| Message ID | 20220516152038.39594-5-konstantin.meskhidze@huawei.com (mailing list archive) |
|---|---|
| State | Handled Elsewhere |
| Headers | show |
| Series | Network support for Landlock | expand |
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@huawei.com> > --- > > 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. > 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? > -{ > - 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. > 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. > 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. :/ > 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. > + > #endif /* _SECURITY_LANDLOCK_RULESET_H */ > -- > 2.25.1 >
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@huawei.com> >> --- >> >> 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 >> > .
On 16/05/2022 19:43, Konstantin Meskhidze wrote: > > > 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@huawei.com> [...] >>> -/* >>> - * @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 Right. Please create a commit which only moves these helpers without modifying them, and explain in the commit message that this removes inlined code. We'll see later if this adds a visible performance impact. [...] >>> @@ -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? I just run `clang-format-14 -i` on files before each commit. Some editors such as VSCode can handle the clang-format configuration (which is in the Linux source tree). >> >>> 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. checkpatch.pl doesn't warn about whitespace changes. > 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? They are in the .clang-format file. It would be much easier to just run clang-format-14 -i on your changed files. I guess you had different changes between consecutive commits.
5/16/2022 9:28 PM, Mickaël Salaün пишет: > > On 16/05/2022 19:43, Konstantin Meskhidze wrote: >> >> >> 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@huawei.com> > > [...] > >>>> -/* >>>> - * @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 > > Right. Please create a commit which only moves these helpers without > modifying them, and explain in the commit message that this removes > inlined code. We'll see later if this adds a visible performance impact. > Ok. I will create towo commits - the first one moves helpers to ruleset.c/h and the second one changes helpers to support network. > [...] > >>>> @@ -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? > > I just run `clang-format-14 -i` on files before each commit. Some > editors such as VSCode can handle the clang-format configuration (which > is in the Linux source tree). > Ok. I have updated installed cloang-format-14 executable and setup my VSCode to use .clang-format file. > >>> >>>> 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. > > checkpatch.pl doesn't warn about whitespace changes. yep. I will use Vscode clang plugin to follow the required code style. > > >> 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? > > They are in the .clang-format file. It would be much easier to just run > clang-format-14 -i on your changed files. I guess you had different > changes between consecutive commits. Yep. Thnank you for help here. > .
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]) -{ - 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)); 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; - 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); 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); + #endif /* _SECURITY_LANDLOCK_RULESET_H */
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@huawei.com> --- Changes since v3: * Splits commit. * Refactoring landlock_unmask_layers functions. 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(-) -- 2.25.1