diff options
Diffstat (limited to 'tools/testing/selftests/filesystems/mount-notify/mount-notify_test_ns.c')
| -rw-r--r-- | tools/testing/selftests/filesystems/mount-notify/mount-notify_test_ns.c | 557 |
1 files changed, 557 insertions, 0 deletions
diff --git a/tools/testing/selftests/filesystems/mount-notify/mount-notify_test_ns.c b/tools/testing/selftests/filesystems/mount-notify/mount-notify_test_ns.c new file mode 100644 index 000000000000..090a5ca65004 --- /dev/null +++ b/tools/testing/selftests/filesystems/mount-notify/mount-notify_test_ns.c @@ -0,0 +1,557 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +// Copyright (c) 2025 Miklos Szeredi <miklos@szeredi.hu> + +#define _GNU_SOURCE +#include <fcntl.h> +#include <sched.h> +#include <stdio.h> +#include <string.h> +#include <sys/stat.h> +#include <sys/mount.h> +#include <unistd.h> +#include <sys/syscall.h> + +#include "../../kselftest_harness.h" +#include "../../pidfd/pidfd.h" +#include "../statmount/statmount.h" +#include "../utils.h" + +// Needed for linux/fanotify.h +#ifndef __kernel_fsid_t +typedef struct { + int val[2]; +} __kernel_fsid_t; +#endif + +#include <sys/fanotify.h> + +static const char root_mntpoint_templ[] = "/tmp/mount-notify_test_root.XXXXXX"; + +static const int mark_types[] = { + FAN_MARK_FILESYSTEM, + FAN_MARK_MOUNT, + FAN_MARK_INODE +}; + +static const int mark_cmds[] = { + FAN_MARK_ADD, + FAN_MARK_REMOVE, + FAN_MARK_FLUSH +}; + +#define NUM_FAN_FDS ARRAY_SIZE(mark_cmds) + +FIXTURE(fanotify) { + int fan_fd[NUM_FAN_FDS]; + char buf[256]; + unsigned int rem; + void *next; + char root_mntpoint[sizeof(root_mntpoint_templ)]; + int orig_root; + int orig_ns_fd; + int ns_fd; + uint64_t root_id; +}; + +FIXTURE_SETUP(fanotify) +{ + int i, ret; + + self->orig_ns_fd = open("/proc/self/ns/mnt", O_RDONLY); + ASSERT_GE(self->orig_ns_fd, 0); + + ret = setup_userns(); + ASSERT_EQ(ret, 0); + + self->ns_fd = open("/proc/self/ns/mnt", O_RDONLY); + ASSERT_GE(self->ns_fd, 0); + + strcpy(self->root_mntpoint, root_mntpoint_templ); + ASSERT_NE(mkdtemp(self->root_mntpoint), NULL); + + self->orig_root = open("/", O_PATH | O_CLOEXEC); + ASSERT_GE(self->orig_root, 0); + + ASSERT_EQ(mount("tmpfs", self->root_mntpoint, "tmpfs", 0, NULL), 0); + + ASSERT_EQ(chroot(self->root_mntpoint), 0); + + ASSERT_EQ(chdir("/"), 0); + + ASSERT_EQ(mkdir("a", 0700), 0); + + ASSERT_EQ(mkdir("b", 0700), 0); + + self->root_id = get_unique_mnt_id("/"); + ASSERT_NE(self->root_id, 0); + + for (i = 0; i < NUM_FAN_FDS; i++) { + int fan_fd = fanotify_init(FAN_REPORT_FID, 0); + // Verify that watching tmpfs mounted inside userns is allowed + ret = fanotify_mark(fan_fd, FAN_MARK_ADD | mark_types[i], + FAN_OPEN, AT_FDCWD, "/"); + ASSERT_EQ(ret, 0); + // ...but watching entire orig root filesystem is not allowed + ret = fanotify_mark(fan_fd, FAN_MARK_ADD | FAN_MARK_FILESYSTEM, + FAN_OPEN, self->orig_root, "."); + ASSERT_NE(ret, 0); + close(fan_fd); + + self->fan_fd[i] = fanotify_init(FAN_REPORT_MNT | FAN_NONBLOCK, + 0); + ASSERT_GE(self->fan_fd[i], 0); + // Verify that watching mntns where group was created is allowed + ret = fanotify_mark(self->fan_fd[i], FAN_MARK_ADD | + FAN_MARK_MNTNS, + FAN_MNT_ATTACH | FAN_MNT_DETACH, + self->ns_fd, NULL); + ASSERT_EQ(ret, 0); + // ...but watching orig mntns is not allowed + ret = fanotify_mark(self->fan_fd[i], FAN_MARK_ADD | + FAN_MARK_MNTNS, + FAN_MNT_ATTACH | FAN_MNT_DETACH, + self->orig_ns_fd, NULL); + ASSERT_NE(ret, 0); + // On fd[0] we do an extra ADD that changes nothing. + // On fd[1]/fd[2] we REMOVE/FLUSH which removes the mark. + ret = fanotify_mark(self->fan_fd[i], mark_cmds[i] | + FAN_MARK_MNTNS, + FAN_MNT_ATTACH | FAN_MNT_DETACH, + self->ns_fd, NULL); + ASSERT_EQ(ret, 0); + } + + self->rem = 0; +} + +FIXTURE_TEARDOWN(fanotify) +{ + int i; + + ASSERT_EQ(self->rem, 0); + for (i = 0; i < NUM_FAN_FDS; i++) + close(self->fan_fd[i]); + + ASSERT_EQ(fchdir(self->orig_root), 0); + + ASSERT_EQ(chroot("."), 0); + + EXPECT_EQ(umount2(self->root_mntpoint, MNT_DETACH), 0); + EXPECT_EQ(chdir(self->root_mntpoint), 0); + EXPECT_EQ(chdir("/"), 0); + EXPECT_EQ(rmdir(self->root_mntpoint), 0); +} + +static uint64_t expect_notify(struct __test_metadata *const _metadata, + FIXTURE_DATA(fanotify) *self, + uint64_t *mask) +{ + struct fanotify_event_metadata *meta; + struct fanotify_event_info_mnt *mnt; + unsigned int thislen; + + if (!self->rem) { + ssize_t len; + int i; + + for (i = NUM_FAN_FDS - 1; i >= 0; i--) { + len = read(self->fan_fd[i], self->buf, + sizeof(self->buf)); + if (i > 0) { + // Groups 1,2 should get EAGAIN + ASSERT_EQ(len, -1); + ASSERT_EQ(errno, EAGAIN); + } else { + // Group 0 should get events + ASSERT_GT(len, 0); + } + } + + self->rem = len; + self->next = (void *) self->buf; + } + + meta = self->next; + ASSERT_TRUE(FAN_EVENT_OK(meta, self->rem)); + + thislen = meta->event_len; + self->rem -= thislen; + self->next += thislen; + + *mask = meta->mask; + thislen -= sizeof(*meta); + + mnt = ((void *) meta) + meta->event_len - thislen; + + ASSERT_EQ(thislen, sizeof(*mnt)); + + return mnt->mnt_id; +} + +static void expect_notify_n(struct __test_metadata *const _metadata, + FIXTURE_DATA(fanotify) *self, + unsigned int n, uint64_t mask[], uint64_t mnts[]) +{ + unsigned int i; + + for (i = 0; i < n; i++) + mnts[i] = expect_notify(_metadata, self, &mask[i]); +} + +static uint64_t expect_notify_mask(struct __test_metadata *const _metadata, + FIXTURE_DATA(fanotify) *self, + uint64_t expect_mask) +{ + uint64_t mntid, mask; + + mntid = expect_notify(_metadata, self, &mask); + ASSERT_EQ(expect_mask, mask); + + return mntid; +} + + +static void expect_notify_mask_n(struct __test_metadata *const _metadata, + FIXTURE_DATA(fanotify) *self, + uint64_t mask, unsigned int n, uint64_t mnts[]) +{ + unsigned int i; + + for (i = 0; i < n; i++) + mnts[i] = expect_notify_mask(_metadata, self, mask); +} + +static void verify_mount_ids(struct __test_metadata *const _metadata, + const uint64_t list1[], const uint64_t list2[], + size_t num) +{ + unsigned int i, j; + + // Check that neither list has any duplicates + for (i = 0; i < num; i++) { + for (j = 0; j < num; j++) { + if (i != j) { + ASSERT_NE(list1[i], list1[j]); + ASSERT_NE(list2[i], list2[j]); + } + } + } + // Check that all list1 memebers can be found in list2. Together with + // the above it means that the list1 and list2 represent the same sets. + for (i = 0; i < num; i++) { + for (j = 0; j < num; j++) { + if (list1[i] == list2[j]) + break; + } + ASSERT_NE(j, num); + } +} + +static void check_mounted(struct __test_metadata *const _metadata, + const uint64_t mnts[], size_t num) +{ + ssize_t ret; + uint64_t *list; + + list = malloc((num + 1) * sizeof(list[0])); + ASSERT_NE(list, NULL); + + ret = listmount(LSMT_ROOT, 0, 0, list, num + 1, 0); + ASSERT_EQ(ret, num); + + verify_mount_ids(_metadata, mnts, list, num); + + free(list); +} + +static void setup_mount_tree(struct __test_metadata *const _metadata, + int log2_num) +{ + int ret, i; + + ret = mount("", "/", NULL, MS_SHARED, NULL); + ASSERT_EQ(ret, 0); + + for (i = 0; i < log2_num; i++) { + ret = mount("/", "/", NULL, MS_BIND, NULL); + ASSERT_EQ(ret, 0); + } +} + +TEST_F(fanotify, bind) +{ + int ret; + uint64_t mnts[2] = { self->root_id }; + + ret = mount("/", "/", NULL, MS_BIND, NULL); + ASSERT_EQ(ret, 0); + + mnts[1] = expect_notify_mask(_metadata, self, FAN_MNT_ATTACH); + ASSERT_NE(mnts[0], mnts[1]); + + check_mounted(_metadata, mnts, 2); + + // Cleanup + uint64_t detach_id; + ret = umount("/"); + ASSERT_EQ(ret, 0); + + detach_id = expect_notify_mask(_metadata, self, FAN_MNT_DETACH); + ASSERT_EQ(detach_id, mnts[1]); + + check_mounted(_metadata, mnts, 1); +} + +TEST_F(fanotify, move) +{ + int ret; + uint64_t mnts[2] = { self->root_id }; + uint64_t move_id; + + ret = mount("/", "/a", NULL, MS_BIND, NULL); + ASSERT_EQ(ret, 0); + + mnts[1] = expect_notify_mask(_metadata, self, FAN_MNT_ATTACH); + ASSERT_NE(mnts[0], mnts[1]); + + check_mounted(_metadata, mnts, 2); + + ret = move_mount(AT_FDCWD, "/a", AT_FDCWD, "/b", 0); + ASSERT_EQ(ret, 0); + + move_id = expect_notify_mask(_metadata, self, FAN_MNT_ATTACH | FAN_MNT_DETACH); + ASSERT_EQ(move_id, mnts[1]); + + // Cleanup + ret = umount("/b"); + ASSERT_EQ(ret, 0); + + check_mounted(_metadata, mnts, 1); +} + +TEST_F(fanotify, propagate) +{ + const unsigned int log2_num = 4; + const unsigned int num = (1 << log2_num); + uint64_t mnts[num]; + + setup_mount_tree(_metadata, log2_num); + + expect_notify_mask_n(_metadata, self, FAN_MNT_ATTACH, num - 1, mnts + 1); + + mnts[0] = self->root_id; + check_mounted(_metadata, mnts, num); + + // Cleanup + int ret; + uint64_t mnts2[num]; + ret = umount2("/", MNT_DETACH); + ASSERT_EQ(ret, 0); + + ret = mount("", "/", NULL, MS_PRIVATE, NULL); + ASSERT_EQ(ret, 0); + + mnts2[0] = self->root_id; + expect_notify_mask_n(_metadata, self, FAN_MNT_DETACH, num - 1, mnts2 + 1); + verify_mount_ids(_metadata, mnts, mnts2, num); + + check_mounted(_metadata, mnts, 1); +} + +TEST_F(fanotify, fsmount) +{ + int ret, fs, mnt; + uint64_t mnts[2] = { self->root_id }; + + fs = fsopen("tmpfs", 0); + ASSERT_GE(fs, 0); + + ret = fsconfig(fs, FSCONFIG_CMD_CREATE, 0, 0, 0); + ASSERT_EQ(ret, 0); + + mnt = fsmount(fs, 0, 0); + ASSERT_GE(mnt, 0); + + close(fs); + + ret = move_mount(mnt, "", AT_FDCWD, "/a", MOVE_MOUNT_F_EMPTY_PATH); + ASSERT_EQ(ret, 0); + + close(mnt); + + mnts[1] = expect_notify_mask(_metadata, self, FAN_MNT_ATTACH); + ASSERT_NE(mnts[0], mnts[1]); + + check_mounted(_metadata, mnts, 2); + + // Cleanup + uint64_t detach_id; + ret = umount("/a"); + ASSERT_EQ(ret, 0); + + detach_id = expect_notify_mask(_metadata, self, FAN_MNT_DETACH); + ASSERT_EQ(detach_id, mnts[1]); + + check_mounted(_metadata, mnts, 1); +} + +TEST_F(fanotify, reparent) +{ + uint64_t mnts[6] = { self->root_id }; + uint64_t dmnts[3]; + uint64_t masks[3]; + unsigned int i; + int ret; + + // Create setup with a[1] -> b[2] propagation + ret = mount("/", "/a", NULL, MS_BIND, NULL); + ASSERT_EQ(ret, 0); + + ret = mount("", "/a", NULL, MS_SHARED, NULL); + ASSERT_EQ(ret, 0); + + ret = mount("/a", "/b", NULL, MS_BIND, NULL); + ASSERT_EQ(ret, 0); + + ret = mount("", "/b", NULL, MS_SLAVE, NULL); + ASSERT_EQ(ret, 0); + + expect_notify_mask_n(_metadata, self, FAN_MNT_ATTACH, 2, mnts + 1); + + check_mounted(_metadata, mnts, 3); + + // Mount on a[3], which is propagated to b[4] + ret = mount("/", "/a", NULL, MS_BIND, NULL); + ASSERT_EQ(ret, 0); + + expect_notify_mask_n(_metadata, self, FAN_MNT_ATTACH, 2, mnts + 3); + + check_mounted(_metadata, mnts, 5); + + // Mount on b[5], not propagated + ret = mount("/", "/b", NULL, MS_BIND, NULL); + ASSERT_EQ(ret, 0); + + mnts[5] = expect_notify_mask(_metadata, self, FAN_MNT_ATTACH); + + check_mounted(_metadata, mnts, 6); + + // Umount a[3], which is propagated to b[4], but not b[5] + // This will result in b[5] "falling" on b[2] + ret = umount("/a"); + ASSERT_EQ(ret, 0); + + expect_notify_n(_metadata, self, 3, masks, dmnts); + verify_mount_ids(_metadata, mnts + 3, dmnts, 3); + + for (i = 0; i < 3; i++) { + if (dmnts[i] == mnts[5]) { + ASSERT_EQ(masks[i], FAN_MNT_ATTACH | FAN_MNT_DETACH); + } else { + ASSERT_EQ(masks[i], FAN_MNT_DETACH); + } + } + + mnts[3] = mnts[5]; + check_mounted(_metadata, mnts, 4); + + // Cleanup + ret = umount("/b"); + ASSERT_EQ(ret, 0); + + ret = umount("/a"); + ASSERT_EQ(ret, 0); + + ret = umount("/b"); + ASSERT_EQ(ret, 0); + + expect_notify_mask_n(_metadata, self, FAN_MNT_DETACH, 3, dmnts); + verify_mount_ids(_metadata, mnts + 1, dmnts, 3); + + check_mounted(_metadata, mnts, 1); +} + +TEST_F(fanotify, rmdir) +{ + uint64_t mnts[3] = { self->root_id }; + int ret; + + ret = mount("/", "/a", NULL, MS_BIND, NULL); + ASSERT_EQ(ret, 0); + + ret = mount("/", "/a/b", NULL, MS_BIND, NULL); + ASSERT_EQ(ret, 0); + + expect_notify_mask_n(_metadata, self, FAN_MNT_ATTACH, 2, mnts + 1); + + check_mounted(_metadata, mnts, 3); + + ret = chdir("/a"); + ASSERT_EQ(ret, 0); + + ret = fork(); + ASSERT_GE(ret, 0); + + if (ret == 0) { + chdir("/"); + unshare(CLONE_NEWNS); + mount("", "/", NULL, MS_REC|MS_PRIVATE, NULL); + umount2("/a", MNT_DETACH); + // This triggers a detach in the other namespace + rmdir("/a"); + exit(0); + } + wait(NULL); + + expect_notify_mask_n(_metadata, self, FAN_MNT_DETACH, 2, mnts + 1); + check_mounted(_metadata, mnts, 1); + + // Cleanup + ret = chdir("/"); + ASSERT_EQ(ret, 0); +} + +TEST_F(fanotify, pivot_root) +{ + uint64_t mnts[3] = { self->root_id }; + uint64_t mnts2[3]; + int ret; + + ret = mount("tmpfs", "/a", "tmpfs", 0, NULL); + ASSERT_EQ(ret, 0); + + mnts[2] = expect_notify_mask(_metadata, self, FAN_MNT_ATTACH); + + ret = mkdir("/a/new", 0700); + ASSERT_EQ(ret, 0); + + ret = mkdir("/a/old", 0700); + ASSERT_EQ(ret, 0); + + ret = mount("/a", "/a/new", NULL, MS_BIND, NULL); + ASSERT_EQ(ret, 0); + + mnts[1] = expect_notify_mask(_metadata, self, FAN_MNT_ATTACH); + check_mounted(_metadata, mnts, 3); + + ret = syscall(SYS_pivot_root, "/a/new", "/a/new/old"); + ASSERT_EQ(ret, 0); + + expect_notify_mask_n(_metadata, self, FAN_MNT_ATTACH | FAN_MNT_DETACH, 2, mnts2); + verify_mount_ids(_metadata, mnts, mnts2, 2); + check_mounted(_metadata, mnts, 3); + + // Cleanup + ret = syscall(SYS_pivot_root, "/old", "/old/a/new"); + ASSERT_EQ(ret, 0); + + ret = umount("/a/new"); + ASSERT_EQ(ret, 0); + + ret = umount("/a"); + ASSERT_EQ(ret, 0); + + check_mounted(_metadata, mnts, 1); +} + +TEST_HARNESS_MAIN |