diff --git a/Documentation/security/landlock.rst b/Documentation/security/landlock.rst index e0fc54a..3e4d4d0 100644 --- a/Documentation/security/landlock.rst +++ b/Documentation/security/landlock.rst @@ -7,7 +7,7 @@ Landlock LSM: kernel documentation ================================== :Author: Mickaël Salaün -:Date: March 2025 +:Date: September 2025 Landlock's goal is to create scoped access-control (i.e. sandboxing). To harden a whole system, this feature should be available to any process, @@ -110,6 +110,12 @@ Filesystem .. kernel-doc:: security/landlock/fs.h :identifiers: +Process credential +------------------ + +.. kernel-doc:: security/landlock/cred.h + :identifiers: + Ruleset and domain ------------------ @@ -128,6 +134,9 @@ makes the reasoning much easier and helps avoid pitfalls. .. kernel-doc:: security/landlock/ruleset.h :identifiers: +.. kernel-doc:: security/landlock/domain.h + :identifiers: + Additional documentation ======================== diff --git a/security/landlock/errata/abi-1.h b/security/landlock/errata/abi-1.h new file mode 100644 index 0000000..e8a2bff --- /dev/null +++ b/security/landlock/errata/abi-1.h @@ -0,0 +1,16 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ + +/** + * DOC: erratum_3 + * + * Erratum 3: Disconnected directory handling + * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + * + * This fix addresses an issue with disconnected directories that occur when a + * directory is moved outside the scope of a bind mount. The change ensures + * that evaluated access rights include both those from the disconnected file + * hierarchy down to its filesystem root and those from the related mount point + * hierarchy. This prevents access right widening through rename or link + * actions. + */ +LANDLOCK_ERRATUM(3) diff --git a/security/landlock/fs.c b/security/landlock/fs.c index cee2b6f..fe79487 100644 --- a/security/landlock/fs.c +++ b/security/landlock/fs.c @@ -714,7 +714,8 @@ static void test_is_eacces_with_write(struct kunit *const test) * is_access_to_paths_allowed - Check accesses for requests with a common path * * @domain: Domain to check against. - * @path: File hierarchy to walk through. + * @path: File hierarchy to walk through. For refer checks, this would be + * the common mountpoint. * @access_request_parent1: Accesses to check, once @layer_masks_parent1 is * equal to @layer_masks_parent2 (if any). This is tied to the unique * requested path for most actions, or the source in case of a refer action @@ -837,7 +838,6 @@ static bool is_access_to_paths_allowed( * restriction. */ while (true) { - struct dentry *parent_dentry; const struct landlock_rule *rule; /* @@ -909,21 +909,33 @@ jump_up: break; } } + if (unlikely(IS_ROOT(walker_path.dentry))) { - /* - * Stops at disconnected root directories. Only allows - * access to internal filesystems (e.g. nsfs, which is - * reachable through /proc//ns/). - */ - if (walker_path.mnt->mnt_flags & MNT_INTERNAL) { + if (likely(walker_path.mnt->mnt_flags & MNT_INTERNAL)) { + /* + * Stops and allows access when reaching disconnected root + * directories that are part of internal filesystems (e.g. nsfs, + * which is reachable through /proc//ns/). + */ allowed_parent1 = true; allowed_parent2 = true; + break; } - break; + + /* + * We reached a disconnected root directory from a bind mount. + * Let's continue the walk with the mount point we missed. + */ + dput(walker_path.dentry); + walker_path.dentry = walker_path.mnt->mnt_root; + dget(walker_path.dentry); + } else { + struct dentry *const parent_dentry = + dget_parent(walker_path.dentry); + + dput(walker_path.dentry); + walker_path.dentry = parent_dentry; } - parent_dentry = dget_parent(walker_path.dentry); - dput(walker_path.dentry); - walker_path.dentry = parent_dentry; } path_put(&walker_path); @@ -1021,6 +1033,9 @@ static access_mask_t maybe_remove(const struct dentry *const dentry) * file. While walking from @dir to @mnt_root, we record all the domain's * allowed accesses in @layer_masks_dom. * + * Because of disconnected directories, this walk may not reach @mnt_dir. In + * this case, the walk will continue to @mnt_dir after this call. + * * This is similar to is_access_to_paths_allowed() but much simpler because it * only handles walking on the same mount point and only checks one set of * accesses. @@ -1062,8 +1077,11 @@ static bool collect_domain_accesses( break; } - /* We should not reach a root other than @mnt_root. */ - if (dir == mnt_root || WARN_ON_ONCE(IS_ROOT(dir))) + /* + * Stops at the mount point or the filesystem root for a disconnected + * directory. + */ + if (dir == mnt_root || unlikely(IS_ROOT(dir))) break; parent_dentry = dget_parent(dir); diff --git a/security/landlock/ruleset.c b/security/landlock/ruleset.c index ce7940e..dfcdc19 100644 --- a/security/landlock/ruleset.c +++ b/security/landlock/ruleset.c @@ -83,6 +83,10 @@ static void build_check_rule(void) .num_layers = ~0, }; + /* + * Checks that .num_layers is large enough for at least + * LANDLOCK_MAX_NUM_LAYERS layers. + */ BUILD_BUG_ON(rule.num_layers < LANDLOCK_MAX_NUM_LAYERS); } @@ -290,6 +294,10 @@ static void build_check_layer(void) .access = ~0, }; + /* + * Checks that .level and .access are large enough to contain their expected + * maximum values. + */ BUILD_BUG_ON(layer.level < LANDLOCK_MAX_NUM_LAYERS); BUILD_BUG_ON(layer.access < LANDLOCK_MASK_ACCESS_FS); } @@ -644,8 +652,8 @@ bool landlock_unmask_layers(const struct landlock_rule *const rule, bool is_empty; /* - * Records in @layer_masks which layer grants access to each - * requested access. + * Records in @layer_masks which layer grants access to each requested + * access: bit cleared if the related layer grants access. */ is_empty = true; for_each_set_bit(access_bit, &access_req, masks_array_size) { diff --git a/security/landlock/ruleset.h b/security/landlock/ruleset.h index 5da9a64..1a78cba 100644 --- a/security/landlock/ruleset.h +++ b/security/landlock/ruleset.h @@ -27,7 +27,7 @@ struct landlock_hierarchy; */ struct landlock_layer { /** - * @level: Position of this layer in the layer stack. + * @level: Position of this layer in the layer stack. Starts from 1. */ u16 level; /** diff --git a/tools/testing/selftests/landlock/Makefile b/tools/testing/selftests/landlock/Makefile index a3f4499..044b83b 100644 --- a/tools/testing/selftests/landlock/Makefile +++ b/tools/testing/selftests/landlock/Makefile @@ -4,7 +4,7 @@ CFLAGS += -Wall -O2 $(KHDR_INCLUDES) -LOCAL_HDRS += common.h +LOCAL_HDRS += $(wildcard *.h) src_test := $(wildcard *_test.c) diff --git a/tools/testing/selftests/landlock/fs_test.c b/tools/testing/selftests/landlock/fs_test.c index fa0f18e..eee814e 100644 --- a/tools/testing/selftests/landlock/fs_test.c +++ b/tools/testing/selftests/landlock/fs_test.c @@ -2267,6 +2267,22 @@ static int test_exchange(const char *const oldpath, const char *const newpath) return 0; } +static int test_renameat(int olddirfd, const char *oldpath, int newdirfd, + const char *newpath) +{ + if (renameat2(olddirfd, oldpath, newdirfd, newpath, 0)) + return errno; + return 0; +} + +static int test_exchangeat(int olddirfd, const char *oldpath, int newdirfd, + const char *newpath) +{ + if (renameat2(olddirfd, oldpath, newdirfd, newpath, RENAME_EXCHANGE)) + return errno; + return 0; +} + TEST_F_FORK(layout1, rename_file) { const struct rule rules[] = { @@ -4561,6 +4577,18 @@ TEST_F_FORK(ioctl, handle_file_access_file) FIXTURE(layout1_bind) {}; /* clang-format on */ +static const char bind_dir_s1d3[] = TMP_DIR "/s2d1/s2d2/s1d3"; +static const char bind_file1_s1d3[] = TMP_DIR "/s2d1/s2d2/s1d3/f1"; + +/* Move targets for disconnected path tests. */ +static const char dir_s4d1[] = TMP_DIR "/s4d1"; +static const char file1_s4d1[] = TMP_DIR "/s4d1/f1"; +static const char file2_s4d1[] = TMP_DIR "/s4d1/f2"; +static const char dir_s4d2[] = TMP_DIR "/s4d1/s4d2"; +static const char file1_s4d2[] = TMP_DIR "/s4d1/s4d2/f1"; +static const char file1_name[] = "f1"; +static const char file2_name[] = "f2"; + FIXTURE_SETUP(layout1_bind) { prepare_layout(_metadata); @@ -4576,14 +4604,14 @@ FIXTURE_TEARDOWN_PARENT(layout1_bind) { /* umount(dir_s2d2)) is handled by namespace lifetime. */ + remove_path(file1_s4d1); + remove_path(file2_s4d1); + remove_layout1(_metadata); cleanup_layout(_metadata); } -static const char bind_dir_s1d3[] = TMP_DIR "/s2d1/s2d2/s1d3"; -static const char bind_file1_s1d3[] = TMP_DIR "/s2d1/s2d2/s1d3/f1"; - /* * layout1_bind hierarchy: * @@ -4594,20 +4622,25 @@ static const char bind_file1_s1d3[] = TMP_DIR "/s2d1/s2d2/s1d3/f1"; * │   └── s1d2 * │   ├── f1 * │   ├── f2 - * │   └── s1d3 + * │   └── s1d3 [disconnected by path_disconnected] * │   ├── f1 * │   └── f2 * ├── s2d1 * │   ├── f1 - * │   └── s2d2 + * │   └── s2d2 [bind mount from s1d2] * │   ├── f1 * │   ├── f2 * │   └── s1d3 * │   ├── f1 * │   └── f2 - * └── s3d1 - * └── s3d2 - * └── s3d3 + * ├── s3d1 + * │   └── s3d2 + * │   └── s3d3 + * └── s4d1 [renamed from s1d3 by path_disconnected] + *    ├── f1 + *    ├── f2 + * └── s4d2 + * └── f1 */ TEST_F_FORK(layout1_bind, no_restriction) @@ -4806,6 +4839,1431 @@ TEST_F_FORK(layout1_bind, reparent_cross_mount) ASSERT_EQ(0, rename(bind_file1_s1d3, file1_s2d2)); } +/* + * Make sure access to file through a disconnected path works as expected. + * This test moves s1d3 to s4d1. + */ +TEST_F_FORK(layout1_bind, path_disconnected) +{ + const struct rule layer1_allow_all[] = { + { + .path = TMP_DIR, + .access = ACCESS_ALL, + }, + {}, + }; + const struct rule layer2_allow_just_f1[] = { + { + .path = file1_s1d3, + .access = LANDLOCK_ACCESS_FS_READ_FILE, + }, + {}, + }; + const struct rule layer3_only_s1d2[] = { + { + .path = dir_s1d2, + .access = LANDLOCK_ACCESS_FS_READ_FILE, + }, + {}, + }; + + /* Landlock should not deny access just because it is disconnected. */ + int ruleset_fd_l1 = + create_ruleset(_metadata, ACCESS_ALL, layer1_allow_all); + + /* Creates the new ruleset now before we move the dir containing the file. */ + int ruleset_fd_l2 = + create_ruleset(_metadata, ACCESS_RW, layer2_allow_just_f1); + int ruleset_fd_l3 = + create_ruleset(_metadata, ACCESS_RW, layer3_only_s1d2); + int bind_s1d3_fd; + + ASSERT_LE(0, ruleset_fd_l1); + ASSERT_LE(0, ruleset_fd_l2); + ASSERT_LE(0, ruleset_fd_l3); + + enforce_ruleset(_metadata, ruleset_fd_l1); + EXPECT_EQ(0, close(ruleset_fd_l1)); + + bind_s1d3_fd = open(bind_dir_s1d3, O_PATH | O_CLOEXEC); + ASSERT_LE(0, bind_s1d3_fd); + + /* Tests access is possible before we move. */ + EXPECT_EQ(0, test_open_rel(bind_s1d3_fd, file1_name, O_RDONLY)); + EXPECT_EQ(0, test_open_rel(bind_s1d3_fd, file2_name, O_RDONLY)); + EXPECT_EQ(0, test_open_rel(bind_s1d3_fd, "..", O_RDONLY | O_DIRECTORY)); + + /* Makes it disconnected. */ + ASSERT_EQ(0, rename(dir_s1d3, dir_s4d1)) + { + TH_LOG("Failed to rename %s to %s: %s", dir_s1d3, dir_s4d1, + strerror(errno)); + } + + /* Tests that access is still possible. */ + EXPECT_EQ(0, test_open_rel(bind_s1d3_fd, file1_name, O_RDONLY)); + EXPECT_EQ(0, test_open_rel(bind_s1d3_fd, file2_name, O_RDONLY)); + + /* + * Tests that ".." is not possible (not because of Landlock, but just + * because it's disconnected). + */ + EXPECT_EQ(ENOENT, + test_open_rel(bind_s1d3_fd, "..", O_RDONLY | O_DIRECTORY)); + + /* This should still work with a narrower rule. */ + enforce_ruleset(_metadata, ruleset_fd_l2); + EXPECT_EQ(0, close(ruleset_fd_l2)); + + EXPECT_EQ(0, test_open(file1_s4d1, O_RDONLY)); + /* + * Accessing a file through a disconnected file descriptor can still be + * allowed by a rule tied to this file, even if it is no longer visible in + * its mount point. + */ + EXPECT_EQ(0, test_open_rel(bind_s1d3_fd, file1_name, O_RDONLY)); + EXPECT_EQ(EACCES, test_open_rel(bind_s1d3_fd, file2_name, O_RDONLY)); + + enforce_ruleset(_metadata, ruleset_fd_l3); + EXPECT_EQ(0, close(ruleset_fd_l3)); + + EXPECT_EQ(EACCES, test_open(file1_s4d1, O_RDONLY)); + /* + * Accessing a file through a disconnected file descriptor can still be + * allowed by a rule tied to the original mount point, even if it is no + * longer visible in its mount point. + */ + EXPECT_EQ(0, test_open_rel(bind_s1d3_fd, file1_name, O_RDONLY)); + EXPECT_EQ(EACCES, test_open_rel(bind_s1d3_fd, file2_name, O_RDONLY)); +} + +/* + * Test that renameat with disconnected paths works under Landlock. This test + * moves s1d3 to s4d2, so that we can have a rule allowing refers on the move + * target's immediate parent. + */ +TEST_F_FORK(layout1_bind, path_disconnected_rename) +{ + const struct rule layer1[] = { + { + .path = dir_s1d2, + .access = LANDLOCK_ACCESS_FS_REFER | + LANDLOCK_ACCESS_FS_MAKE_DIR | + LANDLOCK_ACCESS_FS_REMOVE_DIR | + LANDLOCK_ACCESS_FS_MAKE_REG | + LANDLOCK_ACCESS_FS_REMOVE_FILE | + LANDLOCK_ACCESS_FS_READ_FILE, + }, + { + .path = dir_s4d1, + .access = LANDLOCK_ACCESS_FS_REFER | + LANDLOCK_ACCESS_FS_MAKE_DIR | + LANDLOCK_ACCESS_FS_REMOVE_DIR | + LANDLOCK_ACCESS_FS_MAKE_REG | + LANDLOCK_ACCESS_FS_REMOVE_FILE | + LANDLOCK_ACCESS_FS_READ_FILE, + }, + {} + }; + + /* This layer only handles LANDLOCK_ACCESS_FS_READ_FILE. */ + const struct rule layer2_only_s1d2[] = { + { + .path = dir_s1d2, + .access = LANDLOCK_ACCESS_FS_READ_FILE, + }, + {}, + }; + int ruleset_fd_l1, ruleset_fd_l2; + pid_t child_pid; + int bind_s1d3_fd, status; + + ASSERT_EQ(0, mkdir(dir_s4d1, 0755)) + { + TH_LOG("Failed to create %s: %s", dir_s4d1, strerror(errno)); + } + ruleset_fd_l1 = create_ruleset(_metadata, ACCESS_ALL, layer1); + ruleset_fd_l2 = create_ruleset(_metadata, LANDLOCK_ACCESS_FS_READ_FILE, + layer2_only_s1d2); + ASSERT_LE(0, ruleset_fd_l1); + ASSERT_LE(0, ruleset_fd_l2); + + enforce_ruleset(_metadata, ruleset_fd_l1); + EXPECT_EQ(0, close(ruleset_fd_l1)); + + bind_s1d3_fd = open(bind_dir_s1d3, O_PATH | O_CLOEXEC); + ASSERT_LE(0, bind_s1d3_fd); + EXPECT_EQ(0, test_open_rel(bind_s1d3_fd, file1_name, O_RDONLY)); + + /* Tests ENOENT priority over EACCES for disconnected directory. */ + EXPECT_EQ(EACCES, test_open_rel(bind_s1d3_fd, "..", O_DIRECTORY)); + ASSERT_EQ(0, rename(dir_s1d3, dir_s4d2)) + { + TH_LOG("Failed to rename %s to %s: %s", dir_s1d3, dir_s4d2, + strerror(errno)); + } + EXPECT_EQ(ENOENT, test_open_rel(bind_s1d3_fd, "..", O_DIRECTORY)); + + /* + * The file is no longer under s1d2 but we should still be able to access it + * with layer 2 because its mount point is evaluated as the first valid + * directory because it was initially a parent. Do a fork to test this so + * we don't prevent ourselves from renaming it back later. + */ + child_pid = fork(); + ASSERT_LE(0, child_pid); + if (child_pid == 0) { + enforce_ruleset(_metadata, ruleset_fd_l2); + EXPECT_EQ(0, close(ruleset_fd_l2)); + EXPECT_EQ(0, test_open_rel(bind_s1d3_fd, file1_name, O_RDONLY)); + EXPECT_EQ(EACCES, test_open(file1_s4d2, O_RDONLY)); + + /* + * Tests that access widening checks indeed prevents us from renaming it + * back. + */ + EXPECT_EQ(-1, rename(dir_s4d2, dir_s1d3)); + EXPECT_EQ(EXDEV, errno); + + /* + * Including through the now disconnected fd (but it should return + * EXDEV). + */ + EXPECT_EQ(-1, renameat(bind_s1d3_fd, file1_name, AT_FDCWD, + file1_s2d2)); + EXPECT_EQ(EXDEV, errno); + _exit(_metadata->exit_code); + return; + } + + EXPECT_EQ(child_pid, waitpid(child_pid, &status, 0)); + EXPECT_EQ(1, WIFEXITED(status)); + EXPECT_EQ(EXIT_SUCCESS, WEXITSTATUS(status)); + + ASSERT_EQ(0, rename(dir_s4d2, dir_s1d3)) + { + TH_LOG("Failed to rename %s back to %s: %s", dir_s4d1, dir_s1d3, + strerror(errno)); + } + + /* Now checks that we can access it under l2. */ + child_pid = fork(); + ASSERT_LE(0, child_pid); + if (child_pid == 0) { + enforce_ruleset(_metadata, ruleset_fd_l2); + EXPECT_EQ(0, close(ruleset_fd_l2)); + EXPECT_EQ(0, test_open_rel(bind_s1d3_fd, file1_name, O_RDONLY)); + EXPECT_EQ(0, test_open(file1_s1d3, O_RDONLY)); + _exit(_metadata->exit_code); + return; + } + + EXPECT_EQ(child_pid, waitpid(child_pid, &status, 0)); + EXPECT_EQ(1, WIFEXITED(status)); + EXPECT_EQ(EXIT_SUCCESS, WEXITSTATUS(status)); + + /* + * Also test that we can rename via a disconnected path. We move the + * dir back to the disconnected place first, then we rename file1 to + * file2 through our dir fd. + */ + ASSERT_EQ(0, rename(dir_s1d3, dir_s4d2)) + { + TH_LOG("Failed to rename %s to %s: %s", dir_s1d3, dir_s4d2, + strerror(errno)); + } + ASSERT_EQ(0, + renameat(bind_s1d3_fd, file1_name, bind_s1d3_fd, file2_name)) + { + TH_LOG("Failed to rename %s to %s within disconnected %s: %s", + file1_name, file2_name, bind_dir_s1d3, strerror(errno)); + } + EXPECT_EQ(0, test_open_rel(bind_s1d3_fd, file2_name, O_RDONLY)); + ASSERT_EQ(0, renameat(bind_s1d3_fd, file2_name, AT_FDCWD, file1_s2d2)) + { + TH_LOG("Failed to rename %s to %s through disconnected %s: %s", + file2_name, file1_s2d2, bind_dir_s1d3, strerror(errno)); + } + EXPECT_EQ(0, test_open(file1_s2d2, O_RDONLY)); + EXPECT_EQ(0, test_open(file1_s1d2, O_RDONLY)); + + /* Move it back using the disconnected path as the target. */ + ASSERT_EQ(0, renameat(AT_FDCWD, file1_s2d2, bind_s1d3_fd, file1_name)) + { + TH_LOG("Failed to rename %s to %s through disconnected %s: %s", + file1_s1d2, file1_name, bind_dir_s1d3, strerror(errno)); + } + + /* Now make it connected again. */ + ASSERT_EQ(0, rename(dir_s4d2, dir_s1d3)) + { + TH_LOG("Failed to rename %s back to %s: %s", dir_s4d2, dir_s1d3, + strerror(errno)); + } + + /* Checks again that we can access it under l2. */ + enforce_ruleset(_metadata, ruleset_fd_l2); + EXPECT_EQ(0, close(ruleset_fd_l2)); + EXPECT_EQ(0, test_open_rel(bind_s1d3_fd, file1_name, O_RDONLY)); + EXPECT_EQ(0, test_open(file1_s1d3, O_RDONLY)); +} + +/* + * Test that linkat(2) with disconnected paths works under Landlock. This + * test moves s1d3 to s4d1. + */ +TEST_F_FORK(layout1_bind, path_disconnected_link) +{ + /* Ruleset to be applied after renaming s1d3 to s4d1. */ + const struct rule layer1[] = { + { + .path = dir_s4d1, + .access = LANDLOCK_ACCESS_FS_REFER | + LANDLOCK_ACCESS_FS_READ_FILE | + LANDLOCK_ACCESS_FS_MAKE_REG | + LANDLOCK_ACCESS_FS_REMOVE_FILE, + }, + { + .path = dir_s2d2, + .access = LANDLOCK_ACCESS_FS_REFER | + LANDLOCK_ACCESS_FS_READ_FILE | + LANDLOCK_ACCESS_FS_MAKE_REG | + LANDLOCK_ACCESS_FS_REMOVE_FILE, + }, + {} + }; + int ruleset_fd, bind_s1d3_fd; + + /* Removes unneeded files created by layout1, otherwise it will EEXIST. */ + ASSERT_EQ(0, unlink(file1_s1d2)); + ASSERT_EQ(0, unlink(file2_s1d3)); + + bind_s1d3_fd = open(bind_dir_s1d3, O_PATH | O_CLOEXEC); + ASSERT_LE(0, bind_s1d3_fd); + EXPECT_EQ(0, test_open_rel(bind_s1d3_fd, file1_name, O_RDONLY)); + + /* Disconnects bind_s1d3_fd. */ + ASSERT_EQ(0, rename(dir_s1d3, dir_s4d1)) + { + TH_LOG("Failed to rename %s to %s: %s", dir_s1d3, dir_s4d1, + strerror(errno)); + } + + /* Need this later to test different parent link. */ + ASSERT_EQ(0, mkdir(dir_s4d2, 0755)) + { + TH_LOG("Failed to create %s: %s", dir_s4d2, strerror(errno)); + } + + ruleset_fd = create_ruleset(_metadata, ACCESS_ALL, layer1); + ASSERT_LE(0, ruleset_fd); + enforce_ruleset(_metadata, ruleset_fd); + EXPECT_EQ(0, close(ruleset_fd)); + + /* From disconnected to connected. */ + ASSERT_EQ(0, linkat(bind_s1d3_fd, file1_name, AT_FDCWD, file1_s2d2, 0)) + { + TH_LOG("Failed to link %s to %s via disconnected %s: %s", + file1_name, file1_s2d2, bind_dir_s1d3, strerror(errno)); + } + + /* Tests that we can access via the new link... */ + EXPECT_EQ(0, test_open(file1_s2d2, O_RDONLY)) + { + TH_LOG("Failed to open newly linked %s: %s", file1_s2d2, + strerror(errno)); + } + + /* ...as well as the old one. */ + EXPECT_EQ(0, test_open(file1_s4d1, O_RDONLY)) + { + TH_LOG("Failed to open original %s: %s", file1_s4d1, + strerror(errno)); + } + + /* From connected to disconnected. */ + ASSERT_EQ(0, unlink(file1_s4d1)); + ASSERT_EQ(0, linkat(AT_FDCWD, file1_s2d2, bind_s1d3_fd, file2_name, 0)) + { + TH_LOG("Failed to link %s to %s via disconnected %s: %s", + file1_s2d2, file2_name, bind_dir_s1d3, strerror(errno)); + } + EXPECT_EQ(0, test_open(file2_s4d1, O_RDONLY)); + ASSERT_EQ(0, unlink(file1_s2d2)); + + /* From disconnected to disconnected (same parent). */ + ASSERT_EQ(0, + linkat(bind_s1d3_fd, file2_name, bind_s1d3_fd, file1_name, 0)) + { + TH_LOG("Failed to link %s to %s within disconnected %s: %s", + file2_name, file1_name, bind_dir_s1d3, strerror(errno)); + } + EXPECT_EQ(0, test_open(file1_s4d1, O_RDONLY)) + { + TH_LOG("Failed to open newly linked %s: %s", file1_s4d1, + strerror(errno)); + } + EXPECT_EQ(0, test_open_rel(bind_s1d3_fd, file1_name, O_RDONLY)) + { + TH_LOG("Failed to open %s through newly created link under disconnected path: %s", + file1_name, strerror(errno)); + } + ASSERT_EQ(0, unlink(file2_s4d1)); + + /* From disconnected to disconnected (different parent). */ + ASSERT_EQ(0, + linkat(bind_s1d3_fd, file1_name, bind_s1d3_fd, "s4d2/f1", 0)) + { + TH_LOG("Failed to link %s to %s within disconnected %s: %s", + file1_name, "s4d2/f1", bind_dir_s1d3, strerror(errno)); + } + EXPECT_EQ(0, test_open(file1_s4d2, O_RDONLY)) + { + TH_LOG("Failed to open %s after link: %s", file1_s4d2, + strerror(errno)); + } + EXPECT_EQ(0, test_open_rel(bind_s1d3_fd, "s4d2/f1", O_RDONLY)) + { + TH_LOG("Failed to open %s through disconnected path after link: %s", + "s4d2/f1", strerror(errno)); + } +} + +/* + * layout4_disconnected_leafs with bind mount and renames: + * + * tmp + * ├── s1d1 + * │   └── s1d2 [source of the bind mount] + * │ ├── s1d31 + * │   │ └── s1d41 [now renamed beneath s3d1] + * │ │ ├── f1 + * │ │ └── f2 + * │   └── s1d32 + * │ └── s1d42 [now renamed beneath s4d1] + * │ ├── f3 + * │ └── f4 + * ├── s2d1 + * │   └── s2d2 [bind mount of s1d2] + * │ ├── s1d31 + * │   │ └── s1d41 [opened FD, now renamed beneath s3d1] + * │ │ ├── f1 + * │ │ └── f2 + * │   └── s1d32 + * │ └── s1d42 [opened FD, now renamed beneath s4d1] + * │ ├── f3 + * │ └── f4 + * ├── s3d1 + * │  └── s1d41 [renamed here] + * │ ├── f1 + * │ └── f2 + * └── s4d1 + * └── s1d42 [renamed here] + * ├── f3 + * └── f4 + */ +/* clang-format off */ +FIXTURE(layout4_disconnected_leafs) { + int s2d2_fd; +}; +/* clang-format on */ + +FIXTURE_SETUP(layout4_disconnected_leafs) +{ + prepare_layout(_metadata); + + create_file(_metadata, TMP_DIR "/s1d1/s1d2/s1d31/s1d41/f1"); + create_file(_metadata, TMP_DIR "/s1d1/s1d2/s1d31/s1d41/f2"); + create_file(_metadata, TMP_DIR "/s1d1/s1d2/s1d32/s1d42/f3"); + create_file(_metadata, TMP_DIR "/s1d1/s1d2/s1d32/s1d42/f4"); + create_directory(_metadata, TMP_DIR "/s2d1/s2d2"); + create_directory(_metadata, TMP_DIR "/s3d1"); + create_directory(_metadata, TMP_DIR "/s4d1"); + + self->s2d2_fd = + open(TMP_DIR "/s2d1/s2d2", O_DIRECTORY | O_PATH | O_CLOEXEC); + ASSERT_LE(0, self->s2d2_fd); + + set_cap(_metadata, CAP_SYS_ADMIN); + ASSERT_EQ(0, mount(TMP_DIR "/s1d1/s1d2", TMP_DIR "/s2d1/s2d2", NULL, + MS_BIND, NULL)); + clear_cap(_metadata, CAP_SYS_ADMIN); +} + +FIXTURE_TEARDOWN_PARENT(layout4_disconnected_leafs) +{ + /* umount(TMP_DIR "/s2d1") is handled by namespace lifetime. */ + + /* Removes files after renames. */ + remove_path(TMP_DIR "/s3d1/s1d41/f1"); + remove_path(TMP_DIR "/s3d1/s1d41/f2"); + remove_path(TMP_DIR "/s4d1/s1d42/f1"); + remove_path(TMP_DIR "/s4d1/s1d42/f3"); + remove_path(TMP_DIR "/s4d1/s1d42/f4"); + remove_path(TMP_DIR "/s4d1/s1d42/f5"); + + cleanup_layout(_metadata); +} + +FIXTURE_VARIANT(layout4_disconnected_leafs) +{ + /* + * Parent of the bind mount source. It should always be ignored when + * testing against files under the s1d41 or s1d42 disconnected directories. + */ + const __u64 allowed_s1d1; + /* + * Source of bind mount (to s2d2). It should always be enforced when + * testing against files under the s1d41 or s1d42 disconnected directories. + */ + const __u64 allowed_s1d2; + /* + * Original parent of s1d41. It should always be ignored when testing + * against files under the s1d41 disconnected directory. + */ + const __u64 allowed_s1d31; + /* + * Original parent of s1d42. It should always be ignored when testing + * against files under the s1d42 disconnected directory. + */ + const __u64 allowed_s1d32; + /* + * Opened and disconnected source directory. It should always be enforced + * when testing against files under the s1d41 disconnected directory. + */ + const __u64 allowed_s1d41; + /* + * Opened and disconnected source directory. It should always be enforced + * when testing against files under the s1d42 disconnected directory. + */ + const __u64 allowed_s1d42; + /* + * File in the s1d41 disconnected directory. It should always be enforced + * when testing against itself under the s1d41 disconnected directory. + */ + const __u64 allowed_f1; + /* + * File in the s1d41 disconnected directory. It should always be enforced + * when testing against itself under the s1d41 disconnected directory. + */ + const __u64 allowed_f2; + /* + * File in the s1d42 disconnected directory. It should always be enforced + * when testing against itself under the s1d42 disconnected directory. + */ + const __u64 allowed_f3; + /* + * Parent of the bind mount destination. It should always be enforced when + * testing against files under the s1d41 or s1d42 disconnected directories. + */ + const __u64 allowed_s2d1; + /* + * Directory covered by the bind mount. It should always be ignored when + * testing against files under the s1d41 or s1d42 disconnected directories. + */ + const __u64 allowed_s2d2; + /* + * New parent of the renamed s1d41. It should always be ignored when + * testing against files under the s1d41 disconnected directory. + */ + const __u64 allowed_s3d1; + /* + * New parent of the renamed s1d42. It should always be ignored when + * testing against files under the s1d42 disconnected directory. + */ + const __u64 allowed_s4d1; + + /* Expected result of the call to open([fd:s1d41]/f1, O_RDONLY). */ + const int expected_read_result; + /* Expected result of the call to renameat([fd:s1d41]/f1, [fd:s1d42]/f1). */ + const int expected_rename_result; + /* + * Expected result of the call to renameat([fd:s1d41]/f2, [fd:s1d42]/f3, + * RENAME_EXCHANGE). + */ + const int expected_exchange_result; + /* Expected result of the call to renameat([fd:s1d42]/f4, [fd:s1d42]/f5). */ + const int expected_same_dir_rename_result; +}; + +/* clang-format off */ +FIXTURE_VARIANT_ADD(layout4_disconnected_leafs, s1d1_mount_src_parent) { + /* clang-format on */ + .allowed_s1d1 = LANDLOCK_ACCESS_FS_REFER | + LANDLOCK_ACCESS_FS_READ_FILE | + LANDLOCK_ACCESS_FS_EXECUTE | + LANDLOCK_ACCESS_FS_MAKE_REG, + .expected_read_result = EACCES, + .expected_same_dir_rename_result = EACCES, + .expected_rename_result = EACCES, + .expected_exchange_result = EACCES, +}; + +/* clang-format off */ +FIXTURE_VARIANT_ADD(layout4_disconnected_leafs, s1d2_mount_src_refer) { + /* clang-format on */ + .allowed_s1d2 = LANDLOCK_ACCESS_FS_REFER | LANDLOCK_ACCESS_FS_READ_FILE, + .expected_read_result = 0, + .expected_same_dir_rename_result = EACCES, + .expected_rename_result = EACCES, + .expected_exchange_result = EACCES, +}; + +/* clang-format off */ +FIXTURE_VARIANT_ADD(layout4_disconnected_leafs, s1d2_mount_src_create) { + /* clang-format on */ + .allowed_s1d2 = LANDLOCK_ACCESS_FS_READ_FILE | + LANDLOCK_ACCESS_FS_MAKE_REG, + .expected_read_result = 0, + .expected_same_dir_rename_result = 0, + .expected_rename_result = EXDEV, + .expected_exchange_result = EXDEV, +}; + +/* clang-format off */ +FIXTURE_VARIANT_ADD(layout4_disconnected_leafs, s1d2_mount_src_rename) { + /* clang-format on */ + .allowed_s1d2 = LANDLOCK_ACCESS_FS_REFER | LANDLOCK_ACCESS_FS_MAKE_REG, + .expected_read_result = EACCES, + .expected_same_dir_rename_result = 0, + .expected_rename_result = 0, + .expected_exchange_result = 0, +}; + +/* clang-format off */ +FIXTURE_VARIANT_ADD(layout4_disconnected_leafs, s1d31_s1d32_old_parent) { + /* clang-format on */ + .allowed_s1d31 = LANDLOCK_ACCESS_FS_REFER | + LANDLOCK_ACCESS_FS_READ_FILE | + LANDLOCK_ACCESS_FS_EXECUTE | + LANDLOCK_ACCESS_FS_MAKE_REG, + .allowed_s1d32 = LANDLOCK_ACCESS_FS_REFER | + LANDLOCK_ACCESS_FS_READ_FILE | + LANDLOCK_ACCESS_FS_EXECUTE | + LANDLOCK_ACCESS_FS_MAKE_REG, + .expected_read_result = EACCES, + .expected_same_dir_rename_result = EACCES, + .expected_rename_result = EACCES, + .expected_exchange_result = EACCES, +}; + +/* clang-format off */ +FIXTURE_VARIANT_ADD(layout4_disconnected_leafs, s1d41_s1d42_disconnected_refer) { + /* clang-format on */ + .allowed_s1d41 = LANDLOCK_ACCESS_FS_REFER | + LANDLOCK_ACCESS_FS_READ_FILE, + .allowed_s1d42 = LANDLOCK_ACCESS_FS_REFER | + LANDLOCK_ACCESS_FS_READ_FILE, + .expected_read_result = 0, + .expected_same_dir_rename_result = EACCES, + .expected_rename_result = EACCES, + .expected_exchange_result = EACCES, +}; + +/* clang-format off */ +FIXTURE_VARIANT_ADD(layout4_disconnected_leafs, s1d41_s1d42_disconnected_create) { + /* clang-format on */ + .allowed_s1d41 = LANDLOCK_ACCESS_FS_READ_FILE | + LANDLOCK_ACCESS_FS_MAKE_REG, + .allowed_s1d42 = LANDLOCK_ACCESS_FS_READ_FILE | + LANDLOCK_ACCESS_FS_MAKE_REG, + .expected_read_result = 0, + .expected_same_dir_rename_result = 0, + .expected_rename_result = EXDEV, + .expected_exchange_result = EXDEV, +}; + +/* clang-format off */ +FIXTURE_VARIANT_ADD(layout4_disconnected_leafs, s1d41_s1d42_disconnected_rename_even) { + /* clang-format on */ + .allowed_s1d41 = LANDLOCK_ACCESS_FS_REFER | LANDLOCK_ACCESS_FS_MAKE_REG, + .allowed_s1d42 = LANDLOCK_ACCESS_FS_REFER | LANDLOCK_ACCESS_FS_MAKE_REG, + .expected_read_result = EACCES, + .expected_same_dir_rename_result = 0, + .expected_rename_result = 0, + .expected_exchange_result = 0, +}; + +/* The destination directory has more access right. */ +/* clang-format off */ +FIXTURE_VARIANT_ADD(layout4_disconnected_leafs, s1d41_s1d42_disconnected_rename_more) { + /* clang-format on */ + .allowed_s1d41 = LANDLOCK_ACCESS_FS_REFER | LANDLOCK_ACCESS_FS_MAKE_REG, + .allowed_s1d42 = LANDLOCK_ACCESS_FS_REFER | + LANDLOCK_ACCESS_FS_MAKE_REG | + LANDLOCK_ACCESS_FS_EXECUTE, + .expected_read_result = EACCES, + .expected_same_dir_rename_result = 0, + /* Access denied. */ + .expected_rename_result = EXDEV, + .expected_exchange_result = EXDEV, +}; + +/* The destination directory has less access right. */ +/* clang-format off */ +FIXTURE_VARIANT_ADD(layout4_disconnected_leafs, s1d41_s1d42_disconnected_rename_less) { + /* clang-format on */ + .allowed_s1d41 = LANDLOCK_ACCESS_FS_REFER | + LANDLOCK_ACCESS_FS_MAKE_REG | + LANDLOCK_ACCESS_FS_EXECUTE, + .allowed_s1d42 = LANDLOCK_ACCESS_FS_REFER | LANDLOCK_ACCESS_FS_MAKE_REG, + .expected_read_result = EACCES, + .expected_same_dir_rename_result = 0, + /* Access allowed. */ + .expected_rename_result = 0, + .expected_exchange_result = EXDEV, +}; + +/* clang-format off */ +FIXTURE_VARIANT_ADD(layout4_disconnected_leafs, s2d1_mount_dst_parent_create) { + /* clang-format on */ + .allowed_s2d1 = LANDLOCK_ACCESS_FS_READ_FILE | + LANDLOCK_ACCESS_FS_MAKE_REG, + .expected_read_result = 0, + .expected_same_dir_rename_result = 0, + .expected_rename_result = EXDEV, + .expected_exchange_result = EXDEV, +}; + +/* clang-format off */ +FIXTURE_VARIANT_ADD(layout4_disconnected_leafs, s2d1_mount_dst_parent_refer) { + /* clang-format on */ + .allowed_s2d1 = LANDLOCK_ACCESS_FS_REFER | LANDLOCK_ACCESS_FS_READ_FILE, + .expected_read_result = 0, + .expected_same_dir_rename_result = EACCES, + .expected_rename_result = EACCES, + .expected_exchange_result = EACCES, +}; + +/* clang-format off */ +FIXTURE_VARIANT_ADD(layout4_disconnected_leafs, s2d1_mount_dst_parent_mini) { + /* clang-format on */ + .allowed_s2d1 = LANDLOCK_ACCESS_FS_REFER | + LANDLOCK_ACCESS_FS_READ_FILE | + LANDLOCK_ACCESS_FS_MAKE_REG, + .expected_read_result = 0, + .expected_same_dir_rename_result = 0, + .expected_rename_result = 0, + .expected_exchange_result = 0, +}; + +/* clang-format off */ +FIXTURE_VARIANT_ADD(layout4_disconnected_leafs, s2d2_covered_by_mount) { + /* clang-format on */ + .allowed_s2d2 = LANDLOCK_ACCESS_FS_REFER | + LANDLOCK_ACCESS_FS_READ_FILE | + LANDLOCK_ACCESS_FS_EXECUTE | + LANDLOCK_ACCESS_FS_MAKE_REG, + .expected_read_result = EACCES, + .expected_same_dir_rename_result = EACCES, + .expected_rename_result = EACCES, + .expected_exchange_result = EACCES, +}; + +/* Tests collect_domain_accesses(). */ +/* clang-format off */ +FIXTURE_VARIANT_ADD(layout4_disconnected_leafs, s3d1_s4d1_new_parent_refer) { + /* clang-format on */ + .allowed_s3d1 = LANDLOCK_ACCESS_FS_REFER | LANDLOCK_ACCESS_FS_READ_FILE, + .allowed_s4d1 = LANDLOCK_ACCESS_FS_REFER | LANDLOCK_ACCESS_FS_READ_FILE, + .expected_read_result = 0, + .expected_same_dir_rename_result = EACCES, + .expected_rename_result = EACCES, + .expected_exchange_result = EACCES, +}; + +/* clang-format off */ +FIXTURE_VARIANT_ADD(layout4_disconnected_leafs, s3d1_s4d1_new_parent_create) { + /* clang-format on */ + .allowed_s3d1 = LANDLOCK_ACCESS_FS_READ_FILE | + LANDLOCK_ACCESS_FS_MAKE_REG, + .allowed_s4d1 = LANDLOCK_ACCESS_FS_READ_FILE | + LANDLOCK_ACCESS_FS_MAKE_REG, + .expected_read_result = 0, + .expected_same_dir_rename_result = 0, + .expected_rename_result = EXDEV, + .expected_exchange_result = EXDEV, +}; + +FIXTURE_VARIANT_ADD(layout4_disconnected_leafs, + s3d1_s4d1_disconnected_rename_even){ + /* clang-format on */ + .allowed_s3d1 = LANDLOCK_ACCESS_FS_REFER | LANDLOCK_ACCESS_FS_MAKE_REG, + .allowed_s4d1 = LANDLOCK_ACCESS_FS_REFER | LANDLOCK_ACCESS_FS_MAKE_REG, + .expected_read_result = EACCES, + .expected_same_dir_rename_result = 0, + .expected_rename_result = 0, + .expected_exchange_result = 0, +}; + +/* The destination directory has more access right. */ +/* clang-format off */ +FIXTURE_VARIANT_ADD(layout4_disconnected_leafs, s3d1_s4d1_disconnected_rename_more) { + /* clang-format on */ + .allowed_s3d1 = LANDLOCK_ACCESS_FS_REFER | LANDLOCK_ACCESS_FS_MAKE_REG, + .allowed_s4d1 = LANDLOCK_ACCESS_FS_REFER | LANDLOCK_ACCESS_FS_MAKE_REG | + LANDLOCK_ACCESS_FS_EXECUTE, + .expected_read_result = EACCES, + .expected_same_dir_rename_result = 0, + /* Access denied. */ + .expected_rename_result = EXDEV, + .expected_exchange_result = EXDEV, +}; + +/* The destination directory has less access right. */ +/* clang-format off */ +FIXTURE_VARIANT_ADD(layout4_disconnected_leafs, s3d1_s4d1_disconnected_rename_less) { + /* clang-format on */ + .allowed_s3d1 = LANDLOCK_ACCESS_FS_REFER | LANDLOCK_ACCESS_FS_MAKE_REG | + LANDLOCK_ACCESS_FS_EXECUTE, + .allowed_s4d1 = LANDLOCK_ACCESS_FS_REFER | LANDLOCK_ACCESS_FS_MAKE_REG, + .expected_read_result = EACCES, + .expected_same_dir_rename_result = 0, + /* Access allowed. */ + .expected_rename_result = 0, + .expected_exchange_result = EXDEV, +}; + +/* clang-format off */ +FIXTURE_VARIANT_ADD(layout4_disconnected_leafs, f1_f2_f3) { + /* clang-format on */ + .allowed_f1 = LANDLOCK_ACCESS_FS_READ_FILE, + .allowed_f2 = LANDLOCK_ACCESS_FS_READ_FILE, + .allowed_f3 = LANDLOCK_ACCESS_FS_READ_FILE, + .expected_read_result = 0, + .expected_same_dir_rename_result = EACCES, + .expected_rename_result = EACCES, + .expected_exchange_result = EACCES, +}; + +TEST_F_FORK(layout4_disconnected_leafs, read_rename_exchange) +{ + const __u64 handled_access = + LANDLOCK_ACCESS_FS_REFER | LANDLOCK_ACCESS_FS_READ_FILE | + LANDLOCK_ACCESS_FS_EXECUTE | LANDLOCK_ACCESS_FS_MAKE_REG; + const struct rule rules[] = { + { + .path = TMP_DIR "/s1d1", + .access = variant->allowed_s1d1, + }, + { + .path = TMP_DIR "/s1d1/s1d2", + .access = variant->allowed_s1d2, + }, + { + .path = TMP_DIR "/s1d1/s1d2/s1d31", + .access = variant->allowed_s1d31, + }, + { + .path = TMP_DIR "/s1d1/s1d2/s1d32", + .access = variant->allowed_s1d32, + }, + { + .path = TMP_DIR "/s1d1/s1d2/s1d31/s1d41", + .access = variant->allowed_s1d41, + }, + { + .path = TMP_DIR "/s1d1/s1d2/s1d32/s1d42", + .access = variant->allowed_s1d42, + }, + { + .path = TMP_DIR "/s1d1/s1d2/s1d31/s1d41/f1", + .access = variant->allowed_f1, + }, + { + .path = TMP_DIR "/s1d1/s1d2/s1d31/s1d41/f2", + .access = variant->allowed_f2, + }, + { + .path = TMP_DIR "/s1d1/s1d2/s1d32/s1d42/f3", + .access = variant->allowed_f3, + }, + { + .path = TMP_DIR "/s2d1", + .access = variant->allowed_s2d1, + }, + /* s2d2_fd */ + { + .path = TMP_DIR "/s3d1", + .access = variant->allowed_s3d1, + }, + { + .path = TMP_DIR "/s4d1", + .access = variant->allowed_s4d1, + }, + {}, + }; + int ruleset_fd, s1d41_bind_fd, s1d42_bind_fd; + + ruleset_fd = create_ruleset(_metadata, handled_access, rules); + ASSERT_LE(0, ruleset_fd); + + /* Adds rule for the covered directory. */ + if (variant->allowed_s2d2) { + ASSERT_EQ(0, landlock_add_rule( + ruleset_fd, LANDLOCK_RULE_PATH_BENEATH, + &(struct landlock_path_beneath_attr){ + .parent_fd = self->s2d2_fd, + .allowed_access = + variant->allowed_s2d2, + }, + 0)); + } + EXPECT_EQ(0, close(self->s2d2_fd)); + + s1d41_bind_fd = open(TMP_DIR "/s2d1/s2d2/s1d31/s1d41", + O_DIRECTORY | O_PATH | O_CLOEXEC); + ASSERT_LE(0, s1d41_bind_fd); + s1d42_bind_fd = open(TMP_DIR "/s2d1/s2d2/s1d32/s1d42", + O_DIRECTORY | O_PATH | O_CLOEXEC); + ASSERT_LE(0, s1d42_bind_fd); + + /* Disconnects and checks source and destination directories. */ + EXPECT_EQ(0, test_open_rel(s1d41_bind_fd, "..", O_DIRECTORY)); + EXPECT_EQ(0, test_open_rel(s1d42_bind_fd, "..", O_DIRECTORY)); + /* Renames to make it accessible through s3d1/s1d41 */ + ASSERT_EQ(0, test_renameat(AT_FDCWD, TMP_DIR "/s1d1/s1d2/s1d31/s1d41", + AT_FDCWD, TMP_DIR "/s3d1/s1d41")); + /* Renames to make it accessible through s4d1/s1d42 */ + ASSERT_EQ(0, test_renameat(AT_FDCWD, TMP_DIR "/s1d1/s1d2/s1d32/s1d42", + AT_FDCWD, TMP_DIR "/s4d1/s1d42")); + EXPECT_EQ(ENOENT, test_open_rel(s1d41_bind_fd, "..", O_DIRECTORY)); + EXPECT_EQ(ENOENT, test_open_rel(s1d42_bind_fd, "..", O_DIRECTORY)); + + enforce_ruleset(_metadata, ruleset_fd); + EXPECT_EQ(0, close(ruleset_fd)); + + EXPECT_EQ(variant->expected_read_result, + test_open_rel(s1d41_bind_fd, "f1", O_RDONLY)); + + EXPECT_EQ(variant->expected_rename_result, + test_renameat(s1d41_bind_fd, "f1", s1d42_bind_fd, "f1")); + EXPECT_EQ(variant->expected_exchange_result, + test_exchangeat(s1d41_bind_fd, "f2", s1d42_bind_fd, "f3")); + + EXPECT_EQ(variant->expected_same_dir_rename_result, + test_renameat(s1d42_bind_fd, "f4", s1d42_bind_fd, "f5")); +} + +/* + * layout5_disconnected_branch before rename: + * + * tmp + * ├── s1d1 + * │   └── s1d2 [source of the first bind mount] + * │   └── s1d3 + * │   ├── s1d41 + * │   │   ├── f1 + * │   │   └── f2 + * │   └── s1d42 + * │   ├── f3 + * │   └── f4 + * ├── s2d1 + * │   └── s2d2 [source of the second bind mount] + * │   └── s2d3 + * │   └── s2d4 [first s1d2 bind mount] + * │   └── s1d3 + * │   ├── s1d41 + * │   │   ├── f1 + * │   │   └── f2 + * │   └── s1d42 + * │   ├── f3 + * │   └── f4 + * ├── s3d1 + * │   └── s3d2 [second s2d2 bind mount] + * │   └── s2d3 + * │   └── s2d4 [first s1d2 bind mount] + * │   └── s1d3 + * │   ├── s1d41 + * │   │   ├── f1 + * │   │   └── f2 + * │   └── s1d42 + * │   ├── f3 + * │   └── f4 + * └── s4d1 + * + * After rename: + * + * tmp + * ├── s1d1 + * │   └── s1d2 [source of the first bind mount] + * │   └── s1d3 + * │   ├── s1d41 + * │   │   ├── f1 + * │   │   └── f2 + * │   └── s1d42 + * │   ├── f3 + * │   └── f4 + * ├── s2d1 + * │   └── s2d2 [source of the second bind mount] + * ├── s3d1 + * │   └── s3d2 [second s2d2 bind mount] + * └── s4d1 + * └── s2d3 [renamed here] + * └── s2d4 [first s1d2 bind mount] + * └── s1d3 + * ├── s1d41 + * │   ├── f1 + * │   └── f2 + * └── s1d42 + * ├── f3 + * └── f4 + * + * Decision path for access from the s3d1/s3d2/s2d3/s2d4/s1d3 file descriptor: + * 1. first bind mount: s1d3 -> s1d2 + * 2. second bind mount: s2d3 + * 3. tmp mount: s4d1 -> tmp [disconnected branch] + * 4. second bind mount: s2d2 + * 5. tmp mount: s3d1 -> tmp + * 6. parent mounts: [...] -> / + * + * The s4d1 directory is evaluated even if it is not in the s2d2 mount. + */ + +/* clang-format off */ +FIXTURE(layout5_disconnected_branch) { + int s2d4_fd, s3d2_fd; +}; +/* clang-format on */ + +FIXTURE_SETUP(layout5_disconnected_branch) +{ + prepare_layout(_metadata); + + create_file(_metadata, TMP_DIR "/s1d1/s1d2/s1d3/s1d41/f1"); + create_file(_metadata, TMP_DIR "/s1d1/s1d2/s1d3/s1d41/f2"); + create_file(_metadata, TMP_DIR "/s1d1/s1d2/s1d3/s1d42/f3"); + create_file(_metadata, TMP_DIR "/s1d1/s1d2/s1d3/s1d42/f4"); + create_directory(_metadata, TMP_DIR "/s2d1/s2d2/s2d3/s2d4"); + create_directory(_metadata, TMP_DIR "/s3d1/s3d2"); + create_directory(_metadata, TMP_DIR "/s4d1"); + + self->s2d4_fd = open(TMP_DIR "/s2d1/s2d2/s2d3/s2d4", + O_DIRECTORY | O_PATH | O_CLOEXEC); + ASSERT_LE(0, self->s2d4_fd); + + self->s3d2_fd = + open(TMP_DIR "/s3d1/s3d2", O_DIRECTORY | O_PATH | O_CLOEXEC); + ASSERT_LE(0, self->s3d2_fd); + + set_cap(_metadata, CAP_SYS_ADMIN); + ASSERT_EQ(0, mount(TMP_DIR "/s1d1/s1d2", TMP_DIR "/s2d1/s2d2/s2d3/s2d4", + NULL, MS_BIND, NULL)); + ASSERT_EQ(0, mount(TMP_DIR "/s2d1/s2d2", TMP_DIR "/s3d1/s3d2", NULL, + MS_BIND | MS_REC, NULL)); + clear_cap(_metadata, CAP_SYS_ADMIN); +} + +FIXTURE_TEARDOWN_PARENT(layout5_disconnected_branch) +{ + /* Bind mounts are handled by namespace lifetime. */ + + /* Removes files after renames. */ + remove_path(TMP_DIR "/s1d1/s1d2/s1d3/s1d41/f1"); + remove_path(TMP_DIR "/s1d1/s1d2/s1d3/s1d41/f2"); + remove_path(TMP_DIR "/s1d1/s1d2/s1d3/s1d42/f1"); + remove_path(TMP_DIR "/s1d1/s1d2/s1d3/s1d42/f3"); + remove_path(TMP_DIR "/s1d1/s1d2/s1d3/s1d42/f4"); + remove_path(TMP_DIR "/s1d1/s1d2/s1d3/s1d42/f5"); + + cleanup_layout(_metadata); +} + +FIXTURE_VARIANT(layout5_disconnected_branch) +{ + /* + * Parent of all files. It should always be enforced when testing against + * files under the s1d41 or s1d42 disconnected directories. + */ + const __u64 allowed_base; + /* + * Parent of the first bind mount source. It should always be ignored when + * testing against files under the s1d41 or s1d42 disconnected directories. + */ + const __u64 allowed_s1d1; + const __u64 allowed_s1d2; + const __u64 allowed_s1d3; + const __u64 allowed_s2d1; + const __u64 allowed_s2d2; + const __u64 allowed_s2d3; + const __u64 allowed_s2d4; + const __u64 allowed_s3d1; + const __u64 allowed_s3d2; + const __u64 allowed_s4d1; + + /* Expected result of the call to open([fd:s1d3]/s1d41/f1, O_RDONLY). */ + const int expected_read_result; + /* + * Expected result of the call to renameat([fd:s1d3]/s1d41/f1, + * [fd:s1d3]/s1d42/f1). + */ + const int expected_rename_result; + /* + * Expected result of the call to renameat([fd:s1d3]/s1d41/f2, + * [fd:s1d3]/s1d42/f3, RENAME_EXCHANGE). + */ + const int expected_exchange_result; + /* + * Expected result of the call to renameat([fd:s1d3]/s1d42/f4, + * [fd:s1d3]/s1d42/f5). + */ + const int expected_same_dir_rename_result; +}; + +/* clang-format off */ +FIXTURE_VARIANT_ADD(layout5_disconnected_branch, s1d1_mount1_src_parent) { + /* clang-format on */ + .allowed_s1d1 = LANDLOCK_ACCESS_FS_REFER | + LANDLOCK_ACCESS_FS_READ_FILE | + LANDLOCK_ACCESS_FS_EXECUTE | + LANDLOCK_ACCESS_FS_MAKE_REG, + .expected_read_result = EACCES, + .expected_same_dir_rename_result = EACCES, + .expected_rename_result = EACCES, + .expected_exchange_result = EACCES, +}; + +/* clang-format off */ +FIXTURE_VARIANT_ADD(layout5_disconnected_branch, s1d2_mount1_src_refer) { + /* clang-format on */ + .allowed_s1d2 = LANDLOCK_ACCESS_FS_REFER | LANDLOCK_ACCESS_FS_READ_FILE, + .expected_read_result = 0, + .expected_same_dir_rename_result = EACCES, + .expected_rename_result = EACCES, + .expected_exchange_result = EACCES, +}; + +/* clang-format off */ +FIXTURE_VARIANT_ADD(layout5_disconnected_branch, s1d2_mount1_src_create) { + /* clang-format on */ + .allowed_s1d2 = LANDLOCK_ACCESS_FS_READ_FILE | + LANDLOCK_ACCESS_FS_MAKE_REG, + .expected_read_result = 0, + .expected_same_dir_rename_result = 0, + .expected_rename_result = EXDEV, + .expected_exchange_result = EXDEV, +}; + +/* clang-format off */ +FIXTURE_VARIANT_ADD(layout5_disconnected_branch, s1d2_mount1_src_rename) { + /* clang-format on */ + .allowed_s1d2 = LANDLOCK_ACCESS_FS_REFER | LANDLOCK_ACCESS_FS_MAKE_REG, + .expected_read_result = EACCES, + .expected_same_dir_rename_result = 0, + .expected_rename_result = 0, + .expected_exchange_result = 0, +}; + +/* clang-format off */ +FIXTURE_VARIANT_ADD(layout5_disconnected_branch, s1d3_fd_refer) { + /* clang-format on */ + .allowed_s1d3 = LANDLOCK_ACCESS_FS_REFER | LANDLOCK_ACCESS_FS_READ_FILE, + .expected_read_result = 0, + .expected_same_dir_rename_result = EACCES, + .expected_rename_result = EACCES, + .expected_exchange_result = EACCES, +}; + +/* clang-format off */ +FIXTURE_VARIANT_ADD(layout5_disconnected_branch, s1d3_fd_create) { + /* clang-format on */ + .allowed_s1d3 = LANDLOCK_ACCESS_FS_READ_FILE | + LANDLOCK_ACCESS_FS_MAKE_REG, + .expected_read_result = 0, + .expected_same_dir_rename_result = 0, + .expected_rename_result = EXDEV, + .expected_exchange_result = EXDEV, +}; + +/* clang-format off */ +FIXTURE_VARIANT_ADD(layout5_disconnected_branch, s1d3_fd_rename) { + /* clang-format on */ + .allowed_s1d3 = LANDLOCK_ACCESS_FS_REFER | LANDLOCK_ACCESS_FS_MAKE_REG, + .expected_read_result = EACCES, + .expected_same_dir_rename_result = 0, + .expected_rename_result = 0, + .expected_exchange_result = 0, +}; + +/* clang-format off */ +FIXTURE_VARIANT_ADD(layout5_disconnected_branch, s1d3_fd_full) { + /* clang-format on */ + .allowed_s1d3 = LANDLOCK_ACCESS_FS_REFER | + LANDLOCK_ACCESS_FS_READ_FILE | + LANDLOCK_ACCESS_FS_EXECUTE | + LANDLOCK_ACCESS_FS_MAKE_REG, + .expected_read_result = 0, + .expected_same_dir_rename_result = 0, + .expected_rename_result = 0, + .expected_exchange_result = 0, +}; + +/* clang-format off */ +FIXTURE_VARIANT_ADD(layout5_disconnected_branch, s2d1_mount2_src_parent) { + /* clang-format on */ + .allowed_s2d1 = LANDLOCK_ACCESS_FS_REFER | + LANDLOCK_ACCESS_FS_READ_FILE | + LANDLOCK_ACCESS_FS_EXECUTE | + LANDLOCK_ACCESS_FS_MAKE_REG, + .expected_read_result = EACCES, + .expected_same_dir_rename_result = EACCES, + .expected_rename_result = EACCES, + .expected_exchange_result = EACCES, +}; + +/* clang-format off */ +FIXTURE_VARIANT_ADD(layout5_disconnected_branch, s2d2_mount2_src_refer) { + /* clang-format on */ + .allowed_s2d2 = LANDLOCK_ACCESS_FS_REFER | LANDLOCK_ACCESS_FS_READ_FILE, + .expected_read_result = 0, + .expected_same_dir_rename_result = EACCES, + .expected_rename_result = EACCES, + .expected_exchange_result = EACCES, +}; + +/* clang-format off */ +FIXTURE_VARIANT_ADD(layout5_disconnected_branch, s2d2_mount2_src_create) { + /* clang-format on */ + .allowed_s2d2 = LANDLOCK_ACCESS_FS_READ_FILE | + LANDLOCK_ACCESS_FS_MAKE_REG, + .expected_read_result = 0, + .expected_same_dir_rename_result = 0, + .expected_rename_result = EXDEV, + .expected_exchange_result = EXDEV, +}; + +/* clang-format off */ +FIXTURE_VARIANT_ADD(layout5_disconnected_branch, s2d2_mount2_src_rename) { + /* clang-format on */ + .allowed_s2d2 = LANDLOCK_ACCESS_FS_REFER | LANDLOCK_ACCESS_FS_MAKE_REG, + .expected_read_result = EACCES, + .expected_same_dir_rename_result = 0, + .expected_rename_result = 0, + .expected_exchange_result = 0, +}; + +/* clang-format off */ +FIXTURE_VARIANT_ADD(layout5_disconnected_branch, s2d3_mount1_dst_parent_refer) { + /* clang-format on */ + .allowed_s2d3 = LANDLOCK_ACCESS_FS_REFER | LANDLOCK_ACCESS_FS_READ_FILE, + .expected_read_result = 0, + .expected_same_dir_rename_result = EACCES, + .expected_rename_result = EACCES, + .expected_exchange_result = EACCES, +}; + +/* clang-format off */ +FIXTURE_VARIANT_ADD(layout5_disconnected_branch, s2d3_mount1_dst_parent_create) { + /* clang-format on */ + .allowed_s2d3 = LANDLOCK_ACCESS_FS_READ_FILE | + LANDLOCK_ACCESS_FS_MAKE_REG, + .expected_read_result = 0, + .expected_same_dir_rename_result = 0, + .expected_rename_result = EXDEV, + .expected_exchange_result = EXDEV, +}; + +/* clang-format off */ +FIXTURE_VARIANT_ADD(layout5_disconnected_branch, s2d3_mount1_dst_parent_rename) { + /* clang-format on */ + .allowed_s2d3 = LANDLOCK_ACCESS_FS_REFER | LANDLOCK_ACCESS_FS_MAKE_REG, + .expected_read_result = EACCES, + .expected_same_dir_rename_result = 0, + .expected_rename_result = 0, + .expected_exchange_result = 0, +}; + +/* clang-format off */ +FIXTURE_VARIANT_ADD(layout5_disconnected_branch, s2d4_mount1_dst) { + /* clang-format on */ + .allowed_s2d4 = LANDLOCK_ACCESS_FS_REFER | + LANDLOCK_ACCESS_FS_READ_FILE | + LANDLOCK_ACCESS_FS_EXECUTE | + LANDLOCK_ACCESS_FS_MAKE_REG, + .expected_read_result = EACCES, + .expected_same_dir_rename_result = EACCES, + .expected_rename_result = EACCES, + .expected_exchange_result = EACCES, +}; + +/* clang-format off */ +FIXTURE_VARIANT_ADD(layout5_disconnected_branch, s3d1_mount2_dst_parent_refer) { + /* clang-format on */ + .allowed_s3d1 = LANDLOCK_ACCESS_FS_REFER | LANDLOCK_ACCESS_FS_READ_FILE, + .expected_read_result = 0, + .expected_same_dir_rename_result = EACCES, + .expected_rename_result = EACCES, + .expected_exchange_result = EACCES, +}; + +/* clang-format off */ +FIXTURE_VARIANT_ADD(layout5_disconnected_branch, s3d1_mount2_dst_parent_create) { + /* clang-format on */ + .allowed_s3d1 = LANDLOCK_ACCESS_FS_READ_FILE | + LANDLOCK_ACCESS_FS_MAKE_REG, + .expected_read_result = 0, + .expected_same_dir_rename_result = 0, + .expected_rename_result = EXDEV, + .expected_exchange_result = EXDEV, +}; + +/* clang-format off */ +FIXTURE_VARIANT_ADD(layout5_disconnected_branch, s3d1_mount2_dst_parent_rename) { + /* clang-format on */ + .allowed_s3d1 = LANDLOCK_ACCESS_FS_REFER | LANDLOCK_ACCESS_FS_MAKE_REG, + .expected_read_result = EACCES, + .expected_same_dir_rename_result = 0, + .expected_rename_result = 0, + .expected_exchange_result = 0, +}; + +/* clang-format off */ +FIXTURE_VARIANT_ADD(layout5_disconnected_branch, s3d2_mount1_dst) { + /* clang-format on */ + .allowed_s3d2 = LANDLOCK_ACCESS_FS_REFER | + LANDLOCK_ACCESS_FS_READ_FILE | + LANDLOCK_ACCESS_FS_EXECUTE | + LANDLOCK_ACCESS_FS_MAKE_REG, + .expected_read_result = EACCES, + .expected_same_dir_rename_result = EACCES, + .expected_rename_result = EACCES, + .expected_exchange_result = EACCES, +}; + +/* clang-format off */ +FIXTURE_VARIANT_ADD(layout5_disconnected_branch, s4d1_rename_parent_refer) { + /* clang-format on */ + .allowed_s4d1 = LANDLOCK_ACCESS_FS_REFER | LANDLOCK_ACCESS_FS_READ_FILE, + .expected_read_result = 0, + .expected_same_dir_rename_result = EACCES, + .expected_rename_result = EACCES, + .expected_exchange_result = EACCES, +}; + +/* clang-format off */ +FIXTURE_VARIANT_ADD(layout5_disconnected_branch, s4d1_rename_parent_create) { + /* clang-format on */ + .allowed_s4d1 = LANDLOCK_ACCESS_FS_READ_FILE | + LANDLOCK_ACCESS_FS_MAKE_REG, + .expected_read_result = 0, + .expected_same_dir_rename_result = 0, + .expected_rename_result = EXDEV, + .expected_exchange_result = EXDEV, +}; + +/* clang-format off */ +FIXTURE_VARIANT_ADD(layout5_disconnected_branch, s4d1_rename_parent_rename) { + /* clang-format on */ + .allowed_s4d1 = LANDLOCK_ACCESS_FS_REFER | LANDLOCK_ACCESS_FS_MAKE_REG, + .expected_read_result = EACCES, + .expected_same_dir_rename_result = 0, + .expected_rename_result = 0, + .expected_exchange_result = 0, +}; + +TEST_F_FORK(layout5_disconnected_branch, read_rename_exchange) +{ + const __u64 handled_access = + LANDLOCK_ACCESS_FS_REFER | LANDLOCK_ACCESS_FS_READ_FILE | + LANDLOCK_ACCESS_FS_EXECUTE | LANDLOCK_ACCESS_FS_MAKE_REG; + const struct rule rules[] = { + { + .path = TMP_DIR "/s1d1", + .access = variant->allowed_s1d1, + }, + { + .path = TMP_DIR "/s1d1/s1d2", + .access = variant->allowed_s1d2, + }, + { + .path = TMP_DIR "/s1d1/s1d2/s1d3", + .access = variant->allowed_s1d3, + }, + { + .path = TMP_DIR "/s2d1", + .access = variant->allowed_s2d1, + }, + { + .path = TMP_DIR "/s2d1/s2d2", + .access = variant->allowed_s2d2, + }, + { + .path = TMP_DIR "/s2d1/s2d2/s2d3", + .access = variant->allowed_s2d3, + }, + /* s2d4_fd */ + { + .path = TMP_DIR "/s3d1", + .access = variant->allowed_s3d1, + }, + /* s3d2_fd */ + { + .path = TMP_DIR "/s4d1", + .access = variant->allowed_s4d1, + }, + {}, + }; + int ruleset_fd, s1d3_bind_fd; + + ruleset_fd = create_ruleset(_metadata, handled_access, rules); + ASSERT_LE(0, ruleset_fd); + + /* Adds rules for the covered directories. */ + if (variant->allowed_s2d4) { + ASSERT_EQ(0, landlock_add_rule( + ruleset_fd, LANDLOCK_RULE_PATH_BENEATH, + &(struct landlock_path_beneath_attr){ + .parent_fd = self->s2d4_fd, + .allowed_access = + variant->allowed_s2d4, + }, + 0)); + } + EXPECT_EQ(0, close(self->s2d4_fd)); + + if (variant->allowed_s3d2) { + ASSERT_EQ(0, landlock_add_rule( + ruleset_fd, LANDLOCK_RULE_PATH_BENEATH, + &(struct landlock_path_beneath_attr){ + .parent_fd = self->s3d2_fd, + .allowed_access = + variant->allowed_s3d2, + }, + 0)); + } + EXPECT_EQ(0, close(self->s3d2_fd)); + + s1d3_bind_fd = open(TMP_DIR "/s3d1/s3d2/s2d3/s2d4/s1d3", + O_DIRECTORY | O_PATH | O_CLOEXEC); + ASSERT_LE(0, s1d3_bind_fd); + + /* Disconnects and checks source and destination directories. */ + EXPECT_EQ(0, test_open_rel(s1d3_bind_fd, "..", O_DIRECTORY)); + EXPECT_EQ(0, test_open_rel(s1d3_bind_fd, "../..", O_DIRECTORY)); + /* Renames to make it accessible through s3d1/s1d41 */ + ASSERT_EQ(0, test_renameat(AT_FDCWD, TMP_DIR "/s2d1/s2d2/s2d3", + AT_FDCWD, TMP_DIR "/s4d1/s2d3")); + EXPECT_EQ(0, test_open_rel(s1d3_bind_fd, "..", O_DIRECTORY)); + EXPECT_EQ(ENOENT, test_open_rel(s1d3_bind_fd, "../..", O_DIRECTORY)); + + enforce_ruleset(_metadata, ruleset_fd); + EXPECT_EQ(0, close(ruleset_fd)); + + EXPECT_EQ(variant->expected_read_result, + test_open_rel(s1d3_bind_fd, "s1d41/f1", O_RDONLY)); + + EXPECT_EQ(variant->expected_rename_result, + test_renameat(s1d3_bind_fd, "s1d41/f1", s1d3_bind_fd, + "s1d42/f1")); + EXPECT_EQ(variant->expected_exchange_result, + test_exchangeat(s1d3_bind_fd, "s1d41/f2", s1d3_bind_fd, + "s1d42/f3")); + + EXPECT_EQ(variant->expected_same_dir_rename_result, + test_renameat(s1d3_bind_fd, "s1d42/f4", s1d3_bind_fd, + "s1d42/f5")); +} + #define LOWER_BASE TMP_DIR "/lower" #define LOWER_DATA LOWER_BASE "/data" static const char lower_fl1[] = LOWER_DATA "/fl1";