// SPDX-License-Identifier: GPL-2.0
#define _GNU_SOURCE
#include <cap-ng.h>
#include <linux/capability.h>
#include <stdbool.h>
#include <string.h>
#include <stdio.h>
#include <fcntl.h>
#include <errno.h>
#include <stdarg.h>
#include <sched.h>
#include <sys/mount.h>
#include <limits.h>
#include <libgen.h>
#include <malloc.h>
#include <sys/wait.h>
#include <sys/prctl.h>
#include <sys/stat.h>
#include "../kselftest.h"
static int nerrs;
static pid_t mpid; /* main() pid is used to avoid duplicate test counts */
static void vmaybe_write_file(bool enoent_ok, char *filename, char *fmt, va_list ap)
{
char buf[4096];
int fd;
ssize_t written;
int buf_len;
buf_len = vsnprintf(buf, sizeof(buf), fmt, ap);
if (buf_len < 0)
ksft_exit_fail_msg("vsnprintf failed - %s\n", strerror(errno));
if (buf_len >= sizeof(buf))
ksft_exit_fail_msg("vsnprintf output truncated\n");
fd = open(filename, O_WRONLY);
if (fd < 0) {
if ((errno == ENOENT) && enoent_ok)
return;
ksft_exit_fail_msg("open of %s failed - %s\n",
filename, strerror(errno));
}
written = write(fd, buf, buf_len);
if (written != buf_len) {
if (written >= 0) {
ksft_exit_fail_msg("short write to %s\n", filename);
} else {
ksft_exit_fail_msg("write to %s failed - %s\n",
filename, strerror(errno));
}
}
if (close(fd) != 0) {
ksft_exit_fail_msg("close of %s failed - %s\n",
filename, strerror(errno));
}
}
static void maybe_write_file(char *filename, char *fmt, ...)
{
va_list ap;
va_start(ap, fmt);
vmaybe_write_file(true, filename, fmt, ap);
va_end(ap);
}
static void write_file(char *filename, char *fmt, ...)
{
va_list ap;
va_start(ap, fmt);
vmaybe_write_file(false, filename, fmt, ap);
va_end(ap);
}
static bool create_and_enter_ns(uid_t inner_uid)
{
uid_t outer_uid;
gid_t outer_gid;
int i, ret;
bool have_outer_privilege;
outer_uid = getuid();
outer_gid = getgid();
if (outer_uid == 0 && unshare(CLONE_NEWNS) == 0) {
ksft_print_msg("[NOTE]\tUsing global UIDs for tests\n");
if (prctl(PR_SET_KEEPCAPS, 1, 0, 0, 0) != 0)
ksft_exit_fail_msg("PR_SET_KEEPCAPS - %s\n",
strerror(errno));
if (setresuid(inner_uid, inner_uid, -1) != 0)
ksft_exit_fail_msg("setresuid - %s\n", strerror(errno));
// Re-enable effective caps
ret = capng_get_caps_process();
if (ret == -1)
ksft_exit_fail_msg("capng_get_caps_process failed\n");
for (i = 0; i < CAP_LAST_CAP; i++)
if (capng_have_capability(CAPNG_PERMITTED, i))
capng_update(CAPNG_ADD, CAPNG_EFFECTIVE, i);
if (capng_apply(CAPNG_SELECT_CAPS) != 0)
ksft_exit_fail_msg(
"capng_apply - %s\n", strerror(errno));
have_outer_privilege = true;
} else if (unshare(CLONE_NEWUSER | CLONE_NEWNS) == 0) {
ksft_print_msg("[NOTE]\tUsing a user namespace for tests\n");
maybe_write_file("/proc/self/setgroups", "deny");
write_file("/proc/self/uid_map", "%d %d 1", inner_uid, outer_uid);
write_file("/proc/self/gid_map", "0 %d 1", outer_gid);
have_outer_privilege = false;
} else {
ksft_exit_skip("must be root or be able to create a userns\n");
}
if (mount("none", "/", NULL, MS_REC | MS_PRIVATE, NULL) != 0)
ksft_exit_fail_msg("remount everything private - %s\n",
strerror(errno));
return have_outer_privilege;
}
static void chdir_to_tmpfs(void)
{
char cwd[PATH_MAX];
if (getcwd(cwd, sizeof(cwd)) != cwd)
ksft_exit_fail_msg("getcwd - %s\n", strerror(errno));
if (mount("private_tmp", ".", "tmpfs", 0, "mode=0777") != 0)
ksft_exit_fail_msg("mount private tmpfs - %s\n",
strerror(errno));
if (chdir(cwd) != 0)
ksft_exit_fail_msg("chdir to private tmpfs - %s\n",
strerror(errno));
}
static void copy_fromat_to(int fromfd, const char *fromname, const char *toname)
{
int from = openat(fromfd, fromname, O_RDONLY);
if (from == -1)
ksft_exit_fail_msg("open copy source - %s\n", strerror(errno));
int to = open(toname, O_CREAT | O_WRONLY | O_EXCL, 0700);
while (true) {
char buf[4096];
ssize_t sz = read(from, buf, sizeof(buf));
if (sz == 0)
break;
if (sz < 0)
ksft_exit_fail_msg("read - %s\n", strerror(errno));
if (write(to, buf, sz) != sz)
/* no short writes on tmpfs */
ksft_exit_fail_msg("write - %s\n", strerror(errno));
}
close(from);
close(to);
}
static bool fork_wait(void)
{
pid_t child = fork();
if (child == 0) {
nerrs = 0;
return true;
} else if (child > 0) {
int status;
if (waitpid(child, &status, 0) != child ||
!WIFEXITED(status)) {
ksft_print_msg("Child died\n");
nerrs++;
} else if (WEXITSTATUS(status) != 0) {
ksft_print_msg("Child failed\n");
nerrs++;
} else {
/* don't print this message for mpid */
if (getpid() != mpid)
ksft_test_result_pass("Passed\n");
}
return false;
} else {
ksft_exit_fail_msg("fork - %s\n", strerror(errno));
return false;
}
}
static void exec_other_validate_cap(const char *name,
bool eff, bool perm, bool inh, bool ambient)
{
execl(name, name, (eff ? "1" : "0"),
(perm ? "1" : "0"), (inh ? "1" : "0"), (ambient ? "1" : "0"),
NULL);
ksft_exit_fail_msg("execl - %s\n", strerror(errno));
}
static void exec_validate_cap(bool eff, bool perm, bool inh, bool ambient)
{
exec_other_validate_cap("./validate_cap", eff, perm, inh, ambient);
}
static int do_tests(int uid, const char *our_path)
{
int ret;
bool have_outer_privilege = create_and_enter_ns(uid);
int ourpath_fd = open(our_path, O_RDONLY | O_DIRECTORY);
if (ourpath_fd == -1)
ksft_exit_fail_msg("open '%s' - %s\n",
our_path, strerror(errno));
chdir_to_tmpfs();
copy_fromat_to(ourpath_fd, "validate_cap", "validate_cap");
if (have_outer_privilege) {
uid_t gid = getegid();
copy_fromat_to(ourpath_fd, "validate_cap",
"validate_cap_suidroot");
if (chown("validate_cap_suidroot", 0, -1) != 0)
ksft_exit_fail_msg("chown - %s\n", strerror(errno));
if (chmod("validate_cap_suidroot", S_ISUID | 0700) != 0)
ksft_exit_fail_msg("chmod - %s\n", strerror(errno));
copy_fromat_to(ourpath_fd, "validate_cap",
"validate_cap_suidnonroot");
if (chown("validate_cap_suidnonroot", uid + 1, -1) != 0)
ksft_exit_fail_msg("chown - %s\n", strerror(errno));
if (chmod("validate_cap_suidnonroot", S_ISUID | 0700) != 0)
ksft_exit_fail_msg("chmod - %s\n", strerror(errno));
copy_fromat_to(ourpath_fd, "validate_cap",
"validate_cap_sgidroot");
if (chown("validate_cap_sgidroot", -1, 0) != 0)
ksft_exit_fail_msg("chown - %s\n", strerror(errno));
if (chmod("validate_cap_sgidroot", S_ISGID | 0710) != 0)
ksft_exit_fail_msg("chmod - %s\n", strerror(errno));
copy_fromat_to(ourpath_fd, "validate_cap",
"validate_cap_sgidnonroot");
if (chown("validate_cap_sgidnonroot", -1, gid + 1) != 0)
ksft_exit_fail_msg("chown - %s\n", strerror(errno));
if (chmod("validate_cap_sgidnonroot", S_ISGID | 0710) != 0)
ksft_exit_fail_msg("chmod - %s\n", strerror(errno));
}
ret = capng_get_caps_process();
if (ret == -1)
ksft_exit_fail_msg("capng_get_caps_process failed\n");
/* Make sure that i starts out clear */
capng_update(CAPNG_DROP, CAPNG_INHERITABLE, CAP_NET_BIND_SERVICE);
if (capng_apply(CAPNG_SELECT_CAPS) != 0)
ksft_exit_fail_msg("capng_apply - %s\n", strerror(errno));
if (uid == 0) {
ksft_print_msg("[RUN]\tRoot => ep\n");
if (fork_wait())
exec_validate_cap(true, true, false, false);
} else {
ksft_print_msg("[RUN]\tNon-root => no caps\n");
if (fork_wait())
exec_validate_cap(false, false, false, false);
}
ksft_print_msg("Check cap_ambient manipulation rules\n");
/* We should not be able to add ambient caps yet. */
if (prctl(PR_CAP_AMBIENT, PR_CAP_AMBIENT_RAISE, CAP_NET_BIND_SERVICE, 0, 0, 0) != -1 || errno != EPERM) {
if (errno == EINVAL)
ksft_test_result_fail(
"PR_CAP_AMBIENT_RAISE isn't supported\n");
else
ksft_test_result_fail(
"PR_CAP_AMBIENT_RAISE should have failed eith EPERM on a non-inheritable cap\n");
return 1;
}
ksft_test_result_pass(
"PR_CAP_AMBIENT_RAISE failed on non-inheritable cap\n");
capng_update(CAPNG_ADD, CAPNG_INHERITABLE, CAP_NET_RAW);
capng_update(CAPNG_DROP, CAPNG_PERMITTED, CAP_NET_RAW);
capng_update(CAPNG_DROP, CAPNG_EFFECTIVE, CAP_NET_RAW);
if (capng_apply(CAPNG_SELECT_CAPS) != 0)
ksft_exit_fail_msg("capng_apply - %s\n", strerror(errno));
if (prctl(PR_CAP_AMBIENT, PR_CAP_AMBIENT_RAISE, CAP_NET_RAW, 0, 0, 0) != -1 || errno != EPERM) {
ksft_test_result_fail(
"PR_CAP_AMBIENT_RAISE should have failed on a non-permitted cap\n");
return 1;
}
ksft_test_result_pass(
"PR_CAP_AMBIENT_RAISE failed on non-permitted cap\n");
capng_update(CAPNG_ADD, CAPNG_INHERITABLE, CAP_NET_BIND_SERVICE);
if (capng_apply(CAPNG_SELECT_CAPS) != 0)
ksft_exit_fail_msg("capng_apply - %s\n", strerror(errno));
if (prctl(PR_CAP_AMBIENT, PR_CAP_AMBIENT_RAISE, CAP_NET_BIND_SERVICE, 0, 0, 0) != 0) {
ksft_test_result_fail(
"PR_CAP_AMBIENT_RAISE should have succeeded\n");
return 1;
}
ksft_test_result_pass("PR_CAP_AMBIENT_RAISE worked\n");
if (prctl(PR_CAP_AMBIENT, PR_CAP_AMBIENT_IS_SET, CAP_NET_BIND_SERVICE, 0, 0, 0) != 1) {
ksft_test_result_fail("PR_CAP_AMBIENT_IS_SET is broken\n");
return 1;
}
if (prctl(PR_CAP_AMBIENT, PR_CAP_AMBIENT_CLEAR_ALL, 0, 0, 0, 0) != 0)
ksft_exit_fail_msg("PR_CAP_AMBIENT_CLEAR_ALL - %s\n",
strerror(errno));
if (prctl(PR_CAP_AMBIENT, PR_CAP_AMBIENT_IS_SET, CAP_NET_BIND_SERVICE, 0, 0, 0) != 0) {
ksft_test_result_fail(
"PR_CAP_AMBIENT_CLEAR_ALL didn't work\n");
return 1;
}
if (prctl(PR_CAP_AMBIENT, PR_CAP_AMBIENT_RAISE, CAP_NET_BIND_SERVICE, 0, 0, 0) != 0)
ksft_exit_fail_msg("PR_CAP_AMBIENT_RAISE - %s\n",
strerror(errno));
capng_update(CAPNG_DROP, CAPNG_INHERITABLE, CAP_NET_BIND_SERVICE);
if (capng_apply(CAPNG_SELECT_CAPS) != 0)
ksft_exit_fail_msg("capng_apply - %s\n", strerror(errno));
if (prctl(PR_CAP_AMBIENT, PR_CAP_AMBIENT_IS_SET, CAP_NET_BIND_SERVICE, 0, 0, 0) != 0) {
ksft_test_result_fail("Dropping I should have dropped A\n");
return 1;
}
ksft_test_result_pass("Basic manipulation appears to work\n");
capng_update(CAPNG_ADD, CAPNG_INHERITABLE, CAP_NET_BIND_SERVICE);
if (capng_apply(CAPNG_SELECT_CAPS) != 0)
ksft_exit_fail_msg("capng_apply - %s\n", strerror(errno));
if (uid == 0) {
ksft_print_msg("[RUN]\tRoot +i => eip\n");
if (fork_wait())
exec_validate_cap(true, true, true, false);
} else {
ksft_print_msg("[RUN]\tNon-root +i => i\n");
if (fork_wait())
exec_validate_cap(false, false, true, false);
}
if (prctl(PR_CAP_AMBIENT, PR_CAP_AMBIENT_RAISE, CAP_NET_BIND_SERVICE, 0, 0, 0) != 0)
ksft_exit_fail_msg("PR_CAP_AMBIENT_RAISE - %s\n",
strerror(errno));
ksft_print_msg("[RUN]\tUID %d +ia => eipa\n", uid);
if (fork_wait())
exec_validate_cap(true, true, true, true);
/* The remaining tests need real privilege */
if (!have_outer_privilege) {
ksft_test_result_skip("SUID/SGID tests (needs privilege)\n");
goto done;
}
if (uid == 0) {
ksft_print_msg("[RUN]\tRoot +ia, suidroot => eipa\n");
if (fork_wait())
exec_other_validate_cap("./validate_cap_suidroot",
true, true, true, true);
ksft_print_msg("[RUN]\tRoot +ia, suidnonroot => ip\n");
if (fork_wait())
exec_other_validate_cap("./validate_cap_suidnonroot",
false, true, true, false);
ksft_print_msg("[RUN]\tRoot +ia, sgidroot => eipa\n");
if (fork_wait())
exec_other_validate_cap("./validate_cap_sgidroot",
true, true, true, true);
if (fork_wait()) {
ksft_print_msg(
"[RUN]\tRoot, gid != 0, +ia, sgidroot => eip\n");
if (setresgid(1, 1, 1) != 0)
ksft_exit_fail_msg("setresgid - %s\n",
strerror(errno));
exec_other_validate_cap("./validate_cap_sgidroot",
true, true, true, false);
}
ksft_print_msg("[RUN]\tRoot +ia, sgidnonroot => eip\n");
if (fork_wait())
exec_other_validate_cap("./validate_cap_sgidnonroot",
true, true, true, false);
} else {
ksft_print_msg("[RUN]\tNon-root +ia, sgidnonroot => i\n");
if (fork_wait())
exec_other_validate_cap("./validate_cap_sgidnonroot",
false, false, true, false);
if (fork_wait()) {
ksft_print_msg("[RUN]\tNon-root +ia, sgidroot => i\n");
if (setresgid(1, 1, 1) != 0)
ksft_exit_fail_msg("setresgid - %s\n",
strerror(errno));
exec_other_validate_cap("./validate_cap_sgidroot",
false, false, true, false);
}
}
done:
ksft_print_cnts();
return nerrs ? 1 : 0;
}
int main(int argc, char **argv)
{
char *tmp1, *tmp2, *our_path;
/* Find our path */
tmp1 = strdup(argv[0]);
if (!tmp1)
ksft_exit_fail_msg("strdup - %s\n", strerror(errno));
tmp2 = dirname(tmp1);
our_path = strdup(tmp2);
if (!our_path)
ksft_exit_fail_msg("strdup - %s\n", strerror(errno));
free(tmp1);
mpid = getpid();
if (fork_wait()) {
ksft_print_header();
ksft_set_plan(12);
ksft_print_msg("[RUN]\t+++ Tests with uid == 0 +++\n");
return do_tests(0, our_path);
}
ksft_print_msg("==================================================\n");
if (fork_wait()) {
ksft_print_header();
ksft_set_plan(9);
ksft_print_msg("[RUN]\t+++ Tests with uid != 0 +++\n");
return do_tests(1, our_path);
}
return nerrs ? 1 : 0;
}
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