diff options
| -rw-r--r-- | Documentation/userspace-api/landlock.rst | 4 | ||||
| -rw-r--r-- | security/landlock/fs.c | 17 | ||||
| -rw-r--r-- | security/landlock/limits.h | 2 | ||||
| -rw-r--r-- | security/landlock/ruleset.h | 4 | ||||
| -rw-r--r-- | tools/testing/selftests/landlock/fs_test.c | 2 |
5 files changed, 15 insertions, 14 deletions
diff --git a/Documentation/userspace-api/landlock.rst b/Documentation/userspace-api/landlock.rst index f35552ff19ba..b68e7a51009f 100644 --- a/Documentation/userspace-api/landlock.rst +++ b/Documentation/userspace-api/landlock.rst @@ -267,8 +267,8 @@ restrict such paths with dedicated ruleset flags. Ruleset layers -------------- -There is a limit of 64 layers of stacked rulesets. This can be an issue for a -task willing to enforce a new ruleset in complement to its 64 inherited +There is a limit of 16 layers of stacked rulesets. This can be an issue for a +task willing to enforce a new ruleset in complement to its 16 inherited rulesets. Once this limit is reached, sys_landlock_restrict_self() returns E2BIG. It is then strongly suggested to carefully build rulesets once in the life of a thread, especially for applications able to launch other applications diff --git a/security/landlock/fs.c b/security/landlock/fs.c index d4006add8bdf..f48c0a3b1e75 100644 --- a/security/landlock/fs.c +++ b/security/landlock/fs.c @@ -183,10 +183,10 @@ int landlock_append_fs_rule(struct landlock_ruleset *const ruleset, /* Access-control management */ -static inline u64 unmask_layers(const struct landlock_ruleset *const domain, - const struct path *const path, - const access_mask_t access_request, - u64 layer_mask) +static inline layer_mask_t +unmask_layers(const struct landlock_ruleset *const domain, + const struct path *const path, const access_mask_t access_request, + layer_mask_t layer_mask) { const struct landlock_rule *rule; const struct inode *inode; @@ -212,11 +212,11 @@ static inline u64 unmask_layers(const struct landlock_ruleset *const domain, */ for (i = 0; i < rule->num_layers; i++) { const struct landlock_layer *const layer = &rule->layers[i]; - const u64 layer_level = BIT_ULL(layer->level - 1); + const layer_mask_t layer_bit = BIT_ULL(layer->level - 1); /* Checks that the layer grants access to the full request. */ if ((layer->access & access_request) == access_request) { - layer_mask &= ~layer_level; + layer_mask &= ~layer_bit; if (layer_mask == 0) return layer_mask; @@ -231,12 +231,9 @@ static int check_access_path(const struct landlock_ruleset *const domain, { bool allowed = false; struct path walker_path; - u64 layer_mask; + layer_mask_t layer_mask; size_t i; - /* Make sure all layers can be checked. */ - BUILD_BUG_ON(BITS_PER_TYPE(layer_mask) < LANDLOCK_MAX_NUM_LAYERS); - if (!access_request) return 0; if (WARN_ON_ONCE(!domain || !path)) diff --git a/security/landlock/limits.h b/security/landlock/limits.h index 41372f22837f..17c2a2e7fe1e 100644 --- a/security/landlock/limits.h +++ b/security/landlock/limits.h @@ -15,7 +15,7 @@ /* clang-format off */ -#define LANDLOCK_MAX_NUM_LAYERS 64 +#define LANDLOCK_MAX_NUM_LAYERS 16 #define LANDLOCK_MAX_NUM_RULES U32_MAX #define LANDLOCK_LAST_ACCESS_FS LANDLOCK_ACCESS_FS_MAKE_SYM diff --git a/security/landlock/ruleset.h b/security/landlock/ruleset.h index 8d5717594931..521af2848951 100644 --- a/security/landlock/ruleset.h +++ b/security/landlock/ruleset.h @@ -23,6 +23,10 @@ typedef u16 access_mask_t; /* Makes sure all filesystem access rights can be stored. */ static_assert(BITS_PER_TYPE(access_mask_t) >= LANDLOCK_NUM_ACCESS_FS); +typedef u16 layer_mask_t; +/* Makes sure all layers can be checked. */ +static_assert(BITS_PER_TYPE(layer_mask_t) >= LANDLOCK_MAX_NUM_LAYERS); + /** * struct landlock_layer - Access rights for a given layer */ diff --git a/tools/testing/selftests/landlock/fs_test.c b/tools/testing/selftests/landlock/fs_test.c index a8f54c4462eb..e13f046a172a 100644 --- a/tools/testing/selftests/landlock/fs_test.c +++ b/tools/testing/selftests/landlock/fs_test.c @@ -1159,7 +1159,7 @@ TEST_F_FORK(layout1, max_layers) const int ruleset_fd = create_ruleset(_metadata, ACCESS_RW, rules); ASSERT_LE(0, ruleset_fd); - for (i = 0; i < 64; i++) + for (i = 0; i < 16; i++) enforce_ruleset(_metadata, ruleset_fd); for (i = 0; i < 2; i++) { |