diff options
Diffstat (limited to 'security/landlock')
| -rw-r--r-- | security/landlock/fs.c | 74 | ||||
| -rw-r--r-- | security/landlock/ruleset.h | 24 | ||||
| -rw-r--r-- | security/landlock/syscalls.c | 2 |
3 files changed, 60 insertions, 40 deletions
diff --git a/security/landlock/fs.c b/security/landlock/fs.c index 6953801619ac..e8d680c2c80a 100644 --- a/security/landlock/fs.c +++ b/security/landlock/fs.c @@ -151,16 +151,6 @@ retry: /* clang-format on */ /* - * All access rights that are denied by default whether they are handled or not - * by a ruleset/layer. This must be ORed with all ruleset->fs_access_masks[] - * entries when we need to get the absolute handled access masks. - */ -/* clang-format off */ -#define ACCESS_INITIALLY_DENIED ( \ - LANDLOCK_ACCESS_FS_REFER) -/* clang-format on */ - -/* * @path: Should have been checked by get_path_from_fd(). */ int landlock_append_fs_rule(struct landlock_ruleset *const ruleset, @@ -179,8 +169,7 @@ int landlock_append_fs_rule(struct landlock_ruleset *const ruleset, /* Transforms relative access rights to absolute ones. */ access_rights |= LANDLOCK_MASK_ACCESS_FS & - ~(landlock_get_fs_access_mask(ruleset, 0) | - ACCESS_INITIALLY_DENIED); + ~landlock_get_fs_access_mask(ruleset, 0); object = get_inode_object(d_backing_inode(path->dentry)); if (IS_ERR(object)) return PTR_ERR(object); @@ -287,15 +276,16 @@ 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) +static access_mask_t +get_raw_handled_fs_accesses(const struct landlock_ruleset *const domain) { - access_mask_t access_dom = ACCESS_INITIALLY_DENIED; + access_mask_t access_dom = 0; size_t layer_level; for (layer_level = 0; layer_level < domain->num_layers; layer_level++) - access_dom |= landlock_get_fs_access_mask(domain, layer_level); - return access_dom & LANDLOCK_MASK_ACCESS_FS; + access_dom |= + landlock_get_raw_fs_access_mask(domain, layer_level); + return access_dom; } /** @@ -331,13 +321,8 @@ init_layer_masks(const struct landlock_ruleset *const domain, for_each_set_bit(access_bit, &access_req, ARRAY_SIZE(*layer_masks)) { - /* - * Artificially handles all initially denied by default - * access rights. - */ if (BIT_ULL(access_bit) & - (landlock_get_fs_access_mask(domain, layer_level) | - ACCESS_INITIALLY_DENIED)) { + landlock_get_fs_access_mask(domain, layer_level)) { (*layer_masks)[access_bit] |= BIT_ULL(layer_level); handled_accesses |= BIT_ULL(access_bit); @@ -347,6 +332,25 @@ init_layer_masks(const struct landlock_ruleset *const domain, return handled_accesses; } +static access_mask_t +get_handled_fs_accesses(const struct landlock_ruleset *const domain) +{ + /* Handles all initially denied by default access rights. */ + return get_raw_handled_fs_accesses(domain) | + LANDLOCK_ACCESS_FS_INITIALLY_DENIED; +} + +static const struct landlock_ruleset *get_current_fs_domain(void) +{ + const struct landlock_ruleset *const dom = + landlock_get_current_domain(); + + if (!dom || !get_raw_handled_fs_accesses(dom)) + return NULL; + + return dom; +} + /* * Check that a destination file hierarchy has more restrictions than a source * file hierarchy. This is only used for link and rename actions. @@ -519,7 +523,7 @@ static bool is_access_to_paths_allowed( * a superset of the meaningful requested accesses). */ access_masked_parent1 = access_masked_parent2 = - get_handled_accesses(domain); + get_handled_fs_accesses(domain); is_dom_check = true; } else { if (WARN_ON_ONCE(dentry_child1 || dentry_child2)) @@ -651,8 +655,7 @@ static inline int check_access_path(const struct landlock_ruleset *const domain, static inline int current_check_access_path(const struct path *const path, const access_mask_t access_request) { - const struct landlock_ruleset *const dom = - landlock_get_current_domain(); + const struct landlock_ruleset *const dom = get_current_fs_domain(); if (!dom) return 0; @@ -815,8 +818,7 @@ static int current_check_refer_path(struct dentry *const old_dentry, struct dentry *const new_dentry, const bool removable, const bool exchange) { - const struct landlock_ruleset *const dom = - landlock_get_current_domain(); + const struct landlock_ruleset *const dom = get_current_fs_domain(); bool allow_parent1, allow_parent2; access_mask_t access_request_parent1, access_request_parent2; struct path mnt_dir; @@ -1050,7 +1052,7 @@ static int hook_sb_mount(const char *const dev_name, const struct path *const path, const char *const type, const unsigned long flags, void *const data) { - if (!landlock_get_current_domain()) + if (!get_current_fs_domain()) return 0; return -EPERM; } @@ -1058,7 +1060,7 @@ static int hook_sb_mount(const char *const dev_name, static int hook_move_mount(const struct path *const from_path, const struct path *const to_path) { - if (!landlock_get_current_domain()) + if (!get_current_fs_domain()) return 0; return -EPERM; } @@ -1069,14 +1071,14 @@ static int hook_move_mount(const struct path *const from_path, */ static int hook_sb_umount(struct vfsmount *const mnt, const int flags) { - if (!landlock_get_current_domain()) + if (!get_current_fs_domain()) return 0; return -EPERM; } static int hook_sb_remount(struct super_block *const sb, void *const mnt_opts) { - if (!landlock_get_current_domain()) + if (!get_current_fs_domain()) return 0; return -EPERM; } @@ -1092,7 +1094,7 @@ static int hook_sb_remount(struct super_block *const sb, void *const mnt_opts) static int hook_sb_pivotroot(const struct path *const old_path, const struct path *const new_path) { - if (!landlock_get_current_domain()) + if (!get_current_fs_domain()) return 0; return -EPERM; } @@ -1128,8 +1130,7 @@ static int hook_path_mknod(const struct path *const dir, struct dentry *const dentry, const umode_t mode, const unsigned int dev) { - const struct landlock_ruleset *const dom = - landlock_get_current_domain(); + const struct landlock_ruleset *const dom = get_current_fs_domain(); if (!dom) return 0; @@ -1208,8 +1209,7 @@ static int hook_file_open(struct file *const file) layer_mask_t layer_masks[LANDLOCK_NUM_ACCESS_FS] = {}; access_mask_t open_access_request, full_access_request, allowed_access; const access_mask_t optional_access = LANDLOCK_ACCESS_FS_TRUNCATE; - const struct landlock_ruleset *const dom = - landlock_get_current_domain(); + const struct landlock_ruleset *const dom = get_current_fs_domain(); if (!dom) return 0; diff --git a/security/landlock/ruleset.h b/security/landlock/ruleset.h index 8c99c323b06c..6e2ad1546ab3 100644 --- a/security/landlock/ruleset.h +++ b/security/landlock/ruleset.h @@ -15,10 +15,21 @@ #include <linux/rbtree.h> #include <linux/refcount.h> #include <linux/workqueue.h> +#include <uapi/linux/landlock.h> #include "limits.h" #include "object.h" +/* + * All access rights that are denied by default whether they are handled or not + * by a ruleset/layer. This must be ORed with all ruleset->access_masks[] + * entries when we need to get the absolute handled access masks. + */ +/* clang-format off */ +#define LANDLOCK_ACCESS_FS_INITIALLY_DENIED ( \ + LANDLOCK_ACCESS_FS_REFER) +/* clang-format on */ + typedef u16 access_mask_t; /* Makes sure all filesystem access rights can be stored. */ static_assert(BITS_PER_TYPE(access_mask_t) >= LANDLOCK_NUM_ACCESS_FS); @@ -196,12 +207,21 @@ landlock_add_fs_access_mask(struct landlock_ruleset *const ruleset, } static inline access_mask_t -landlock_get_fs_access_mask(const struct landlock_ruleset *const ruleset, - const u16 layer_level) +landlock_get_raw_fs_access_mask(const struct landlock_ruleset *const ruleset, + const u16 layer_level) { return (ruleset->access_masks[layer_level] >> LANDLOCK_SHIFT_ACCESS_FS) & LANDLOCK_MASK_ACCESS_FS; } +static inline access_mask_t +landlock_get_fs_access_mask(const struct landlock_ruleset *const ruleset, + const u16 layer_level) +{ + /* Handles all initially denied by default access rights. */ + return landlock_get_raw_fs_access_mask(ruleset, layer_level) | + LANDLOCK_ACCESS_FS_INITIALLY_DENIED; +} + #endif /* _SECURITY_LANDLOCK_RULESET_H */ diff --git a/security/landlock/syscalls.c b/security/landlock/syscalls.c index 7ec6bbed7117..d35cd5d304db 100644 --- a/security/landlock/syscalls.c +++ b/security/landlock/syscalls.c @@ -349,7 +349,7 @@ SYSCALL_DEFINE4(landlock_add_rule, const int, ruleset_fd, * Checks that allowed_access matches the @ruleset constraints * (ruleset->access_masks[0] is automatically upgraded to 64-bits). */ - mask = landlock_get_fs_access_mask(ruleset, 0); + mask = landlock_get_raw_fs_access_mask(ruleset, 0); if ((path_beneath_attr.allowed_access | mask) != mask) { err = -EINVAL; goto out_put_ruleset; |