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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 <gnoack@google.com>
Cc: Paul Moore <paul@paul-moore.com>
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 <mic@digikod.net>
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Extend struct landlock_cred_security with a domain_exec bitmask to
identify which Landlock domain were created by the current task's bprm.
The whole bitmask is reset on each execve(2) call.
Cc: Günther Noack <gnoack@google.com>
Cc: Paul Moore <paul@paul-moore.com>
Link: https://lore.kernel.org/r/20250320190717.2287696-9-mic@digikod.net
Signed-off-by: Mickaël Salaün <mic@digikod.net>
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This cosmetic change is needed for audit support, specifically to be
able to filter according to cross-execution boundaries.
Add landlock_get_applicable_subject(), mainly a copy of
landlock_get_applicable_domain(), which will fully replace it in a
following commit.
Optimize current_check_access_path() to only handle the access request.
Partially replace get_current_fs_domain() with explicit calls to
landlock_get_applicable_subject(). The remaining ones will follow with
more changes.
Remove explicit domain->num_layers check which is now part of the
landlock_get_applicable_subject() call.
Cc: Günther Noack <gnoack@google.com>
Link: https://lore.kernel.org/r/20250320190717.2287696-5-mic@digikod.net
Signed-off-by: Mickaël Salaün <mic@digikod.net>
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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 <fahimitahera@gmail.com>
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 <mic@digikod.net>
Signed-off-by: Mickaël Salaün <mic@digikod.net>
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Let's follow a consistent and documented coding style. Everything may
not be to our liking but it is better than tacit knowledge. Moreover,
this will help maintain style consistency between different developers.
This contains only whitespace changes.
Automatically formatted with:
clang-format-14 -i security/landlock/*.[ch] include/uapi/linux/landlock.h
Link: https://lore.kernel.org/r/20220506160513.523257-3-mic@digikod.net
Cc: stable@vger.kernel.org
Signed-off-by: Mickaël Salaün <mic@digikod.net>
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Process's credentials point to a Landlock domain, which is underneath
implemented with a ruleset. In the following commits, this domain is
used to check and enforce the ptrace and filesystem security policies.
A domain is inherited from a parent to its child the same way a thread
inherits a seccomp policy.
Cc: James Morris <jmorris@namei.org>
Signed-off-by: Mickaël Salaün <mic@linux.microsoft.com>
Reviewed-by: Jann Horn <jannh@google.com>
Acked-by: Serge Hallyn <serge@hallyn.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20210422154123.13086-4-mic@digikod.net
Signed-off-by: James Morris <jamorris@linux.microsoft.com>
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