The patch below was submitted to be applied to the 5.18-stable tree.

I fail to see how this patch meets the stable kernel rules as found at Documentation/process/stable-kernel-rules.rst.

I could be totally wrong, and if so, please respond to stable@vger.kernel.org and let me know why this patch should be applied. Otherwise, it is now dropped from my patch queues, never to be seen again.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 6a1bdd4a0bfc30fa4fa2b3a979e6525f28996db9 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Micka=C3=ABl=20Sala=C3=BCn?= mic@digikod.net Date: Fri, 6 May 2022 18:08:16 +0200 Subject: [PATCH] selftests/landlock: Fully test file rename with "remove" access MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit

These tests were missing to check the check_access_path() call with all combinations of maybe_remove(old_dentry) and maybe_remove(new_dentry).

Extend layout1.link with a new complementary test and check that REMOVE_FILE is not required to link a file.

Cc: Shuah Khan shuah@kernel.org Link: https://lore.kernel.org/r/20220506160820.524344-7-mic@digikod.net Cc: stable@vger.kernel.org Signed-off-by: Mickaël Salaün mic@digikod.net

diff --git a/tools/testing/selftests/landlock/fs_test.c b/tools/testing/selftests/landlock/fs_test.c index 75f9358512df..9165f6adf7b9 100644 --- a/tools/testing/selftests/landlock/fs_test.c +++ b/tools/testing/selftests/landlock/fs_test.c @@ -1659,15 +1659,21 @@ TEST_F_FORK(layout1, execute)

TEST_F_FORK(layout1, link) { - const struct rule rules[] = { + const struct rule layer1[] = { { .path = dir_s1d2, .access = LANDLOCK_ACCESS_FS_MAKE_REG, }, {}, }; - const int ruleset_fd = - create_ruleset(_metadata, rules[0].access, rules); + const struct rule layer2[] = { + { + .path = dir_s1d3, + .access = LANDLOCK_ACCESS_FS_REMOVE_FILE, + }, + {}, + }; + int ruleset_fd = create_ruleset(_metadata, layer1[0].access, layer1);

ASSERT_LE(0, ruleset_fd);

@@ -1680,14 +1686,30 @@ TEST_F_FORK(layout1, link)

ASSERT_EQ(-1, link(file2_s1d1, file1_s1d1)); ASSERT_EQ(EACCES, errno); + /* Denies linking because of reparenting. */ ASSERT_EQ(-1, link(file1_s2d1, file1_s1d2)); ASSERT_EQ(EXDEV, errno); ASSERT_EQ(-1, link(file2_s1d2, file1_s1d3)); ASSERT_EQ(EXDEV, errno); + ASSERT_EQ(-1, link(file2_s1d3, file1_s1d2)); + ASSERT_EQ(EXDEV, errno);

ASSERT_EQ(0, link(file2_s1d2, file1_s1d2)); ASSERT_EQ(0, link(file2_s1d3, file1_s1d3)); + + /* Prepares for next unlinks. */ + ASSERT_EQ(0, unlink(file2_s1d2)); + ASSERT_EQ(0, unlink(file2_s1d3)); + + ruleset_fd = create_ruleset(_metadata, layer2[0].access, layer2); + ASSERT_LE(0, ruleset_fd); + enforce_ruleset(_metadata, ruleset_fd); + ASSERT_EQ(0, close(ruleset_fd)); + + /* Checks that linkind doesn't require the ability to delete a file. */ + ASSERT_EQ(0, link(file1_s1d2, file2_s1d2)); + ASSERT_EQ(0, link(file1_s1d3, file2_s1d3)); }

TEST_F_FORK(layout1, rename_file) @@ -1708,7 +1730,6 @@ TEST_F_FORK(layout1, rename_file)

ASSERT_LE(0, ruleset_fd);

- ASSERT_EQ(0, unlink(file1_s1d1)); ASSERT_EQ(0, unlink(file1_s1d2));

enforce_ruleset(_metadata, ruleset_fd); @@ -1744,9 +1765,15 @@ TEST_F_FORK(layout1, rename_file) ASSERT_EQ(-1, renameat2(AT_FDCWD, dir_s2d2, AT_FDCWD, file1_s2d1, RENAME_EXCHANGE)); ASSERT_EQ(EACCES, errno); + /* Checks that file1_s2d1 cannot be removed (instead of ENOTDIR). */ + ASSERT_EQ(-1, rename(dir_s2d2, file1_s2d1)); + ASSERT_EQ(EACCES, errno); ASSERT_EQ(-1, renameat2(AT_FDCWD, file1_s2d1, AT_FDCWD, dir_s2d2, RENAME_EXCHANGE)); ASSERT_EQ(EACCES, errno); + /* Checks that file1_s1d1 cannot be removed (instead of EISDIR). */ + ASSERT_EQ(-1, rename(file1_s1d1, dir_s1d2)); + ASSERT_EQ(EACCES, errno);

/* Renames files with different parents. */ ASSERT_EQ(-1, rename(file1_s2d2, file1_s1d2)); @@ -1809,9 +1836,15 @@ TEST_F_FORK(layout1, rename_dir) ASSERT_EQ(-1, renameat2(AT_FDCWD, dir_s1d1, AT_FDCWD, dir_s2d1, RENAME_EXCHANGE)); ASSERT_EQ(EACCES, errno); + /* Checks that dir_s1d2 cannot be removed (instead of ENOTDIR). */ + ASSERT_EQ(-1, rename(dir_s1d2, file1_s1d1)); + ASSERT_EQ(EACCES, errno); ASSERT_EQ(-1, renameat2(AT_FDCWD, file1_s1d1, AT_FDCWD, dir_s1d2, RENAME_EXCHANGE)); ASSERT_EQ(EACCES, errno); + /* Checks that dir_s1d2 cannot be removed (instead of EISDIR). */ + ASSERT_EQ(-1, rename(file1_s1d1, dir_s1d2)); + ASSERT_EQ(EACCES, errno);

/* * Exchanges and renames directory to the same parent, which allows