LANDLOCK_ACCESS_FS_READ_FILE)
/* clang-format on */
+/*
+ * All access rights that are denied by default whether they are handled or not
+ * by a ruleset/layer. This must be ORed with all ruleset->fs_access_masks[]
+ * entries when we need to get the absolute handled access masks.
+ */
+/* clang-format off */
+#define ACCESS_INITIALLY_DENIED ( \
+ LANDLOCK_ACCESS_FS_REFER)
+/* clang-format on */
+
/*
* @path: Should have been checked by get_path_from_fd().
*/
return -EINVAL;
/* Transforms relative access rights to absolute ones. */
- access_rights |= LANDLOCK_MASK_ACCESS_FS & ~ruleset->fs_access_masks[0];
+ access_rights |=
+ LANDLOCK_MASK_ACCESS_FS &
+ ~(ruleset->fs_access_masks[0] | ACCESS_INITIALLY_DENIED);
object = get_inode_object(d_backing_inode(path->dentry));
if (IS_ERR(object))
return PTR_ERR(object);
static inline access_mask_t
get_handled_accesses(const struct landlock_ruleset *const domain)
{
- access_mask_t access_dom = 0;
- unsigned long access_bit;
-
- for (access_bit = 0; access_bit < LANDLOCK_NUM_ACCESS_FS;
- access_bit++) {
- size_t layer_level;
+ access_mask_t access_dom = ACCESS_INITIALLY_DENIED;
+ size_t layer_level;
- for (layer_level = 0; layer_level < domain->num_layers;
- layer_level++) {
- if (domain->fs_access_masks[layer_level] &
- BIT_ULL(access_bit)) {
- access_dom |= BIT_ULL(access_bit);
- break;
- }
- }
- }
- return access_dom;
+ for (layer_level = 0; layer_level < domain->num_layers; layer_level++)
+ access_dom |= domain->fs_access_masks[layer_level];
+ return access_dom & LANDLOCK_MASK_ACCESS_FS;
}
static inline access_mask_t
for_each_set_bit(access_bit, &access_req,
ARRAY_SIZE(*layer_masks)) {
- if (domain->fs_access_masks[layer_level] &
- BIT_ULL(access_bit)) {
+ /*
+ * Artificially handles all initially denied by default
+ * access rights.
+ */
+ if (BIT_ULL(access_bit) &
+ (domain->fs_access_masks[layer_level] |
+ ACCESS_INITIALLY_DENIED)) {
(*layer_masks)[access_bit] |=
BIT_ULL(layer_level);
handled_accesses |= BIT_ULL(access_bit);
NULL, NULL);
}
- /* Backward compatibility: no reparenting support. */
- if (!(get_handled_accesses(dom) & LANDLOCK_ACCESS_FS_REFER))
- return -EXDEV;
-
access_request_parent1 |= LANDLOCK_ACCESS_FS_REFER;
access_request_parent2 |= LANDLOCK_ACCESS_FS_REFER;
*
* Copyright © 2017-2020 Mickaël Salaün <mic@digikod.net>
* Copyright © 2020 ANSSI
- * Copyright © 2020-2021 Microsoft Corporation
+ * Copyright © 2020-2022 Microsoft Corporation
*/
#define _GNU_SOURCE
ASSERT_EQ(EINVAL, errno);
path_beneath.allowed_access &= ~LANDLOCK_ACCESS_FS_EXECUTE;
+ /* Tests with denied-by-default access right. */
+ path_beneath.allowed_access |= LANDLOCK_ACCESS_FS_REFER;
+ ASSERT_EQ(-1, landlock_add_rule(ruleset_fd, LANDLOCK_RULE_PATH_BENEATH,
+ &path_beneath, 0));
+ ASSERT_EQ(EINVAL, errno);
+ path_beneath.allowed_access &= ~LANDLOCK_ACCESS_FS_REFER;
+
/* Test with unknown (64-bits) value. */
path_beneath.allowed_access |= (1ULL << 60);
ASSERT_EQ(-1, landlock_add_rule(ruleset_fd, LANDLOCK_RULE_PATH_BENEATH,
ASSERT_EQ(0, link(file1_s1d3, file2_s1d3));
}
+static int test_rename(const char *const oldpath, const char *const newpath)
+{
+ if (rename(oldpath, newpath))
+ return errno;
+ return 0;
+}
+
+static int test_exchange(const char *const oldpath, const char *const newpath)
+{
+ if (renameat2(AT_FDCWD, oldpath, AT_FDCWD, newpath, RENAME_EXCHANGE))
+ return errno;
+ return 0;
+}
+
TEST_F_FORK(layout1, rename_file)
{
const struct rule rules[] = {
* to a different directory (which allows file removal).
*/
ASSERT_EQ(-1, rename(file1_s2d1, file1_s1d3));
- ASSERT_EQ(EXDEV, errno);
+ ASSERT_EQ(EACCES, errno);
ASSERT_EQ(-1, renameat2(AT_FDCWD, file1_s2d1, AT_FDCWD, file1_s1d3,
RENAME_EXCHANGE));
- ASSERT_EQ(EXDEV, errno);
+ ASSERT_EQ(EACCES, errno);
ASSERT_EQ(-1, renameat2(AT_FDCWD, dir_s2d2, AT_FDCWD, file1_s1d3,
RENAME_EXCHANGE));
ASSERT_EQ(EXDEV, errno);
ASSERT_EQ(EXDEV, errno);
ASSERT_EQ(0, unlink(file1_s1d3));
ASSERT_EQ(-1, rename(file1_s2d1, file1_s1d3));
- ASSERT_EQ(EXDEV, errno);
+ ASSERT_EQ(EACCES, errno);
/* Exchanges and renames files with same parent. */
ASSERT_EQ(0, renameat2(AT_FDCWD, file2_s2d3, AT_FDCWD, file1_s2d3,
ASSERT_EQ(0, rename(dir_s1d3, dir_s2d3));
}
+/* Checks renames beneath dir_s1d1. */
+static void refer_denied_by_default(struct __test_metadata *const _metadata,
+ const struct rule layer1[],
+ const int layer1_err,
+ const struct rule layer2[])
+{
+ int ruleset_fd;
+
+ ASSERT_EQ(0, unlink(file1_s1d2));
+
+ ruleset_fd = create_ruleset(_metadata, layer1[0].access, layer1);
+ ASSERT_LE(0, ruleset_fd);
+ enforce_ruleset(_metadata, ruleset_fd);
+ ASSERT_EQ(0, close(ruleset_fd));
+
+ /*
+ * If the first layer handles LANDLOCK_ACCESS_FS_REFER (according to
+ * layer1_err), then it allows some different-parent renames and links.
+ */
+ ASSERT_EQ(layer1_err, test_rename(file1_s1d1, file1_s1d2));
+ if (layer1_err == 0)
+ ASSERT_EQ(layer1_err, test_rename(file1_s1d2, file1_s1d1));
+ ASSERT_EQ(layer1_err, test_exchange(file2_s1d1, file2_s1d2));
+ ASSERT_EQ(layer1_err, test_exchange(file2_s1d2, file2_s1d1));
+
+ 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));
+
+ /*
+ * Now, either the first or the second layer does not handle
+ * LANDLOCK_ACCESS_FS_REFER, which means that any different-parent
+ * renames and links are denied, thus making the layer handling
+ * LANDLOCK_ACCESS_FS_REFER null and void.
+ */
+ ASSERT_EQ(EXDEV, test_rename(file1_s1d1, file1_s1d2));
+ ASSERT_EQ(EXDEV, test_exchange(file2_s1d1, file2_s1d2));
+ ASSERT_EQ(EXDEV, test_exchange(file2_s1d2, file2_s1d1));
+}
+
+const struct rule layer_dir_s1d1_refer[] = {
+ {
+ .path = dir_s1d1,
+ .access = LANDLOCK_ACCESS_FS_REFER,
+ },
+ {},
+};
+
+const struct rule layer_dir_s1d1_execute[] = {
+ {
+ /* Matches a parent directory. */
+ .path = dir_s1d1,
+ .access = LANDLOCK_ACCESS_FS_EXECUTE,
+ },
+ {},
+};
+
+const struct rule layer_dir_s2d1_execute[] = {
+ {
+ /* Does not match a parent directory. */
+ .path = dir_s2d1,
+ .access = LANDLOCK_ACCESS_FS_EXECUTE,
+ },
+ {},
+};
+
+/*
+ * Tests precedence over renames: denied by default for different parent
+ * directories, *with* a rule matching a parent directory, but not directly
+ * denying access (with MAKE_REG nor REMOVE).
+ */
+TEST_F_FORK(layout1, refer_denied_by_default1)
+{
+ refer_denied_by_default(_metadata, layer_dir_s1d1_refer, 0,
+ layer_dir_s1d1_execute);
+}
+
+/*
+ * Same test but this time turning around the ABI version order: the first
+ * layer does not handle LANDLOCK_ACCESS_FS_REFER.
+ */
+TEST_F_FORK(layout1, refer_denied_by_default2)
+{
+ refer_denied_by_default(_metadata, layer_dir_s1d1_execute, EXDEV,
+ layer_dir_s1d1_refer);
+}
+
+/*
+ * Tests precedence over renames: denied by default for different parent
+ * directories, *without* a rule matching a parent directory, but not directly
+ * denying access (with MAKE_REG nor REMOVE).
+ */
+TEST_F_FORK(layout1, refer_denied_by_default3)
+{
+ refer_denied_by_default(_metadata, layer_dir_s1d1_refer, 0,
+ layer_dir_s2d1_execute);
+}
+
+/*
+ * Same test but this time turning around the ABI version order: the first
+ * layer does not handle LANDLOCK_ACCESS_FS_REFER.
+ */
+TEST_F_FORK(layout1, refer_denied_by_default4)
+{
+ refer_denied_by_default(_metadata, layer_dir_s2d1_execute, EXDEV,
+ layer_dir_s1d1_refer);
+}
+
TEST_F_FORK(layout1, reparent_link)
{
const struct rule layer1[] = {
ASSERT_EQ(EXDEV, errno);
/*
- * However, moving the file2_s1d3 file below dir_s2d3 is allowed
- * because it cannot inherit MAKE_REG nor MAKE_DIR rights (which are
- * dedicated to directories).
+ * Moving the file2_s1d3 file below dir_s2d3 is denied because the
+ * second layer does not handle REFER, which is always denied by
+ * default.
*/
- ASSERT_EQ(0, rename(file2_s1d3, file1_s2d3));
+ ASSERT_EQ(-1, rename(file2_s1d3, file1_s2d3));
+ ASSERT_EQ(EXDEV, errno);
}
TEST_F_FORK(layout1, reparent_exdev_layers_rename2)
ASSERT_EQ(EACCES, errno);
ASSERT_EQ(-1, rename(file1_s1d1, file1_s2d3));
ASSERT_EQ(EXDEV, errno);
- /* Modify layout! */
- ASSERT_EQ(0, rename(file2_s1d2, file1_s2d3));
+ /*
+ * Modifying the layout is now denied because the second layer does not
+ * handle REFER, which is always denied by default.
+ */
+ ASSERT_EQ(-1, rename(file2_s1d2, file1_s2d3));
+ ASSERT_EQ(EXDEV, errno);
/* Without REFER source, EACCES wins over EXDEV. */
ASSERT_EQ(-1, rename(dir_s1d1, file1_s2d2));
projects / kernel.git / commitdiff