diff options
Diffstat (limited to '')
| -rw-r--r-- | tools/testing/selftests/mount/.gitignore | 3 | ||||
| -rw-r--r-- | tools/testing/selftests/mount/Makefile | 9 | ||||
| -rw-r--r-- | tools/testing/selftests/mount/config | 1 | ||||
| -rw-r--r-- | tools/testing/selftests/mount/nosymfollow-test.c | 218 | ||||
| -rwxr-xr-x | tools/testing/selftests/mount/run_nosymfollow.sh | 4 | ||||
| -rwxr-xr-x | tools/testing/selftests/mount/run_unprivileged_remount.sh | 12 | ||||
| -rw-r--r-- | tools/testing/selftests/mount/unprivileged-remount-test.c | 371 |
7 files changed, 618 insertions, 0 deletions
diff --git a/tools/testing/selftests/mount/.gitignore b/tools/testing/selftests/mount/.gitignore new file mode 100644 index 000000000..17f2d8415 --- /dev/null +++ b/tools/testing/selftests/mount/.gitignore @@ -0,0 +1,3 @@ +# SPDX-License-Identifier: GPL-2.0-only +unprivileged-remount-test +nosymfollow-test diff --git a/tools/testing/selftests/mount/Makefile b/tools/testing/selftests/mount/Makefile new file mode 100644 index 000000000..2d9454841 --- /dev/null +++ b/tools/testing/selftests/mount/Makefile @@ -0,0 +1,9 @@ +# SPDX-License-Identifier: GPL-2.0 +# Makefile for mount selftests. +CFLAGS = -Wall \ + -O2 + +TEST_PROGS := run_unprivileged_remount.sh run_nosymfollow.sh +TEST_GEN_FILES := unprivileged-remount-test nosymfollow-test + +include ../lib.mk diff --git a/tools/testing/selftests/mount/config b/tools/testing/selftests/mount/config new file mode 100644 index 000000000..416bd53ce --- /dev/null +++ b/tools/testing/selftests/mount/config @@ -0,0 +1 @@ +CONFIG_USER_NS=y diff --git a/tools/testing/selftests/mount/nosymfollow-test.c b/tools/testing/selftests/mount/nosymfollow-test.c new file mode 100644 index 000000000..650d6d80a --- /dev/null +++ b/tools/testing/selftests/mount/nosymfollow-test.c @@ -0,0 +1,218 @@ +// SPDX-License-Identifier: GPL-2.0 +#define _GNU_SOURCE +#include <errno.h> +#include <fcntl.h> +#include <limits.h> +#include <sched.h> +#include <stdarg.h> +#include <stdbool.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <sys/mount.h> +#include <sys/stat.h> +#include <sys/types.h> +#include <sys/vfs.h> +#include <unistd.h> + +#ifndef MS_NOSYMFOLLOW +# define MS_NOSYMFOLLOW 256 /* Do not follow symlinks */ +#endif + +#ifndef ST_NOSYMFOLLOW +# define ST_NOSYMFOLLOW 0x2000 /* Do not follow symlinks */ +#endif + +#define DATA "/tmp/data" +#define LINK "/tmp/symlink" +#define TMP "/tmp" + +static void die(char *fmt, ...) +{ + va_list ap; + + va_start(ap, fmt); + vfprintf(stderr, fmt, ap); + va_end(ap); + exit(EXIT_FAILURE); +} + +static void vmaybe_write_file(bool enoent_ok, char *filename, char *fmt, + va_list ap) +{ + ssize_t written; + char buf[4096]; + int buf_len; + int fd; + + buf_len = vsnprintf(buf, sizeof(buf), fmt, ap); + if (buf_len < 0) + die("vsnprintf failed: %s\n", strerror(errno)); + + if (buf_len >= sizeof(buf)) + die("vsnprintf output truncated\n"); + + fd = open(filename, O_WRONLY); + if (fd < 0) { + if ((errno == ENOENT) && enoent_ok) + return; + die("open of %s failed: %s\n", filename, strerror(errno)); + } + + written = write(fd, buf, buf_len); + if (written != buf_len) { + if (written >= 0) { + die("short write to %s\n", filename); + } else { + die("write to %s failed: %s\n", + filename, strerror(errno)); + } + } + + if (close(fd) != 0) + die("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 void create_and_enter_ns(void) +{ + uid_t uid = getuid(); + gid_t gid = getgid(); + + if (unshare(CLONE_NEWUSER) != 0) + die("unshare(CLONE_NEWUSER) failed: %s\n", strerror(errno)); + + maybe_write_file("/proc/self/setgroups", "deny"); + write_file("/proc/self/uid_map", "0 %d 1", uid); + write_file("/proc/self/gid_map", "0 %d 1", gid); + + if (setgid(0) != 0) + die("setgid(0) failed %s\n", strerror(errno)); + if (setuid(0) != 0) + die("setuid(0) failed %s\n", strerror(errno)); + + if (unshare(CLONE_NEWNS) != 0) + die("unshare(CLONE_NEWNS) failed: %s\n", strerror(errno)); +} + +static void setup_symlink(void) +{ + int data, err; + + data = creat(DATA, O_RDWR); + if (data < 0) + die("creat failed: %s\n", strerror(errno)); + + err = symlink(DATA, LINK); + if (err < 0) + die("symlink failed: %s\n", strerror(errno)); + + if (close(data) != 0) + die("close of %s failed: %s\n", DATA, strerror(errno)); +} + +static void test_link_traversal(bool nosymfollow) +{ + int link; + + link = open(LINK, 0, O_RDWR); + if (nosymfollow) { + if ((link != -1 || errno != ELOOP)) { + die("link traversal unexpected result: %d, %s\n", + link, strerror(errno)); + } + } else { + if (link < 0) + die("link traversal failed: %s\n", strerror(errno)); + + if (close(link) != 0) + die("close of link failed: %s\n", strerror(errno)); + } +} + +static void test_readlink(void) +{ + char buf[4096]; + ssize_t ret; + + bzero(buf, sizeof(buf)); + + ret = readlink(LINK, buf, sizeof(buf)); + if (ret < 0) + die("readlink failed: %s\n", strerror(errno)); + if (strcmp(buf, DATA) != 0) + die("readlink strcmp failed: '%s' '%s'\n", buf, DATA); +} + +static void test_realpath(void) +{ + char *path = realpath(LINK, NULL); + + if (!path) + die("realpath failed: %s\n", strerror(errno)); + if (strcmp(path, DATA) != 0) + die("realpath strcmp failed\n"); + + free(path); +} + +static void test_statfs(bool nosymfollow) +{ + struct statfs buf; + int ret; + + ret = statfs(TMP, &buf); + if (ret) + die("statfs failed: %s\n", strerror(errno)); + + if (nosymfollow) { + if ((buf.f_flags & ST_NOSYMFOLLOW) == 0) + die("ST_NOSYMFOLLOW not set on %s\n", TMP); + } else { + if ((buf.f_flags & ST_NOSYMFOLLOW) != 0) + die("ST_NOSYMFOLLOW set on %s\n", TMP); + } +} + +static void run_tests(bool nosymfollow) +{ + test_link_traversal(nosymfollow); + test_readlink(); + test_realpath(); + test_statfs(nosymfollow); +} + +int main(int argc, char **argv) +{ + create_and_enter_ns(); + + if (mount("testing", TMP, "ramfs", 0, NULL) != 0) + die("mount failed: %s\n", strerror(errno)); + + setup_symlink(); + run_tests(false); + + if (mount("testing", TMP, "ramfs", MS_REMOUNT|MS_NOSYMFOLLOW, NULL) != 0) + die("remount failed: %s\n", strerror(errno)); + + run_tests(true); + + return EXIT_SUCCESS; +} diff --git a/tools/testing/selftests/mount/run_nosymfollow.sh b/tools/testing/selftests/mount/run_nosymfollow.sh new file mode 100755 index 000000000..5fbbf0304 --- /dev/null +++ b/tools/testing/selftests/mount/run_nosymfollow.sh @@ -0,0 +1,4 @@ +#!/bin/bash +# SPDX-License-Identifier: GPL-2.0 + +./nosymfollow-test diff --git a/tools/testing/selftests/mount/run_unprivileged_remount.sh b/tools/testing/selftests/mount/run_unprivileged_remount.sh new file mode 100755 index 000000000..4ab8f507d --- /dev/null +++ b/tools/testing/selftests/mount/run_unprivileged_remount.sh @@ -0,0 +1,12 @@ +#!/bin/bash +# SPDX-License-Identifier: GPL-2.0 +# Kselftest framework requirement - SKIP code is 4. +ksft_skip=4 + +# Run mount selftests +if [ -f /proc/self/uid_map ] ; then + ./unprivileged-remount-test ; +else + echo "WARN: No /proc/self/uid_map exist, test skipped." ; + exit $ksft_skip +fi diff --git a/tools/testing/selftests/mount/unprivileged-remount-test.c b/tools/testing/selftests/mount/unprivileged-remount-test.c new file mode 100644 index 000000000..584dc6bc3 --- /dev/null +++ b/tools/testing/selftests/mount/unprivileged-remount-test.c @@ -0,0 +1,371 @@ +// SPDX-License-Identifier: GPL-2.0 +#define _GNU_SOURCE +#include <sched.h> +#include <stdio.h> +#include <errno.h> +#include <string.h> +#include <sys/types.h> +#include <sys/mount.h> +#include <sys/wait.h> +#include <sys/vfs.h> +#include <sys/statvfs.h> +#include <stdlib.h> +#include <unistd.h> +#include <fcntl.h> +#include <grp.h> +#include <stdbool.h> +#include <stdarg.h> + +#ifndef CLONE_NEWNS +# define CLONE_NEWNS 0x00020000 +#endif +#ifndef CLONE_NEWUTS +# define CLONE_NEWUTS 0x04000000 +#endif +#ifndef CLONE_NEWIPC +# define CLONE_NEWIPC 0x08000000 +#endif +#ifndef CLONE_NEWNET +# define CLONE_NEWNET 0x40000000 +#endif +#ifndef CLONE_NEWUSER +# define CLONE_NEWUSER 0x10000000 +#endif +#ifndef CLONE_NEWPID +# define CLONE_NEWPID 0x20000000 +#endif + +#ifndef MS_REC +# define MS_REC 16384 +#endif +#ifndef MS_RELATIME +# define MS_RELATIME (1 << 21) +#endif +#ifndef MS_STRICTATIME +# define MS_STRICTATIME (1 << 24) +#endif + +static void die(char *fmt, ...) +{ + va_list ap; + va_start(ap, fmt); + vfprintf(stderr, fmt, ap); + va_end(ap); + exit(EXIT_FAILURE); +} + +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) { + die("vsnprintf failed: %s\n", + strerror(errno)); + } + if (buf_len >= sizeof(buf)) { + die("vsnprintf output truncated\n"); + } + + fd = open(filename, O_WRONLY); + if (fd < 0) { + if ((errno == ENOENT) && enoent_ok) + return; + die("open of %s failed: %s\n", + filename, strerror(errno)); + } + written = write(fd, buf, buf_len); + if (written != buf_len) { + if (written >= 0) { + die("short write to %s\n", filename); + } else { + die("write to %s failed: %s\n", + filename, strerror(errno)); + } + } + if (close(fd) != 0) { + die("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 int read_mnt_flags(const char *path) +{ + int ret; + struct statvfs stat; + int mnt_flags; + + ret = statvfs(path, &stat); + if (ret != 0) { + die("statvfs of %s failed: %s\n", + path, strerror(errno)); + } + if (stat.f_flag & ~(ST_RDONLY | ST_NOSUID | ST_NODEV | \ + ST_NOEXEC | ST_NOATIME | ST_NODIRATIME | ST_RELATIME | \ + ST_SYNCHRONOUS | ST_MANDLOCK)) { + die("Unrecognized mount flags\n"); + } + mnt_flags = 0; + if (stat.f_flag & ST_RDONLY) + mnt_flags |= MS_RDONLY; + if (stat.f_flag & ST_NOSUID) + mnt_flags |= MS_NOSUID; + if (stat.f_flag & ST_NODEV) + mnt_flags |= MS_NODEV; + if (stat.f_flag & ST_NOEXEC) + mnt_flags |= MS_NOEXEC; + if (stat.f_flag & ST_NOATIME) + mnt_flags |= MS_NOATIME; + if (stat.f_flag & ST_NODIRATIME) + mnt_flags |= MS_NODIRATIME; + if (stat.f_flag & ST_RELATIME) + mnt_flags |= MS_RELATIME; + if (stat.f_flag & ST_SYNCHRONOUS) + mnt_flags |= MS_SYNCHRONOUS; + if (stat.f_flag & ST_MANDLOCK) + mnt_flags |= ST_MANDLOCK; + + return mnt_flags; +} + +static void create_and_enter_userns(void) +{ + uid_t uid; + gid_t gid; + + uid = getuid(); + gid = getgid(); + + if (unshare(CLONE_NEWUSER) !=0) { + die("unshare(CLONE_NEWUSER) failed: %s\n", + strerror(errno)); + } + + maybe_write_file("/proc/self/setgroups", "deny"); + write_file("/proc/self/uid_map", "0 %d 1", uid); + write_file("/proc/self/gid_map", "0 %d 1", gid); + + if (setgid(0) != 0) { + die ("setgid(0) failed %s\n", + strerror(errno)); + } + if (setuid(0) != 0) { + die("setuid(0) failed %s\n", + strerror(errno)); + } +} + +static +bool test_unpriv_remount(const char *fstype, const char *mount_options, + int mount_flags, int remount_flags, int invalid_flags) +{ + pid_t child; + + child = fork(); + if (child == -1) { + die("fork failed: %s\n", + strerror(errno)); + } + if (child != 0) { /* parent */ + pid_t pid; + int status; + pid = waitpid(child, &status, 0); + if (pid == -1) { + die("waitpid failed: %s\n", + strerror(errno)); + } + if (pid != child) { + die("waited for %d got %d\n", + child, pid); + } + if (!WIFEXITED(status)) { + die("child did not terminate cleanly\n"); + } + return WEXITSTATUS(status) == EXIT_SUCCESS ? true : false; + } + + create_and_enter_userns(); + if (unshare(CLONE_NEWNS) != 0) { + die("unshare(CLONE_NEWNS) failed: %s\n", + strerror(errno)); + } + + if (mount("testing", "/tmp", fstype, mount_flags, mount_options) != 0) { + die("mount of %s with options '%s' on /tmp failed: %s\n", + fstype, + mount_options? mount_options : "", + strerror(errno)); + } + + create_and_enter_userns(); + + if (unshare(CLONE_NEWNS) != 0) { + die("unshare(CLONE_NEWNS) failed: %s\n", + strerror(errno)); + } + + if (mount("/tmp", "/tmp", "none", + MS_REMOUNT | MS_BIND | remount_flags, NULL) != 0) { + /* system("cat /proc/self/mounts"); */ + die("remount of /tmp failed: %s\n", + strerror(errno)); + } + + if (mount("/tmp", "/tmp", "none", + MS_REMOUNT | MS_BIND | invalid_flags, NULL) == 0) { + /* system("cat /proc/self/mounts"); */ + die("remount of /tmp with invalid flags " + "succeeded unexpectedly\n"); + } + exit(EXIT_SUCCESS); +} + +static bool test_unpriv_remount_simple(int mount_flags) +{ + return test_unpriv_remount("ramfs", NULL, mount_flags, mount_flags, 0); +} + +static bool test_unpriv_remount_atime(int mount_flags, int invalid_flags) +{ + return test_unpriv_remount("ramfs", NULL, mount_flags, mount_flags, + invalid_flags); +} + +static bool test_priv_mount_unpriv_remount(void) +{ + pid_t child; + int ret; + const char *orig_path = "/dev"; + const char *dest_path = "/tmp"; + int orig_mnt_flags, remount_mnt_flags; + + child = fork(); + if (child == -1) { + die("fork failed: %s\n", + strerror(errno)); + } + if (child != 0) { /* parent */ + pid_t pid; + int status; + pid = waitpid(child, &status, 0); + if (pid == -1) { + die("waitpid failed: %s\n", + strerror(errno)); + } + if (pid != child) { + die("waited for %d got %d\n", + child, pid); + } + if (!WIFEXITED(status)) { + die("child did not terminate cleanly\n"); + } + return WEXITSTATUS(status) == EXIT_SUCCESS ? true : false; + } + + orig_mnt_flags = read_mnt_flags(orig_path); + + create_and_enter_userns(); + ret = unshare(CLONE_NEWNS); + if (ret != 0) { + die("unshare(CLONE_NEWNS) failed: %s\n", + strerror(errno)); + } + + ret = mount(orig_path, dest_path, "bind", MS_BIND | MS_REC, NULL); + if (ret != 0) { + die("recursive bind mount of %s onto %s failed: %s\n", + orig_path, dest_path, strerror(errno)); + } + + ret = mount(dest_path, dest_path, "none", + MS_REMOUNT | MS_BIND | orig_mnt_flags , NULL); + if (ret != 0) { + /* system("cat /proc/self/mounts"); */ + die("remount of /tmp failed: %s\n", + strerror(errno)); + } + + remount_mnt_flags = read_mnt_flags(dest_path); + if (orig_mnt_flags != remount_mnt_flags) { + die("Mount flags unexpectedly changed during remount of %s originally mounted on %s\n", + dest_path, orig_path); + } + exit(EXIT_SUCCESS); +} + +int main(int argc, char **argv) +{ + if (!test_unpriv_remount_simple(MS_RDONLY)) { + die("MS_RDONLY malfunctions\n"); + } + if (!test_unpriv_remount("devpts", "newinstance", MS_NODEV, MS_NODEV, 0)) { + die("MS_NODEV malfunctions\n"); + } + if (!test_unpriv_remount_simple(MS_NOSUID)) { + die("MS_NOSUID malfunctions\n"); + } + if (!test_unpriv_remount_simple(MS_NOEXEC)) { + die("MS_NOEXEC malfunctions\n"); + } + if (!test_unpriv_remount_atime(MS_RELATIME, + MS_NOATIME)) + { + die("MS_RELATIME malfunctions\n"); + } + if (!test_unpriv_remount_atime(MS_STRICTATIME, + MS_NOATIME)) + { + die("MS_STRICTATIME malfunctions\n"); + } + if (!test_unpriv_remount_atime(MS_NOATIME, + MS_STRICTATIME)) + { + die("MS_NOATIME malfunctions\n"); + } + if (!test_unpriv_remount_atime(MS_RELATIME|MS_NODIRATIME, + MS_NOATIME)) + { + die("MS_RELATIME|MS_NODIRATIME malfunctions\n"); + } + if (!test_unpriv_remount_atime(MS_STRICTATIME|MS_NODIRATIME, + MS_NOATIME)) + { + die("MS_STRICTATIME|MS_NODIRATIME malfunctions\n"); + } + if (!test_unpriv_remount_atime(MS_NOATIME|MS_NODIRATIME, + MS_STRICTATIME)) + { + die("MS_NOATIME|MS_DIRATIME malfunctions\n"); + } + if (!test_unpriv_remount("ramfs", NULL, MS_STRICTATIME, 0, MS_NOATIME)) + { + die("Default atime malfunctions\n"); + } + if (!test_priv_mount_unpriv_remount()) { + die("Mount flags unexpectedly changed after remount\n"); + } + return EXIT_SUCCESS; +} |