// SPDX-License-Identifier: GPL-2.0-or-later
#define _GNU_SOURCE
#include <assert.h>
#include <fcntl.h>
#include <limits.h>
#include <sched.h>
#include <stdlib.h>
#include <sys/mount.h>
#include <sys/stat.h>
#include <sys/wait.h>
#include <linux/nsfs.h>
#include <linux/stat.h>
#include "statmount.h"
#include "../../kselftest.h"
#define NSID_PASS 0
#define NSID_FAIL 1
#define NSID_SKIP 2
#define NSID_ERROR 3
static void handle_result(int ret, const char *testname)
{
if (ret == NSID_PASS)
ksft_test_result_pass("%s\n", testname);
else if (ret == NSID_FAIL)
ksft_test_result_fail("%s\n", testname);
else if (ret == NSID_ERROR)
ksft_exit_fail_msg("%s\n", testname);
else
ksft_test_result_skip("%s\n", testname);
}
static inline int wait_for_pid(pid_t pid)
{
int status, ret;
again:
ret = waitpid(pid, &status, 0);
if (ret == -1) {
if (errno == EINTR)
goto again;
ksft_print_msg("waitpid returned -1, errno=%d\n", errno);
return -1;
}
if (!WIFEXITED(status)) {
ksft_print_msg(
"waitpid !WIFEXITED, WIFSIGNALED=%d, WTERMSIG=%d\n",
WIFSIGNALED(status), WTERMSIG(status));
return -1;
}
ret = WEXITSTATUS(status);
return ret;
}
static int get_mnt_ns_id(const char *mnt_ns, uint64_t *mnt_ns_id)
{
int fd = open(mnt_ns, O_RDONLY);
if (fd < 0) {
ksft_print_msg("failed to open for ns %s: %s\n",
mnt_ns, strerror(errno));
sleep(60);
return NSID_ERROR;
}
if (ioctl(fd, NS_GET_MNTNS_ID, mnt_ns_id) < 0) {
ksft_print_msg("failed to get the nsid for ns %s: %s\n",
mnt_ns, strerror(errno));
return NSID_ERROR;
}
close(fd);
return NSID_PASS;
}
static int get_mnt_id(const char *path, uint64_t *mnt_id)
{
struct statx sx;
int ret;
ret = statx(AT_FDCWD, path, 0, STATX_MNT_ID_UNIQUE, &sx);
if (ret == -1) {
ksft_print_msg("retrieving unique mount ID for %s: %s\n", path,
strerror(errno));
return NSID_ERROR;
}
if (!(sx.stx_mask & STATX_MNT_ID_UNIQUE)) {
ksft_print_msg("no unique mount ID available for %s\n", path);
return NSID_ERROR;
}
*mnt_id = sx.stx_mnt_id;
return NSID_PASS;
}
static int write_file(const char *path, const char *val)
{
int fd = open(path, O_WRONLY);
size_t len = strlen(val);
int ret;
if (fd == -1) {
ksft_print_msg("opening %s for write: %s\n", path, strerror(errno));
return NSID_ERROR;
}
ret = write(fd, val, len);
if (ret == -1) {
ksft_print_msg("writing to %s: %s\n", path, strerror(errno));
return NSID_ERROR;
}
if (ret != len) {
ksft_print_msg("short write to %s\n", path);
return NSID_ERROR;
}
ret = close(fd);
if (ret == -1) {
ksft_print_msg("closing %s\n", path);
return NSID_ERROR;
}
return NSID_PASS;
}
static int setup_namespace(void)
{
int ret;
char buf[32];
uid_t uid = getuid();
gid_t gid = getgid();
ret = unshare(CLONE_NEWNS|CLONE_NEWUSER|CLONE_NEWPID);
if (ret == -1)
ksft_exit_fail_msg("unsharing mountns and userns: %s\n",
strerror(errno));
sprintf(buf, "0 %d 1", uid);
ret = write_file("/proc/self/uid_map", buf);
if (ret != NSID_PASS)
return ret;
ret = write_file("/proc/self/setgroups", "deny");
if (ret != NSID_PASS)
return ret;
sprintf(buf, "0 %d 1", gid);
ret = write_file("/proc/self/gid_map", buf);
if (ret != NSID_PASS)
return ret;
ret = mount("", "/", NULL, MS_REC|MS_PRIVATE, NULL);
if (ret == -1) {
ksft_print_msg("making mount tree private: %s\n",
strerror(errno));
return NSID_ERROR;
}
return NSID_PASS;
}
static int _test_statmount_mnt_ns_id(void)
{
struct statmount sm;
uint64_t mnt_ns_id;
uint64_t root_id;
int ret;
ret = get_mnt_ns_id("/proc/self/ns/mnt", &mnt_ns_id);
if (ret != NSID_PASS)
return ret;
ret = get_mnt_id("/", &root_id);
if (ret != NSID_PASS)
return ret;
ret = statmount(root_id, 0, STATMOUNT_MNT_NS_ID, &sm, sizeof(sm), 0);
if (ret == -1) {
ksft_print_msg("statmount mnt ns id: %s\n", strerror(errno));
return NSID_ERROR;
}
if (sm.size != sizeof(sm)) {
ksft_print_msg("unexpected size: %u != %u\n", sm.size,
(uint32_t)sizeof(sm));
return NSID_FAIL;
}
if (sm.mask != STATMOUNT_MNT_NS_ID) {
ksft_print_msg("statmount mnt ns id unavailable\n");
return NSID_SKIP;
}
if (sm.mnt_ns_id != mnt_ns_id) {
ksft_print_msg("unexpected mnt ns ID: 0x%llx != 0x%llx\n",
(unsigned long long)sm.mnt_ns_id,
(unsigned long long)mnt_ns_id);
return NSID_FAIL;
}
return NSID_PASS;
}
static void test_statmount_mnt_ns_id(void)
{
pid_t pid;
int ret;
pid = fork();
if (pid < 0)
ksft_exit_fail_msg("failed to fork: %s\n", strerror(errno));
/* We're the original pid, wait for the result. */
if (pid != 0) {
ret = wait_for_pid(pid);
handle_result(ret, "test statmount ns id");
return;
}
ret = setup_namespace();
if (ret != NSID_PASS)
exit(ret);
ret = _test_statmount_mnt_ns_id();
exit(ret);
}
static int validate_external_listmount(pid_t pid, uint64_t child_nr_mounts)
{
uint64_t list[256];
uint64_t mnt_ns_id;
uint64_t nr_mounts;
char buf[256];
int ret;
/* Get the mount ns id for our child. */
snprintf(buf, sizeof(buf), "/proc/%lu/ns/mnt", (unsigned long)pid);
ret = get_mnt_ns_id(buf, &mnt_ns_id);
nr_mounts = listmount(LSMT_ROOT, mnt_ns_id, 0, list, 256, 0);
if (nr_mounts == (uint64_t)-1) {
ksft_print_msg("listmount: %s\n", strerror(errno));
return NSID_ERROR;
}
if (nr_mounts != child_nr_mounts) {
ksft_print_msg("listmount results is %zi != %zi\n", nr_mounts,
child_nr_mounts);
return NSID_FAIL;
}
/* Validate that all of our entries match our mnt_ns_id. */
for (int i = 0; i < nr_mounts; i++) {
struct statmount sm;
ret = statmount(list[i], mnt_ns_id, STATMOUNT_MNT_NS_ID, &sm,
sizeof(sm), 0);
if (ret < 0) {
ksft_print_msg("statmount mnt ns id: %s\n", strerror(errno));
return NSID_ERROR;
}
if (sm.mask != STATMOUNT_MNT_NS_ID) {
ksft_print_msg("statmount mnt ns id unavailable\n");
return NSID_SKIP;
}
if (sm.mnt_ns_id != mnt_ns_id) {
ksft_print_msg("listmount gave us the wrong ns id: 0x%llx != 0x%llx\n",
(unsigned long long)sm.mnt_ns_id,
(unsigned long long)mnt_ns_id);
return NSID_FAIL;
}
}
return NSID_PASS;
}
static void test_listmount_ns(void)
{
uint64_t nr_mounts;
char pval;
int child_ready_pipe[2];
int parent_ready_pipe[2];
pid_t pid;
int ret, child_ret;
if (pipe(child_ready_pipe) < 0)
ksft_exit_fail_msg("failed to create the child pipe: %s\n",
strerror(errno));
if (pipe(parent_ready_pipe) < 0)
ksft_exit_fail_msg("failed to create the parent pipe: %s\n",
strerror(errno));
pid = fork();
if (pid < 0)
ksft_exit_fail_msg("failed to fork: %s\n", strerror(errno));
if (pid == 0) {
char cval;
uint64_t list[256];
close(child_ready_pipe[0]);
close(parent_ready_pipe[1]);
ret = setup_namespace();
if (ret != NSID_PASS)
exit(ret);
nr_mounts = listmount(LSMT_ROOT, 0, 0, list, 256, 0);
if (nr_mounts == (uint64_t)-1) {
ksft_print_msg("listmount: %s\n", strerror(errno));
exit(NSID_FAIL);
}
/*
* Tell our parent how many mounts we have, and then wait for it
* to tell us we're done.
*/
write(child_ready_pipe[1], &nr_mounts, sizeof(nr_mounts));
read(parent_ready_pipe[0], &cval, sizeof(cval));
exit(NSID_PASS);
}
close(child_ready_pipe[1]);
close(parent_ready_pipe[0]);
/* Wait until the child has created everything. */
if (read(child_ready_pipe[0], &nr_mounts, sizeof(nr_mounts)) !=
sizeof(nr_mounts))
ret = NSID_ERROR;
ret = validate_external_listmount(pid, nr_mounts);
if (write(parent_ready_pipe[1], &pval, sizeof(pval)) != sizeof(pval))
ret = NSID_ERROR;
child_ret = wait_for_pid(pid);
if (child_ret != NSID_PASS)
ret = child_ret;
handle_result(ret, "test listmount ns id");
}
int main(void)
{
int ret;
ksft_print_header();
ret = statmount(0, 0, 0, NULL, 0, 0);
assert(ret == -1);
if (errno == ENOSYS)
ksft_exit_skip("statmount() syscall not supported\n");
ksft_set_plan(2);
test_statmount_mnt_ns_id();
test_listmount_ns();
if (ksft_get_fail_cnt() + ksft_get_error_cnt() > 0)
ksft_exit_fail();
else
ksft_exit_pass();
}
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