[PATCH 13/34] selftests: add idmapped mounts xattr selftest

From: Tycho Andersen <tycho(a)tycho.pizza&gt; Add some tests for setting extended attributes on idmapped mounts. Signed-off-by: Tycho Andersen <tycho(a)tycho.pizza&gt; Signed-off-by: Christian Brauner <christian.brauner(a)ubuntu.com&gt; --- .../testing/selftests/idmap_mounts/.gitignore | 1 + tools/testing/selftests/idmap_mounts/Makefile | 8 + tools/testing/selftests/idmap_mounts/config | 1 + tools/testing/selftests/idmap_mounts/xattr.c | 389 ++++++++++++++++++ 4 files changed, 399 insertions(+) create mode 100644 tools/testing/selftests/idmap_mounts/.gitignore create mode 100644 tools/testing/selftests/idmap_mounts/Makefile create mode 100644 tools/testing/selftests/idmap_mounts/config create mode 100644 tools/testing/selftests/idmap_mounts/xattr.c diff --git a/tools/testing/selftests/idmap_mounts/.gitignore b/tools/testing/selftests/idmap_mounts/.gitignore new file mode 100644 index 000000000000..18c5e90522ad --- /dev/null +++ b/tools/testing/selftests/idmap_mounts/.gitignore @@ -0,0 +1 @@ +xattr diff --git a/tools/testing/selftests/idmap_mounts/Makefile b/tools/testing/selftests/idmap_mounts/Makefile new file mode 100644 index 000000000000..ce0549b09b2a --- /dev/null +++ b/tools/testing/selftests/idmap_mounts/Makefile @@ -0,0 +1,8 @@ +# SPDX-License-Identifier: GPL-2.0 +# Makefile for mount selftests. +CFLAGS = -g -I../../../../usr/include/ -Wall -O2 -pthread + +TEST_GEN_FILES += xattr + +include ../lib.mk + diff --git a/tools/testing/selftests/idmap_mounts/config b/tools/testing/selftests/idmap_mounts/config new file mode 100644 index 000000000000..80730abc534b --- /dev/null +++ b/tools/testing/selftests/idmap_mounts/config @@ -0,0 +1 @@ +CONFIG_IDMAP_MOUNTS=y diff --git a/tools/testing/selftests/idmap_mounts/xattr.c b/tools/testing/selftests/idmap_mounts/xattr.c new file mode 100644 index 000000000000..a3d70294ce43 --- /dev/null +++ b/tools/testing/selftests/idmap_mounts/xattr.c @@ -0,0 +1,389 @@ +// SPDX-License-Identifier: GPL-2.0 +#define _GNU_SOURCE +#include <fcntl.h> +#include <sched.h> +#include <sys/mount.h> +#include <sys/stat.h> +#include <sys/types.h> +#include <linux/limits.h> + +#include "../kselftest_harness.h" + +#ifndef __NR_mount_setattr + #if defined __alpha__ + #define __NR_mount_setattr 551 + #elif defined _MIPS_SIM + #if _MIPS_SIM == _MIPS_SIM_ABI32 /* o32 */ + #define __NR_mount_setattr 4441 + #endif + #if _MIPS_SIM == _MIPS_SIM_NABI32 /* n32 */ + #define __NR_mount_setattr 6441 + #endif + #if _MIPS_SIM == _MIPS_SIM_ABI64 /* n64 */ + #define __NR_mount_setattr 5441 + #endif + #elif defined __ia64__ + #define __NR_mount_setattr (441 + 1024) + #else + #define __NR_mount_setattr 441 + #endif + +#ifndef __NR_open_tree + #if defined __alpha__ + #define __NR_open_tree 538 + #elif defined _MIPS_SIM + #if _MIPS_SIM == _MIPS_SIM_ABI32 /* o32 */ + #define __NR_open_tree 4428 + #endif + #if _MIPS_SIM == _MIPS_SIM_NABI32 /* n32 */ + #define __NR_open_tree 6428 + #endif + #if _MIPS_SIM == _MIPS_SIM_ABI64 /* n64 */ + #define __NR_open_tree 5428 + #endif + #elif defined __ia64__ + #define __NR_open_tree (428 + 1024) + #else + #define __NR_open_tree 428 + #endif +#endif + +#ifndef __NR_move_mount + #if defined __alpha__ + #define __NR_move_mount 539 + #elif defined _MIPS_SIM + #if _MIPS_SIM == _MIPS_SIM_ABI32 /* o32 */ + #define __NR_move_mount 4429 + #endif + #if _MIPS_SIM == _MIPS_SIM_NABI32 /* n32 */ + #define __NR_move_mount 6429 + #endif + #if _MIPS_SIM == _MIPS_SIM_ABI64 /* n64 */ + #define __NR_move_mount 5429 + #endif + #elif defined __ia64__ + #define __NR_move_mount (428 + 1024) + #else + #define __NR_move_mount 429 + #endif +#endif + + +struct mount_attr { + __u64 attr_set; + __u64 attr_clr; + __u64 propagation; + __u32 userns; +}; +#endif + +#ifndef MOVE_MOUNT_F_EMPTY_PATH +#define MOVE_MOUNT_F_EMPTY_PATH 0x00000004 /* Empty from path permitted */ +#endif + +#ifndef MOUNT_ATTR_SHIFT +#define MOUNT_ATTR_SHIFT 0x00100000 +#endif + +#ifndef OPEN_TREE_CLONE +#define OPEN_TREE_CLONE 1 +#endif + +#ifndef OPEN_TREE_CLOEXEC +#define OPEN_TREE_CLOEXEC O_CLOEXEC +#endif + +#ifndef AT_RECURSIVE +#define AT_RECURSIVE 0x8000 /* Apply to the entire subtree */ +#endif + +static inline int sys_mount_setattr(int dfd, const char *path, unsigned int flags, + struct mount_attr *attr, size_t size) +{ + return syscall(__NR_mount_setattr, dfd, path, flags, attr, size); +} + +static inline int sys_open_tree(int dfd, const char *filename, unsigned int flags) +{ + return syscall(__NR_open_tree, dfd, filename, flags); +} + +static inline int sys_move_mount(int from_dfd, const char *from_pathname, int to_dfd, + const char *to_pathname, unsigned int flags) +{ + return syscall(__NR_move_mount, from_dfd, from_pathname, to_dfd, to_pathname, flags); +} + + +static ssize_t write_nointr(int fd, const void *buf, size_t count) +{ + ssize_t ret; + + do { + ret = write(fd, buf, count); + } while (ret < 0 && errno == EINTR); + + return ret; +} + +static int write_file(const char *path, const void *buf, size_t count) +{ + int fd; + ssize_t ret; + + fd = open(path, O_WRONLY | O_CLOEXEC | O_NOCTTY | O_NOFOLLOW); + if (fd < 0) + return -1; + + ret = write_nointr(fd, buf, count); + close(fd); + if (ret < 0 || (size_t)ret != count) + return -1; + + return 0; +} + +static int map_ids(pid_t pid, unsigned long nsid, unsigned long hostid, + unsigned long range) +{ + char map[100], procfile[256]; + + snprintf(procfile, sizeof(procfile), "/proc/%d/setgroups", pid); + if (write_file(procfile, "deny", sizeof("deny") - 1) && + errno != ENOENT) + return -1; + + snprintf(procfile, sizeof(procfile), "/proc/%d/uid_map", pid); + snprintf(map, sizeof(map), "%lu %lu %lu", nsid, hostid, range); + if (write_file(procfile, map, strlen(map))) + return -1; + + + snprintf(procfile, sizeof(procfile), "/proc/%d/gid_map", pid); + snprintf(map, sizeof(map), "%lu %lu %lu", nsid, hostid, range); + if (write_file(procfile, map, strlen(map))) + return -1; + + return 0; +} + +#define __STACK_SIZE (8 * 1024 * 1024) +static pid_t do_clone(int (*fn)(void *), void *arg, int flags) +{ + void *stack; + + stack = malloc(__STACK_SIZE); + if (!stack) + return -ENOMEM; + +#ifdef __ia64__ + return __clone2(fn, stack, __STACK_SIZE, flags | SIGCHLD, arg, NULL); +#else + return clone(fn, stack + __STACK_SIZE, flags | SIGCHLD, arg, NULL); +#endif +} + +static int get_userns_fd_cb(void *data) +{ + return kill(getpid(), SIGSTOP); +} + +static int get_userns_fd(unsigned long nsid, unsigned long hostid, + unsigned long range) +{ + int ret; + pid_t pid; + char path[256]; + + pid = do_clone(get_userns_fd_cb, NULL, CLONE_NEWUSER | CLONE_NEWNS); + if (pid < 0) + return -errno; + + ret = map_ids(pid, nsid, hostid, range); + if (ret < 0) + return ret; + + snprintf(path, sizeof(path), "/proc/%d/ns/user", pid); + ret = open(path, O_RDONLY | O_CLOEXEC); + kill(pid, SIGKILL); + return ret; +} + +struct run_as_data { + int userns; + int (*f)(void *data); + void *data; +}; + +static int run_in_cb(void *data) +{ + struct run_as_data *rad = data; + + if (setns(rad->userns, CLONE_NEWUSER) < 0) { + perror("setns"); + return 1; + } + + if (setuid(100010)) { + perror("setuid"); + return 1; + } + + if (setgid(100010)) { + perror("setgid"); + return 1; + } + + return rad->f(rad->data); +} + +static int wait_for_pid(pid_t pid) +{ + int status, ret; + +again: + ret = waitpid(pid, &status, 0); + if (ret == -1) { + if (errno == EINTR) + goto again; + + return -1; + } + + if (!WIFEXITED(status)) + return -1; + + return WEXITSTATUS(status); +} + +static int run_in(int userns, int (*f)(void *), void *f_data) +{ + pid_t pid; + struct run_as_data data; + + data.userns = userns; + data.f = f; + data.data = f_data; + pid = do_clone(run_in_cb, &data, 0); + if (pid < 0) + return -errno; + + return wait_for_pid(pid); +} + +FIXTURE(ext4_xattr) {}; + +FIXTURE_SETUP(ext4_xattr) +{ + int fd; + + fd = open("/tmp/idmap_mounts.ext4", O_CREAT | O_WRONLY, 0600); + ASSERT_GE(fd, 0); + ASSERT_EQ(ftruncate(fd, 640 * 1024), 0); + ASSERT_EQ(close(fd), 0); + ASSERT_EQ(system("mkfs.ext4 /tmp/idmap_mounts.ext4"), 0); + ASSERT_EQ(mkdir("/tmp/ext4", 0777), 0); + ASSERT_EQ(system("mount -o loop -t ext4 /tmp/idmap_mounts.ext4 /tmp/ext4"), 0); +} + +FIXTURE_TEARDOWN(ext4_xattr) +{ + umount("/tmp/ext4/dest"); + umount("/tmp/ext4"); + rmdir("/tmp/ext4"); + unlink("/tmp/idmap_mounts.ext4"); +} + +struct getacl_should_be_data { + char path[256]; + uid_t uid; +}; + +static int getacl_should_be_uid(void *data) +{ + struct getacl_should_be_data *ssb = data; + char cmd[512]; + int ret; + + snprintf(cmd, sizeof(cmd), "getfacl %s | grep user:%u:rwx", ssb->path, ssb->uid); + ret = system(cmd); + if (ret < 0) { + perror("system"); + return -1; + } + if (!WIFEXITED(ret)) + return -1; + return WEXITSTATUS(ret); +} + +static int ls_path(void *data) +{ + char cmd[PATH_MAX]; + char *path = data; + int ret; + + snprintf(cmd, sizeof(cmd), "ls %s", path); + ret = system(cmd); + if (ret < 0) { + perror("system"); + return -1; + } + if (!WIFEXITED(ret)) + return -1; + return WEXITSTATUS(ret); +} + +TEST_F(ext4_xattr, setattr_didnt_work) +{ + int mount_fd, ret; + struct mount_attr attr = {}; + struct getacl_should_be_data ssb; + + ASSERT_EQ(mkdir("/tmp/ext4/source", 0777), 0); + ASSERT_EQ(mkdir("/tmp/ext4/dest", 0777), 0); + + mount_fd = sys_open_tree(-EBADF, "/tmp/ext4/source", + OPEN_TREE_CLONE | OPEN_TREE_CLOEXEC | AT_EMPTY_PATH); + ASSERT_GE(mount_fd, 0); + + ASSERT_EQ(sys_move_mount(mount_fd, "", -EBADF, "/tmp/ext4/dest", + MOVE_MOUNT_F_EMPTY_PATH), 0); + + attr.attr_set = MOUNT_ATTR_SHIFT; + attr.userns = get_userns_fd(100010, 100020, 5); + ASSERT_GE(attr.userns, 0); + ret = sys_mount_setattr(mount_fd, "", AT_EMPTY_PATH | AT_RECURSIVE, + &attr, sizeof(attr)); + ASSERT_EQ(close(mount_fd), 0); + ASSERT_EQ(ret, 0); + + ASSERT_EQ(mkdir("/tmp/ext4/source/foo", 0700), 0); + ASSERT_EQ(chown("/tmp/ext4/source/foo", 100010, 100010), 0); + + ASSERT_EQ(system("setfacl -m u:100010:rwx /tmp/ext4/source/foo"), 0); + EXPECT_EQ(system("getfacl /tmp/ext4/source/foo | grep user:100010:rwx"), 0); + EXPECT_EQ(system("getfacl /tmp/ext4/dest/foo | grep user:100020:rwx"), 0); + + snprintf(ssb.path, sizeof(ssb.path), "/tmp/ext4/source/foo"); + ssb.uid = 4294967295; + EXPECT_EQ(run_in(attr.userns, getacl_should_be_uid, &ssb), 0); + + snprintf(ssb.path, sizeof(ssb.path), "/tmp/ext4/dest/foo"); + ssb.uid = 100010; + EXPECT_EQ(run_in(attr.userns, getacl_should_be_uid, &ssb), 0); + + /* + * now, dir is owned by someone else in the user namespace, but we can + * still read it because of acls + */ + ASSERT_EQ(chown("/tmp/ext4/source/foo", 100012, 100012), 0); + EXPECT_EQ(run_in(attr.userns, ls_path, "/tmp/ext4/dest/foo"), 0); + + /* + * if we delete the acls, the ls should fail because it's 700. + */ + ASSERT_EQ(system("setfacl --remove-all /tmp/ext4/source/foo"), 0); + EXPECT_NE(run_in(attr.userns, ls_path, "/tmp/ext4/dest/foo"), 0); +} + +TEST_HARNESS_MAIN -- 2.29.0