5/16/2022 8:14 PM, Mickaël Salaün пишет:
On 16/05/2022 17:20, Konstantin Meskhidze wrote:Unmask_layers(), init_layer_masks() and get_handled_accesses() helper functions move to ruleset.c and rule_type argument is added. This modification supports implementing new rule types into next landlock versions. Signed-off-by: Konstantin Meskhidze <konstantin.meskhidze@xxxxxxxxxx> --- Changes since v3: * Splits commit. * Refactoring landlock_unmask_layers functions.Please sort changes in antichronological order. It is easier to look at the first lines to get the last changes.
Ok. I will. Thanks
Changes since v4: * Refactoring init_layer_masks(), get_handled_accesses() and unmask_layers() functions to support multiple rule types. * Refactoring landlock_get_fs_access_mask() function with LANDLOCK_MASK_ACCESS_FS mask. > --- security/landlock/fs.c | 158 ++++++++---------------------------- security/landlock/ruleset.c | 152 +++++++++++++++++++++++++++++++--- security/landlock/ruleset.h | 17 +++- 3 files changed, 192 insertions(+), 135 deletions(-) diff --git a/security/landlock/fs.c b/security/landlock/fs.c index 5de24d4dd74c..3506e182b23e 100644 --- a/security/landlock/fs.c +++ b/security/landlock/fs.c@@ -211,60 +211,6 @@ find_rule(const struct landlock_ruleset *const domain,return rule; } -/*- * @layer_masks is read and may be updated according to the access request and- * the matching rule. - *- * Returns true if the request is allowed (i.e. relevant layer masks for the- * request are empty). - */ -static inline bool -unmask_layers(const struct landlock_rule *const rule, - const access_mask_t access_request, - layer_mask_t (*const layer_masks)[LANDLOCK_NUM_ACCESS_FS])Moving these entire blocks of code make the review/diff impossible. Why moving these helpers?
Cause these helpers are going to be used both for filesystem and network. I moved them into ruleset.c/h
-{ - size_t layer_level; - - if (!access_request || !layer_masks) - return true; - if (!rule) - return false; - - /* - * An access is granted if, for each policy layer, at least one rule - * encountered on the pathwalk grants the requested access,- * regardless of its position in the layer stack. We must then check - * the remaining layers for each inode, from the first added layer to - * the last one. When there is multiple requested accesses, for each - * policy layer, the full set of requested accesses may not be granted- * by only one rule, but by the union (binary OR) of multiple rules. - * E.g. /a/b <execute> + /a <read> => /a/b <execute + read> - */- for (layer_level = 0; layer_level < rule->num_layers; layer_level++) {- const struct landlock_layer *const layer = - &rule->layers[layer_level]; - const layer_mask_t layer_bit = BIT_ULL(layer->level - 1); - const unsigned long access_req = access_request; - unsigned long access_bit; - bool is_empty; - - /* - * Records in @layer_masks which layer grants access to each - * requested access. - */ - is_empty = true; - for_each_set_bit(access_bit, &access_req, - ARRAY_SIZE(*layer_masks)) { - if (layer->access & BIT_ULL(access_bit)) - (*layer_masks)[access_bit] &= ~layer_bit; - is_empty = is_empty && !(*layer_masks)[access_bit]; - } - if (is_empty) - return true; - } - return false; -} - /** Allows access to pseudo filesystems that will never be mountable (e.g.* sockfs, pipefs), but can still be reachable through@@ -277,59 +223,6 @@ static inline bool is_nouser_or_private(const struct dentry *dentry)unlikely(IS_PRIVATE(d_backing_inode(dentry)))); } -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; - - for (layer_level = 0; layer_level < domain->num_layers; - layer_level++) { - if (landlock_get_fs_access_mask(domain, layer_level) & - BIT_ULL(access_bit)) { - access_dom |= BIT_ULL(access_bit); - break; - } - } - } - return access_dom; -} - -static inline access_mask_t -init_layer_masks(const struct landlock_ruleset *const domain, - const access_mask_t access_request, - layer_mask_t (*const layer_masks)[LANDLOCK_NUM_ACCESS_FS]) -{ - access_mask_t handled_accesses = 0; - size_t layer_level; - - memset(layer_masks, 0, sizeof(*layer_masks));- /* An empty access request can happen because of O_WRONLY | O_RDWR. */- if (!access_request) - return 0; - - /* Saves all handled accesses per layer. */- for (layer_level = 0; layer_level < domain->num_layers; layer_level++) {- const unsigned long access_req = access_request; - unsigned long access_bit; - - for_each_set_bit(access_bit, &access_req, - ARRAY_SIZE(*layer_masks)) { - if (landlock_get_fs_access_mask(domain, layer_level) & - BIT_ULL(access_bit)) { - (*layer_masks)[access_bit] |= - BIT_ULL(layer_level); - handled_accesses |= BIT_ULL(access_bit); - } - } - } - return handled_accesses; -} - /** Check that a destination file hierarchy has more restrictions than a source* file hierarchy. This is only used for link and rename actions. @@ -506,7 +399,8 @@ static int check_access_path_dual( * a superset of the meaningful requested accesses). */ access_masked_parent1 = access_masked_parent2 = - get_handled_accesses(domain); + get_handled_accesses(domain, LANDLOCK_RULE_PATH_BENEATH, + LANDLOCK_NUM_ACCESS_FS); is_dom_check = true; } else { if (WARN_ON_ONCE(dentry_child1 || dentry_child2)) @@ -519,17 +413,25 @@ static int check_access_path_dual( if (unlikely(dentry_child1)) { unmask_layers(find_rule(domain, dentry_child1), - init_layer_masks(domain, LANDLOCK_MASK_ACCESS_FS, - &_layer_masks_child1), - &_layer_masks_child1); + init_layer_masks(domain, + LANDLOCK_MASK_ACCESS_FS, + &_layer_masks_child1, + sizeof(_layer_masks_child1), + LANDLOCK_RULE_PATH_BENEATH), + &_layer_masks_child1, + ARRAY_SIZE(_layer_masks_child1));There is a lot of formatting diff and that makes the review difficult. Please format everything with clang-format-14.
Ok. Do you have some tool that helps you with editing code with clang format?
layer_masks_child1 = &_layer_masks_child1; child1_is_directory = d_is_dir(dentry_child1); } if (unlikely(dentry_child2)) { unmask_layers(find_rule(domain, dentry_child2), - init_layer_masks(domain, LANDLOCK_MASK_ACCESS_FS, - &_layer_masks_child2), - &_layer_masks_child2); + init_layer_masks(domain, + LANDLOCK_MASK_ACCESS_FS, + &_layer_masks_child2, + sizeof(_layer_masks_child2), + LANDLOCK_RULE_PATH_BENEATH), + &_layer_masks_child2, + ARRAY_SIZE(_layer_masks_child2)); layer_masks_child2 = &_layer_masks_child2; child2_is_directory = d_is_dir(dentry_child2); } @@ -582,14 +484,15 @@ static int check_access_path_dual( rule = find_rule(domain, walker_path.dentry); allowed_parent1 = unmask_layers(rule, access_masked_parent1, - layer_masks_parent1); + layer_masks_parent1, + ARRAY_SIZE(*layer_masks_parent1)); allowed_parent2 = unmask_layers(rule, access_masked_parent2, - layer_masks_parent2); + layer_masks_parent2, + ARRAY_SIZE(*layer_masks_parent2)); /* Stops when a rule from each layer grants access. */ if (allowed_parent1 && allowed_parent2) break; -There is no place for such formatting/whitespace patches.
I missed that. scripts/checkpatch.pl did not show any problem here. I will fix it. Thanks.
jump_up: if (walker_path.dentry == walker_path.mnt->mnt_root) { if (follow_up(&walker_path)) {@@ -645,7 +548,9 @@ static inline int check_access_path(const struct landlock_ruleset *const domain,{ layer_mask_t layer_masks[LANDLOCK_NUM_ACCESS_FS] = {};- access_request = init_layer_masks(domain, access_request, &layer_masks);+ access_request = init_layer_masks(domain, access_request, + &layer_masks, sizeof(layer_masks), + LANDLOCK_RULE_PATH_BENEATH); return check_access_path_dual(domain, path, access_request, &layer_masks, NULL, 0, NULL, NULL); } @@ -729,7 +634,8 @@ static bool collect_domain_accesses( return true; access_dom = init_layer_masks(domain, LANDLOCK_MASK_ACCESS_FS, - layer_masks_dom); + layer_masks_dom, sizeof(*layer_masks_dom), + LANDLOCK_RULE_PATH_BENEATH); dget(dir); while (true) { @@ -737,7 +643,8 @@ static bool collect_domain_accesses( /* Gets all layers allowing all domain accesses. */ if (unmask_layers(find_rule(domain, dir), access_dom, - layer_masks_dom)) { + layer_masks_dom, + ARRAY_SIZE(*layer_masks_dom))) { /* * Stops when all handled accesses are allowed by at * least one rule in each layer.@@ -851,9 +758,10 @@ static int current_check_refer_path(struct dentry *const old_dentry,* The LANDLOCK_ACCESS_FS_REFER access right is not required * for same-directory referer (i.e. no reparenting). */ - access_request_parent1 = init_layer_masks( - dom, access_request_parent1 | access_request_parent2, - &layer_masks_parent1); + access_request_parent1 = init_layer_masks(dom, + access_request_parent1 | access_request_parent2, + &layer_masks_parent1, sizeof(layer_masks_parent1), + LANDLOCK_RULE_PATH_BENEATH); return check_access_path_dual(dom, new_dir, access_request_parent1, &layer_masks_parent1, NULL, 0,@@ -861,7 +769,9 @@ static int current_check_refer_path(struct dentry *const old_dentry,} /* Backward compatibility: no reparenting support. */ - if (!(get_handled_accesses(dom) & LANDLOCK_ACCESS_FS_REFER)) + if (!(get_handled_accesses(dom, LANDLOCK_RULE_PATH_BENEATH, + LANDLOCK_NUM_ACCESS_FS) & + LANDLOCK_ACCESS_FS_REFER)) return -EXDEV; access_request_parent1 |= LANDLOCK_ACCESS_FS_REFER; diff --git a/security/landlock/ruleset.c b/security/landlock/ruleset.c index 4b4c9953bb32..c4ed783d655b 100644 --- a/security/landlock/ruleset.c +++ b/security/landlock/ruleset.c@@ -233,7 +233,8 @@ static int insert_rule(struct landlock_ruleset *const ruleset,&(*layers)[0]); if (IS_ERR(new_rule)) return PTR_ERR(new_rule);- rb_replace_node(&this->node, &new_rule->node, &ruleset->root_inode);+ rb_replace_node(&this->node, &new_rule->node, + &ruleset->root_inode);This is a pure formatting hunk. :/
Thats strange, cause in my editor I have normal aligment of arguments. Could please share clang-format-14 tab size and other format parameters?
free_rule(this, rule_type); break; }@@ -246,7 +247,8 @@ static int insert_rule(struct landlock_ruleset *const ruleset,return -E2BIG; switch (rule_type) { case LANDLOCK_RULE_PATH_BENEATH: - new_rule = create_rule(object_ptr, 0, layers, num_layers, NULL); + new_rule = create_rule(object_ptr, 0, layers, + num_layers, NULL); if (IS_ERR(new_rule)) return PTR_ERR(new_rule); rb_link_node(&new_rule->node, parent_node, walker_node);@@ -281,8 +283,8 @@ int landlock_insert_rule(struct landlock_ruleset *const ruleset,} }; build_check_layer();- return insert_rule(ruleset, object_ptr, object_data, rule_type, &layers,- ARRAY_SIZE(layers)); + return insert_rule(ruleset, object_ptr, object_data, rule_type, + &layers, ARRAY_SIZE(layers)); }static inline void get_hierarchy(struct landlock_hierarchy *const hierarchy) @@ -335,8 +337,9 @@ static int tree_merge(struct landlock_ruleset *const src,switch (rule_type) { case LANDLOCK_RULE_PATH_BENEATH:- err = insert_rule(dst, walker_rule->object.ptr, 0, rule_type,- &layers, ARRAY_SIZE(layers)); + err = insert_rule(dst, walker_rule->object.ptr, 0, + rule_type, &layers, + ARRAY_SIZE(layers)); break; } if (err)@@ -433,9 +436,13 @@ static int inherit_ruleset(struct landlock_ruleset *const parent,err = -EINVAL; goto out_unlock; }- /* Copies the parent layer stack and leaves a space for the new layer. */+ /* + * Copies the parent layer stack and leaves a space + * for the new layer. + */ memcpy(child->access_masks, parent->access_masks, - flex_array_size(parent, access_masks, parent->num_layers)); + flex_array_size(parent, access_masks, + parent->num_layers)); if (WARN_ON_ONCE(!parent->hierarchy)) { err = -EINVAL;@@ -455,8 +462,9 @@ static void free_ruleset(struct landlock_ruleset *const ruleset)struct landlock_rule *freeme, *next; might_sleep();- rbtree_postorder_for_each_entry_safe(freeme, next, &ruleset->root_inode,- node) + rbtree_postorder_for_each_entry_safe(freeme, next, + &ruleset->root_inode, + node) free_rule(freeme, LANDLOCK_RULE_PATH_BENEATH); put_hierarchy(ruleset->hierarchy); kfree(ruleset); @@ -577,3 +585,127 @@ const struct landlock_rule *landlock_find_rule( } return NULL; } + +access_mask_t get_handled_accesses( + const struct landlock_ruleset *const domain, + u16 rule_type, u16 num_access) +{ + access_mask_t access_dom = 0; + unsigned long access_bit; + + switch (rule_type) { + case LANDLOCK_RULE_PATH_BENEATH: + for (access_bit = 0; access_bit < LANDLOCK_NUM_ACCESS_FS; + access_bit++) { + size_t layer_level; + + for (layer_level = 0; layer_level < domain->num_layers; + layer_level++) { + if (landlock_get_fs_access_mask(domain, + layer_level) & + BIT_ULL(access_bit)) { + access_dom |= BIT_ULL(access_bit); + break; + } + } + } + break; + default: + break; + } + return access_dom; +} + +/*+ * @layer_masks is read and may be updated according to the access request and+ * the matching rule. + *+ * Returns true if the request is allowed (i.e. relevant layer masks for the+ * request are empty). + */ +bool unmask_layers(const struct landlock_rule *const rule, + const access_mask_t access_request, + layer_mask_t (*const layer_masks)[], size_t masks_array_size) +{ + size_t layer_level; + + if (!access_request || !layer_masks) + return true; + if (!rule) + return false; + + /* + * An access is granted if, for each policy layer, at least one rule + * encountered on the pathwalk grants the requested access,+ * regardless of its position in the layer stack. We must then check + * the remaining layers for each inode, from the first added layer to + * the last one. When there is multiple requested accesses, for each + * policy layer, the full set of requested accesses may not be granted+ * by only one rule, but by the union (binary OR) of multiple rules. + * E.g. /a/b <execute> + /a <read> => /a/b <execute + read> + */+ for (layer_level = 0; layer_level < rule->num_layers; layer_level++) {+ const struct landlock_layer *const layer = + &rule->layers[layer_level]; + const layer_mask_t layer_bit = BIT_ULL(layer->level - 1); + const unsigned long access_req = access_request; + unsigned long access_bit; + bool is_empty; + + /* + * Records in @layer_masks which layer grants access to each + * requested access. + */ + is_empty = true; + for_each_set_bit(access_bit, &access_req, masks_array_size) { + if (layer->access & BIT_ULL(access_bit)) + (*layer_masks)[access_bit] &= ~layer_bit; + is_empty = is_empty && !(*layer_masks)[access_bit]; + } + if (is_empty) + return true; + } + return false; +} ++access_mask_t init_layer_masks(const struct landlock_ruleset *const domain,+ const access_mask_t access_request, + layer_mask_t (*const layer_masks)[], + size_t masks_size, + u16 rule_type) +{ + access_mask_t handled_accesses = 0; + size_t layer_level; + + memset(layer_masks, 0, masks_size); ++ /* An empty access request can happen because of O_WRONLY | O_RDWR. */+ if (!access_request) + return 0; + + /* Saves all handled accesses per layer. */ + for (layer_level = 0; layer_level < domain->num_layers; + layer_level++) { + const unsigned long access_req = access_request; + unsigned long access_bit; + + switch (rule_type) { + case LANDLOCK_RULE_PATH_BENEATH: + for_each_set_bit(access_bit, &access_req, + LANDLOCK_NUM_ACCESS_FS) { + if (landlock_get_fs_access_mask(domain, + layer_level) & + BIT_ULL(access_bit)) { + (*layer_masks)[access_bit] |= + BIT_ULL(layer_level); + handled_accesses |= + BIT_ULL(access_bit); + } + } + break; + default: + return 0; + } + } + return handled_accesses; +} diff --git a/security/landlock/ruleset.h b/security/landlock/ruleset.h index 3066e5d7180c..f3cd890d0348 100644 --- a/security/landlock/ruleset.h +++ b/security/landlock/ruleset.h @@ -195,7 +195,22 @@ static inline u32 landlock_get_fs_access_mask( const struct landlock_ruleset *ruleset, u16 mask_level) { - return ruleset->access_masks[mask_level];+ return (ruleset->access_masks[mask_level] & LANDLOCK_MASK_ACCESS_FS);} +access_mask_t get_handled_accesses( + const struct landlock_ruleset *const domain, + u16 rule_type, u16 num_access); + +bool unmask_layers(const struct landlock_rule *const rule, + const access_mask_t access_request, + layer_mask_t (*const layer_masks)[], + size_t masks_array_size); ++access_mask_t init_layer_masks(const struct landlock_ruleset *const domain,+ const access_mask_t access_request, + layer_mask_t (*const layer_masks)[], + size_t masks_size, + u16 rule_type);These declarations are useless.
I moved helpers in rulset.c/h to use them both for filesystem and network.
+ #endif /* _SECURITY_LANDLOCK_RULESET_H */ -- 2.25.1.
