@@ -33,6 +33,7 @@ TARGETS += memfd
TARGETS += memory-hotplug
TARGETS += mincore
TARGETS += mount
+TARGETS += mount_setattr
TARGETS += mqueue
TARGETS += net
TARGETS += net/forwarding
new file mode 100644
@@ -0,0 +1 @@
+mount_setattr_test
new file mode 100644
@@ -0,0 +1,7 @@
+# SPDX-License-Identifier: GPL-2.0
+# Makefile for mount selftests.
+CFLAGS = -g -I../../../../usr/include/ -Wall -O2 -pthread
+
+TEST_GEN_FILES += mount_setattr_test
+
+include ../lib.mk
new file mode 100644
@@ -0,0 +1 @@
+CONFIG_USER_NS=y
new file mode 100644
@@ -0,0 +1,1424 @@
+// SPDX-License-Identifier: GPL-2.0
+#define _GNU_SOURCE
+#include <sched.h>
+#include <stdio.h>
+#include <errno.h>
+#include <pthread.h>
+#include <string.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <sys/mount.h>
+#include <sys/wait.h>
+#include <sys/vfs.h>
+#include <sys/statvfs.h>
+#include <sys/sysinfo.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <grp.h>
+#include <stdbool.h>
+#include <stdarg.h>
+
+#include "../kselftest_harness.h"
+
+#ifndef CLONE_NEWNS
+#define CLONE_NEWNS 0x00020000
+#endif
+
+#ifndef CLONE_NEWUSER
+#define CLONE_NEWUSER 0x10000000
+#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
+
+#ifndef MOUNT_ATTR_RDONLY
+#define MOUNT_ATTR_RDONLY 0x00000001
+#endif
+
+#ifndef MOUNT_ATTR_NOSUID
+#define MOUNT_ATTR_NOSUID 0x00000002
+#endif
+
+#ifndef MOUNT_ATTR_NOEXEC
+#define MOUNT_ATTR_NOEXEC 0x00000008
+#endif
+
+#ifndef MOUNT_ATTR_NODIRATIME
+#define MOUNT_ATTR_NODIRATIME 0x00000080
+#endif
+
+#ifndef MOUNT_ATTR__ATIME
+#define MOUNT_ATTR__ATIME 0x00000070
+#endif
+
+#ifndef MOUNT_ATTR_RELATIME
+#define MOUNT_ATTR_RELATIME 0x00000000
+#endif
+
+#ifndef MOUNT_ATTR_NOATIME
+#define MOUNT_ATTR_NOATIME 0x00000010
+#endif
+
+#ifndef MOUNT_ATTR_STRICTATIME
+#define MOUNT_ATTR_STRICTATIME 0x00000020
+#endif
+
+#ifndef AT_RECURSIVE
+#define AT_RECURSIVE 0x8000
+#endif
+
+#ifndef MS_SHARED
+#define MS_SHARED (1 << 20)
+#endif
+
+#define DEFAULT_THREADS 4
+#define ptr_to_int(p) ((int)((intptr_t)(p)))
+#define int_to_ptr(u) ((void *)((intptr_t)(u)))
+
+#ifndef __NR_mount_setattr
+ #if defined __alpha__
+ #define __NR_mount_setattr 552
+ #elif defined _MIPS_SIM
+ #if _MIPS_SIM == _MIPS_SIM_ABI32 /* o32 */
+ #define __NR_mount_setattr (442 + 4000)
+ #endif
+ #if _MIPS_SIM == _MIPS_SIM_NABI32 /* n32 */
+ #define __NR_mount_setattr (442 + 6000)
+ #endif
+ #if _MIPS_SIM == _MIPS_SIM_ABI64 /* n64 */
+ #define __NR_mount_setattr (442 + 5000)
+ #endif
+ #elif defined __ia64__
+ #define __NR_mount_setattr (442 + 1024)
+ #else
+ #define __NR_mount_setattr 442
+ #endif
+
+struct mount_attr {
+ __u64 attr_set;
+ __u64 attr_clr;
+ __u64 propagation;
+ __u64 userns_fd;
+};
+#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 MOUNT_ATTR_IDMAP
+#define MOUNT_ATTR_IDMAP 0x00100000
+#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);
+}
+
+#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_open_tree(int dfd, const char *filename, unsigned int flags)
+{
+ return syscall(__NR_open_tree, dfd, filename, 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 create_and_enter_userns(void)
+{
+ uid_t uid;
+ gid_t gid;
+ char map[100];
+
+ uid = getuid();
+ gid = getgid();
+
+ if (unshare(CLONE_NEWUSER))
+ return -1;
+
+ if (write_file("/proc/self/setgroups", "deny", sizeof("deny") - 1) &&
+ errno != ENOENT)
+ return -1;
+
+ snprintf(map, sizeof(map), "0 %d 1", uid);
+ if (write_file("/proc/self/uid_map", map, strlen(map)))
+ return -1;
+
+
+ snprintf(map, sizeof(map), "0 %d 1", gid);
+ if (write_file("/proc/self/gid_map", map, strlen(map)))
+ return -1;
+
+ if (setgid(0))
+ return -1;
+
+ if (setuid(0))
+ return -1;
+
+ return 0;
+}
+
+static int prepare_unpriv_mountns(void)
+{
+ if (create_and_enter_userns())
+ return -1;
+
+ if (unshare(CLONE_NEWNS))
+ return -1;
+
+ if (mount(NULL, "/", NULL, MS_REC | MS_PRIVATE, 0))
+ return -1;
+
+ return 0;
+}
+
+static int read_mnt_flags(const char *path)
+{
+ int ret;
+ struct statvfs stat;
+ unsigned int mnt_flags;
+
+ ret = statvfs(path, &stat);
+ if (ret != 0)
+ return -EINVAL;
+
+ if (stat.f_flag &
+ ~(ST_RDONLY | ST_NOSUID | ST_NODEV | ST_NOEXEC | ST_NOATIME |
+ ST_NODIRATIME | ST_RELATIME | ST_SYNCHRONOUS | ST_MANDLOCK))
+ return -EINVAL;
+
+ 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 char *get_field(char *src, int nfields)
+{
+ int i;
+ char *p = src;
+
+ for (i = 0; i < nfields; i++) {
+ while (*p && *p != ' ' && *p != '\t')
+ p++;
+
+ if (!*p)
+ break;
+
+ p++;
+ }
+
+ return p;
+}
+
+static void null_endofword(char *word)
+{
+ while (*word && *word != ' ' && *word != '\t')
+ word++;
+ *word = '\0';
+}
+
+static bool is_shared_mount(const char *path)
+{
+ size_t len = 0;
+ char *line = NULL;
+ FILE *f = NULL;
+
+ f = fopen("/proc/self/mountinfo", "re");
+ if (!f)
+ return false;
+
+ while (getline(&line, &len, f) != -1) {
+ char *opts, *target;
+
+ target = get_field(line, 4);
+ if (!target)
+ continue;
+
+ opts = get_field(target, 2);
+ if (!opts)
+ continue;
+
+ null_endofword(target);
+
+ if (strcmp(target, path) != 0)
+ continue;
+
+ null_endofword(opts);
+ if (strstr(opts, "shared:"))
+ return true;
+ }
+
+ free(line);
+ fclose(f);
+
+ return false;
+}
+
+static void *mount_setattr_thread(void *data)
+{
+ struct mount_attr attr = {
+ .attr_set = MOUNT_ATTR_RDONLY | MOUNT_ATTR_NOSUID,
+ .attr_clr = 0,
+ .propagation = MS_SHARED,
+ };
+
+ if (sys_mount_setattr(-1, "/mnt/A", AT_RECURSIVE, &attr, sizeof(attr)))
+ pthread_exit(int_to_ptr(-1));
+
+ pthread_exit(int_to_ptr(0));
+}
+
+/* Attempt to de-conflict with the selftests tree. */
+#ifndef SKIP
+#define SKIP(s, ...) XFAIL(s, ##__VA_ARGS__)
+#endif
+
+static bool mount_setattr_supported(void)
+{
+ int ret;
+
+ ret = sys_mount_setattr(-EBADF, "", AT_EMPTY_PATH, NULL, 0);
+ if (ret < 0 && errno == ENOSYS)
+ return false;
+
+ return true;
+}
+
+FIXTURE(mount_setattr) {
+};
+
+FIXTURE_SETUP(mount_setattr)
+{
+ if (!mount_setattr_supported())
+ SKIP(return, "mount_setattr syscall not supported");
+
+ ASSERT_EQ(prepare_unpriv_mountns(), 0);
+
+ (void)umount2("/mnt", MNT_DETACH);
+ (void)umount2("/tmp", MNT_DETACH);
+
+ ASSERT_EQ(mount("testing", "/tmp", "tmpfs", MS_NOATIME | MS_NODEV,
+ "size=100000,mode=700"), 0);
+
+ ASSERT_EQ(mkdir("/tmp/B", 0777), 0);
+
+ ASSERT_EQ(mount("testing", "/tmp/B", "tmpfs", MS_NOATIME | MS_NODEV,
+ "size=100000,mode=700"), 0);
+
+ ASSERT_EQ(mkdir("/tmp/B/BB", 0777), 0);
+
+ ASSERT_EQ(mount("testing", "/tmp/B/BB", "tmpfs", MS_NOATIME | MS_NODEV,
+ "size=100000,mode=700"), 0);
+
+ ASSERT_EQ(mount("testing", "/mnt", "tmpfs", MS_NOATIME | MS_NODEV,
+ "size=100000,mode=700"), 0);
+
+ ASSERT_EQ(mkdir("/mnt/A", 0777), 0);
+
+ ASSERT_EQ(mount("testing", "/mnt/A", "tmpfs", MS_NOATIME | MS_NODEV,
+ "size=100000,mode=700"), 0);
+
+ ASSERT_EQ(mkdir("/mnt/A/AA", 0777), 0);
+
+ ASSERT_EQ(mount("/tmp", "/mnt/A/AA", NULL, MS_BIND | MS_REC, NULL), 0);
+
+ ASSERT_EQ(mkdir("/mnt/B", 0777), 0);
+
+ ASSERT_EQ(mount("testing", "/mnt/B", "ramfs",
+ MS_NOATIME | MS_NODEV | MS_NOSUID, 0), 0);
+
+ ASSERT_EQ(mkdir("/mnt/B/BB", 0777), 0);
+
+ ASSERT_EQ(mount("testing", "/tmp/B/BB", "devpts",
+ MS_RELATIME | MS_NOEXEC | MS_RDONLY, 0), 0);
+}
+
+FIXTURE_TEARDOWN(mount_setattr)
+{
+ if (!mount_setattr_supported())
+ SKIP(return, "mount_setattr syscall not supported");
+
+ (void)umount2("/mnt/A", MNT_DETACH);
+ (void)umount2("/tmp", MNT_DETACH);
+}
+
+TEST_F(mount_setattr, invalid_attributes)
+{
+ struct mount_attr invalid_attr = {
+ .attr_set = (1U << 31),
+ };
+
+ if (!mount_setattr_supported())
+ SKIP(return, "mount_setattr syscall not supported");
+
+ ASSERT_NE(sys_mount_setattr(-1, "/mnt/A", AT_RECURSIVE, &invalid_attr,
+ sizeof(invalid_attr)), 0);
+
+ invalid_attr.attr_set = 0;
+ invalid_attr.attr_clr = (1U << 31);
+ ASSERT_NE(sys_mount_setattr(-1, "/mnt/A", AT_RECURSIVE, &invalid_attr,
+ sizeof(invalid_attr)), 0);
+
+ invalid_attr.attr_clr = 0;
+ invalid_attr.propagation = (1U << 31);
+ ASSERT_NE(sys_mount_setattr(-1, "/mnt/A", AT_RECURSIVE, &invalid_attr,
+ sizeof(invalid_attr)), 0);
+
+ invalid_attr.attr_set = (1U << 31);
+ invalid_attr.attr_clr = (1U << 31);
+ invalid_attr.propagation = (1U << 31);
+ ASSERT_NE(sys_mount_setattr(-1, "/mnt/A", AT_RECURSIVE, &invalid_attr,
+ sizeof(invalid_attr)), 0);
+
+ ASSERT_NE(sys_mount_setattr(-1, "mnt/A", AT_RECURSIVE, &invalid_attr,
+ sizeof(invalid_attr)), 0);
+}
+
+TEST_F(mount_setattr, extensibility)
+{
+ unsigned int old_flags = 0, new_flags = 0, expected_flags = 0;
+ char *s = "dummy";
+ struct mount_attr invalid_attr = {};
+ struct mount_attr_large {
+ struct mount_attr attr1;
+ struct mount_attr attr2;
+ struct mount_attr attr3;
+ } large_attr = {};
+
+ if (!mount_setattr_supported())
+ SKIP(return, "mount_setattr syscall not supported");
+
+ old_flags = read_mnt_flags("/mnt/A");
+ ASSERT_GT(old_flags, 0);
+
+ ASSERT_NE(sys_mount_setattr(-1, "/mnt/A", AT_RECURSIVE, NULL,
+ sizeof(invalid_attr)), 0);
+ ASSERT_EQ(errno, EFAULT);
+
+ ASSERT_NE(sys_mount_setattr(-1, "/mnt/A", AT_RECURSIVE, (void *)s,
+ sizeof(invalid_attr)), 0);
+ ASSERT_EQ(errno, EINVAL);
+
+ ASSERT_NE(sys_mount_setattr(-1, "/mnt/A", AT_RECURSIVE, &invalid_attr, 0), 0);
+ ASSERT_EQ(errno, EINVAL);
+
+ ASSERT_NE(sys_mount_setattr(-1, "/mnt/A", AT_RECURSIVE, &invalid_attr,
+ sizeof(invalid_attr) / 2), 0);
+ ASSERT_EQ(errno, EINVAL);
+
+ ASSERT_NE(sys_mount_setattr(-1, "/mnt/A", AT_RECURSIVE, &invalid_attr,
+ sizeof(invalid_attr) / 2), 0);
+ ASSERT_EQ(errno, EINVAL);
+
+ ASSERT_EQ(sys_mount_setattr(-1, "/mnt/A", AT_RECURSIVE,
+ (void *)&large_attr, sizeof(large_attr)), 0);
+
+ large_attr.attr3.attr_set = MOUNT_ATTR_RDONLY;
+ ASSERT_NE(sys_mount_setattr(-1, "/mnt/A", AT_RECURSIVE,
+ (void *)&large_attr, sizeof(large_attr)), 0);
+
+ large_attr.attr3.attr_set = 0;
+ large_attr.attr1.attr_set = MOUNT_ATTR_RDONLY;
+ ASSERT_EQ(sys_mount_setattr(-1, "/mnt/A", AT_RECURSIVE,
+ (void *)&large_attr, sizeof(large_attr)), 0);
+
+ expected_flags = old_flags;
+ expected_flags |= MS_RDONLY;
+
+ new_flags = read_mnt_flags("/mnt/A");
+ ASSERT_EQ(new_flags, expected_flags);
+
+ new_flags = read_mnt_flags("/mnt/A/AA");
+ ASSERT_EQ(new_flags, expected_flags);
+
+ new_flags = read_mnt_flags("/mnt/A/AA/B");
+ ASSERT_EQ(new_flags, expected_flags);
+
+ new_flags = read_mnt_flags("/mnt/A/AA/B/BB");
+ ASSERT_EQ(new_flags, expected_flags);
+}
+
+TEST_F(mount_setattr, basic)
+{
+ unsigned int old_flags = 0, new_flags = 0, expected_flags = 0;
+ struct mount_attr attr = {
+ .attr_set = MOUNT_ATTR_RDONLY | MOUNT_ATTR_NOEXEC | MOUNT_ATTR_RELATIME,
+ .attr_clr = MOUNT_ATTR__ATIME,
+ };
+
+ if (!mount_setattr_supported())
+ SKIP(return, "mount_setattr syscall not supported");
+
+ old_flags = read_mnt_flags("/mnt/A");
+ ASSERT_GT(old_flags, 0);
+
+ ASSERT_EQ(sys_mount_setattr(-1, "/mnt/A", 0, &attr, sizeof(attr)), 0);
+
+ expected_flags = old_flags;
+ expected_flags |= MS_RDONLY;
+ expected_flags |= MS_NOEXEC;
+ expected_flags &= ~MS_NOATIME;
+ expected_flags |= MS_RELATIME;
+
+ new_flags = read_mnt_flags("/mnt/A");
+ ASSERT_EQ(new_flags, expected_flags);
+
+ new_flags = read_mnt_flags("/mnt/A/AA");
+ ASSERT_EQ(new_flags, old_flags);
+
+ new_flags = read_mnt_flags("/mnt/A/AA/B");
+ ASSERT_EQ(new_flags, old_flags);
+
+ new_flags = read_mnt_flags("/mnt/A/AA/B/BB");
+ ASSERT_EQ(new_flags, old_flags);
+}
+
+TEST_F(mount_setattr, basic_recursive)
+{
+ int fd;
+ unsigned int old_flags = 0, new_flags = 0, expected_flags = 0;
+ struct mount_attr attr = {
+ .attr_set = MOUNT_ATTR_RDONLY | MOUNT_ATTR_NOEXEC | MOUNT_ATTR_RELATIME,
+ .attr_clr = MOUNT_ATTR__ATIME,
+ };
+
+ if (!mount_setattr_supported())
+ SKIP(return, "mount_setattr syscall not supported");
+
+ old_flags = read_mnt_flags("/mnt/A");
+ ASSERT_GT(old_flags, 0);
+
+ ASSERT_EQ(sys_mount_setattr(-1, "/mnt/A", AT_RECURSIVE, &attr, sizeof(attr)), 0);
+
+ expected_flags = old_flags;
+ expected_flags |= MS_RDONLY;
+ expected_flags |= MS_NOEXEC;
+ expected_flags &= ~MS_NOATIME;
+ expected_flags |= MS_RELATIME;
+
+ new_flags = read_mnt_flags("/mnt/A");
+ ASSERT_EQ(new_flags, expected_flags);
+
+ new_flags = read_mnt_flags("/mnt/A/AA");
+ ASSERT_EQ(new_flags, expected_flags);
+
+ new_flags = read_mnt_flags("/mnt/A/AA/B");
+ ASSERT_EQ(new_flags, expected_flags);
+
+ new_flags = read_mnt_flags("/mnt/A/AA/B/BB");
+ ASSERT_EQ(new_flags, expected_flags);
+
+ memset(&attr, 0, sizeof(attr));
+ attr.attr_clr = MOUNT_ATTR_RDONLY;
+ attr.propagation = MS_SHARED;
+ ASSERT_EQ(sys_mount_setattr(-1, "/mnt/A", AT_RECURSIVE, &attr, sizeof(attr)), 0);
+
+ expected_flags &= ~MS_RDONLY;
+ new_flags = read_mnt_flags("/mnt/A");
+ ASSERT_EQ(new_flags, expected_flags);
+
+ ASSERT_EQ(is_shared_mount("/mnt/A"), true);
+
+ new_flags = read_mnt_flags("/mnt/A/AA");
+ ASSERT_EQ(new_flags, expected_flags);
+
+ ASSERT_EQ(is_shared_mount("/mnt/A/AA"), true);
+
+ new_flags = read_mnt_flags("/mnt/A/AA/B");
+ ASSERT_EQ(new_flags, expected_flags);
+
+ ASSERT_EQ(is_shared_mount("/mnt/A/AA/B"), true);
+
+ new_flags = read_mnt_flags("/mnt/A/AA/B/BB");
+ ASSERT_EQ(new_flags, expected_flags);
+
+ ASSERT_EQ(is_shared_mount("/mnt/A/AA/B/BB"), true);
+
+ fd = open("/mnt/A/AA/B/b", O_RDWR | O_CLOEXEC | O_CREAT | O_EXCL, 0777);
+ ASSERT_GE(fd, 0);
+
+ /*
+ * We're holding a fd open for writing so this needs to fail somewhere
+ * in the middle and the mount options need to be unchanged.
+ */
+ attr.attr_set = MOUNT_ATTR_RDONLY;
+ ASSERT_LT(sys_mount_setattr(-1, "/mnt/A", AT_RECURSIVE, &attr, sizeof(attr)), 0);
+
+ new_flags = read_mnt_flags("/mnt/A");
+ ASSERT_EQ(new_flags, expected_flags);
+
+ ASSERT_EQ(is_shared_mount("/mnt/A"), true);
+
+ new_flags = read_mnt_flags("/mnt/A/AA");
+ ASSERT_EQ(new_flags, expected_flags);
+
+ ASSERT_EQ(is_shared_mount("/mnt/A/AA"), true);
+
+ new_flags = read_mnt_flags("/mnt/A/AA/B");
+ ASSERT_EQ(new_flags, expected_flags);
+
+ ASSERT_EQ(is_shared_mount("/mnt/A/AA/B"), true);
+
+ new_flags = read_mnt_flags("/mnt/A/AA/B/BB");
+ ASSERT_EQ(new_flags, expected_flags);
+
+ ASSERT_EQ(is_shared_mount("/mnt/A/AA/B/BB"), true);
+
+ EXPECT_EQ(close(fd), 0);
+}
+
+TEST_F(mount_setattr, mount_has_writers)
+{
+ int fd, dfd;
+ unsigned int old_flags = 0, new_flags = 0;
+ struct mount_attr attr = {
+ .attr_set = MOUNT_ATTR_RDONLY | MOUNT_ATTR_NOEXEC | MOUNT_ATTR_RELATIME,
+ .attr_clr = MOUNT_ATTR__ATIME,
+ .propagation = MS_SHARED,
+ };
+
+ if (!mount_setattr_supported())
+ SKIP(return, "mount_setattr syscall not supported");
+
+ old_flags = read_mnt_flags("/mnt/A");
+ ASSERT_GT(old_flags, 0);
+
+ fd = open("/mnt/A/AA/B/b", O_RDWR | O_CLOEXEC | O_CREAT | O_EXCL, 0777);
+ ASSERT_GE(fd, 0);
+
+ /*
+ * We're holding a fd open to a mount somwhere in the middle so this
+ * needs to fail somewhere in the middle. After this the mount options
+ * need to be unchanged.
+ */
+ ASSERT_LT(sys_mount_setattr(-1, "/mnt/A", AT_RECURSIVE, &attr, sizeof(attr)), 0);
+
+ new_flags = read_mnt_flags("/mnt/A");
+ ASSERT_EQ(new_flags, old_flags);
+
+ ASSERT_EQ(is_shared_mount("/mnt/A"), false);
+
+ new_flags = read_mnt_flags("/mnt/A/AA");
+ ASSERT_EQ(new_flags, old_flags);
+
+ ASSERT_EQ(is_shared_mount("/mnt/A/AA"), false);
+
+ new_flags = read_mnt_flags("/mnt/A/AA/B");
+ ASSERT_EQ(new_flags, old_flags);
+
+ ASSERT_EQ(is_shared_mount("/mnt/A/AA/B"), false);
+
+ new_flags = read_mnt_flags("/mnt/A/AA/B/BB");
+ ASSERT_EQ(new_flags, old_flags);
+
+ ASSERT_EQ(is_shared_mount("/mnt/A/AA/B/BB"), false);
+
+ dfd = open("/mnt/A/AA/B", O_DIRECTORY | O_CLOEXEC);
+ ASSERT_GE(dfd, 0);
+ EXPECT_EQ(fsync(dfd), 0);
+ EXPECT_EQ(close(dfd), 0);
+
+ EXPECT_EQ(fsync(fd), 0);
+ EXPECT_EQ(close(fd), 0);
+
+ /* All writers are gone so this should succeed. */
+ ASSERT_EQ(sys_mount_setattr(-1, "/mnt/A", AT_RECURSIVE, &attr, sizeof(attr)), 0);
+}
+
+TEST_F(mount_setattr, mixed_mount_options)
+{
+ unsigned int old_flags1 = 0, old_flags2 = 0, new_flags = 0, expected_flags = 0;
+ struct mount_attr attr = {
+ .attr_clr = MOUNT_ATTR_RDONLY | MOUNT_ATTR_NOSUID | MOUNT_ATTR_NOEXEC | MOUNT_ATTR__ATIME,
+ .attr_set = MOUNT_ATTR_RELATIME,
+ };
+
+ if (!mount_setattr_supported())
+ SKIP(return, "mount_setattr syscall not supported");
+
+ old_flags1 = read_mnt_flags("/mnt/B");
+ ASSERT_GT(old_flags1, 0);
+
+ old_flags2 = read_mnt_flags("/mnt/B/BB");
+ ASSERT_GT(old_flags2, 0);
+
+ ASSERT_EQ(sys_mount_setattr(-1, "/mnt/B", AT_RECURSIVE, &attr, sizeof(attr)), 0);
+
+ expected_flags = old_flags2;
+ expected_flags &= ~(MS_RDONLY | MS_NOEXEC | MS_NOATIME | MS_NOSUID);
+ expected_flags |= MS_RELATIME;
+
+ new_flags = read_mnt_flags("/mnt/B");
+ ASSERT_EQ(new_flags, expected_flags);
+
+ expected_flags = old_flags2;
+ expected_flags &= ~(MS_RDONLY | MS_NOEXEC | MS_NOATIME | MS_NOSUID);
+ expected_flags |= MS_RELATIME;
+
+ new_flags = read_mnt_flags("/mnt/B/BB");
+ ASSERT_EQ(new_flags, expected_flags);
+}
+
+TEST_F(mount_setattr, time_changes)
+{
+ unsigned int old_flags = 0, new_flags = 0, expected_flags = 0;
+ struct mount_attr attr = {
+ .attr_set = MOUNT_ATTR_NODIRATIME | MOUNT_ATTR_NOATIME,
+ };
+
+ if (!mount_setattr_supported())
+ SKIP(return, "mount_setattr syscall not supported");
+
+ ASSERT_NE(sys_mount_setattr(-1, "/mnt/A", AT_RECURSIVE, &attr, sizeof(attr)), 0);
+
+ attr.attr_set = MOUNT_ATTR_STRICTATIME;
+ ASSERT_NE(sys_mount_setattr(-1, "/mnt/A", AT_RECURSIVE, &attr, sizeof(attr)), 0);
+
+ attr.attr_set = MOUNT_ATTR_STRICTATIME | MOUNT_ATTR_NOATIME;
+ ASSERT_NE(sys_mount_setattr(-1, "/mnt/A", AT_RECURSIVE, &attr, sizeof(attr)), 0);
+
+ attr.attr_set = MOUNT_ATTR_STRICTATIME | MOUNT_ATTR_NOATIME;
+ attr.attr_clr = MOUNT_ATTR__ATIME;
+ ASSERT_NE(sys_mount_setattr(-1, "/mnt/A", AT_RECURSIVE, &attr, sizeof(attr)), 0);
+
+ attr.attr_set = 0;
+ attr.attr_clr = MOUNT_ATTR_STRICTATIME;
+ ASSERT_NE(sys_mount_setattr(-1, "/mnt/A", AT_RECURSIVE, &attr, sizeof(attr)), 0);
+
+ attr.attr_clr = MOUNT_ATTR_NOATIME;
+ ASSERT_NE(sys_mount_setattr(-1, "/mnt/A", AT_RECURSIVE, &attr, sizeof(attr)), 0);
+
+ old_flags = read_mnt_flags("/mnt/A");
+ ASSERT_GT(old_flags, 0);
+
+ attr.attr_set = MOUNT_ATTR_NODIRATIME | MOUNT_ATTR_NOATIME;
+ attr.attr_clr = MOUNT_ATTR__ATIME;
+ ASSERT_EQ(sys_mount_setattr(-1, "/mnt/A", AT_RECURSIVE, &attr, sizeof(attr)), 0);
+
+ expected_flags = old_flags;
+ expected_flags |= MS_NOATIME;
+ expected_flags |= MS_NODIRATIME;
+
+ new_flags = read_mnt_flags("/mnt/A");
+ ASSERT_EQ(new_flags, expected_flags);
+
+ new_flags = read_mnt_flags("/mnt/A/AA");
+ ASSERT_EQ(new_flags, expected_flags);
+
+ new_flags = read_mnt_flags("/mnt/A/AA/B");
+ ASSERT_EQ(new_flags, expected_flags);
+
+ new_flags = read_mnt_flags("/mnt/A/AA/B/BB");
+ ASSERT_EQ(new_flags, expected_flags);
+
+ memset(&attr, 0, sizeof(attr));
+ attr.attr_set &= ~MOUNT_ATTR_NOATIME;
+ attr.attr_set |= MOUNT_ATTR_RELATIME;
+ attr.attr_clr |= MOUNT_ATTR__ATIME;
+ ASSERT_EQ(sys_mount_setattr(-1, "/mnt/A", AT_RECURSIVE, &attr, sizeof(attr)), 0);
+
+ expected_flags &= ~MS_NOATIME;
+ expected_flags |= MS_RELATIME;
+
+ new_flags = read_mnt_flags("/mnt/A");
+ ASSERT_EQ(new_flags, expected_flags);
+
+ new_flags = read_mnt_flags("/mnt/A/AA");
+ ASSERT_EQ(new_flags, expected_flags);
+
+ new_flags = read_mnt_flags("/mnt/A/AA/B");
+ ASSERT_EQ(new_flags, expected_flags);
+
+ new_flags = read_mnt_flags("/mnt/A/AA/B/BB");
+ ASSERT_EQ(new_flags, expected_flags);
+
+ memset(&attr, 0, sizeof(attr));
+ attr.attr_set &= ~MOUNT_ATTR_RELATIME;
+ attr.attr_set |= MOUNT_ATTR_STRICTATIME;
+ attr.attr_clr |= MOUNT_ATTR__ATIME;
+ ASSERT_EQ(sys_mount_setattr(-1, "/mnt/A", AT_RECURSIVE, &attr, sizeof(attr)), 0);
+
+ expected_flags &= ~MS_RELATIME;
+
+ new_flags = read_mnt_flags("/mnt/A");
+ ASSERT_EQ(new_flags, expected_flags);
+
+ new_flags = read_mnt_flags("/mnt/A/AA");
+ ASSERT_EQ(new_flags, expected_flags);
+
+ new_flags = read_mnt_flags("/mnt/A/AA/B");
+ ASSERT_EQ(new_flags, expected_flags);
+
+ new_flags = read_mnt_flags("/mnt/A/AA/B/BB");
+ ASSERT_EQ(new_flags, expected_flags);
+
+ memset(&attr, 0, sizeof(attr));
+ attr.attr_set &= ~MOUNT_ATTR_STRICTATIME;
+ attr.attr_set |= MOUNT_ATTR_NOATIME;
+ attr.attr_clr |= MOUNT_ATTR__ATIME;
+ ASSERT_EQ(sys_mount_setattr(-1, "/mnt/A", AT_RECURSIVE, &attr, sizeof(attr)), 0);
+
+ expected_flags |= MS_NOATIME;
+ new_flags = read_mnt_flags("/mnt/A");
+ ASSERT_EQ(new_flags, expected_flags);
+
+ new_flags = read_mnt_flags("/mnt/A/AA");
+ ASSERT_EQ(new_flags, expected_flags);
+
+ new_flags = read_mnt_flags("/mnt/A/AA/B");
+ ASSERT_EQ(new_flags, expected_flags);
+
+ new_flags = read_mnt_flags("/mnt/A/AA/B/BB");
+ ASSERT_EQ(new_flags, expected_flags);
+
+ memset(&attr, 0, sizeof(attr));
+ ASSERT_EQ(sys_mount_setattr(-1, "/mnt/A", AT_RECURSIVE, &attr, sizeof(attr)), 0);
+
+ new_flags = read_mnt_flags("/mnt/A");
+ ASSERT_EQ(new_flags, expected_flags);
+
+ new_flags = read_mnt_flags("/mnt/A/AA");
+ ASSERT_EQ(new_flags, expected_flags);
+
+ new_flags = read_mnt_flags("/mnt/A/AA/B");
+ ASSERT_EQ(new_flags, expected_flags);
+
+ new_flags = read_mnt_flags("/mnt/A/AA/B/BB");
+ ASSERT_EQ(new_flags, expected_flags);
+
+ memset(&attr, 0, sizeof(attr));
+ attr.attr_clr = MOUNT_ATTR_NODIRATIME;
+ ASSERT_EQ(sys_mount_setattr(-1, "/mnt/A", AT_RECURSIVE, &attr, sizeof(attr)), 0);
+
+ expected_flags &= ~MS_NODIRATIME;
+
+ new_flags = read_mnt_flags("/mnt/A");
+ ASSERT_EQ(new_flags, expected_flags);
+
+ new_flags = read_mnt_flags("/mnt/A/AA");
+ ASSERT_EQ(new_flags, expected_flags);
+
+ new_flags = read_mnt_flags("/mnt/A/AA/B");
+ ASSERT_EQ(new_flags, expected_flags);
+
+ new_flags = read_mnt_flags("/mnt/A/AA/B/BB");
+ ASSERT_EQ(new_flags, expected_flags);
+}
+
+TEST_F(mount_setattr, multi_threaded)
+{
+ int i, j, nthreads, ret = 0;
+ unsigned int old_flags = 0, new_flags = 0, expected_flags = 0;
+ pthread_attr_t pattr;
+ pthread_t threads[DEFAULT_THREADS];
+
+ if (!mount_setattr_supported())
+ SKIP(return, "mount_setattr syscall not supported");
+
+ old_flags = read_mnt_flags("/mnt/A");
+ ASSERT_GT(old_flags, 0);
+
+ /* Try to change mount options from multiple threads. */
+ nthreads = get_nprocs_conf();
+ if (nthreads > DEFAULT_THREADS)
+ nthreads = DEFAULT_THREADS;
+
+ pthread_attr_init(&pattr);
+ for (i = 0; i < nthreads; i++)
+ ASSERT_EQ(pthread_create(&threads[i], &pattr, mount_setattr_thread, NULL), 0);
+
+ for (j = 0; j < i; j++) {
+ void *retptr = NULL;
+
+ EXPECT_EQ(pthread_join(threads[j], &retptr), 0);
+
+ ret += ptr_to_int(retptr);
+ EXPECT_EQ(ret, 0);
+ }
+ pthread_attr_destroy(&pattr);
+
+ ASSERT_EQ(ret, 0);
+
+ expected_flags = old_flags;
+ expected_flags |= MS_RDONLY;
+ expected_flags |= MS_NOSUID;
+ new_flags = read_mnt_flags("/mnt/A");
+ ASSERT_EQ(new_flags, expected_flags);
+
+ ASSERT_EQ(is_shared_mount("/mnt/A"), true);
+
+ new_flags = read_mnt_flags("/mnt/A/AA");
+ ASSERT_EQ(new_flags, expected_flags);
+
+ ASSERT_EQ(is_shared_mount("/mnt/A/AA"), true);
+
+ new_flags = read_mnt_flags("/mnt/A/AA/B");
+ ASSERT_EQ(new_flags, expected_flags);
+
+ ASSERT_EQ(is_shared_mount("/mnt/A/AA/B"), true);
+
+ new_flags = read_mnt_flags("/mnt/A/AA/B/BB");
+ ASSERT_EQ(new_flags, expected_flags);
+
+ ASSERT_EQ(is_shared_mount("/mnt/A/AA/B/BB"), true);
+}
+
+TEST_F(mount_setattr, wrong_user_namespace)
+{
+ int ret;
+ struct mount_attr attr = {
+ .attr_set = MOUNT_ATTR_RDONLY,
+ };
+
+ if (!mount_setattr_supported())
+ SKIP(return, "mount_setattr syscall not supported");
+
+ EXPECT_EQ(create_and_enter_userns(), 0);
+ ret = sys_mount_setattr(-1, "/mnt/A", AT_RECURSIVE, &attr, sizeof(attr));
+ ASSERT_LT(ret, 0);
+ ASSERT_EQ(errno, EPERM);
+}
+
+TEST_F(mount_setattr, wrong_mount_namespace)
+{
+ int fd, ret;
+ struct mount_attr attr = {
+ .attr_set = MOUNT_ATTR_RDONLY,
+ };
+
+ if (!mount_setattr_supported())
+ SKIP(return, "mount_setattr syscall not supported");
+
+ fd = open("/mnt/A", O_DIRECTORY | O_CLOEXEC);
+ ASSERT_GE(fd, 0);
+
+ ASSERT_EQ(unshare(CLONE_NEWNS), 0);
+
+ ret = sys_mount_setattr(fd, "", AT_EMPTY_PATH | AT_RECURSIVE, &attr, sizeof(attr));
+ ASSERT_LT(ret, 0);
+ ASSERT_EQ(errno, EINVAL);
+}
+
+FIXTURE(mount_setattr_idmapped) {
+};
+
+FIXTURE_SETUP(mount_setattr_idmapped)
+{
+ int img_fd = -EBADF;
+
+ ASSERT_EQ(unshare(CLONE_NEWNS), 0);
+
+ ASSERT_EQ(mount(NULL, "/", NULL, MS_REC | MS_PRIVATE, 0), 0);
+
+ (void)umount2("/mnt", MNT_DETACH);
+ (void)umount2("/tmp", MNT_DETACH);
+
+ ASSERT_EQ(mount("testing", "/tmp", "tmpfs", MS_NOATIME | MS_NODEV,
+ "size=100000,mode=700"), 0);
+
+ ASSERT_EQ(mkdir("/tmp/B", 0777), 0);
+ ASSERT_EQ(mknodat(-EBADF, "/tmp/B/b", S_IFREG | 0644, 0), 0);
+ ASSERT_EQ(chown("/tmp/B/b", 0, 0), 0);
+
+ ASSERT_EQ(mount("testing", "/tmp/B", "tmpfs", MS_NOATIME | MS_NODEV,
+ "size=100000,mode=700"), 0);
+
+ ASSERT_EQ(mkdir("/tmp/B/BB", 0777), 0);
+ ASSERT_EQ(mknodat(-EBADF, "/tmp/B/BB/b", S_IFREG | 0644, 0), 0);
+ ASSERT_EQ(chown("/tmp/B/BB/b", 0, 0), 0);
+
+ ASSERT_EQ(mount("testing", "/tmp/B/BB", "tmpfs", MS_NOATIME | MS_NODEV,
+ "size=100000,mode=700"), 0);
+
+ ASSERT_EQ(mount("testing", "/mnt", "tmpfs", MS_NOATIME | MS_NODEV,
+ "size=100000,mode=700"), 0);
+
+ ASSERT_EQ(mkdir("/mnt/A", 0777), 0);
+
+ ASSERT_EQ(mount("testing", "/mnt/A", "tmpfs", MS_NOATIME | MS_NODEV,
+ "size=100000,mode=700"), 0);
+
+ ASSERT_EQ(mkdir("/mnt/A/AA", 0777), 0);
+
+ ASSERT_EQ(mount("/tmp", "/mnt/A/AA", NULL, MS_BIND | MS_REC, NULL), 0);
+
+ ASSERT_EQ(mkdir("/mnt/B", 0777), 0);
+
+ ASSERT_EQ(mount("testing", "/mnt/B", "ramfs",
+ MS_NOATIME | MS_NODEV | MS_NOSUID, 0), 0);
+
+ ASSERT_EQ(mkdir("/mnt/B/BB", 0777), 0);
+
+ ASSERT_EQ(mount("testing", "/tmp/B/BB", "devpts",
+ MS_RELATIME | MS_NOEXEC | MS_RDONLY, 0), 0);
+
+ ASSERT_EQ(mkdir("/mnt/C", 0777), 0);
+ ASSERT_EQ(mkdir("/mnt/D", 0777), 0);
+ img_fd = openat(-EBADF, "/mnt/C/ext4.img", O_CREAT | O_WRONLY, 0600);
+ ASSERT_GE(img_fd, 0);
+ ASSERT_EQ(ftruncate(img_fd, 1024 * 2048), 0);
+ ASSERT_EQ(system("mkfs.ext4 -q /mnt/C/ext4.img"), 0);
+ ASSERT_EQ(system("mount -o loop -t ext4 /mnt/C/ext4.img /mnt/D/"), 0);
+ ASSERT_EQ(close(img_fd), 0);
+}
+
+FIXTURE_TEARDOWN(mount_setattr_idmapped)
+{
+ (void)umount2("/mnt/A", MNT_DETACH);
+ (void)umount2("/tmp", MNT_DETACH);
+}
+
+/**
+ * Validate that negative fd values are rejected.
+ */
+TEST_F(mount_setattr_idmapped, invalid_fd_negative)
+{
+ struct mount_attr attr = {
+ .attr_set = MOUNT_ATTR_IDMAP,
+ .userns_fd = -EBADF,
+ };
+
+ if (!mount_setattr_supported())
+ SKIP(return, "mount_setattr syscall not supported");
+
+ ASSERT_NE(sys_mount_setattr(-1, "/", 0, &attr, sizeof(attr)), 0) {
+ TH_LOG("failure: created idmapped mount with negative fd");
+ }
+}
+
+/**
+ * Validate that excessively large fd values are rejected.
+ */
+TEST_F(mount_setattr_idmapped, invalid_fd_large)
+{
+ struct mount_attr attr = {
+ .attr_set = MOUNT_ATTR_IDMAP,
+ .userns_fd = INT64_MAX,
+ };
+
+ if (!mount_setattr_supported())
+ SKIP(return, "mount_setattr syscall not supported");
+
+ ASSERT_NE(sys_mount_setattr(-1, "/", 0, &attr, sizeof(attr)), 0) {
+ TH_LOG("failure: created idmapped mount with too large fd value");
+ }
+}
+
+/**
+ * Validate that closed fd values are rejected.
+ */
+TEST_F(mount_setattr_idmapped, invalid_fd_closed)
+{
+ int fd;
+ struct mount_attr attr = {
+ .attr_set = MOUNT_ATTR_IDMAP,
+ };
+
+ if (!mount_setattr_supported())
+ SKIP(return, "mount_setattr syscall not supported");
+
+ fd = open("/dev/null", O_RDONLY | O_CLOEXEC);
+ ASSERT_GE(fd, 0);
+ ASSERT_GE(close(fd), 0);
+
+ attr.userns_fd = fd;
+ ASSERT_NE(sys_mount_setattr(-1, "/", 0, &attr, sizeof(attr)), 0) {
+ TH_LOG("failure: created idmapped mount with closed fd");
+ }
+}
+
+/**
+ * Validate that the initial user namespace is rejected.
+ */
+TEST_F(mount_setattr_idmapped, invalid_fd_initial_userns)
+{
+ int open_tree_fd = -EBADF;
+ struct mount_attr attr = {
+ .attr_set = MOUNT_ATTR_IDMAP,
+ };
+
+ if (!mount_setattr_supported())
+ SKIP(return, "mount_setattr syscall not supported");
+
+ open_tree_fd = sys_open_tree(-EBADF, "/mnt/D",
+ AT_NO_AUTOMOUNT |
+ AT_SYMLINK_NOFOLLOW |
+ OPEN_TREE_CLOEXEC | OPEN_TREE_CLONE);
+ ASSERT_GE(open_tree_fd, 0);
+
+ attr.userns_fd = open("/proc/1/ns/user", O_RDONLY | O_CLOEXEC);
+ ASSERT_GE(attr.userns_fd, 0);
+ ASSERT_NE(sys_mount_setattr(open_tree_fd, "", AT_EMPTY_PATH, &attr, sizeof(attr)), 0);
+ ASSERT_EQ(errno, EPERM);
+ ASSERT_EQ(close(attr.userns_fd), 0);
+ ASSERT_EQ(close(open_tree_fd), 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/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 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 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);
+ 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);
+ wait_for_pid(pid);
+ return ret;
+}
+
+/**
+ * Validate that an attached mount in our mount namespace can be idmapped.
+ * (The kernel enforces that the mount's mount namespace and the caller's mount
+ * namespace match.)
+ */
+TEST_F(mount_setattr_idmapped, attached_mount_inside_current_mount_namespace)
+{
+ int open_tree_fd = -EBADF;
+ struct mount_attr attr = {
+ .attr_set = MOUNT_ATTR_IDMAP,
+ };
+
+ if (!mount_setattr_supported())
+ SKIP(return, "mount_setattr syscall not supported");
+
+ open_tree_fd = sys_open_tree(-EBADF, "/mnt/D",
+ AT_EMPTY_PATH |
+ AT_NO_AUTOMOUNT |
+ AT_SYMLINK_NOFOLLOW |
+ OPEN_TREE_CLOEXEC);
+ ASSERT_GE(open_tree_fd, 0);
+
+ attr.userns_fd = get_userns_fd(0, 10000, 10000);
+ ASSERT_GE(attr.userns_fd, 0);
+ ASSERT_EQ(sys_mount_setattr(open_tree_fd, "", AT_EMPTY_PATH, &attr, sizeof(attr)), 0);
+ ASSERT_EQ(close(attr.userns_fd), 0);
+ ASSERT_EQ(close(open_tree_fd), 0);
+}
+
+/**
+ * Validate that idmapping a mount is rejected if the mount's mount namespace
+ * and our mount namespace don't match.
+ * (The kernel enforces that the mount's mount namespace and the caller's mount
+ * namespace match.)
+ */
+TEST_F(mount_setattr_idmapped, attached_mount_outside_current_mount_namespace)
+{
+ int open_tree_fd = -EBADF;
+ struct mount_attr attr = {
+ .attr_set = MOUNT_ATTR_IDMAP,
+ };
+
+ if (!mount_setattr_supported())
+ SKIP(return, "mount_setattr syscall not supported");
+
+ open_tree_fd = sys_open_tree(-EBADF, "/mnt/D",
+ AT_EMPTY_PATH |
+ AT_NO_AUTOMOUNT |
+ AT_SYMLINK_NOFOLLOW |
+ OPEN_TREE_CLOEXEC);
+ ASSERT_GE(open_tree_fd, 0);
+
+ ASSERT_EQ(unshare(CLONE_NEWNS), 0);
+
+ attr.userns_fd = get_userns_fd(0, 10000, 10000);
+ ASSERT_GE(attr.userns_fd, 0);
+ ASSERT_NE(sys_mount_setattr(open_tree_fd, "", AT_EMPTY_PATH, &attr,
+ sizeof(attr)), 0);
+ ASSERT_EQ(close(attr.userns_fd), 0);
+ ASSERT_EQ(close(open_tree_fd), 0);
+}
+
+/**
+ * Validate that an attached mount in our mount namespace can be idmapped.
+ */
+TEST_F(mount_setattr_idmapped, detached_mount_inside_current_mount_namespace)
+{
+ int open_tree_fd = -EBADF;
+ struct mount_attr attr = {
+ .attr_set = MOUNT_ATTR_IDMAP,
+ };
+
+ if (!mount_setattr_supported())
+ SKIP(return, "mount_setattr syscall not supported");
+
+ open_tree_fd = sys_open_tree(-EBADF, "/mnt/D",
+ AT_EMPTY_PATH |
+ AT_NO_AUTOMOUNT |
+ AT_SYMLINK_NOFOLLOW |
+ OPEN_TREE_CLOEXEC |
+ OPEN_TREE_CLONE);
+ ASSERT_GE(open_tree_fd, 0);
+
+ /* Changing mount properties on a detached mount. */
+ attr.userns_fd = get_userns_fd(0, 10000, 10000);
+ ASSERT_GE(attr.userns_fd, 0);
+ ASSERT_EQ(sys_mount_setattr(open_tree_fd, "",
+ AT_EMPTY_PATH, &attr, sizeof(attr)), 0);
+ ASSERT_EQ(close(attr.userns_fd), 0);
+ ASSERT_EQ(close(open_tree_fd), 0);
+}
+
+/**
+ * Validate that a detached mount not in our mount namespace can be idmapped.
+ */
+TEST_F(mount_setattr_idmapped, detached_mount_outside_current_mount_namespace)
+{
+ int open_tree_fd = -EBADF;
+ struct mount_attr attr = {
+ .attr_set = MOUNT_ATTR_IDMAP,
+ };
+
+ if (!mount_setattr_supported())
+ SKIP(return, "mount_setattr syscall not supported");
+
+ open_tree_fd = sys_open_tree(-EBADF, "/mnt/D",
+ AT_EMPTY_PATH |
+ AT_NO_AUTOMOUNT |
+ AT_SYMLINK_NOFOLLOW |
+ OPEN_TREE_CLOEXEC |
+ OPEN_TREE_CLONE);
+ ASSERT_GE(open_tree_fd, 0);
+
+ ASSERT_EQ(unshare(CLONE_NEWNS), 0);
+
+ /* Changing mount properties on a detached mount. */
+ attr.userns_fd = get_userns_fd(0, 10000, 10000);
+ ASSERT_GE(attr.userns_fd, 0);
+ ASSERT_EQ(sys_mount_setattr(open_tree_fd, "",
+ AT_EMPTY_PATH, &attr, sizeof(attr)), 0);
+ ASSERT_EQ(close(attr.userns_fd), 0);
+ ASSERT_EQ(close(open_tree_fd), 0);
+}
+
+/**
+ * Validate that currently changing the idmapping of an idmapped mount fails.
+ */
+TEST_F(mount_setattr_idmapped, change_idmapping)
+{
+ int open_tree_fd = -EBADF;
+ struct mount_attr attr = {
+ .attr_set = MOUNT_ATTR_IDMAP,
+ };
+
+ if (!mount_setattr_supported())
+ SKIP(return, "mount_setattr syscall not supported");
+
+ open_tree_fd = sys_open_tree(-EBADF, "/mnt/D",
+ AT_EMPTY_PATH |
+ AT_NO_AUTOMOUNT |
+ AT_SYMLINK_NOFOLLOW |
+ OPEN_TREE_CLOEXEC |
+ OPEN_TREE_CLONE);
+ ASSERT_GE(open_tree_fd, 0);
+
+ attr.userns_fd = get_userns_fd(0, 10000, 10000);
+ ASSERT_GE(attr.userns_fd, 0);
+ ASSERT_EQ(sys_mount_setattr(open_tree_fd, "",
+ AT_EMPTY_PATH, &attr, sizeof(attr)), 0);
+ ASSERT_EQ(close(attr.userns_fd), 0);
+
+ /* Change idmapping on a detached mount that is already idmapped. */
+ attr.userns_fd = get_userns_fd(0, 20000, 10000);
+ ASSERT_GE(attr.userns_fd, 0);
+ ASSERT_NE(sys_mount_setattr(open_tree_fd, "", AT_EMPTY_PATH, &attr, sizeof(attr)), 0);
+ ASSERT_EQ(close(attr.userns_fd), 0);
+ ASSERT_EQ(close(open_tree_fd), 0);
+}
+
+static bool expected_uid_gid(int dfd, const char *path, int flags,
+ uid_t expected_uid, gid_t expected_gid)
+{
+ int ret;
+ struct stat st;
+
+ ret = fstatat(dfd, path, &st, flags);
+ if (ret < 0)
+ return false;
+
+ return st.st_uid == expected_uid && st.st_gid == expected_gid;
+}
+
+TEST_F(mount_setattr_idmapped, idmap_mount_tree_invalid)
+{
+ int open_tree_fd = -EBADF;
+ struct mount_attr attr = {
+ .attr_set = MOUNT_ATTR_IDMAP,
+ };
+
+ if (!mount_setattr_supported())
+ SKIP(return, "mount_setattr syscall not supported");
+
+ ASSERT_EQ(expected_uid_gid(-EBADF, "/tmp/B/b", 0, 0, 0), 0);
+ ASSERT_EQ(expected_uid_gid(-EBADF, "/tmp/B/BB/b", 0, 0, 0), 0);
+
+ open_tree_fd = sys_open_tree(-EBADF, "/mnt/A",
+ AT_RECURSIVE |
+ AT_EMPTY_PATH |
+ AT_NO_AUTOMOUNT |
+ AT_SYMLINK_NOFOLLOW |
+ OPEN_TREE_CLOEXEC |
+ OPEN_TREE_CLONE);
+ ASSERT_GE(open_tree_fd, 0);
+
+ attr.userns_fd = get_userns_fd(0, 10000, 10000);
+ ASSERT_GE(attr.userns_fd, 0);
+ ASSERT_NE(sys_mount_setattr(open_tree_fd, "", AT_EMPTY_PATH, &attr, sizeof(attr)), 0);
+ ASSERT_EQ(close(attr.userns_fd), 0);
+ ASSERT_EQ(close(open_tree_fd), 0);
+
+ ASSERT_EQ(expected_uid_gid(-EBADF, "/tmp/B/b", 0, 0, 0), 0);
+ ASSERT_EQ(expected_uid_gid(-EBADF, "/tmp/B/BB/b", 0, 0, 0), 0);
+ ASSERT_EQ(expected_uid_gid(open_tree_fd, "B/b", 0, 0, 0), 0);
+ ASSERT_EQ(expected_uid_gid(open_tree_fd, "B/BB/b", 0, 0, 0), 0);
+}
+
+TEST_HARNESS_MAIN
Add a range of selftests for the new mount_setattr() syscall to verify that it works as expected. This tests that: - no invalid flags can be specified - changing properties of a single mount works and leaves other mounts in the mount tree unchanged - changing a mount tre to read-only when one of the mounts has writers fails and leaves the whole mount tree unchanged - changing mount properties from multiple threads works - changing atime settings works - changing mount propagation works - changing the mount options of a mount tree where the individual mounts in the tree have different mount options only changes the flags that were requested to change - changing mount options from another mount namespace fails - changing mount options from another user namespace fails - idmapped mounts Note, the main test-suite for idmapped mounts is part of xfstests and is pretty huge. These tests here just make sure that the syscalls bits work correctly. TAP version 13 1..20 # Starting 20 tests from 3 test cases. # RUN mount_setattr.invalid_attributes ... # OK mount_setattr.invalid_attributes ok 1 mount_setattr.invalid_attributes # RUN mount_setattr.extensibility ... # OK mount_setattr.extensibility ok 2 mount_setattr.extensibility # RUN mount_setattr.basic ... # OK mount_setattr.basic ok 3 mount_setattr.basic # RUN mount_setattr.basic_recursive ... # OK mount_setattr.basic_recursive ok 4 mount_setattr.basic_recursive # RUN mount_setattr.mount_has_writers ... # OK mount_setattr.mount_has_writers ok 5 mount_setattr.mount_has_writers # RUN mount_setattr.mixed_mount_options ... # OK mount_setattr.mixed_mount_options ok 6 mount_setattr.mixed_mount_options # RUN mount_setattr.time_changes ... # OK mount_setattr.time_changes ok 7 mount_setattr.time_changes # RUN mount_setattr.multi_threaded ... # OK mount_setattr.multi_threaded ok 8 mount_setattr.multi_threaded # RUN mount_setattr.wrong_user_namespace ... # OK mount_setattr.wrong_user_namespace ok 9 mount_setattr.wrong_user_namespace # RUN mount_setattr.wrong_mount_namespace ... # OK mount_setattr.wrong_mount_namespace ok 10 mount_setattr.wrong_mount_namespace # RUN mount_setattr_idmapped.invalid_fd_negative ... # OK mount_setattr_idmapped.invalid_fd_negative ok 11 mount_setattr_idmapped.invalid_fd_negative # RUN mount_setattr_idmapped.invalid_fd_large ... # OK mount_setattr_idmapped.invalid_fd_large ok 12 mount_setattr_idmapped.invalid_fd_large # RUN mount_setattr_idmapped.invalid_fd_closed ... # OK mount_setattr_idmapped.invalid_fd_closed ok 13 mount_setattr_idmapped.invalid_fd_closed # RUN mount_setattr_idmapped.invalid_fd_initial_userns ... # OK mount_setattr_idmapped.invalid_fd_initial_userns ok 14 mount_setattr_idmapped.invalid_fd_initial_userns # RUN mount_setattr_idmapped.attached_mount_inside_current_mount_namespace ... # OK mount_setattr_idmapped.attached_mount_inside_current_mount_namespace ok 15 mount_setattr_idmapped.attached_mount_inside_current_mount_namespace # RUN mount_setattr_idmapped.attached_mount_outside_current_mount_namespace ... # OK mount_setattr_idmapped.attached_mount_outside_current_mount_namespace ok 16 mount_setattr_idmapped.attached_mount_outside_current_mount_namespace # RUN mount_setattr_idmapped.detached_mount_inside_current_mount_namespace ... # OK mount_setattr_idmapped.detached_mount_inside_current_mount_namespace ok 17 mount_setattr_idmapped.detached_mount_inside_current_mount_namespace # RUN mount_setattr_idmapped.detached_mount_outside_current_mount_namespace ... # OK mount_setattr_idmapped.detached_mount_outside_current_mount_namespace ok 18 mount_setattr_idmapped.detached_mount_outside_current_mount_namespace # RUN mount_setattr_idmapped.change_idmapping ... # OK mount_setattr_idmapped.change_idmapping ok 19 mount_setattr_idmapped.change_idmapping # RUN mount_setattr_idmapped.idmap_mount_tree_invalid ... # OK mount_setattr_idmapped.idmap_mount_tree_invalid ok 20 mount_setattr_idmapped.idmap_mount_tree_invalid # PASSED: 20 / 20 tests passed. # Totals: pass:20 fail:0 xfail:0 xpass:0 skip:0 error:0 Link: https://lore.kernel.org/r/20210112220124.837960-8-christian.brauner@ubuntu.com Link: https://lore.kernel.org/r/20210112220124.837960-42-christian.brauner@ubuntu.com Cc: Christoph Hellwig <hch@lst.de> Cc: David Howells <dhowells@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: linux-fsdevel@vger.kernel.org Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com> --- /* v2 */ unchanged /* v3 */ - Christoph Hellwig <hch@lst.de>, Darrick J. Wong <darrick.wong@oracle.com>: - Port main test-suite to xfstests. /* v4 */ unchanged /* v5 */ unchanged base-commit: 7c53f6b671f4aba70ff15e1b05148b10d58c2837 /* v6 */ unchanged base-commit: 19c329f6808995b142b3966301f217c831e7cf31 --- tools/testing/selftests/Makefile | 1 + .../selftests/mount_setattr/.gitignore | 1 + .../testing/selftests/mount_setattr/Makefile | 7 + tools/testing/selftests/mount_setattr/config | 1 + .../mount_setattr/mount_setattr_test.c | 1424 +++++++++++++++++ 5 files changed, 1434 insertions(+) create mode 100644 tools/testing/selftests/mount_setattr/.gitignore create mode 100644 tools/testing/selftests/mount_setattr/Makefile create mode 100644 tools/testing/selftests/mount_setattr/config create mode 100644 tools/testing/selftests/mount_setattr/mount_setattr_test.c