kernel/linux.git/include/uapi/linux/landlock.h, branch v6.19.11

landlock: Clarify documentation for the IOCTL access right

2026-01-12T16:07:21+00:00

Move the description of the LANDLOCK_ACCESS_FS_IOCTL_DEV access right together with the file access rights. This group of access rights applies to files (in this case device files), and they can be added to file or directory inodes using landlock_add_rule(2). The check for that works the same for all file access rights, including LANDLOCK_ACCESS_FS_IOCTL_DEV. Invoking ioctl(2) on directory FDs can not currently be restricted with Landlock. Having it grouped separately in the documentation is a remnant from earlier revisions of the LANDLOCK_ACCESS_FS_IOCTL_DEV patch set. Link: https://lore.kernel.org/all/20260108.Thaex5ruach2@digikod.net/ Signed-off-by: Günther Noack Link: https://lore.kernel.org/r/20260111175203.6545-2-gnoack3000@gmail.com Signed-off-by: Mickaël Salaün

landlock: Update log documentation

2025-04-17T09:09:10+00:00

Fix and improve documentation related to landlock_restrict_self(2)'s flags. Update the LANDLOCK_RESTRICT_SELF_LOG_SAME_EXEC_OFF documentation according to the current semantic. Cc: Günther Noack Cc: Paul Moore Link: https://lore.kernel.org/r/20250416154716.1799902-3-mic@digikod.net Signed-off-by: Mickaël Salaün

landlock: Fix documentation for landlock_restrict_self(2)

2025-04-17T09:09:10+00:00

Fix, deduplicate, and improve rendering of landlock_restrict_self(2)'s flags documentation. The flags are now rendered like the syscall's parameters and description. Cc: Günther Noack Cc: Paul Moore Link: https://lore.kernel.org/r/20250416154716.1799902-2-mic@digikod.net Signed-off-by: Mickaël Salaün

landlock: Fix documentation for landlock_create_ruleset(2)

2025-04-17T09:09:07+00:00

Move and fix the flags documentation, and improve formatting. It makes more sense and it eases maintenance to document syscall flags in landlock.h, where they are defined. This is already the case for landlock_restrict_self(2)'s flags. The flags are now rendered like the syscall's parameters and description. Cc: Günther Noack Cc: Paul Moore Link: https://lore.kernel.org/r/20250416154716.1799902-1-mic@digikod.net Signed-off-by: Mickaël Salaün

landlock: Add LANDLOCK_RESTRICT_SELF_LOG_SUBDOMAINS_OFF

2025-03-26T12:59:43+00:00

Add LANDLOCK_RESTRICT_SELF_LOG_SUBDOMAINS_OFF for the case of sandboxer tools, init systems, or runtime containers launching programs sandboxing themselves in an inconsistent way. Setting this flag should only depends on runtime configuration (i.e. not hardcoded). We don't create a new ruleset's option because this should not be part of the security policy: only the task that enforces the policy (not the one that create it) knows if itself or its children may request denied actions. This is the first and only flag that can be set without actually restricting the caller (i.e. without providing a ruleset). Extend struct landlock_cred_security with a u8 log_subdomains_off. struct landlock_file_security is still 16 bytes. Cc: Günther Noack Cc: Paul Moore Closes: https://github.com/landlock-lsm/linux/issues/3 Link: https://lore.kernel.org/r/20250320190717.2287696-19-mic@digikod.net [mic: Fix comment] Signed-off-by: Mickaël Salaün

landlock: Add LANDLOCK_RESTRICT_SELF_LOG__EXEC_ flags

2025-03-26T12:59:42+00:00

Most of the time we want to log denied access because they should not happen and such information helps diagnose issues. However, when sandboxing processes that we know will try to access denied resources (e.g. unknown, bogus, or malicious binary), we might want to not log related access requests that might fill up logs. By default, denied requests are logged until the task call execve(2). If the LANDLOCK_RESTRICT_SELF_LOG_SAME_EXEC_OFF flag is set, denied requests will not be logged for the same executed file. If the LANDLOCK_RESTRICT_SELF_LOG_NEW_EXEC_ON flag is set, denied requests from after an execve(2) call will be logged. The rationale is that a program should know its own behavior, but not necessarily the behavior of other programs. Because LANDLOCK_RESTRICT_SELF_LOG_SAME_EXEC_OFF is set for a specific Landlock domain, it makes it possible to selectively mask some access requests that would be logged by a parent domain, which might be handy for unprivileged processes to limit logs. However, system administrators should still use the audit filtering mechanism. There is intentionally no audit nor sysctl configuration to re-enable these logs. This is delegated to the user space program. Increment the Landlock ABI version to reflect this interface change. Cc: Günther Noack Cc: Paul Moore Link: https://lore.kernel.org/r/20250320190717.2287696-18-mic@digikod.net [mic: Rename variables and fix __maybe_unused] Signed-off-by: Mickaël Salaün

landlock: Add the errata interface

2025-03-21T11:12:19+00:00

Some fixes may require user space to check if they are applied on the running kernel before using a specific feature. For instance, this applies when a restriction was previously too restrictive and is now getting relaxed (e.g. for compatibility reasons). However, non-visible changes for legitimate use (e.g. security fixes) do not require an erratum. Because fixes are backported down to a specific Landlock ABI, we need a way to avoid cherry-pick conflicts. The solution is to only update a file related to the lower ABI impacted by this issue. All the ABI files are then used to create a bitmask of fixes. The new errata interface is similar to the one used to get the supported Landlock ABI version, but it returns a bitmask instead because the order of fixes may not match the order of versions, and not all fixes may apply to all versions. The actual errata will come with dedicated commits. The description is not actually used in the code but serves as documentation. Create the landlock_abi_version symbol and use its value to check errata consistency. Update test_base's create_ruleset_checks_ordering tests and add errata tests. This commit is backportable down to the first version of Landlock. Fixes: 3532b0b4352c ("landlock: Enable user space to infer supported features") Cc: Günther Noack Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20250318161443.279194-3-mic@digikod.net Signed-off-by: Mickaël Salaün

landlock: Minor typo and grammar fixes in IPC scoping documentation

2025-02-14T08:23:08+00:00

* Fix some whitespace, punctuation and minor grammar. * Add a missing sentence about the minimum ABI version, to stay in line with the section next to it. Cc: Tahera Fahimi Cc: Tanya Agarwal Signed-off-by: Günther Noack Link: https://lore.kernel.org/r/20250124154445.162841-1-gnoack@google.com [mic: Add newlines, update doc date] Signed-off-by: Mickaël Salaün

landlock: Add signal scoping

2024-09-16T21:50:52+00:00

Currently, a sandbox process is not restricted to sending a signal (e.g. SIGKILL) to a process outside the sandbox environment. The ability to send a signal for a sandboxed process should be scoped the same way abstract UNIX sockets are scoped. Therefore, we extend the "scoped" field in a ruleset with LANDLOCK_SCOPE_SIGNAL to specify that a ruleset will deny sending any signal from within a sandbox process to its parent (i.e. any parent sandbox or non-sandboxed processes). This patch adds file_set_fowner and file_free_security hooks to set and release a pointer to the file owner's domain. This pointer, fown_domain in landlock_file_security will be used in file_send_sigiotask to check if the process can send a signal. The ruleset_with_unknown_scope test is updated to support LANDLOCK_SCOPE_SIGNAL. This depends on two new changes: - commit 1934b212615d ("file: reclaim 24 bytes from f_owner"): replace container_of(fown, struct file, f_owner) with fown->file . - commit 26f204380a3c ("fs: Fix file_set_fowner LSM hook inconsistencies"): lock before calling the hook. Signed-off-by: Tahera Fahimi Closes: https://github.com/landlock-lsm/linux/issues/8 Link: https://lore.kernel.org/r/df2b4f880a2ed3042992689a793ea0951f6798a5.1725657727.git.fahimitahera@gmail.com [mic: Update landlock_get_current_domain()'s return type, improve and fix locking in hook_file_set_fowner(), simplify and fix sleepable call and locking issue in hook_file_send_sigiotask() and rebase on the latest VFS tree, simplify hook_task_kill() and quickly return when not sandboxed, improve comments, rename LANDLOCK_SCOPED_SIGNAL] Co-developed-by: Mickaël Salaün Signed-off-by: Mickaël Salaün

landlock: Add abstract UNIX socket scoping

2024-09-16T21:50:45+00:00

Introduce a new "scoped" member to landlock_ruleset_attr that can specify LANDLOCK_SCOPE_ABSTRACT_UNIX_SOCKET to restrict connection to abstract UNIX sockets from a process outside of the socket's domain. Two hooks are implemented to enforce these restrictions: unix_stream_connect and unix_may_send. Closes: https://github.com/landlock-lsm/linux/issues/7 Signed-off-by: Tahera Fahimi Link: https://lore.kernel.org/r/5f7ad85243b78427242275b93481cfc7c127764b.1725494372.git.fahimitahera@gmail.com [mic: Fix commit message formatting, improve documentation, simplify hook_unix_may_send(), and cosmetic fixes including rename of LANDLOCK_SCOPED_ABSTRACT_UNIX_SOCKET] Co-developed-by: Mickaël Salaün Signed-off-by: Mickaël Salaün