_wait())
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exec_other_validate_cap("./validate_cap_suidnonroot",
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false, true, true, false);
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ksft_print_msg("[RUN]\tRoot +ia, sgidroot => eipa\n");
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if (fork_wait())
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exec_other_validate_cap("./validate_cap_sgidroot",
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true, true, true, true);
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if (fork_wait()) {
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ksft_print_msg(
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"[RUN]\tRoot, gid != 0, +ia, sgidroot => eip\n");
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if (setresgid(1, 1, 1) != 0)
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ksft_exit_fail_msg("setresgid - %s\n",
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strerror(errno));
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exec_other_validate_cap("./validate_cap_sgidroot",
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true, true, true, false);
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}
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ksft_print_msg("[RUN]\tRoot +ia, sgidnonroot => eip\n");
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if (fork_wait())
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exec_other_validate_cap("./validate_cap_sgidnonroot",
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true, true, true, false);
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} else {
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ksft_print_msg("[RUN]\tNon-root +ia, sgidnonroot => i\n");
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if (fork_wait())
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exec_other_validate_cap("./validate_cap_sgidnonroot",
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false, false, true, false);
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if (fork_wait()) {
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ksft_print_msg("[RUN]\tNon-root +ia, sgidroot => i\n");
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if (setresgid(1, 1, 1) != 0)
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ksft_exit_fail_msg("setresgid - %s\n",
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strerror(errno));
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exec_other_validate_cap("./validate_cap_sgidroot",
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false, false, true, false);
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}
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}
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done:
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ksft_print_cnts();
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return nerrs ? 1 : 0;
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}
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int main(int argc, char **argv)
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{
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char *tmp1, *tmp2, *our_path;
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ksft_print_header();
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/* Find our path */
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tmp1 = strdup(argv[0]);
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if (!tmp1)
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ksft_exit_fail_msg("strdup - %s\n", strerror(errno));
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tmp2 = dirname(tmp1);
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our_path = strdup(tmp2);
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if (!our_path)
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ksft_exit_fail_msg("strdup - %s\n", strerror(errno));
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free(tmp1);
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mpid = getpid();
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if (fork_wait()) {
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ksft_print_msg("[RUN]\t+++ Tests with uid == 0 +++\n");
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return do_tests(0, our_path);
|
|
}
|
|
|
|
ksft_print_msg("==================================================\n");
|
|
|
|
if (fork_wait()) {
|
|
ksft_print_msg("[RUN]\t+++ Tests with uid != 0 +++\n");
|
|
return do_tests(1, our_path);
|
|
}
|
|
|
|
return nerrs ? 1 : 0;
|
|
}
|