linux.git/security/landlock/ruleset.h, branch master

landlock: Fix kernel-doc for the nested quiet layer flag

2026-07-10T10:59:09Z

kernel-doc emits "Excess struct member 'quiet' description in 'landlock_layer'" because "quiet" is a bitfield inside the named nested struct "flags", but its inline comment used the bare member name "@quiet:", which kernel-doc attributes to the enclosing landlock_layer. Use the canonical dotted notation "@flags.quiet:" so kernel-doc resolves the nested member, and include it in the generated documentation. Cc: Justin Suess Cc: Tingmao Wang Fixes: a260c0055665 ("landlock: Add a place for flags to layer rules") Link: https://patch.msgid.link/20260703141711.2016964-1-mic@digikod.net Signed-off-by: Mickaël Salaün

landlock: Add API support and docs for the quiet flags

2026-06-14T18:17:19Z

Adds the UAPI for the quiet flags feature (but not the implementation yet). Even though currently LANDLOCK_ADD_RULE_QUIET only affects audit logging, in the future this can also be used as part of a supervisor mechanism, where it will also suppress denial notifications on a per-object basis. Thus the name is deliberately generic, as opposed to e.g. LANDLOCK_ADD_RULE_LOG_QUIET. According to pahole, even after adding the struct access_masks quiet_masks in struct landlock_hierarchy, the u32 log_* bitfield still only has a size of 2 bytes, so there's minimal wasted space. Assisted-by: GitHub-Copilot:claude-opus-4.8 Signed-off-by: Tingmao Wang [mic: Update date, fix comment formatting] Link: https://patch.msgid.link/031184748a8e74c0bb02f1fa13d7a3f10918c627.1781228815.git.m@maowtm.org Signed-off-by: Mickaël Salaün

landlock: Add a place for flags to layer rules

2026-06-14T18:17:18Z

To avoid unnecessarily increasing the size of struct landlock_layer, we make the layer level a u8 and use the space to store the flags struct. struct layer_access_masks is renamed to struct layer_masks, and a new field is added to track whether a quiet flag rule is seen for each layer. Through use of bitfields, this does not increase the size of the struct. Cc: Justin Suess Assisted-by: GitHub-Copilot:claude-opus-4.8 copilot-review Signed-off-by: Tingmao Wang Co-developed-by: Justin Suess Signed-off-by: Justin Suess Tested-by: Justin Suess Link: https://patch.msgid.link/be3fec3927bc9faaacd4ce0e7f0d1ff5474e2210.1781228815.git.m@maowtm.org [mic: Fix comment formatting] Signed-off-by: Mickaël Salaün

landlock: Improve kernel-doc "Return:" section consistency

2026-04-07T16:51:04Z

The canonical kernel-doc form is "Return:" (singular, without trailing "s"). Normalize all existing "Returns:" occurrences across the Landlock source tree to the canonical form. Also fix capitalization for consistency. Balance descriptions to describe all possible returned values. Consolidate bullet-point return descriptions into inline text for functions with simple two-value or three-value returns for consistency. Cc: Günther Noack Reviewed-by: Günther Noack Link: https://lore.kernel.org/r/20260304193134.250495-3-mic@digikod.net Signed-off-by: Mickaël Salaün

landlock: Transpose the layer masks data structure

2026-02-10T15:46:50Z

The layer masks data structure tracks the requested but unfulfilled access rights during an operation's security check. It stores one bit for each combination of access right and layer index. If the bit is set, that access right is not granted (yet) in the given layer and we have to traverse the path further upwards to grant it. Previously, the layer masks were stored as arrays mapping from access right indices to layer_mask_t. The layer_mask_t value then indicates all layers in which the given access right is still (tentatively) denied. This patch introduces struct layer_access_masks instead: This struct contains an array with the access_mask_t of each (tentatively) denied access right in that layer. The hypothesis of this patch is that this simplifies the code enough so that the resulting code will run faster: * We can use bitwise operations in multiple places where we previously looped over bits individually with macros. (Should require less branch speculation and lends itself to better loop unrolling.) * Code is ~75 lines smaller. Other noteworthy changes: * In no_more_access(), call a new helper function may_refer(), which only solves the asymmetric case. Previously, the code interleaved the checks for the two symmetric cases in RENAME_EXCHANGE. It feels that the code is clearer when renames without RENAME_EXCHANGE are more obviously the normal case. Tradeoffs: This change improves performance, at a slight size increase to the layer masks data structure. This fixes the size of the data structure at 32 bytes for all types of access rights. (64, once we introduce a 17th filesystem access right). For filesystem access rights, at the moment, the data structure has the same size as before, but once we introduce the 17th filesystem access right, it will double in size (from 32 to 64 bytes), as access_mask_t grows from 16 to 32 bit [1]. Link: https://lore.kernel.org/all/20260120.haeCh4li9Vae@digikod.net/ [1] Signed-off-by: Günther Noack Link: https://lore.kernel.org/r/20260206151154.97915-5-gnoack3000@gmail.com [mic: Cosmetic fixes, moved struct layer_access_masks definition] Signed-off-by: Mickaël Salaün

landlock: Minor comments improvements

2025-11-26T19:20:21Z

This patch contains some small comment changes. The first three comments for ruleset.c, I sort of made along the way while working on / trying to understand Landlock, and the one from ruleset.h was from the hashtable patch but extracted here. In fs.c, one comment which I found would have been helpful to me when reading this. Signed-off-by: Tingmao Wang Link: https://lore.kernel.org/r/20250602134150.67189-1-m@maowtm.org Link: https://lore.kernel.org/r/20297185fd71ffbb5ce4fec14b38e5444c719c96.1748379182.git.m@maowtm.org [mic: Squash patches with updated description, cosmetic fixes] Signed-off-by: Mickaël Salaün

landlock: Log mount-related denials

2025-03-26T12:59:39Z

Add audit support for sb_mount, move_mount, sb_umount, sb_remount, and sb_pivot_root hooks. The new related blocker is "fs.change_topology". Audit event sample: type=LANDLOCK_DENY msg=audit(1729738800.349:44): domain=195ba459b blockers=fs.change_topology name="/" dev="tmpfs" ino=1 Remove landlock_get_applicable_domain() and get_current_fs_domain() which are now fully replaced with landlock_get_applicable_subject(). Cc: Günther Noack Link: https://lore.kernel.org/r/20250320190717.2287696-12-mic@digikod.net Signed-off-by: Mickaël Salaün

landlock: Add AUDIT_LANDLOCK_DOMAIN and log domain status

2025-03-26T12:59:38Z

Asynchronously log domain information when it first denies an access. This minimize the amount of generated logs, which makes it possible to always log denials for the current execution since they should not happen. These records are identified with the new AUDIT_LANDLOCK_DOMAIN type. The AUDIT_LANDLOCK_DOMAIN message contains: - the "domain" ID which is described; - the "status" which can either be "allocated" or "deallocated"; - the "mode" which is for now only "enforcing"; - for the "allocated" status, a minimal set of properties to easily identify the task that loaded the domain's policy with landlock_restrict_self(2): "pid", "uid", executable path ("exe"), and command line ("comm"); - for the "deallocated" state, the number of "denials" accounted to this domain, which is at least 1. This requires each domain to save these task properties at creation time in the new struct landlock_details. A reference to the PID is kept for the lifetime of the domain to avoid race conditions when investigating the related task. The executable path is resolved and stored to not keep a reference to the filesystem and block related actions. All these metadata are stored for the lifetime of the related domain and should then be minimal. The required memory is not accounted to the task calling landlock_restrict_self(2) contrary to most other Landlock allocations (see related comment). The AUDIT_LANDLOCK_DOMAIN record follows the first AUDIT_LANDLOCK_ACCESS record for the same domain, which is always followed by AUDIT_SYSCALL and AUDIT_PROCTITLE. This is in line with the audit logic to first record the cause of an event, and then add context with other types of record. Audit event sample for a first denial: type=LANDLOCK_ACCESS msg=audit(1732186800.349:44): domain=195ba459b blockers=ptrace opid=1 ocomm="systemd" type=LANDLOCK_DOMAIN msg=audit(1732186800.349:44): domain=195ba459b status=allocated mode=enforcing pid=300 uid=0 exe="/root/sandboxer" comm="sandboxer" type=SYSCALL msg=audit(1732186800.349:44): arch=c000003e syscall=101 success=no [...] pid=300 auid=0 Audit event sample for a following denial: type=LANDLOCK_ACCESS msg=audit(1732186800.372:45): domain=195ba459b blockers=ptrace opid=1 ocomm="systemd" type=SYSCALL msg=audit(1732186800.372:45): arch=c000003e syscall=101 success=no [...] pid=300 auid=0 Log domain deletion with the "deallocated" state when a domain was previously logged. This makes it possible for log parsers to free potential resources when a domain ID will never show again. The number of denied access requests is useful to easily check how many access requests a domain blocked and potentially if some of them are missing in logs because of audit rate limiting, audit rules, or Landlock log configuration flags (see following commit). Audit event sample for a deletion of a domain that denied something: type=LANDLOCK_DOMAIN msg=audit(1732186800.393:46): domain=195ba459b status=deallocated denials=2 Cc: Günther Noack Acked-by: Paul Moore Link: https://lore.kernel.org/r/20250320190717.2287696-11-mic@digikod.net [mic: Update comment and GFP flag for landlock_log_drop_domain()] Signed-off-by: Mickaël Salaün

landlock: Move domain hierarchy management

2025-03-26T12:59:34Z

Create a new domain.h file containing the struct landlock_hierarchy definition and helpers. This type will grow with audit support. This also prepares for a new domain type. Cc: Günther Noack Link: https://lore.kernel.org/r/20250320190717.2287696-4-mic@digikod.net Reviewed-by: Günther Noack Signed-off-by: Mickaël Salaün

landlock: Move access types

2025-01-17T18:05:34Z

Move LANDLOCK_ACCESS_FS_INITIALLY_DENIED, access_mask_t, struct access_mask, and struct access_masks_all to a dedicated access.h file. Rename LANDLOCK_ACCESS_FS_INITIALLY_DENIED to _LANDLOCK_ACCESS_FS_INITIALLY_DENIED to make it clear that it's not part of UAPI. Add some newlines when appropriate. This file will be extended with following commits, and it will help to avoid dependency loops. Cc: Günther Noack Link: https://lore.kernel.org/r/20250108154338.1129069-6-mic@digikod.net [mic: Fix rebase conflict because of the new cleanup headers] Signed-off-by: Mickaël Salaün