| Message ID | 20221021152644.155136-6-konstantin.meskhidze@huawei.com (mailing list archive) |
|---|---|
| State | Handled Elsewhere |
| Headers | show |
| Series | Network support for Landlock | expand |
On 21/10/2022 17:26, Konstantin Meskhidze wrote: > Adds new key_type argument to init_layer_masks() helper. Add a new key_type argument to the… > Adds masks_array_size argument to unmask_layers() helper. Add a masks_array_size argument to the… The name of these helpers need to be prefixed with "landlock_". > These modifications support implementing new rule types in the next > Landlock versions. > > Co-developed-by: Mickaël Salaün <mic@digikod.net> Signed-off-by: Mickaël Salaün <mic@digikod.net> > Signed-off-by: Konstantin Meskhidze <konstantin.meskhidze@huawei.com> > --- > > Changes since v7: > * Refactors commit message, adds a co-developer. > * Minor fixes. > > Changes since v6: > * Removes masks_size attribute from init_layer_masks(). > * Refactors init_layer_masks() with new landlock_key_type. > > Changes since v5: > * Splits commit. > * Formats code with clang-format-14. > > Changes since v4: > * Refactors init_layer_masks(), get_handled_accesses() > and unmask_layers() functions to support multiple rule types. > * Refactors landlock_get_fs_access_mask() function with > LANDLOCK_MASK_ACCESS_FS mask. > > Changes since v3: > * Splits commit. > * Refactors landlock_unmask_layers functions. > > --- > security/landlock/fs.c | 36 ++++++++++++++++++------------- > security/landlock/ruleset.c | 42 ++++++++++++++++++++++++++----------- > security/landlock/ruleset.h | 11 +++++----- > 3 files changed, 58 insertions(+), 31 deletions(-) > > diff --git a/security/landlock/fs.c b/security/landlock/fs.c > index 240e42a8f788..fe76a11483f8 100644 > --- a/security/landlock/fs.c > +++ b/security/landlock/fs.c > @@ -435,16 +435,20 @@ static bool is_access_to_paths_allowed( > 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); > + &_layer_masks_child1, > + LANDLOCK_KEY_INODE), > + &_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); > + &_layer_masks_child2, > + LANDLOCK_KEY_INODE), > + &_layer_masks_child2, > + ARRAY_SIZE(_layer_masks_child2)); > layer_masks_child2 = &_layer_masks_child2; > child2_is_directory = d_is_dir(dentry_child2); > } > @@ -496,15 +500,16 @@ static bool is_access_to_paths_allowed( > } > > rule = find_rule(domain, walker_path.dentry); > - allowed_parent1 = unmask_layers(rule, access_masked_parent1, > - layer_masks_parent1); > - allowed_parent2 = unmask_layers(rule, access_masked_parent2, > - layer_masks_parent2); > + allowed_parent1 = unmask_layers( > + rule, access_masked_parent1, layer_masks_parent1, > + ARRAY_SIZE(*layer_masks_parent1)); > + allowed_parent2 = unmask_layers( > + rule, access_masked_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)) { > @@ -543,7 +548,8 @@ 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, > + LANDLOCK_KEY_INODE); > if (is_access_to_paths_allowed(domain, path, access_request, > &layer_masks, NULL, 0, NULL, NULL)) > return 0; > @@ -630,7 +636,7 @@ static bool collect_domain_accesses( > return true; > > access_dom = init_layer_masks(domain, LANDLOCK_MASK_ACCESS_FS, > - layer_masks_dom); > + layer_masks_dom, LANDLOCK_KEY_INODE); > > dget(dir); > while (true) { > @@ -638,7 +644,8 @@ 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. > @@ -754,7 +761,7 @@ static int current_check_refer_path(struct dentry *const old_dentry, > */ > access_request_parent1 = init_layer_masks( > dom, access_request_parent1 | access_request_parent2, > - &layer_masks_parent1); > + &layer_masks_parent1, LANDLOCK_KEY_INODE); > if (is_access_to_paths_allowed( > dom, new_dir, access_request_parent1, > &layer_masks_parent1, NULL, 0, NULL, NULL)) > @@ -1131,7 +1138,8 @@ static int hook_file_open(struct file *const file) > > if (is_access_to_paths_allowed( > dom, &file->f_path, > - init_layer_masks(dom, full_access_request, &layer_masks), > + init_layer_masks(dom, full_access_request, &layer_masks, > + LANDLOCK_KEY_INODE), > &layer_masks, NULL, 0, NULL, NULL)) { > allowed_access = full_access_request; > } else { > diff --git a/security/landlock/ruleset.c b/security/landlock/ruleset.c > index 02ab14439c43..c7cf54ba4f6d 100644 > --- a/security/landlock/ruleset.c > +++ b/security/landlock/ruleset.c > @@ -576,13 +576,15 @@ landlock_find_rule(const struct landlock_ruleset *const ruleset, > /* > * @layer_masks is read and may be updated according to the access request and > * the matching rule. > + * @masks_array_size must be equal to ARRAY_SIZE(*layer_masks). > * > * 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)[LANDLOCK_NUM_ACCESS_FS]) > + layer_mask_t (*const layer_masks)[], > + const size_t masks_array_size) > { > size_t layer_level; > > @@ -614,8 +616,7 @@ bool unmask_layers(const struct landlock_rule *const rule, > * requested access. > */ > is_empty = true; > - for_each_set_bit(access_bit, &access_req, > - ARRAY_SIZE(*layer_masks)) { > + 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]; > @@ -626,6 +627,10 @@ bool unmask_layers(const struct landlock_rule *const rule, > return false; > } > > +typedef access_mask_t > +get_access_mask_t(const struct landlock_ruleset *const ruleset, > + const u16 layer_level); > + > /** > * init_layer_masks - Initialize layer masks from an access request > * > @@ -635,19 +640,33 @@ bool unmask_layers(const struct landlock_rule *const rule, > * @domain: The domain that defines the current restrictions. > * @access_request: The requested access rights to check. > * @layer_masks: The layer masks to populate. > + * @key_type: The key type to switch between access masks of different types. > * > * Returns: An access mask where each access right bit is set which is handled > * in any of the active layers in @domain. > */ > -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 init_layer_masks(const struct landlock_ruleset *const domain, > + const access_mask_t access_request, > + layer_mask_t (*const layer_masks)[], > + const enum landlock_key_type key_type) > { > access_mask_t handled_accesses = 0; > - size_t layer_level; > + size_t layer_level, num_access; > + get_access_mask_t *get_access_mask; > + > + switch (key_type) { > + case LANDLOCK_KEY_INODE: > + get_access_mask = landlock_get_fs_access_mask; > + num_access = LANDLOCK_NUM_ACCESS_FS; > + break; > + default: > + WARN_ON_ONCE(1); > + return 0; > + } > + > + memset(layer_masks, 0, > + array_size(sizeof((*layer_masks)[0]), num_access)); > > - memset(layer_masks, 0, sizeof(*layer_masks)); > /* An empty access request can happen because of O_WRONLY | O_RDWR. */ > if (!access_request) > return 0; > @@ -657,14 +676,13 @@ init_layer_masks(const struct landlock_ruleset *const domain, > const unsigned long access_req = access_request; > unsigned long access_bit; > > - for_each_set_bit(access_bit, &access_req, > - ARRAY_SIZE(*layer_masks)) { > + for_each_set_bit(access_bit, &access_req, num_access) { > /* > * Artificially handles all initially denied by default > * access rights. > */ > if (BIT_ULL(access_bit) & > - (landlock_get_fs_access_mask(domain, layer_level) | > + (get_access_mask(domain, layer_level) | > ACCESS_INITIALLY_DENIED)) { > (*layer_masks)[access_bit] |= > BIT_ULL(layer_level); > diff --git a/security/landlock/ruleset.h b/security/landlock/ruleset.h > index 50baff4fcbb4..d9eb79ea9a89 100644 > --- a/security/landlock/ruleset.h > +++ b/security/landlock/ruleset.h > @@ -259,11 +259,12 @@ landlock_get_fs_access_mask(const struct landlock_ruleset *const ruleset, > > 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]); > + layer_mask_t (*const layer_masks)[], > + const 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)[LANDLOCK_NUM_ACCESS_FS]); > +access_mask_t init_layer_masks(const struct landlock_ruleset *const domain, > + const access_mask_t access_request, > + layer_mask_t (*const layer_masks)[], > + const enum landlock_key_type key_type); > > #endif /* _SECURITY_LANDLOCK_RULESET_H */ > -- > 2.25.1 >
11/17/2022 9:42 PM, Mickaël Salaün пишет: > > On 21/10/2022 17:26, Konstantin Meskhidze wrote: >> Adds new key_type argument to init_layer_masks() helper. > > Add a new key_type argument to the… > >> Adds masks_array_size argument to unmask_layers() helper. > > Add a masks_array_size argument to the… > > > The name of these helpers need to be prefixed with "landlock_". > > Thanks. Will be Fixed. >> These modifications support implementing new rule types in the next >> Landlock versions. >> >> Co-developed-by: Mickaël Salaün <mic@digikod.net> > > Signed-off-by: Mickaël Salaün <mic@digikod.net> Got it. > >> Signed-off-by: Konstantin Meskhidze <konstantin.meskhidze@huawei.com> >> --- >> >> Changes since v7: >> * Refactors commit message, adds a co-developer. >> * Minor fixes. >> >> Changes since v6: >> * Removes masks_size attribute from init_layer_masks(). >> * Refactors init_layer_masks() with new landlock_key_type. >> >> Changes since v5: >> * Splits commit. >> * Formats code with clang-format-14. >> >> Changes since v4: >> * Refactors init_layer_masks(), get_handled_accesses() >> and unmask_layers() functions to support multiple rule types. >> * Refactors landlock_get_fs_access_mask() function with >> LANDLOCK_MASK_ACCESS_FS mask. >> >> Changes since v3: >> * Splits commit. >> * Refactors landlock_unmask_layers functions. >> >> --- >> security/landlock/fs.c | 36 ++++++++++++++++++------------- >> security/landlock/ruleset.c | 42 ++++++++++++++++++++++++++----------- >> security/landlock/ruleset.h | 11 +++++----- >> 3 files changed, 58 insertions(+), 31 deletions(-) >> >> diff --git a/security/landlock/fs.c b/security/landlock/fs.c >> index 240e42a8f788..fe76a11483f8 100644 >> --- a/security/landlock/fs.c >> +++ b/security/landlock/fs.c >> @@ -435,16 +435,20 @@ static bool is_access_to_paths_allowed( >> 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); >> + &_layer_masks_child1, >> + LANDLOCK_KEY_INODE), >> + &_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); >> + &_layer_masks_child2, >> + LANDLOCK_KEY_INODE), >> + &_layer_masks_child2, >> + ARRAY_SIZE(_layer_masks_child2)); >> layer_masks_child2 = &_layer_masks_child2; >> child2_is_directory = d_is_dir(dentry_child2); >> } >> @@ -496,15 +500,16 @@ static bool is_access_to_paths_allowed( >> } >> >> rule = find_rule(domain, walker_path.dentry); >> - allowed_parent1 = unmask_layers(rule, access_masked_parent1, >> - layer_masks_parent1); >> - allowed_parent2 = unmask_layers(rule, access_masked_parent2, >> - layer_masks_parent2); >> + allowed_parent1 = unmask_layers( >> + rule, access_masked_parent1, layer_masks_parent1, >> + ARRAY_SIZE(*layer_masks_parent1)); >> + allowed_parent2 = unmask_layers( >> + rule, access_masked_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)) { >> @@ -543,7 +548,8 @@ 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, >> + LANDLOCK_KEY_INODE); >> if (is_access_to_paths_allowed(domain, path, access_request, >> &layer_masks, NULL, 0, NULL, NULL)) >> return 0; >> @@ -630,7 +636,7 @@ static bool collect_domain_accesses( >> return true; >> >> access_dom = init_layer_masks(domain, LANDLOCK_MASK_ACCESS_FS, >> - layer_masks_dom); >> + layer_masks_dom, LANDLOCK_KEY_INODE); >> >> dget(dir); >> while (true) { >> @@ -638,7 +644,8 @@ 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. >> @@ -754,7 +761,7 @@ static int current_check_refer_path(struct dentry *const old_dentry, >> */ >> access_request_parent1 = init_layer_masks( >> dom, access_request_parent1 | access_request_parent2, >> - &layer_masks_parent1); >> + &layer_masks_parent1, LANDLOCK_KEY_INODE); >> if (is_access_to_paths_allowed( >> dom, new_dir, access_request_parent1, >> &layer_masks_parent1, NULL, 0, NULL, NULL)) >> @@ -1131,7 +1138,8 @@ static int hook_file_open(struct file *const file) >> >> if (is_access_to_paths_allowed( >> dom, &file->f_path, >> - init_layer_masks(dom, full_access_request, &layer_masks), >> + init_layer_masks(dom, full_access_request, &layer_masks, >> + LANDLOCK_KEY_INODE), >> &layer_masks, NULL, 0, NULL, NULL)) { >> allowed_access = full_access_request; >> } else { >> diff --git a/security/landlock/ruleset.c b/security/landlock/ruleset.c >> index 02ab14439c43..c7cf54ba4f6d 100644 >> --- a/security/landlock/ruleset.c >> +++ b/security/landlock/ruleset.c >> @@ -576,13 +576,15 @@ landlock_find_rule(const struct landlock_ruleset *const ruleset, >> /* >> * @layer_masks is read and may be updated according to the access request and >> * the matching rule. >> + * @masks_array_size must be equal to ARRAY_SIZE(*layer_masks). >> * >> * 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)[LANDLOCK_NUM_ACCESS_FS]) >> + layer_mask_t (*const layer_masks)[], >> + const size_t masks_array_size) >> { >> size_t layer_level; >> >> @@ -614,8 +616,7 @@ bool unmask_layers(const struct landlock_rule *const rule, >> * requested access. >> */ >> is_empty = true; >> - for_each_set_bit(access_bit, &access_req, >> - ARRAY_SIZE(*layer_masks)) { >> + 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]; >> @@ -626,6 +627,10 @@ bool unmask_layers(const struct landlock_rule *const rule, >> return false; >> } >> >> +typedef access_mask_t >> +get_access_mask_t(const struct landlock_ruleset *const ruleset, >> + const u16 layer_level); >> + >> /** >> * init_layer_masks - Initialize layer masks from an access request >> * >> @@ -635,19 +640,33 @@ bool unmask_layers(const struct landlock_rule *const rule, >> * @domain: The domain that defines the current restrictions. >> * @access_request: The requested access rights to check. >> * @layer_masks: The layer masks to populate. >> + * @key_type: The key type to switch between access masks of different types. >> * >> * Returns: An access mask where each access right bit is set which is handled >> * in any of the active layers in @domain. >> */ >> -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 init_layer_masks(const struct landlock_ruleset *const domain, >> + const access_mask_t access_request, >> + layer_mask_t (*const layer_masks)[], >> + const enum landlock_key_type key_type) >> { >> access_mask_t handled_accesses = 0; >> - size_t layer_level; >> + size_t layer_level, num_access; >> + get_access_mask_t *get_access_mask; >> + >> + switch (key_type) { >> + case LANDLOCK_KEY_INODE: >> + get_access_mask = landlock_get_fs_access_mask; >> + num_access = LANDLOCK_NUM_ACCESS_FS; >> + break; >> + default: >> + WARN_ON_ONCE(1); >> + return 0; >> + } >> + >> + memset(layer_masks, 0, >> + array_size(sizeof((*layer_masks)[0]), num_access)); >> >> - memset(layer_masks, 0, sizeof(*layer_masks)); >> /* An empty access request can happen because of O_WRONLY | O_RDWR. */ >> if (!access_request) >> return 0; >> @@ -657,14 +676,13 @@ init_layer_masks(const struct landlock_ruleset *const domain, >> const unsigned long access_req = access_request; >> unsigned long access_bit; >> >> - for_each_set_bit(access_bit, &access_req, >> - ARRAY_SIZE(*layer_masks)) { >> + for_each_set_bit(access_bit, &access_req, num_access) { >> /* >> * Artificially handles all initially denied by default >> * access rights. >> */ >> if (BIT_ULL(access_bit) & >> - (landlock_get_fs_access_mask(domain, layer_level) | >> + (get_access_mask(domain, layer_level) | >> ACCESS_INITIALLY_DENIED)) { >> (*layer_masks)[access_bit] |= >> BIT_ULL(layer_level); >> diff --git a/security/landlock/ruleset.h b/security/landlock/ruleset.h >> index 50baff4fcbb4..d9eb79ea9a89 100644 >> --- a/security/landlock/ruleset.h >> +++ b/security/landlock/ruleset.h >> @@ -259,11 +259,12 @@ landlock_get_fs_access_mask(const struct landlock_ruleset *const ruleset, >> >> 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]); >> + layer_mask_t (*const layer_masks)[], >> + const 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)[LANDLOCK_NUM_ACCESS_FS]); >> +access_mask_t init_layer_masks(const struct landlock_ruleset *const domain, >> + const access_mask_t access_request, >> + layer_mask_t (*const layer_masks)[], >> + const enum landlock_key_type key_type); >> >> #endif /* _SECURITY_LANDLOCK_RULESET_H */ >> -- >> 2.25.1 >> > .
diff --git a/security/landlock/fs.c b/security/landlock/fs.c index 240e42a8f788..fe76a11483f8 100644 --- a/security/landlock/fs.c +++ b/security/landlock/fs.c @@ -435,16 +435,20 @@ static bool is_access_to_paths_allowed( 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); + &_layer_masks_child1, + LANDLOCK_KEY_INODE), + &_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); + &_layer_masks_child2, + LANDLOCK_KEY_INODE), + &_layer_masks_child2, + ARRAY_SIZE(_layer_masks_child2)); layer_masks_child2 = &_layer_masks_child2; child2_is_directory = d_is_dir(dentry_child2); } @@ -496,15 +500,16 @@ static bool is_access_to_paths_allowed( } rule = find_rule(domain, walker_path.dentry); - allowed_parent1 = unmask_layers(rule, access_masked_parent1, - layer_masks_parent1); - allowed_parent2 = unmask_layers(rule, access_masked_parent2, - layer_masks_parent2); + allowed_parent1 = unmask_layers( + rule, access_masked_parent1, layer_masks_parent1, + ARRAY_SIZE(*layer_masks_parent1)); + allowed_parent2 = unmask_layers( + rule, access_masked_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)) { @@ -543,7 +548,8 @@ 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, + LANDLOCK_KEY_INODE); if (is_access_to_paths_allowed(domain, path, access_request, &layer_masks, NULL, 0, NULL, NULL)) return 0; @@ -630,7 +636,7 @@ static bool collect_domain_accesses( return true; access_dom = init_layer_masks(domain, LANDLOCK_MASK_ACCESS_FS, - layer_masks_dom); + layer_masks_dom, LANDLOCK_KEY_INODE); dget(dir); while (true) { @@ -638,7 +644,8 @@ 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. @@ -754,7 +761,7 @@ static int current_check_refer_path(struct dentry *const old_dentry, */ access_request_parent1 = init_layer_masks( dom, access_request_parent1 | access_request_parent2, - &layer_masks_parent1); + &layer_masks_parent1, LANDLOCK_KEY_INODE); if (is_access_to_paths_allowed( dom, new_dir, access_request_parent1, &layer_masks_parent1, NULL, 0, NULL, NULL)) @@ -1131,7 +1138,8 @@ static int hook_file_open(struct file *const file) if (is_access_to_paths_allowed( dom, &file->f_path, - init_layer_masks(dom, full_access_request, &layer_masks), + init_layer_masks(dom, full_access_request, &layer_masks, + LANDLOCK_KEY_INODE), &layer_masks, NULL, 0, NULL, NULL)) { allowed_access = full_access_request; } else { diff --git a/security/landlock/ruleset.c b/security/landlock/ruleset.c index 02ab14439c43..c7cf54ba4f6d 100644 --- a/security/landlock/ruleset.c +++ b/security/landlock/ruleset.c @@ -576,13 +576,15 @@ landlock_find_rule(const struct landlock_ruleset *const ruleset, /* * @layer_masks is read and may be updated according to the access request and * the matching rule. + * @masks_array_size must be equal to ARRAY_SIZE(*layer_masks). * * 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)[LANDLOCK_NUM_ACCESS_FS]) + layer_mask_t (*const layer_masks)[], + const size_t masks_array_size) { size_t layer_level; @@ -614,8 +616,7 @@ bool unmask_layers(const struct landlock_rule *const rule, * requested access. */ is_empty = true; - for_each_set_bit(access_bit, &access_req, - ARRAY_SIZE(*layer_masks)) { + 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]; @@ -626,6 +627,10 @@ bool unmask_layers(const struct landlock_rule *const rule, return false; } +typedef access_mask_t +get_access_mask_t(const struct landlock_ruleset *const ruleset, + const u16 layer_level); + /** * init_layer_masks - Initialize layer masks from an access request * @@ -635,19 +640,33 @@ bool unmask_layers(const struct landlock_rule *const rule, * @domain: The domain that defines the current restrictions. * @access_request: The requested access rights to check. * @layer_masks: The layer masks to populate. + * @key_type: The key type to switch between access masks of different types. * * Returns: An access mask where each access right bit is set which is handled * in any of the active layers in @domain. */ -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 init_layer_masks(const struct landlock_ruleset *const domain, + const access_mask_t access_request, + layer_mask_t (*const layer_masks)[], + const enum landlock_key_type key_type) { access_mask_t handled_accesses = 0; - size_t layer_level; + size_t layer_level, num_access; + get_access_mask_t *get_access_mask; + + switch (key_type) { + case LANDLOCK_KEY_INODE: + get_access_mask = landlock_get_fs_access_mask; + num_access = LANDLOCK_NUM_ACCESS_FS; + break; + default: + WARN_ON_ONCE(1); + return 0; + } + + memset(layer_masks, 0, + array_size(sizeof((*layer_masks)[0]), num_access)); - memset(layer_masks, 0, sizeof(*layer_masks)); /* An empty access request can happen because of O_WRONLY | O_RDWR. */ if (!access_request) return 0; @@ -657,14 +676,13 @@ init_layer_masks(const struct landlock_ruleset *const domain, const unsigned long access_req = access_request; unsigned long access_bit; - for_each_set_bit(access_bit, &access_req, - ARRAY_SIZE(*layer_masks)) { + for_each_set_bit(access_bit, &access_req, num_access) { /* * Artificially handles all initially denied by default * access rights. */ if (BIT_ULL(access_bit) & - (landlock_get_fs_access_mask(domain, layer_level) | + (get_access_mask(domain, layer_level) | ACCESS_INITIALLY_DENIED)) { (*layer_masks)[access_bit] |= BIT_ULL(layer_level); diff --git a/security/landlock/ruleset.h b/security/landlock/ruleset.h index 50baff4fcbb4..d9eb79ea9a89 100644 --- a/security/landlock/ruleset.h +++ b/security/landlock/ruleset.h @@ -259,11 +259,12 @@ landlock_get_fs_access_mask(const struct landlock_ruleset *const ruleset, 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]); + layer_mask_t (*const layer_masks)[], + const 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)[LANDLOCK_NUM_ACCESS_FS]); +access_mask_t init_layer_masks(const struct landlock_ruleset *const domain, + const access_mask_t access_request, + layer_mask_t (*const layer_masks)[], + const enum landlock_key_type key_type); #endif /* _SECURITY_LANDLOCK_RULESET_H */
Adds new key_type argument to init_layer_masks() helper. Adds masks_array_size argument to unmask_layers() helper. These modifications support implementing new rule types in the next Landlock versions. Co-developed-by: Mickaël Salaün <mic@digikod.net> Signed-off-by: Konstantin Meskhidze <konstantin.meskhidze@huawei.com> --- Changes since v7: * Refactors commit message, adds a co-developer. * Minor fixes. Changes since v6: * Removes masks_size attribute from init_layer_masks(). * Refactors init_layer_masks() with new landlock_key_type. Changes since v5: * Splits commit. * Formats code with clang-format-14. Changes since v4: * Refactors init_layer_masks(), get_handled_accesses() and unmask_layers() functions to support multiple rule types. * Refactors landlock_get_fs_access_mask() function with LANDLOCK_MASK_ACCESS_FS mask. Changes since v3: * Splits commit. * Refactors landlock_unmask_layers functions. --- security/landlock/fs.c | 36 ++++++++++++++++++------------- security/landlock/ruleset.c | 42 ++++++++++++++++++++++++++----------- security/landlock/ruleset.h | 11 +++++----- 3 files changed, 58 insertions(+), 31 deletions(-) -- 2.25.1