* Re: [PATCH 1/3] landlock: Add missing ABI 7 case in documentation example
From: Günther Noack @ 2025-12-23 22:22 UTC (permalink / raw)
To: Samasth Norway Ananda; +Cc: mic, gnoack, linux-security-module, linux-kernel
In-Reply-To: <20251216210248.4150777-1-samasth.norway.ananda@oracle.com>
Hello!
On Tue, Dec 16, 2025 at 01:02:42PM -0800, Samasth Norway Ananda wrote:
> Add the missing case 6 and case 7 handling in the ABI version
> compatibility example to properly handle LANDLOCK_RESTRICT_SELF_LOG_*
> flags for kernels with ABI < 7.
>
> This introduces the supported_restrict_flags variable which is
> initialized with LANDLOCK_RESTRICT_SELF_LOG_NEW_EXEC_ON, removed
> in case 6 for ABI < 7, and passed to landlock_restrict_self() to
> enable logging on supported kernels.
>
> Also fix misleading description of the /usr rule which incorrectly
> stated it "only allow[s] reading" when the code actually allows both
> reading and executing (LANDLOCK_ACCESS_FS_EXECUTE is included in
> allowed_access).
>
> Signed-off-by: Samasth Norway Ananda <samasth.norway.ananda@oracle.com>
Thank you for sending a patch, much appreciated!
You are right to point this out - the logging aspect is a bit hard to
spot when reading the current documentation starting from the code
example.
> ---
> Documentation/userspace-api/landlock.rst | 22 ++++++++++++++++++----
> 1 file changed, 18 insertions(+), 4 deletions(-)
>
> diff --git a/Documentation/userspace-api/landlock.rst b/Documentation/userspace-api/landlock.rst
> index 1d0c2c15c22e..b8caac299056 100644
> --- a/Documentation/userspace-api/landlock.rst
> +++ b/Documentation/userspace-api/landlock.rst
> @@ -97,6 +97,8 @@ version, and only use the available subset of access rights:
> .. code-block:: c
>
> int abi;
> + /* Tracks which landlock_restrict_self() flags are supported */
> + int supported_restrict_flags = LANDLOCK_RESTRICT_SELF_LOG_NEW_EXEC_ON;
This might be confusing, as there are actually more supported flags:
ABI v7 does not only introduce LANDLOCK_RESTRICT_SELF_LOG_NEW_EXEC_ON,
but also LANDLOCK_RESTRICT_SELF_LOG_SAME_EXEC_OFF and
LANDLOCK_RESTRICT_SELF_LOG_SUBDOMAINS_OFF.
I am unconvinced whether it is a good idea to set these flags in the
first example that we have in the documentation, especially if we
don't discuss what these flags do there. If we suggest the wrong
default flags in the example, people might use them in their
production code without realizing what they do. The way that the
logging flags are designed, the assumption was that most users should
be able to pass 0 as flags to landlock_restrict_self() and still get
the relevant parts of the audit logging.
But you are right that an implementation that *does pass* logging
flags will want check the ABI and not pass them on older kernels.
To throw in a constructive suggestion: we could also have "backwards
compatibility for restrict flags" section between the existing case
analysis and the landlock_restrict_self() call? It could then say
something like
When passing a non-zero `flags` argument to
landlock_restrict_self(), the following backwards compatibility
check needs to be taken into account:
/*
* Desired restriction flags, see section suchandsuch.
* This value is only an example and differs by use case.
*/
int restrict_flags = LANDLOCK_RESTRICT_SELF_LOG_NEW_EXEC_ON;
if (abi < 7) {
/* clear the necessary bits */
restrict_flags &= ~...;
}
Readers who do not need to pass any flags could then skip over that
section (I assume these are most readers). The readers who *do* want
to pass flags could merge that logic into the bigger case analysis
themselves, but for the sake of explaining it we would not mix up that
explanation with the access right discussion that much.
WDYT?
> abi = landlock_create_ruleset(NULL, 0, LANDLOCK_CREATE_RULESET_VERSION);
> if (abi < 0) {
> @@ -127,6 +129,17 @@ version, and only use the available subset of access rights:
> /* Removes LANDLOCK_SCOPE_* for ABI < 6 */
> ruleset_attr.scoped &= ~(LANDLOCK_SCOPE_ABSTRACT_UNIX_SOCKET |
> LANDLOCK_SCOPE_SIGNAL);
> + __attribute__((fallthrough));
> + case 6:
> + /*
> + * Removes LANDLOCK_RESTRICT_SELF_LOG_NEW_EXEC_ON for ABI < 7.
> + * Note: This modifies supported_restrict_flags, not ruleset_attr,
> + * because logging flags are passed to landlock_restrict_self().
> + */
> + supported_restrict_flags &= ~LANDLOCK_RESTRICT_SELF_LOG_NEW_EXEC_ON;
If this should be a generic example, we would have to clear the other
two flags here as well.
> + __attribute__((fallthrough));
> + case 7:
> + break;
> }
Thanks,
–Günther
^ permalink raw reply
* Re: [PATCH v2] ima: Fix stack-out-of-bounds in is_bprm_creds_for_exec()
From: Mimi Zohar @ 2025-12-23 21:58 UTC (permalink / raw)
To: Chris J Arges, roberto.sassu
Cc: kernel-team, Dmitry Kasatkin, Eric Snowberg, Paul Moore,
James Morris, Serge E. Hallyn, Mickaël Salaün,
Kees Cook, linux-integrity, linux-security-module, linux-kernel
In-Reply-To: <20251221180128.1026760-1-carges@cloudflare.com>
Hi Chris,
On Sun, 2025-12-21 at 12:01 -0600, Chris J Arges wrote:
> KASAN reported a stack-out-of-bounds access in ima_appraise_measurement
> from is_bprm_creds_for_exec:
>
> BUG: KASAN: stack-out-of-bounds in ima_appraise_measurement+0x12dc/0x16a0
> Read of size 1 at addr ffffc9000160f940 by task sudo/550
> The buggy address belongs to stack of task sudo/550
> and is located at offset 24 in frame:
> ima_appraise_measurement+0x0/0x16a0
> This frame has 2 objects:
> [48, 56) 'file'
> [80, 148) 'hash'
>
> This is caused by using container_of on the *file pointer. This offset
> calculation is what triggers the stack-out-of-bounds error.
>
> In order to fix this, pass in a bprm_is_check boolean which can be set
> depending on how process_measurement is called. If the caller has a
> linux_binprm pointer and the function is BPRM_CHECK we can determine
> is_check and set it then. Otherwise set it to false.
>
> Fixes: 95b3cdafd7cb7 ("ima: instantiate the bprm_creds_for_exec() hook")
>
> Signed-off-by: Chris J Arges <carges@cloudflare.com>
Thank you! I'd appreciate your limiting the line lengths to 80 chars (e.g.
scripts/checkpatch.pl --max-line-length=80).
--
thanks,
Mimi
^ permalink raw reply
* Re: [PATCH v1 5/5] landlock: Fix formatting
From: Günther Noack @ 2025-12-23 21:29 UTC (permalink / raw)
To: Mickaël Salaün
Cc: linux-security-module, Christian Brauner, Mateusz Guzik
In-Reply-To: <20251219193855.825889-5-mic@digikod.net>
On Fri, Dec 19, 2025 at 08:38:51PM +0100, Mickaël Salaün wrote:
> Format with clang-format -i security/landlock/*.[ch]
>
> Cc: Christian Brauner <brauner@kernel.org>
> Cc: Günther Noack <gnoack3000@gmail.com>
> Cc: Mateusz Guzik <mjguzik@gmail.com>
> Fixes: b4dbfd8653b3 ("Coccinelle-based conversion to use ->i_state accessors")
> Signed-off-by: Mickaël Salaün <mic@digikod.net>
> ---
> security/landlock/fs.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/security/landlock/fs.c b/security/landlock/fs.c
> index fe794875ad46..e3c3a8a9ac27 100644
> --- a/security/landlock/fs.c
> +++ b/security/landlock/fs.c
> @@ -1314,7 +1314,8 @@ static void hook_sb_delete(struct super_block *const sb)
> * second call to iput() for the same Landlock object. Also
> * checks I_NEW because such inode cannot be tied to an object.
> */
> - if (inode_state_read(inode) & (I_FREEING | I_WILL_FREE | I_NEW)) {
> + if (inode_state_read(inode) &
> + (I_FREEING | I_WILL_FREE | I_NEW)) {
> spin_unlock(&inode->i_lock);
> continue;
> }
> --
> 2.52.0
>
Reviewed-by: Günther Noack <gnoack3000@gmail.com>
^ permalink raw reply
* Re: [PATCH v1 4/5] landlock: Fix spelling
From: Günther Noack @ 2025-12-23 21:29 UTC (permalink / raw)
To: Mickaël Salaün; +Cc: linux-security-module
In-Reply-To: <20251219193855.825889-4-mic@digikod.net>
On Fri, Dec 19, 2025 at 08:38:50PM +0100, Mickaël Salaün wrote:
> Cc: Günther Noack <gnoack3000@gmail.com>
> Signed-off-by: Mickaël Salaün <mic@digikod.net>
> ---
> security/landlock/domain.h | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/security/landlock/domain.h b/security/landlock/domain.h
> index 7fb70b25f85a..621f054c9a2b 100644
> --- a/security/landlock/domain.h
> +++ b/security/landlock/domain.h
> @@ -97,7 +97,7 @@ struct landlock_hierarchy {
> */
> atomic64_t num_denials;
> /**
> - * @id: Landlock domain ID, sets once at domain creation time.
> + * @id: Landlock domain ID, set once at domain creation time.
> */
> u64 id;
> /**
> --
> 2.52.0
>
Reviewed-by: Günther Noack <gnoack3000@gmail.com>
^ permalink raw reply
* Re: [PATCH v1 3/5] landlock: Clean up hook_ptrace_access_check()
From: Günther Noack @ 2025-12-23 21:29 UTC (permalink / raw)
To: Mickaël Salaün; +Cc: linux-security-module
In-Reply-To: <20251219193855.825889-3-mic@digikod.net>
On Fri, Dec 19, 2025 at 08:38:49PM +0100, Mickaël Salaün wrote:
> Make variable's scope minimal in hook_ptrace_access_check().
>
> Cc: Günther Noack <gnoack3000@gmail.com>
> Signed-off-by: Mickaël Salaün <mic@digikod.net>
Reviewed-by: Günther Noack <gnoack3000@gmail.com>
^ permalink raw reply
* Re: [PATCH v1 2/5] landlock: Improve erratum documentation
From: Günther Noack @ 2025-12-23 21:28 UTC (permalink / raw)
To: Mickaël Salaün; +Cc: linux-security-module
In-Reply-To: <20251219193855.825889-2-mic@digikod.net>
On Fri, Dec 19, 2025 at 08:38:48PM +0100, Mickaël Salaün wrote:
> Improve description about scoped signal handling.
>
> Reported-by: Günther Noack <gnoack3000@gmail.com>
> Signed-off-by: Mickaël Salaün <mic@digikod.net>
Reviewed-by: Günther Noack <gnoack3000@gmail.com>
^ permalink raw reply
* Re: [PATCH v1 1/5] landlock: Remove useless include
From: Günther Noack @ 2025-12-23 21:27 UTC (permalink / raw)
To: Mickaël Salaün; +Cc: linux-security-module, Günther Noack
In-Reply-To: <20251219193855.825889-1-mic@digikod.net>
On Fri, Dec 19, 2025 at 08:38:47PM +0100, Mickaël Salaün wrote:
> Remove useless audit.h include.
>
> Cc: Günther Noack <gnoack@google.com>
> Fixes: 33e65b0d3add ("landlock: Add AUDIT_LANDLOCK_ACCESS and log ptrace denials")
> Signed-off-by: Mickaël Salaün <mic@digikod.net>
> ---
> security/landlock/ruleset.c | 1 -
> 1 file changed, 1 deletion(-)
>
> diff --git a/security/landlock/ruleset.c b/security/landlock/ruleset.c
> index dfcdc19ea268..0a5b0c76b3f7 100644
> --- a/security/landlock/ruleset.c
> +++ b/security/landlock/ruleset.c
> @@ -23,7 +23,6 @@
> #include <linux/workqueue.h>
>
> #include "access.h"
> -#include "audit.h"
> #include "domain.h"
> #include "limits.h"
> #include "object.h"
> --
> 2.52.0
>
Reviewed-by: Günther Noack <gnoack3000@gmail.com>
^ permalink raw reply
* Re: [PATCH] Cred: Remove unused set_security_override_from_ctx()
From: Casey Schaufler @ 2025-12-22 23:32 UTC (permalink / raw)
To: David Howells
Cc: Paul Moore, Linux kernel mailing list, Serge Hallyn,
max.kellermann, LSM List
In-Reply-To: <1075251.1766441984@warthog.procyon.org.uk>
On 12/22/2025 2:19 PM, David Howells wrote:
> Casey Schaufler <casey@schaufler-ca.com> wrote:
>
>> The function set_security_override_from_ctx() has no in-tree callers
>> since 6.14. Remove it.
> It's also declared in include/linux/cred.h
>
> David
Yup. I realized that just after I hit send. V2 coming.
^ permalink raw reply
* Re: [PATCH v3] loadpin: Implement custom proc_handler for enforce
From: Kees Cook @ 2025-12-22 23:12 UTC (permalink / raw)
To: Joel Granados
Cc: Paul Moore, James Morris, Serge E. Hallyn, linux-security-module,
linux-kernel
In-Reply-To: <20251222-jag-const_loadpin-v3-1-6463c440fb90@kernel.org>
On Mon, Dec 22, 2025 at 11:36:35PM +0100, Joel Granados wrote:
> Add a new static variable (loadpin_root_writable) to keep the
> write-ability state of enforce. Remove set_sysctl and const qualify
> loadpin_sysctl_table (moves into .rodata) as there is no longer need to
> change the value of extra1. The new proc_handler_loadpin returns -EINVAL
> when loadpin_root_writable is false and the kernel var (enforce) is
> being written. The old way of modifying the write-ability of enforce
> stayes in loadpin_check and is still set by calling sb_is_writable.
>
> Signed-off-by: Joel Granados <joel.granados@kernel.org>
> ---
> Const qualifying ctl tables is part of the hardening effort in the linux
> kernel.
>
> Changes in v3:
> - Fix compilation for CONFIG_SYSCTL=n
> - Link to v2: https://lore.kernel.org/r/20251219-jag-const_loadpin-v2-1-a1490ab35a1d@kernel.org
>
> Changes in v2:
> - Removed set_sysctl
> - Added new static loadpin_root_writable var to hold the writable state
> - Renamed the variable holding the writable state to loadpin_root_writable
> - Link to v1: https://lore.kernel.org/r/20251215-jag-const_loadpin-v1-1-6842775f4e90@kernel.org
> ---
> Signed-off-by: Joel Granados <joel.granados@kernel.org>
> ---
> security/loadpin/loadpin.c | 43 +++++++++++++++++++------------------------
> 1 file changed, 19 insertions(+), 24 deletions(-)
>
> diff --git a/security/loadpin/loadpin.c b/security/loadpin/loadpin.c
> index 273ffbd6defe1324d6688dec5f9fe6c9401283ed..a6c7e4bfa45d3568e8c36e184388ee7858ba022e 100644
> --- a/security/loadpin/loadpin.c
> +++ b/security/loadpin/loadpin.c
> @@ -52,45 +52,42 @@ static DEFINE_SPINLOCK(pinned_root_spinlock);
> static bool deny_reading_verity_digests;
> #endif
>
> +static bool loadpin_root_writable;
> #ifdef CONFIG_SYSCTL
> -static struct ctl_table loadpin_sysctl_table[] = {
> +// initialized to false
> +
> +static int proc_handler_loadpin(const struct ctl_table *table, int dir,
> + void *buffer, size_t *lenp, loff_t *ppos)
> +{
> + if (!loadpin_root_writable && SYSCTL_USER_TO_KERN(dir))
> + return -EINVAL;
> + return proc_dointvec_minmax(table, dir, buffer, lenp, ppos);
> +}
> +
> +static const struct ctl_table loadpin_sysctl_table[] = {
> {
> .procname = "enforce",
> .data = &enforce,
> .maxlen = sizeof(int),
> .mode = 0644,
> - .proc_handler = proc_dointvec_minmax,
> - .extra1 = SYSCTL_ONE,
> + .proc_handler = proc_handler_loadpin,
> + .extra1 = SYSCTL_ZERO,
> .extra2 = SYSCTL_ONE,
> },
> };
> -
> -static void set_sysctl(bool is_writable)
> -{
> - /*
> - * If load pinning is not enforced via a read-only block
> - * device, allow sysctl to change modes for testing.
> - */
> - if (is_writable)
> - loadpin_sysctl_table[0].extra1 = SYSCTL_ZERO;
> - else
> - loadpin_sysctl_table[0].extra1 = SYSCTL_ONE;
> -}
> -#else
> -static inline void set_sysctl(bool is_writable) { }
> #endif
>
> -static void report_writable(struct super_block *mnt_sb, bool writable)
> +static void report_writable(struct super_block *mnt_sb)
> {
> if (mnt_sb->s_bdev) {
> pr_info("%pg (%u:%u): %s\n", mnt_sb->s_bdev,
> MAJOR(mnt_sb->s_bdev->bd_dev),
> MINOR(mnt_sb->s_bdev->bd_dev),
> - writable ? "writable" : "read-only");
> + loadpin_root_writable ? "writable" : "read-only");
> } else
> pr_info("mnt_sb lacks block device, treating as: writable\n");
>
> - if (!writable)
> + if (!loadpin_root_writable)
> pr_info("load pinning engaged.\n");
> }
>
> @@ -131,7 +128,6 @@ static int loadpin_check(struct file *file, enum kernel_read_file_id id)
> struct super_block *load_root;
> const char *origin = kernel_read_file_id_str(id);
> bool first_root_pin = false;
> - bool load_root_writable;
>
> /* If the file id is excluded, ignore the pinning. */
> if ((unsigned int)id < ARRAY_SIZE(ignore_read_file_id) &&
> @@ -152,7 +148,6 @@ static int loadpin_check(struct file *file, enum kernel_read_file_id id)
> }
>
> load_root = file->f_path.mnt->mnt_sb;
> - load_root_writable = sb_is_writable(load_root);
>
> /* First loaded module/firmware defines the root for all others. */
> spin_lock(&pinned_root_spinlock);
> @@ -168,8 +163,8 @@ static int loadpin_check(struct file *file, enum kernel_read_file_id id)
> spin_unlock(&pinned_root_spinlock);
>
> if (first_root_pin) {
> - report_writable(pinned_root, load_root_writable);
> - set_sysctl(load_root_writable);
> + report_writable(pinned_root);
> + loadpin_root_writable = sb_is_writable(pinned_root);
The report_writable() has to follow the assignment of
loadpin_root_writable. Let's leave the "writable" argument in place for
report_writable(), which would have made this more obvious.
-Kees
> report_load(origin, file, "pinned");
> }
>
>
> ---
> base-commit: 8f0b4cce4481fb22653697cced8d0d04027cb1e8
> change-id: 20251215-jag-const_loadpin-761f052f76c4
>
> Best regards,
> --
> Joel Granados <joel.granados@kernel.org>
>
>
--
Kees Cook
^ permalink raw reply
* [PATCH v3] loadpin: Implement custom proc_handler for enforce
From: Joel Granados @ 2025-12-22 22:36 UTC (permalink / raw)
To: Kees Cook, Paul Moore, James Morris, Serge E. Hallyn
Cc: linux-security-module, linux-kernel, Joel Granados
Add a new static variable (loadpin_root_writable) to keep the
write-ability state of enforce. Remove set_sysctl and const qualify
loadpin_sysctl_table (moves into .rodata) as there is no longer need to
change the value of extra1. The new proc_handler_loadpin returns -EINVAL
when loadpin_root_writable is false and the kernel var (enforce) is
being written. The old way of modifying the write-ability of enforce
stayes in loadpin_check and is still set by calling sb_is_writable.
Signed-off-by: Joel Granados <joel.granados@kernel.org>
---
Const qualifying ctl tables is part of the hardening effort in the linux
kernel.
Changes in v3:
- Fix compilation for CONFIG_SYSCTL=n
- Link to v2: https://lore.kernel.org/r/20251219-jag-const_loadpin-v2-1-a1490ab35a1d@kernel.org
Changes in v2:
- Removed set_sysctl
- Added new static loadpin_root_writable var to hold the writable state
- Renamed the variable holding the writable state to loadpin_root_writable
- Link to v1: https://lore.kernel.org/r/20251215-jag-const_loadpin-v1-1-6842775f4e90@kernel.org
---
Signed-off-by: Joel Granados <joel.granados@kernel.org>
---
security/loadpin/loadpin.c | 43 +++++++++++++++++++------------------------
1 file changed, 19 insertions(+), 24 deletions(-)
diff --git a/security/loadpin/loadpin.c b/security/loadpin/loadpin.c
index 273ffbd6defe1324d6688dec5f9fe6c9401283ed..a6c7e4bfa45d3568e8c36e184388ee7858ba022e 100644
--- a/security/loadpin/loadpin.c
+++ b/security/loadpin/loadpin.c
@@ -52,45 +52,42 @@ static DEFINE_SPINLOCK(pinned_root_spinlock);
static bool deny_reading_verity_digests;
#endif
+static bool loadpin_root_writable;
#ifdef CONFIG_SYSCTL
-static struct ctl_table loadpin_sysctl_table[] = {
+// initialized to false
+
+static int proc_handler_loadpin(const struct ctl_table *table, int dir,
+ void *buffer, size_t *lenp, loff_t *ppos)
+{
+ if (!loadpin_root_writable && SYSCTL_USER_TO_KERN(dir))
+ return -EINVAL;
+ return proc_dointvec_minmax(table, dir, buffer, lenp, ppos);
+}
+
+static const struct ctl_table loadpin_sysctl_table[] = {
{
.procname = "enforce",
.data = &enforce,
.maxlen = sizeof(int),
.mode = 0644,
- .proc_handler = proc_dointvec_minmax,
- .extra1 = SYSCTL_ONE,
+ .proc_handler = proc_handler_loadpin,
+ .extra1 = SYSCTL_ZERO,
.extra2 = SYSCTL_ONE,
},
};
-
-static void set_sysctl(bool is_writable)
-{
- /*
- * If load pinning is not enforced via a read-only block
- * device, allow sysctl to change modes for testing.
- */
- if (is_writable)
- loadpin_sysctl_table[0].extra1 = SYSCTL_ZERO;
- else
- loadpin_sysctl_table[0].extra1 = SYSCTL_ONE;
-}
-#else
-static inline void set_sysctl(bool is_writable) { }
#endif
-static void report_writable(struct super_block *mnt_sb, bool writable)
+static void report_writable(struct super_block *mnt_sb)
{
if (mnt_sb->s_bdev) {
pr_info("%pg (%u:%u): %s\n", mnt_sb->s_bdev,
MAJOR(mnt_sb->s_bdev->bd_dev),
MINOR(mnt_sb->s_bdev->bd_dev),
- writable ? "writable" : "read-only");
+ loadpin_root_writable ? "writable" : "read-only");
} else
pr_info("mnt_sb lacks block device, treating as: writable\n");
- if (!writable)
+ if (!loadpin_root_writable)
pr_info("load pinning engaged.\n");
}
@@ -131,7 +128,6 @@ static int loadpin_check(struct file *file, enum kernel_read_file_id id)
struct super_block *load_root;
const char *origin = kernel_read_file_id_str(id);
bool first_root_pin = false;
- bool load_root_writable;
/* If the file id is excluded, ignore the pinning. */
if ((unsigned int)id < ARRAY_SIZE(ignore_read_file_id) &&
@@ -152,7 +148,6 @@ static int loadpin_check(struct file *file, enum kernel_read_file_id id)
}
load_root = file->f_path.mnt->mnt_sb;
- load_root_writable = sb_is_writable(load_root);
/* First loaded module/firmware defines the root for all others. */
spin_lock(&pinned_root_spinlock);
@@ -168,8 +163,8 @@ static int loadpin_check(struct file *file, enum kernel_read_file_id id)
spin_unlock(&pinned_root_spinlock);
if (first_root_pin) {
- report_writable(pinned_root, load_root_writable);
- set_sysctl(load_root_writable);
+ report_writable(pinned_root);
+ loadpin_root_writable = sb_is_writable(pinned_root);
report_load(origin, file, "pinned");
}
---
base-commit: 8f0b4cce4481fb22653697cced8d0d04027cb1e8
change-id: 20251215-jag-const_loadpin-761f052f76c4
Best regards,
--
Joel Granados <joel.granados@kernel.org>
^ permalink raw reply related
* Re: [PATCH] Cred: Remove unused set_security_override_from_ctx()
From: David Howells @ 2025-12-22 22:19 UTC (permalink / raw)
To: Casey Schaufler
Cc: dhowells, Paul Moore, Linux kernel mailing list, Serge Hallyn,
max.kellermann, LSM List
In-Reply-To: <15895666-464c-4349-9fb2-f24e10aac8c7@schaufler-ca.com>
Casey Schaufler <casey@schaufler-ca.com> wrote:
> The function set_security_override_from_ctx() has no in-tree callers
> since 6.14. Remove it.
It's also declared in include/linux/cred.h
David
^ permalink raw reply
* [PATCH] Cred: Remove unused set_security_override_from_ctx()
From: Casey Schaufler @ 2025-12-22 21:01 UTC (permalink / raw)
To: Paul Moore, David Howells, Linux kernel mailing list,
Serge Hallyn
Cc: max.kellermann, LSM List, Casey Schaufler
In-Reply-To: <15895666-464c-4349-9fb2-f24e10aac8c7.ref@schaufler-ca.com>
The function set_security_override_from_ctx() has no in-tree callers
since 6.14. Remove it.
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
---
kernel/cred.c | 23 -----------------------
1 file changed, 23 deletions(-)
diff --git a/kernel/cred.c b/kernel/cred.c
index a6f686b30da1..12a7b1ce5131 100644
--- a/kernel/cred.c
+++ b/kernel/cred.c
@@ -620,29 +620,6 @@ int set_security_override(struct cred *new, u32 secid)
}
EXPORT_SYMBOL(set_security_override);
-/**
- * set_security_override_from_ctx - Set the security ID in a set of
credentials
- * @new: The credentials to alter
- * @secctx: The LSM security context to generate the security ID from.
- *
- * Set the LSM security ID in a set of credentials so that the subjective
- * security is overridden when an alternative set of credentials is
used. The
- * security ID is specified in string form as a security context to be
- * interpreted by the LSM.
- */
-int set_security_override_from_ctx(struct cred *new, const char *secctx)
-{
- u32 secid;
- int ret;
-
- ret = security_secctx_to_secid(secctx, strlen(secctx), &secid);
- if (ret < 0)
- return ret;
-
- return set_security_override(new, secid);
-}
-EXPORT_SYMBOL(set_security_override_from_ctx);
-
/**
* set_create_files_as - Set the LSM file create context in a set of
credentials
* @new: The credentials to alter
^ permalink raw reply related
* [PATCH] Cred: Remove unused set_security_override_from_ctx()
From: Casey Schaufler @ 2025-12-22 18:02 UTC (permalink / raw)
To: Paul Moore, David Howells, Linux kernel mailing list,
Serge Hallyn
Cc: max.kellermann, LSM List, Casey Schaufler
In-Reply-To: <15895666-464c-4349-9fb2-f24e10aac8c7.ref@schaufler-ca.com>
The function set_security_override_from_ctx() has no in-tree callers
since 6.14. Remove it.
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
---
kernel/cred.c | 23 -----------------------
1 file changed, 23 deletions(-)
diff --git a/kernel/cred.c b/kernel/cred.c
index a6f686b30da1..12a7b1ce5131 100644
--- a/kernel/cred.c
+++ b/kernel/cred.c
@@ -620,29 +620,6 @@ int set_security_override(struct cred *new, u32 secid)
}
EXPORT_SYMBOL(set_security_override);
-/**
- * set_security_override_from_ctx - Set the security ID in a set of credentials
- * @new: The credentials to alter
- * @secctx: The LSM security context to generate the security ID from.
- *
- * Set the LSM security ID in a set of credentials so that the subjective
- * security is overridden when an alternative set of credentials is used. The
- * security ID is specified in string form as a security context to be
- * interpreted by the LSM.
- */
-int set_security_override_from_ctx(struct cred *new, const char *secctx)
-{
- u32 secid;
- int ret;
-
- ret = security_secctx_to_secid(secctx, strlen(secctx), &secid);
- if (ret < 0)
- return ret;
-
- return set_security_override(new, secid);
-}
-EXPORT_SYMBOL(set_security_override_from_ctx);
-
/**
* set_create_files_as - Set the LSM file create context in a set of credentials
* @new: The credentials to alter
^ permalink raw reply related
* [syzbot] [tomoyo?] [mm?] INFO: rcu detected stall in sys_newfstat (4)
From: syzbot @ 2025-12-22 3:48 UTC (permalink / raw)
To: jmorris, linux-kernel, linux-mm, linux-security-module, paul,
penguin-kernel, serge, syzkaller-bugs, takedakn, tomoyo-users_en
Hello,
syzbot found the following issue on:
HEAD commit: 12b95d29eb97 Add linux-next specific files for 20251217
git tree: linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=16bbd31a580000
kernel config: https://syzkaller.appspot.com/x/.config?x=9b53f0e28d100777
dashboard link: https://syzkaller.appspot.com/bug?extid=5fb7dcd004f42cb418d7
compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=11355d92580000
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/0264b4454f47/disk-12b95d29.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/72a383625b53/vmlinux-12b95d29.xz
kernel image: https://storage.googleapis.com/syzbot-assets/6499b25d444f/bzImage-12b95d29.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+5fb7dcd004f42cb418d7@syzkaller.appspotmail.com
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P5966/1:b..l
rcu: (detected by 0, t=10502 jiffies, g=13749, q=681 ncpus=2)
task:udevd state:R running task stack:24376 pid:5966 tgid:5966 ppid:5200 task_flags:0x400140 flags:0x00080000
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5258 [inline]
__schedule+0x150e/0x5070 kernel/sched/core.c:6866
preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7193
irqentry_exit+0x5d8/0x660 kernel/entry/common.c:216
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:lock_acquire+0x16c/0x340 kernel/locking/lockdep.c:5872
Code: 00 00 00 00 9c 8f 44 24 30 f7 44 24 30 00 02 00 00 0f 85 cd 00 00 00 f7 44 24 08 00 02 00 00 74 01 fb 65 48 8b 05 74 3f 25 11 <48> 3b 44 24 58 0f 85 e5 00 00 00 48 83 c4 60 5b 41 5c 41 5d 41 5e
RSP: 0018:ffffc900035174d8 EFLAGS: 00000206
RAX: 550ae36b7d32a800 RBX: 0000000000000000 RCX: 550ae36b7d32a800
RDX: 0000000002aa642d RSI: ffffffff8dc9133e RDI: ffffffff8be243e0
RBP: ffffffff81746f85 R08: ffffffff81746f85 R09: ffffffff8e33f8a0
R10: ffffc90003517698 R11: ffffffff81addf20 R12: 0000000000000002
R13: ffffffff8e33f8a0 R14: 0000000000000000 R15: 0000000000000246
rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
rcu_read_lock include/linux/rcupdate.h:867 [inline]
class_rcu_constructor include/linux/rcupdate.h:1195 [inline]
unwind_next_frame+0xc2/0x23d0 arch/x86/kernel/unwind_orc.c:495
arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25
stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122
kasan_save_stack mm/kasan/common.c:57 [inline]
kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:584
poison_slab_object mm/kasan/common.c:253 [inline]
__kasan_slab_free+0x5c/0x80 mm/kasan/common.c:285
kasan_slab_free include/linux/kasan.h:235 [inline]
slab_free_hook mm/slub.c:2540 [inline]
slab_free mm/slub.c:6674 [inline]
kfree+0x1c0/0x660 mm/slub.c:6882
tomoyo_realpath_from_path+0x598/0x5d0 security/tomoyo/realpath.c:286
tomoyo_get_realpath security/tomoyo/file.c:151 [inline]
tomoyo_path_perm+0x213/0x4b0 security/tomoyo/file.c:822
security_inode_getattr+0x12f/0x330 security/security.c:1869
vfs_getattr fs/stat.c:259 [inline]
vfs_fstat fs/stat.c:281 [inline]
__do_sys_newfstat fs/stat.c:555 [inline]
__se_sys_newfstat fs/stat.c:550 [inline]
__x64_sys_newfstat+0xfc/0x200 fs/stat.c:550
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fcf92911ad7
RSP: 002b:00007ffe4ab44048 EFLAGS: 00000246 ORIG_RAX: 0000000000000005
RAX: ffffffffffffffda RBX: 00005558e4439050 RCX: 00007fcf92911ad7
RDX: 0000000000000000 RSI: 00007ffe4ab44090 RDI: 0000000000000009
RBP: 0000000000000001 R08: 0000000000000620 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00005558ba62e95f
R13: 00005558ba63f660 R14: 0000000000000000 R15: 0000000000000009
</TASK>
rcu: rcu_preempt kthread starved for 10446 jiffies! g13749 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=0
rcu: Unless rcu_preempt kthread gets sufficient CPU time, OOM is now expected behavior.
rcu: RCU grace-period kthread stack dump:
task:rcu_preempt state:R running task stack:27728 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5258 [inline]
__schedule+0x150e/0x5070 kernel/sched/core.c:6866
__schedule_loop kernel/sched/core.c:6948 [inline]
schedule+0x165/0x360 kernel/sched/core.c:6963
schedule_timeout+0x12b/0x270 kernel/time/sleep_timeout.c:99
rcu_gp_fqs_loop+0x301/0x1540 kernel/rcu/tree.c:2083
rcu_gp_kthread+0x99/0x390 kernel/rcu/tree.c:2285
kthread+0x711/0x8a0 kernel/kthread.c:463
ret_from_fork+0x599/0xb30 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
</TASK>
rcu: Stack dump where RCU GP kthread last ran:
CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:pv_native_safe_halt+0x13/0x20 arch/x86/kernel/paravirt.c:82
Code: cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 66 90 0f 00 2d 33 be 21 00 f3 0f 1e fa fb f4 <e9> 48 ee 02 00 cc cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90
RSP: 0018:ffffffff8e007d80 EFLAGS: 000002c6
RAX: da29ab50f81b1900 RBX: ffffffff8197c88a RCX: da29ab50f81b1900
RDX: 0000000000000001 RSI: ffffffff8daa76bd RDI: ffffffff8be243e0
RBP: ffffffff8e007ea8 R08: ffff8880b86336db R09: 1ffff110170c66db
R10: dffffc0000000000 R11: ffffed10170c66dc R12: ffffffff8fc3b070
R13: 1ffffffff1c129b8 R14: 0000000000000000 R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff8881259e1000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b31163fff CR3: 0000000077280000 CR4: 00000000003526f0
Call Trace:
<TASK>
arch_safe_halt arch/x86/include/asm/paravirt.h:107 [inline]
default_idle+0x13/0x20 arch/x86/kernel/process.c:767
default_idle_call+0x73/0xb0 kernel/sched/idle.c:122
cpuidle_idle_call kernel/sched/idle.c:191 [inline]
do_idle+0x1ea/0x520 kernel/sched/idle.c:332
cpu_startup_entry+0x44/0x60 kernel/sched/idle.c:430
rest_init+0x2de/0x300 init/main.c:757
start_kernel+0x3a7/0x400 init/main.c:1206
x86_64_start_reservations+0x24/0x30 arch/x86/kernel/head64.c:310
x86_64_start_kernel+0x143/0x1c0 arch/x86/kernel/head64.c:291
common_startup_64+0x13e/0x147
</TASK>
---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzkaller@googlegroups.com.
syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
If the report is already addressed, let syzbot know by replying with:
#syz fix: exact-commit-title
If you want syzbot to run the reproducer, reply with:
#syz test: git://repo/address.git branch-or-commit-hash
If you attach or paste a git patch, syzbot will apply it before testing.
If you want to overwrite report's subsystems, reply with:
#syz set subsystems: new-subsystem
(See the list of subsystem names on the web dashboard)
If the report is a duplicate of another one, reply with:
#syz dup: exact-subject-of-another-report
If you want to undo deduplication, reply with:
#syz undup
^ permalink raw reply
* Re: [syzbot] [keyrings?] [lsm?] possible deadlock in keyring_clear (3)
From: syzbot @ 2025-12-21 19:47 UTC (permalink / raw)
To: dhowells, jarkko, jmorris, keyrings, linux-kernel,
linux-security-module, paul, serge, syzkaller-bugs
In-Reply-To: <68e54915.a00a0220.298cc0.0480.GAE@google.com>
syzbot has found a reproducer for the following issue on:
HEAD commit: 9094662f6707 Merge tag 'ata-6.19-rc2' of git://git.kernel...
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1022f77c580000
kernel config: https://syzkaller.appspot.com/x/.config?x=513255d80ab78f2b
dashboard link: https://syzkaller.appspot.com/bug?extid=f55b043dacf43776b50c
compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=168a8b1a580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=16c06b1a580000
Downloadable assets:
disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/d900f083ada3/non_bootable_disk-9094662f.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/baa55f8cf722/vmlinux-9094662f.xz
kernel image: https://storage.googleapis.com/syzbot-assets/aaaa8a404a70/bzImage-9094662f.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/7a86e58a207c/mount_2.gz
fsck result: OK (log: https://syzkaller.appspot.com/x/fsck.log?x=12c06b1a580000)
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+f55b043dacf43776b50c@syzkaller.appspotmail.com
======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Not tainted
------------------------------------------------------
kswapd1/79 is trying to acquire lock:
ffff8880433bfcd8 (&type->lock_class){+.+.}-{4:4}, at: keyring_clear+0xaf/0x240 security/keys/keyring.c:1658
but task is already holding lock:
ffffffff8e051820 (fs_reclaim){+.+.}-{0:0}, at: balance_pgdat mm/vmscan.c:6975 [inline]
ffffffff8e051820 (fs_reclaim){+.+.}-{0:0}, at: kswapd+0x92a/0x2820 mm/vmscan.c:7354
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #1 (fs_reclaim){+.+.}-{0:0}:
__fs_reclaim_acquire mm/page_alloc.c:4301 [inline]
fs_reclaim_acquire+0x72/0x100 mm/page_alloc.c:4315
might_alloc include/linux/sched/mm.h:317 [inline]
slab_pre_alloc_hook mm/slub.c:4904 [inline]
slab_alloc_node mm/slub.c:5239 [inline]
__kmalloc_cache_noprof+0x40/0x700 mm/slub.c:5771
kmalloc_noprof include/linux/slab.h:957 [inline]
kzalloc_noprof include/linux/slab.h:1094 [inline]
assoc_array_insert+0x92/0x2f90 lib/assoc_array.c:980
__key_link_begin+0xd6/0x1f0 security/keys/keyring.c:1317
__key_create_or_update+0x41a/0xa30 security/keys/key.c:877
key_create_or_update+0x42/0x60 security/keys/key.c:1021
x509_load_certificate_list+0x145/0x280 crypto/asymmetric_keys/x509_loader.c:31
do_one_initcall+0x1f1/0x800 init/main.c:1378
do_initcall_level+0x104/0x190 init/main.c:1440
do_initcalls+0x59/0xa0 init/main.c:1456
kernel_init_freeable+0x2a7/0x3d0 init/main.c:1688
kernel_init+0x1d/0x1d0 init/main.c:1578
ret_from_fork+0x510/0xa50 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
-> #0 (&type->lock_class){+.+.}-{4:4}:
check_prev_add kernel/locking/lockdep.c:3165 [inline]
check_prevs_add kernel/locking/lockdep.c:3284 [inline]
validate_chain kernel/locking/lockdep.c:3908 [inline]
__lock_acquire+0x15a6/0x2cf0 kernel/locking/lockdep.c:5237
lock_acquire+0x107/0x340 kernel/locking/lockdep.c:5868
down_write+0x96/0x1f0 kernel/locking/rwsem.c:1590
keyring_clear+0xaf/0x240 security/keys/keyring.c:1658
fscrypt_put_master_key+0xca/0x190 fs/crypto/keyring.c:80
put_crypt_info+0x26d/0x310 fs/crypto/keysetup.c:573
fscrypt_put_encryption_info+0xf6/0x140 fs/crypto/keysetup.c:787
ext4_clear_inode+0x170/0x2f0 fs/ext4/super.c:1529
ext4_evict_inode+0x9f6/0xe60 fs/ext4/inode.c:320
evict+0x5f4/0xae0 fs/inode.c:837
__dentry_kill+0x209/0x660 fs/dcache.c:670
shrink_kill+0xa9/0x2c0 fs/dcache.c:1137
shrink_dentry_list+0x2e0/0x5e0 fs/dcache.c:1164
prune_dcache_sb+0x10e/0x180 fs/dcache.c:1246
super_cache_scan+0x369/0x4b0 fs/super.c:222
do_shrink_slab+0x6df/0x10d0 mm/shrinker.c:437
shrink_slab_memcg mm/shrinker.c:550 [inline]
shrink_slab+0x7ef/0x10d0 mm/shrinker.c:628
shrink_one+0x2d9/0x720 mm/vmscan.c:4921
shrink_many mm/vmscan.c:4982 [inline]
lru_gen_shrink_node mm/vmscan.c:5060 [inline]
shrink_node+0x2f7d/0x35b0 mm/vmscan.c:6047
kswapd_shrink_node mm/vmscan.c:6901 [inline]
balance_pgdat mm/vmscan.c:7084 [inline]
kswapd+0x145a/0x2820 mm/vmscan.c:7354
kthread+0x711/0x8a0 kernel/kthread.c:463
ret_from_fork+0x510/0xa50 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
other info that might help us debug this:
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(fs_reclaim);
lock(&type->lock_class);
lock(fs_reclaim);
lock(&type->lock_class);
*** DEADLOCK ***
2 locks held by kswapd1/79:
#0: ffffffff8e051820 (fs_reclaim){+.+.}-{0:0}, at: balance_pgdat mm/vmscan.c:6975 [inline]
#0: ffffffff8e051820 (fs_reclaim){+.+.}-{0:0}, at: kswapd+0x92a/0x2820 mm/vmscan.c:7354
#1: ffff88803fa5a0e0 (&type->s_umount_key#32){++++}-{4:4}, at: super_trylock_shared fs/super.c:563 [inline]
#1: ffff88803fa5a0e0 (&type->s_umount_key#32){++++}-{4:4}, at: super_cache_scan+0x91/0x4b0 fs/super.c:197
stack backtrace:
CPU: 0 UID: 0 PID: 79 Comm: kswapd1 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
Call Trace:
<TASK>
dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
print_circular_bug+0x2e2/0x300 kernel/locking/lockdep.c:2043
check_noncircular+0x12e/0x150 kernel/locking/lockdep.c:2175
check_prev_add kernel/locking/lockdep.c:3165 [inline]
check_prevs_add kernel/locking/lockdep.c:3284 [inline]
validate_chain kernel/locking/lockdep.c:3908 [inline]
__lock_acquire+0x15a6/0x2cf0 kernel/locking/lockdep.c:5237
lock_acquire+0x107/0x340 kernel/locking/lockdep.c:5868
down_write+0x96/0x1f0 kernel/locking/rwsem.c:1590
keyring_clear+0xaf/0x240 security/keys/keyring.c:1658
fscrypt_put_master_key+0xca/0x190 fs/crypto/keyring.c:80
put_crypt_info+0x26d/0x310 fs/crypto/keysetup.c:573
fscrypt_put_encryption_info+0xf6/0x140 fs/crypto/keysetup.c:787
ext4_clear_inode+0x170/0x2f0 fs/ext4/super.c:1529
ext4_evict_inode+0x9f6/0xe60 fs/ext4/inode.c:320
evict+0x5f4/0xae0 fs/inode.c:837
__dentry_kill+0x209/0x660 fs/dcache.c:670
shrink_kill+0xa9/0x2c0 fs/dcache.c:1137
shrink_dentry_list+0x2e0/0x5e0 fs/dcache.c:1164
prune_dcache_sb+0x10e/0x180 fs/dcache.c:1246
super_cache_scan+0x369/0x4b0 fs/super.c:222
do_shrink_slab+0x6df/0x10d0 mm/shrinker.c:437
shrink_slab_memcg mm/shrinker.c:550 [inline]
shrink_slab+0x7ef/0x10d0 mm/shrinker.c:628
shrink_one+0x2d9/0x720 mm/vmscan.c:4921
shrink_many mm/vmscan.c:4982 [inline]
lru_gen_shrink_node mm/vmscan.c:5060 [inline]
shrink_node+0x2f7d/0x35b0 mm/vmscan.c:6047
kswapd_shrink_node mm/vmscan.c:6901 [inline]
balance_pgdat mm/vmscan.c:7084 [inline]
kswapd+0x145a/0x2820 mm/vmscan.c:7354
kthread+0x711/0x8a0 kernel/kthread.c:463
ret_from_fork+0x510/0xa50 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
</TASK>
---
If you want syzbot to run the reproducer, reply with:
#syz test: git://repo/address.git branch-or-commit-hash
If you attach or paste a git patch, syzbot will apply it before testing.
^ permalink raw reply
* [PATCH v6 6/6] landlock: Add documentation for LANDLOCK_ADD_RULE_NO_INHERIT
From: Justin Suess @ 2025-12-21 19:43 UTC (permalink / raw)
To: Mickaël Salaün
Cc: Tingmao Wang, Günther Noack, Justin Suess, Jan Kara,
Abhinav Saxena, linux-security-module
In-Reply-To: <20251221194301.247484-1-utilityemal77@gmail.com>
Adds documentation of the flag to the userspace api, describing
the functionality of the flag and parent directory protections.
Signed-off-by: Justin Suess <utilityemal77@gmail.com>
---
Notes:
v5..v6 changes:
* None
v1..v5 changes:
* Initial addition
Documentation/userspace-api/landlock.rst | 17 +++++++++++++++++
1 file changed, 17 insertions(+)
diff --git a/Documentation/userspace-api/landlock.rst b/Documentation/userspace-api/landlock.rst
index 1d0c2c15c22e..3671cd90fbe2 100644
--- a/Documentation/userspace-api/landlock.rst
+++ b/Documentation/userspace-api/landlock.rst
@@ -604,6 +604,23 @@ Landlock audit events with the ``LANDLOCK_RESTRICT_SELF_LOG_SAME_EXEC_OFF``,
sys_landlock_restrict_self(). See Documentation/admin-guide/LSM/landlock.rst
for more details on audit.
+Filesystem inheritance suppression (ABI < 8)
+-----------------
+
+Starting with the Landlock ABI version 8, it is possible to prevent a directory
+or file from inheriting it's parent's access grants by using the
+``LANDLOCK_ADD_RULE_NO_INHERIT`` flag passed to sys_landlock_add_rule(). This
+can be useful for policies where a parent directory needs broader access than its
+children.
+
+To mitigate sandbox-restart attacks, the inode itself, and ancestors of inodes
+tagged with ``LANDLOCK_ADD_RULE_NO_INHERIT`` cannot be removed, renamed,
+reparented, or linked into/from other directories.
+
+These parent directory protections propagate up to the root. Further inheritance
+for grants originating beneath a ``LANDLOCK_ADD_RULE_NO_INHERIT`` tagged inode
+are not affected unless also tagged with this flag.
+
.. _kernel_support:
Kernel support
--
2.51.0
^ permalink raw reply related
* [PATCH v6 5/6] landlock: Implement KUnit test for LANDLOCK_ADD_RULE_NO_INHERIT
From: Justin Suess @ 2025-12-21 19:43 UTC (permalink / raw)
To: Mickaël Salaün
Cc: Tingmao Wang, Günther Noack, Justin Suess, Jan Kara,
Abhinav Saxena, linux-security-module
In-Reply-To: <20251221194301.247484-1-utilityemal77@gmail.com>
Add a unit test for rule_flag collection, ensuring that access masks
are properly propagated with the flags.
Signed-off-by: Justin Suess <utilityemal77@gmail.com>
---
Notes:
v4..v6 changes:
* None
v2..v3 changes:
* Removing erroneously misplaced code and placed in the proper
patch.
security/landlock/ruleset.c | 89 +++++++++++++++++++++++++++++++++++++
1 file changed, 89 insertions(+)
diff --git a/security/landlock/ruleset.c b/security/landlock/ruleset.c
index adc965de8e4e..5855d8617ab3 100644
--- a/security/landlock/ruleset.c
+++ b/security/landlock/ruleset.c
@@ -22,6 +22,7 @@
#include <linux/spinlock.h>
#include <linux/workqueue.h>
#include <uapi/linux/landlock.h>
+#include <kunit/test.h>
#include "access.h"
#include "domain.h"
@@ -769,3 +770,91 @@ landlock_init_layer_masks(const struct landlock_ruleset *const domain,
}
return handled_accesses;
}
+
+#ifdef CONFIG_SECURITY_LANDLOCK_KUNIT_TEST
+
+/**
+ * test_unmask_layers_no_inherit - Test landlock_unmask_layers() with no_inherit
+ * @test: The KUnit test context.
+ */
+static void test_unmask_layers_no_inherit(struct kunit *const test)
+{
+ struct landlock_rule *rule;
+ layer_mask_t layer_masks[LANDLOCK_NUM_ACCESS_FS];
+ struct collected_rule_flags rule_flags;
+ const access_mask_t access_request = BIT_ULL(0) | BIT_ULL(1);
+ const layer_mask_t layers_initialized = BIT_ULL(0) | BIT_ULL(1);
+ size_t i;
+
+ rule = kzalloc(struct_size(rule, layers, 2), GFP_KERNEL);
+ KUNIT_ASSERT_NOT_NULL(test, rule);
+
+ rule->num_layers = 2;
+
+ /* Layer 1: allows access 0, no_inherit */
+ rule->layers[0].level = 1;
+ rule->layers[0].access = BIT_ULL(0);
+ rule->layers[0].flags.no_inherit = 1;
+
+ /* Layer 2: allows access 1 */
+ rule->layers[1].level = 2;
+ rule->layers[1].access = BIT_ULL(1);
+
+ /* Case 1: No rule_flags provided (should behave normally) */
+ for (i = 0; i < ARRAY_SIZE(layer_masks); i++)
+ layer_masks[i] = layers_initialized;
+
+ landlock_unmask_layers(rule, access_request, &layer_masks,
+ ARRAY_SIZE(layer_masks), NULL);
+
+ /* Access 0 should be unmasked by layer 1 */
+ KUNIT_EXPECT_EQ(test, layer_masks[0], layers_initialized & ~BIT_ULL(0));
+ /* Access 1 should be unmasked by layer 2 */
+ KUNIT_EXPECT_EQ(test, layer_masks[1], layers_initialized & ~BIT_ULL(1));
+
+ /* Case 2: rule_flags provided, no existing no_inherit_masks */
+ for (i = 0; i < ARRAY_SIZE(layer_masks); i++)
+ layer_masks[i] = layers_initialized;
+ memset(&rule_flags, 0, sizeof(rule_flags));
+
+ landlock_unmask_layers(rule, access_request, &layer_masks,
+ ARRAY_SIZE(layer_masks), &rule_flags);
+
+ /* Access 0 should be unmasked by layer 1 */
+ KUNIT_EXPECT_EQ(test, layer_masks[0], layers_initialized & ~BIT_ULL(0));
+ /* Access 1 should be unmasked by layer 2 */
+ KUNIT_EXPECT_EQ(test, layer_masks[1], layers_initialized & ~BIT_ULL(1));
+
+ /* rule_flags should collect no_inherit from layer 1 */
+ KUNIT_EXPECT_EQ(test, rule_flags.no_inherit_masks, (layer_mask_t)BIT_ULL(0));
+
+ /* Case 3: rule_flags provided, layer 1 is masked by no_inherit_masks */
+ for (i = 0; i < ARRAY_SIZE(layer_masks); i++)
+ layer_masks[i] = layers_initialized;
+ memset(&rule_flags, 0, sizeof(rule_flags));
+ rule_flags.no_inherit_masks = BIT_ULL(0); /* Mask layer 1 */
+
+ landlock_unmask_layers(rule, access_request, &layer_masks,
+ ARRAY_SIZE(layer_masks), &rule_flags);
+
+ /* Access 0 should NOT be unmasked by layer 1 because it is skipped */
+ KUNIT_EXPECT_EQ(test, layer_masks[0], layers_initialized);
+ /* Access 1 should be unmasked by layer 2 */
+ KUNIT_EXPECT_EQ(test, layer_masks[1], layers_initialized & ~BIT_ULL(1));
+
+ kfree(rule);
+}
+
+static struct kunit_case ruleset_test_cases[] = {
+ KUNIT_CASE(test_unmask_layers_no_inherit),
+ {}
+};
+
+static struct kunit_suite ruleset_test_suite = {
+ .name = "landlock_ruleset",
+ .test_cases = ruleset_test_cases,
+};
+
+kunit_test_suite(ruleset_test_suite);
+
+#endif /* CONFIG_SECURITY_LANDLOCK_KUNIT_TEST */
--
2.51.0
^ permalink raw reply related
* [PATCH v6 4/6] selftests/landlock: Implement selftests for LANDLOCK_ADD_RULE_NO_INHERIT
From: Justin Suess @ 2025-12-21 19:42 UTC (permalink / raw)
To: Mickaël Salaün
Cc: Tingmao Wang, Günther Noack, Justin Suess, Jan Kara,
Abhinav Saxena, linux-security-module
In-Reply-To: <20251221194301.247484-1-utilityemal77@gmail.com>
Implements 15 selftests for the flag, covering allowed and disallowed
operations on parent and child directories when this flag is set, as
well as multi-layer configurations and flag inheritance / audit
logging. Also tests a bind mount configuration.
Signed-off-by: Justin Suess <utilityemal77@gmail.com>
---
Notes:
v5..v6 changes:
* Remove redundant tree diagram from comment
v4..v5 changes:
* Fixed a bug in a test applying invalid access rights
to a file.
v3..v4 changes:
* Added 4 new tests for bind mount handling, increasing selftests
from 11 -> 15.
v2..v3 changes:
* Also covers flag inheritance, audit logging and
LANDLOCK_ADD_RULE_QUIET suppression.
* Increases number of selftests from 5 -> 11.
tools/testing/selftests/landlock/fs_test.c | 704 +++++++++++++++++++++
1 file changed, 704 insertions(+)
diff --git a/tools/testing/selftests/landlock/fs_test.c b/tools/testing/selftests/landlock/fs_test.c
index 71433fa34e9d..37d4feb016b6 100644
--- a/tools/testing/selftests/landlock/fs_test.c
+++ b/tools/testing/selftests/landlock/fs_test.c
@@ -1484,6 +1484,111 @@ TEST_F_FORK(layout1, inherit_superset)
ASSERT_EQ(0, test_open(file1_s1d3, O_RDONLY));
}
+TEST_F_FORK(layout1, inherit_no_inherit_flag)
+{
+ struct landlock_ruleset_attr ruleset_attr = {
+ .handled_access_fs = ACCESS_RW,
+ };
+ int ruleset_fd;
+
+ ruleset_fd =
+ landlock_create_ruleset(&ruleset_attr, sizeof(ruleset_attr), 0);
+ ASSERT_LE(0, ruleset_fd);
+
+ add_path_beneath(_metadata, ruleset_fd, ACCESS_RW, dir_s1d1, 0);
+ add_path_beneath(_metadata, ruleset_fd, ACCESS_RO, dir_s1d2,
+ LANDLOCK_ADD_RULE_NO_INHERIT);
+
+ enforce_ruleset(_metadata, ruleset_fd);
+ ASSERT_EQ(0, close(ruleset_fd));
+
+ /* Parent directory still grants write access to its direct children. */
+ EXPECT_EQ(0, test_open(dir_s1d1, O_RDONLY | O_DIRECTORY));
+ EXPECT_EQ(0, test_open(file1_s1d1, O_WRONLY));
+
+ /* dir_s1d2 gets only its explicit read-only access rights. */
+ EXPECT_EQ(0, test_open(dir_s1d2, O_RDONLY | O_DIRECTORY));
+ EXPECT_EQ(0, test_open(file1_s1d2, O_RDONLY));
+ EXPECT_EQ(EACCES, test_open(file1_s1d2, O_WRONLY));
+
+ /* Descendants of dir_s1d2 inherit the reduced access mask. */
+ EXPECT_EQ(0, test_open(dir_s1d3, O_RDONLY | O_DIRECTORY));
+ EXPECT_EQ(0, test_open(file1_s1d3, O_RDONLY));
+ EXPECT_EQ(EACCES, test_open(file1_s1d3, O_WRONLY));
+}
+
+TEST_F_FORK(layout1, inherit_no_inherit_nested_levels)
+{
+ int ruleset_fd;
+ struct landlock_ruleset_attr ruleset_attr = {
+ .handled_access_fs = ACCESS_RW | LANDLOCK_ACCESS_FS_REFER |
+ LANDLOCK_ACCESS_FS_REMOVE_FILE |
+ LANDLOCK_ACCESS_FS_REMOVE_DIR,
+ };
+
+ ruleset_fd =
+ landlock_create_ruleset(&ruleset_attr, sizeof(ruleset_attr), 0);
+ ASSERT_LE(0, ruleset_fd);
+
+ /* Level 1: s1d1 (RW + REFER + REMOVE + NO_INHERIT) */
+ add_path_beneath(_metadata, ruleset_fd,
+ ACCESS_RW | LANDLOCK_ACCESS_FS_REFER |
+ LANDLOCK_ACCESS_FS_REMOVE_FILE |
+ LANDLOCK_ACCESS_FS_REMOVE_DIR,
+ dir_s1d1, LANDLOCK_ADD_RULE_NO_INHERIT);
+
+ /* Level 2: s1d2 (RO + NO_INHERIT) */
+ add_path_beneath(_metadata, ruleset_fd, ACCESS_RO, dir_s1d2,
+ LANDLOCK_ADD_RULE_NO_INHERIT);
+
+ /* Level 3: s1d3 (RW + REFER + REMOVE + NO_INHERIT) */
+ add_path_beneath(_metadata, ruleset_fd,
+ ACCESS_RW | LANDLOCK_ACCESS_FS_REFER |
+ LANDLOCK_ACCESS_FS_REMOVE_FILE |
+ LANDLOCK_ACCESS_FS_REMOVE_DIR,
+ dir_s1d3, LANDLOCK_ADD_RULE_NO_INHERIT);
+
+ enforce_ruleset(_metadata, ruleset_fd);
+ ASSERT_EQ(0, close(ruleset_fd));
+
+ /*
+ * Level 3: s1d3
+ * - RW allowed (unlink file)
+ * - REFER allowed (rename file)
+ * - REMOVE_DIR denied (parent s1d2 is part of direct parent tree)
+ */
+ ASSERT_EQ(0, unlink(file1_s1d3));
+ ASSERT_EQ(0, rename(file2_s1d3, file1_s1d3));
+ ASSERT_EQ(0, rename(file1_s1d3, file2_s1d3));
+ ASSERT_EQ(-1, rmdir(dir_s1d3));
+ ASSERT_EQ(EACCES, errno);
+
+ /*
+ * Level 2: s1d2
+ * - RW denied (unlink file), layer is RO
+ * - REFER denied (rename file)
+ * - REMOVE_DIR of s1d2 not allowed (parent s1d1 is part of direct parent tree)
+ */
+ ASSERT_EQ(-1, unlink(file1_s1d2));
+ ASSERT_EQ(EACCES, errno);
+ ASSERT_EQ(-1, rename(file2_s1d2, file1_s1d2));
+ ASSERT_EQ(EACCES, errno);
+ ASSERT_EQ(-1, rmdir(dir_s1d2));
+ ASSERT_EQ(EACCES, errno);
+
+ /*
+ * Level 1: s1d1
+ * - RW allowed
+ * - Rename allowed (except for direct parent tree s1d2)
+ * - REMOVE_DIR denied (parent tmp is denied)
+ */
+ ASSERT_EQ(0, unlink(file1_s1d1));
+ ASSERT_EQ(0, rename(file2_s1d1, file1_s1d1));
+ ASSERT_EQ(0, rename(file1_s1d1, file2_s1d1));
+ ASSERT_EQ(-1, rmdir(dir_s1d1));
+ ASSERT_EQ(EACCES, errno);
+}
+
TEST_F_FORK(layout0, max_layers)
{
int i, err;
@@ -4403,6 +4508,266 @@ TEST_F_FORK(layout1, named_unix_domain_socket_ioctl)
ASSERT_EQ(0, close(cli_fd));
}
+TEST_F_FORK(layout1, inherit_no_inherit_topology_dir)
+{
+ const struct rule rules[] = {
+ {
+ .path = TMP_DIR,
+ .access = ACCESS_RW | LANDLOCK_ACCESS_FS_REMOVE_FILE,
+ },
+ {},
+ };
+ int ruleset_fd;
+
+ ruleset_fd = create_ruleset(_metadata,
+ ACCESS_RW | LANDLOCK_ACCESS_FS_REMOVE_FILE,
+ rules);
+ ASSERT_LE(0, ruleset_fd);
+
+ /* Adds a no-inherit rule on a leaf directory. */
+ add_path_beneath(_metadata, ruleset_fd, ACCESS_RO, dir_s1d3,
+ LANDLOCK_ADD_RULE_NO_INHERIT);
+
+ enforce_ruleset(_metadata, ruleset_fd);
+ ASSERT_EQ(0, close(ruleset_fd));
+
+ /*
+ * Topology modifications of the rule path and its parents are denied.
+ */
+
+ /* Target directory s1d3 */
+ ASSERT_EQ(-1, rmdir(dir_s1d3));
+ ASSERT_EQ(EACCES, errno);
+ ASSERT_EQ(-1, rename(dir_s1d3, dir_s2d3));
+ ASSERT_EQ(EACCES, errno);
+
+ /* Parent directory s1d2 */
+ ASSERT_EQ(-1, rmdir(dir_s1d2));
+ ASSERT_EQ(EACCES, errno);
+ ASSERT_EQ(-1, rename(dir_s1d2, dir_s2d2));
+ ASSERT_EQ(EACCES, errno);
+
+ /* Grandparent directory s1d1 */
+ ASSERT_EQ(-1, rmdir(dir_s1d1));
+ ASSERT_EQ(EACCES, errno);
+ ASSERT_EQ(-1, rename(dir_s1d1, dir_s2d1));
+ ASSERT_EQ(EACCES, errno);
+
+ /*
+ * Sibling operations are allowed.
+ */
+ /* Sibling of s1d3 */
+ ASSERT_EQ(0, unlink(file1_s1d2));
+ /* Sibling of s1d2 */
+ ASSERT_EQ(0, unlink(file1_s1d1));
+
+ /*
+ * Content of the no-inherit directory is restricted by the rule (RO).
+ */
+ ASSERT_EQ(-1, unlink(file1_s1d3));
+ ASSERT_EQ(EACCES, errno);
+}
+
+TEST_F_FORK(layout1, no_inherit_allow_inner_removal)
+{
+ int ruleset_fd;
+ struct landlock_ruleset_attr ruleset_attr = {
+ .handled_access_fs = ACCESS_RW | LANDLOCK_ACCESS_FS_REMOVE_FILE,
+ };
+
+ ruleset_fd =
+ landlock_create_ruleset(&ruleset_attr, sizeof(ruleset_attr), 0);
+ ASSERT_LE(0, ruleset_fd);
+
+ add_path_beneath(_metadata, ruleset_fd,
+ ACCESS_RW | LANDLOCK_ACCESS_FS_REMOVE_FILE, dir_s1d2,
+ LANDLOCK_ADD_RULE_NO_INHERIT);
+
+ enforce_ruleset(_metadata, ruleset_fd);
+ ASSERT_EQ(0, close(ruleset_fd));
+
+ /*
+ * Content of the no-inherit directory is mutable (RW).
+ * This checks that the no-inherit flag does not seal the content.
+ */
+ ASSERT_EQ(0, unlink(file1_s1d2));
+
+ /*
+ * Topology modifications of the rule path are denied.
+ */
+ ASSERT_EQ(-1, rmdir(dir_s1d2));
+ ASSERT_EQ(EACCES, errno);
+ ASSERT_EQ(-1, rename(dir_s1d2, dir_s2d2));
+ ASSERT_EQ(EACCES, errno);
+}
+
+TEST_F_FORK(layout1, inherit_no_inherit_topology_unrelated)
+{
+ const struct rule rules[] = {
+ {
+ .path = TMP_DIR,
+ .access = ACCESS_RW,
+ },
+ {},
+ };
+ static const char unrelated_dir[] = TMP_DIR "/s2d1/unrelated";
+ static const char unrelated_file[] = TMP_DIR "/s2d1/unrelated/f1";
+ int ruleset_fd;
+
+ ruleset_fd = create_ruleset(_metadata, ACCESS_RW, rules);
+ ASSERT_LE(0, ruleset_fd);
+
+ /* Adds a no-inherit rule on a leaf directory unrelated to s2. */
+ add_path_beneath(_metadata, ruleset_fd, ACCESS_RO, dir_s1d3,
+ LANDLOCK_ADD_RULE_NO_INHERIT);
+
+ enforce_ruleset(_metadata, ruleset_fd);
+ ASSERT_EQ(0, close(ruleset_fd));
+
+ /* Ensure we can still create and delete files outside the sealed branch. */
+ ASSERT_EQ(0, mkdir(unrelated_dir, 0700));
+ ASSERT_EQ(0, mknod(unrelated_file, S_IFREG | 0600, 0));
+ ASSERT_EQ(0, unlink(unrelated_file));
+ ASSERT_EQ(0, rmdir(unrelated_dir));
+
+ /* Existing siblings in s2 remain modifiable. */
+ ASSERT_EQ(0, unlink(file1_s2d1));
+ ASSERT_EQ(0, mknod(file1_s2d1, S_IFREG | 0700, 0));
+}
+
+TEST_F_FORK(layout1, inherit_no_inherit_descendant_rw)
+{
+ const struct rule rules[] = {
+ {
+ .path = TMP_DIR,
+ .access = ACCESS_RO,
+ },
+ {},
+ };
+ const __u64 handled_access = ACCESS_RW | LANDLOCK_ACCESS_FS_MAKE_REG |
+ LANDLOCK_ACCESS_FS_REMOVE_FILE;
+ static const char child_file[] =
+ TMP_DIR "/s1d1/s1d2/s1d3/rw_descendant";
+ int ruleset_fd;
+
+ ruleset_fd = create_ruleset(_metadata, handled_access, rules);
+ ASSERT_LE(0, ruleset_fd);
+
+ add_path_beneath(_metadata, ruleset_fd, ACCESS_RO, dir_s1d2,
+ LANDLOCK_ADD_RULE_NO_INHERIT);
+ add_path_beneath(_metadata, ruleset_fd,
+ ACCESS_RW | LANDLOCK_ACCESS_FS_MAKE_REG |
+ LANDLOCK_ACCESS_FS_REMOVE_FILE,
+ dir_s1d3, 0);
+
+ enforce_ruleset(_metadata, ruleset_fd);
+ ASSERT_EQ(0, close(ruleset_fd));
+
+ ASSERT_EQ(0, mknod(child_file, S_IFREG | 0600, 0));
+ ASSERT_EQ(0, unlink(child_file));
+}
+
+TEST_F_FORK(layout1, inherit_no_inherit_topology_file)
+{
+ const struct rule rules[] = {
+ {
+ .path = TMP_DIR,
+ .access = ACCESS_RW,
+ },
+ {},
+ };
+ int ruleset_fd;
+
+ /*
+ * Both file1_s1d2 and file2_s1d2 already exist from the fixture.
+ * file2_s1d2 is in the same directory as file1_s1d2 and will be
+ * used to test inheritance vs. NO_INHERIT behavior.
+ */
+
+ ruleset_fd = create_ruleset(_metadata, ACCESS_RW, rules);
+ ASSERT_LE(0, ruleset_fd);
+
+ /*
+ * Add a NO_INHERIT rule on file1_s1d2 with READ_FILE access.
+ * This should succeed (files can have NO_INHERIT).
+ * Use READ_FILE (not ACCESS_RO which includes READ_DIR) since
+ * directory access rights don't make sense for files.
+ */
+ add_path_beneath(_metadata, ruleset_fd, LANDLOCK_ACCESS_FS_READ_FILE,
+ file1_s1d2, LANDLOCK_ADD_RULE_NO_INHERIT);
+
+ enforce_ruleset(_metadata, ruleset_fd);
+ ASSERT_EQ(0, close(ruleset_fd));
+
+ /*
+ * file1_s1d2 has NO_INHERIT with READ_FILE access only,
+ * so it should only be readable (not inheriting RW from parent TMP_DIR).
+ */
+ ASSERT_EQ(0, test_open(file1_s1d2, O_RDONLY));
+ ASSERT_EQ(EACCES, test_open(file1_s1d2, O_WRONLY));
+
+ /*
+ * file2_s1d2 does not have NO_INHERIT, so it should inherit
+ * RW access from parent TMP_DIR rule.
+ */
+ ASSERT_EQ(0, test_open(file2_s1d2, O_RDONLY));
+ ASSERT_EQ(0, test_open(file2_s1d2, O_WRONLY));
+}
+
+TEST_F_FORK(layout1, inherit_no_inherit_layered)
+{
+ const struct rule layer1_and_2[] = {
+ {
+ .path = TMP_DIR,
+ .access = ACCESS_RW | LANDLOCK_ACCESS_FS_REMOVE_FILE,
+ },
+ {},
+ };
+ int ruleset_fd;
+ static const char unrelated_dir[] = TMP_DIR "/s2d1/unrelated";
+ static const char unrelated_file[] = TMP_DIR "/s2d1/unrelated/f1";
+
+ /* Layer 1: RW on TMP_DIR */
+ ruleset_fd = create_ruleset(_metadata,
+ ACCESS_RW | LANDLOCK_ACCESS_FS_REMOVE_FILE,
+ layer1_and_2);
+ ASSERT_LE(0, ruleset_fd);
+ enforce_ruleset(_metadata, ruleset_fd);
+ ASSERT_EQ(0, close(ruleset_fd));
+
+ /* Layer 2: Add no-inherit RO rule on s1d2 */
+ ruleset_fd = create_ruleset(_metadata,
+ ACCESS_RW | LANDLOCK_ACCESS_FS_REMOVE_FILE,
+ layer1_and_2);
+ ASSERT_LE(0, ruleset_fd);
+ add_path_beneath(_metadata, ruleset_fd, ACCESS_RO, dir_s1d2,
+ LANDLOCK_ADD_RULE_NO_INHERIT);
+ enforce_ruleset(_metadata, ruleset_fd);
+ ASSERT_EQ(0, close(ruleset_fd));
+
+ /* Operations in unrelated areas should still work */
+ ASSERT_EQ(0, mkdir(unrelated_dir, 0700));
+ ASSERT_EQ(0, mknod(unrelated_file, S_IFREG | 0600, 0));
+ ASSERT_EQ(0, unlink(unrelated_file));
+ ASSERT_EQ(0, rmdir(unrelated_dir));
+
+ /* Creating in s1d1 should be allowed (parent still has RW) */
+ ASSERT_EQ(0, mknod(TMP_DIR "/s1d1/newfile", S_IFREG | 0600, 0));
+ ASSERT_EQ(0, unlink(TMP_DIR "/s1d1/newfile"));
+
+ /* Content of s1d2 should be read-only */
+ ASSERT_EQ(-1, unlink(file1_s1d2));
+ ASSERT_EQ(EACCES, errno);
+
+ /* Topology changes to s1d2 should be denied */
+ ASSERT_EQ(-1, rename(dir_s1d2, TMP_DIR "/s2d1/renamed"));
+ ASSERT_EQ(EACCES, errno);
+
+ /* Renaming s1d1 should also be denied (it's an ancestor) */
+ ASSERT_EQ(-1, rename(dir_s1d1, TMP_DIR "/s2d1/renamed"));
+ ASSERT_EQ(EACCES, errno);
+}
+
/* clang-format off */
FIXTURE(ioctl) {};
@@ -5742,6 +6107,251 @@ TEST_F_FORK(layout4_disconnected_leafs, read_rename_exchange)
test_renameat(s1d42_bind_fd, "f4", s1d42_bind_fd, "f5"));
}
+/*
+ * When s1d41 (accessed via the mount at s2d2) is protected with NO_INHERIT,
+ * its parent directories within the mount (s1d31) should be immovable.
+ */
+TEST_F_FORK(layout4_disconnected_leafs, no_inherit_mount_parent_rename)
+{
+ int ruleset_fd, s1d41_bind_fd;
+ struct landlock_ruleset_attr ruleset_attr = {
+ .handled_access_fs = ACCESS_RW | LANDLOCK_ACCESS_FS_REFER |
+ LANDLOCK_ACCESS_FS_REMOVE_FILE |
+ LANDLOCK_ACCESS_FS_REMOVE_DIR,
+ };
+
+ ruleset_fd =
+ landlock_create_ruleset(&ruleset_attr, sizeof(ruleset_attr), 0);
+ ASSERT_LE(0, ruleset_fd);
+
+ /* Allow full access to TMP_DIR. */
+ add_path_beneath(_metadata, ruleset_fd,
+ ACCESS_RW | LANDLOCK_ACCESS_FS_REFER |
+ LANDLOCK_ACCESS_FS_REMOVE_FILE |
+ LANDLOCK_ACCESS_FS_REMOVE_DIR,
+ TMP_DIR, 0);
+
+ /*
+ * Access s1d41 through the bind mount at s2d2 and protect it with
+ * NO_INHERIT. This should seal the parent hierarchy through the mount.
+ */
+ s1d41_bind_fd = open(TMP_DIR "/s2d1/s2d2/s1d31/s1d41",
+ O_DIRECTORY | O_PATH | O_CLOEXEC);
+ ASSERT_LE(0, s1d41_bind_fd);
+
+ ASSERT_EQ(0, landlock_add_rule(ruleset_fd, LANDLOCK_RULE_PATH_BENEATH,
+ &(struct landlock_path_beneath_attr){
+ .parent_fd = s1d41_bind_fd,
+ .allowed_access = ACCESS_RO,
+ },
+ LANDLOCK_ADD_RULE_NO_INHERIT));
+ EXPECT_EQ(0, close(s1d41_bind_fd));
+
+ enforce_ruleset(_metadata, ruleset_fd);
+ ASSERT_EQ(0, close(ruleset_fd));
+
+ /*
+ * s1d31 is the parent of s1d41 within the mount. Renaming it should
+ * be denied because it is part of the protected parent hierarchy.
+ * Test via the mount path.
+ */
+ ASSERT_EQ(-1, rename(TMP_DIR "/s2d1/s2d2/s1d31",
+ TMP_DIR "/s2d1/s2d2/s1d31_renamed"));
+ ASSERT_EQ(EACCES, errno);
+
+ /*
+ * s1d32 is a sibling directory (not in the protected parent chain),
+ * so renaming it should be allowed.
+ */
+ ASSERT_EQ(0, rename(TMP_DIR "/s2d1/s2d2/s1d32",
+ TMP_DIR "/s2d1/s2d2/s1d32_renamed"));
+ ASSERT_EQ(0, rename(TMP_DIR "/s2d1/s2d2/s1d32_renamed",
+ TMP_DIR "/s2d1/s2d2/s1d32"));
+
+ /*
+ * Renaming directories not in the protected parent hierarchy should
+ * still be allowed.
+ */
+ ASSERT_EQ(0, rename(TMP_DIR "/s3d1", TMP_DIR "/s3d1_renamed"));
+ ASSERT_EQ(0, rename(TMP_DIR "/s3d1_renamed", TMP_DIR "/s3d1"));
+}
+
+TEST_F_FORK(layout4_disconnected_leafs, no_inherit_mount_parent_rmdir)
+{
+ int ruleset_fd, s1d41_bind_fd;
+ struct landlock_ruleset_attr ruleset_attr = {
+ .handled_access_fs = ACCESS_RW | LANDLOCK_ACCESS_FS_REFER |
+ LANDLOCK_ACCESS_FS_REMOVE_FILE |
+ LANDLOCK_ACCESS_FS_REMOVE_DIR,
+ };
+
+ ruleset_fd =
+ landlock_create_ruleset(&ruleset_attr, sizeof(ruleset_attr), 0);
+ ASSERT_LE(0, ruleset_fd);
+
+ /* Allow full access to TMP_DIR. */
+ add_path_beneath(_metadata, ruleset_fd,
+ ACCESS_RW | LANDLOCK_ACCESS_FS_REFER |
+ LANDLOCK_ACCESS_FS_REMOVE_FILE |
+ LANDLOCK_ACCESS_FS_REMOVE_DIR,
+ TMP_DIR, 0);
+
+ /*
+ * Access s1d41 through the bind mount at s2d2 and protect it with
+ * NO_INHERIT. This should seal the parent hierarchy through the mount.
+ */
+ s1d41_bind_fd = open(TMP_DIR "/s2d1/s2d2/s1d31/s1d41",
+ O_DIRECTORY | O_PATH | O_CLOEXEC);
+ ASSERT_LE(0, s1d41_bind_fd);
+
+ ASSERT_EQ(0, landlock_add_rule(ruleset_fd, LANDLOCK_RULE_PATH_BENEATH,
+ &(struct landlock_path_beneath_attr){
+ .parent_fd = s1d41_bind_fd,
+ .allowed_access = ACCESS_RO,
+ },
+ LANDLOCK_ADD_RULE_NO_INHERIT));
+ EXPECT_EQ(0, close(s1d41_bind_fd));
+
+ enforce_ruleset(_metadata, ruleset_fd);
+ ASSERT_EQ(0, close(ruleset_fd));
+
+ /*
+ * s1d31 is the parent of s1d41 within the mount. Removing it should
+ * be denied because it is part of the protected parent hierarchy.
+ */
+ ASSERT_EQ(-1, rmdir(TMP_DIR "/s2d1/s2d2/s1d31"));
+ ASSERT_EQ(EACCES, errno);
+
+ /*
+ * Removing an unrelated directory should still be allowed (if empty).
+ */
+ ASSERT_EQ(0, rmdir(TMP_DIR "/s3d1"));
+ ASSERT_EQ(0, mkdir(TMP_DIR "/s3d1", 0755));
+}
+
+TEST_F_FORK(layout4_disconnected_leafs, no_inherit_mount_parent_link)
+{
+ int ruleset_fd, s1d41_bind_fd;
+ struct landlock_ruleset_attr ruleset_attr = {
+ .handled_access_fs = ACCESS_RW | LANDLOCK_ACCESS_FS_REFER |
+ LANDLOCK_ACCESS_FS_REMOVE_FILE |
+ LANDLOCK_ACCESS_FS_REMOVE_DIR |
+ LANDLOCK_ACCESS_FS_MAKE_REG,
+ };
+
+ ruleset_fd =
+ landlock_create_ruleset(&ruleset_attr, sizeof(ruleset_attr), 0);
+ ASSERT_LE(0, ruleset_fd);
+
+ /* Allow full access to TMP_DIR. */
+ add_path_beneath(_metadata, ruleset_fd,
+ ACCESS_RW | LANDLOCK_ACCESS_FS_REFER |
+ LANDLOCK_ACCESS_FS_REMOVE_FILE |
+ LANDLOCK_ACCESS_FS_REMOVE_DIR |
+ LANDLOCK_ACCESS_FS_MAKE_REG,
+ TMP_DIR, 0);
+
+ /*
+ * Access s1d41 through the bind mount at s2d2 and protect it with
+ * NO_INHERIT. This should seal the parent hierarchy through the mount.
+ */
+ s1d41_bind_fd = open(TMP_DIR "/s2d1/s2d2/s1d31/s1d41",
+ O_DIRECTORY | O_PATH | O_CLOEXEC);
+ ASSERT_LE(0, s1d41_bind_fd);
+
+ ASSERT_EQ(0, landlock_add_rule(ruleset_fd, LANDLOCK_RULE_PATH_BENEATH,
+ &(struct landlock_path_beneath_attr){
+ .parent_fd = s1d41_bind_fd,
+ .allowed_access = ACCESS_RO,
+ },
+ LANDLOCK_ADD_RULE_NO_INHERIT));
+ EXPECT_EQ(0, close(s1d41_bind_fd));
+
+ enforce_ruleset(_metadata, ruleset_fd);
+ ASSERT_EQ(0, close(ruleset_fd));
+
+ /*
+ * Creating a hard link within the protected NO_INHERIT directory should
+ * be denied because NO_INHERIT grants only ACCESS_RO (no MAKE_REG).
+ */
+ ASSERT_EQ(-1, linkat(AT_FDCWD, TMP_DIR "/s2d1/s2d2/s1d31/s1d41/f1",
+ AT_FDCWD, TMP_DIR "/s2d1/s2d2/s1d31/s1d41/f1_link",
+ 0));
+ ASSERT_EQ(EACCES, errno);
+
+ /*
+ * Creating links within directories outside the protected chain
+ * (using the mount source path to avoid EXDEV) should still be allowed.
+ */
+ ASSERT_EQ(0, linkat(AT_FDCWD, TMP_DIR "/s1d1/s1d2/s1d32/s1d42/f3",
+ AT_FDCWD, TMP_DIR "/s1d1/s1d2/s1d32/s1d42/f3_link",
+ 0));
+ ASSERT_EQ(0, unlink(TMP_DIR "/s1d1/s1d2/s1d32/s1d42/f3_link"));
+}
+
+/*
+ * Test that NO_INHERIT protection extends to the mount source hierarchy.
+ * If a directory is protected via a mount path, its parents within the
+ * mount source should also be protected from topology changes.
+ */
+TEST_F_FORK(layout4_disconnected_leafs, no_inherit_source_parent_rename)
+{
+ int ruleset_fd, s1d41_bind_fd;
+ struct landlock_ruleset_attr ruleset_attr = {
+ .handled_access_fs = ACCESS_RW | LANDLOCK_ACCESS_FS_REFER |
+ LANDLOCK_ACCESS_FS_REMOVE_FILE |
+ LANDLOCK_ACCESS_FS_REMOVE_DIR,
+ };
+
+ ruleset_fd =
+ landlock_create_ruleset(&ruleset_attr, sizeof(ruleset_attr), 0);
+ ASSERT_LE(0, ruleset_fd);
+
+ /* Allow full access to TMP_DIR. */
+ add_path_beneath(_metadata, ruleset_fd,
+ ACCESS_RW | LANDLOCK_ACCESS_FS_REFER |
+ LANDLOCK_ACCESS_FS_REMOVE_FILE |
+ LANDLOCK_ACCESS_FS_REMOVE_DIR,
+ TMP_DIR, 0);
+
+ /*
+ * Access s1d41 through the bind mount at s2d2 and protect it with
+ * NO_INHERIT. The source mount path parents should also be protected.
+ */
+ s1d41_bind_fd = open(TMP_DIR "/s2d1/s2d2/s1d31/s1d41",
+ O_DIRECTORY | O_PATH | O_CLOEXEC);
+ ASSERT_LE(0, s1d41_bind_fd);
+
+ ASSERT_EQ(0, landlock_add_rule(ruleset_fd, LANDLOCK_RULE_PATH_BENEATH,
+ &(struct landlock_path_beneath_attr){
+ .parent_fd = s1d41_bind_fd,
+ .allowed_access = ACCESS_RO,
+ },
+ LANDLOCK_ADD_RULE_NO_INHERIT));
+ EXPECT_EQ(0, close(s1d41_bind_fd));
+
+ enforce_ruleset(_metadata, ruleset_fd);
+ ASSERT_EQ(0, close(ruleset_fd));
+
+ /*
+ * The mount source is s1d1/s1d2. The protected directory s1d41 is at
+ * s1d1/s1d2/s1d31/s1d41. The parent s1d31 within the mount source
+ * should be protected from topology changes.
+ */
+ ASSERT_EQ(-1, rename(TMP_DIR "/s1d1/s1d2/s1d31",
+ TMP_DIR "/s1d1/s1d2/s1d31_renamed"));
+ ASSERT_EQ(EACCES, errno);
+
+ /*
+ * s1d32 is a sibling, not in the protected parent chain. It should
+ * be renamable.
+ */
+ ASSERT_EQ(0, rename(TMP_DIR "/s1d1/s1d2/s1d32",
+ TMP_DIR "/s1d1/s1d2/s1d32_renamed"));
+ ASSERT_EQ(0, rename(TMP_DIR "/s1d1/s1d2/s1d32_renamed",
+ TMP_DIR "/s1d1/s1d2/s1d32"));
+}
+
/*
* layout5_disconnected_branch before rename:
*
@@ -7226,6 +7836,100 @@ TEST_F(audit_layout1, write_file)
EXPECT_EQ(1, records.domain);
}
+TEST_F(audit_layout1, no_inherit_parent_is_logged)
+{
+ struct audit_records records;
+ struct landlock_ruleset_attr ruleset_attr = {
+ .handled_access_fs = ACCESS_RW,
+ };
+ int ruleset_fd;
+
+ ruleset_fd = landlock_create_ruleset(&ruleset_attr,
+ sizeof(ruleset_attr), 0);
+ ASSERT_LE(0, ruleset_fd);
+
+ /* Base read-only rule at s1d1. */
+ add_path_beneath(_metadata, ruleset_fd, ACCESS_RO, dir_s1d1, 0);
+ /* Descendant s1d1/s1d2/s1d3 forbids inheritance but should still log. */
+ add_path_beneath(_metadata, ruleset_fd, ACCESS_RO, dir_s1d3,
+ LANDLOCK_ADD_RULE_NO_INHERIT);
+
+ enforce_ruleset(_metadata, ruleset_fd);
+
+ EXPECT_EQ(EACCES, test_open(file1_s1d2, O_WRONLY));
+ EXPECT_EQ(0, matches_log_fs(_metadata, self->audit_fd,
+ "fs\\.write_file", file1_s1d2));
+ EXPECT_EQ(0, audit_count_records(self->audit_fd, &records));
+ EXPECT_EQ(0, records.access);
+ EXPECT_EQ(1, records.domain);
+
+ EXPECT_EQ(0, close(ruleset_fd));
+}
+
+TEST_F(audit_layout1, no_inherit_blocks_quiet_flag_inheritance)
+{
+ struct audit_records records;
+ struct landlock_ruleset_attr ruleset_attr = {
+ .handled_access_fs = ACCESS_RW,
+ .quiet_access_fs = ACCESS_RW,
+ };
+ int ruleset_fd;
+
+ ruleset_fd = landlock_create_ruleset(&ruleset_attr,
+ sizeof(ruleset_attr), 0);
+ ASSERT_LE(0, ruleset_fd);
+
+ /* Base read-only rule at tmp/s1d1 with quiet flag. */
+ add_path_beneath(_metadata, ruleset_fd, ACCESS_RO, dir_s1d1,
+ LANDLOCK_ADD_RULE_QUIET);
+ /* Descendant tmp/s1d1/s1d2/s1d3 forbids inheritance of quiet flag and should still log. */
+ add_path_beneath(_metadata, ruleset_fd, ACCESS_RO, dir_s1d3,
+ LANDLOCK_ADD_RULE_NO_INHERIT);
+
+ enforce_ruleset(_metadata, ruleset_fd);
+
+ EXPECT_EQ(EACCES, test_open(file1_s1d3, O_WRONLY));
+ EXPECT_EQ(0, matches_log_fs(_metadata, self->audit_fd,
+ "fs\\.write_file", file1_s1d3));
+ EXPECT_EQ(0, audit_count_records(self->audit_fd, &records));
+ EXPECT_EQ(0, records.access);
+ EXPECT_EQ(1, records.domain);
+
+ EXPECT_EQ(0, close(ruleset_fd));
+}
+
+TEST_F(audit_layout1, no_inherit_quiet_parent)
+{
+ struct audit_records records;
+ struct landlock_ruleset_attr ruleset_attr = {
+ .handled_access_fs = ACCESS_RW,
+ .quiet_access_fs = ACCESS_RW,
+ };
+ int ruleset_fd;
+
+ ruleset_fd = landlock_create_ruleset(&ruleset_attr,
+ sizeof(ruleset_attr), 0);
+ ASSERT_LE(0, ruleset_fd);
+
+ /* Base read-only rule at tmp/s1d1 with quiet flag. */
+ add_path_beneath(_metadata, ruleset_fd, ACCESS_RO, dir_s1d1,
+ LANDLOCK_ADD_RULE_QUIET);
+ /* Access to dir_s1d1 shouldn't log */
+ add_path_beneath(_metadata, ruleset_fd, ACCESS_RO, dir_s1d3,
+ LANDLOCK_ADD_RULE_NO_INHERIT);
+
+ enforce_ruleset(_metadata, ruleset_fd);
+
+ EXPECT_EQ(EACCES, test_open(file1_s1d1, O_WRONLY));
+ EXPECT_NE(0, matches_log_fs(_metadata, self->audit_fd,
+ "fs\\.write_file", file1_s1d1));
+ EXPECT_EQ(0, audit_count_records(self->audit_fd, &records));
+ EXPECT_EQ(0, records.access);
+ EXPECT_EQ(0, records.domain);
+
+ EXPECT_EQ(0, close(ruleset_fd));
+}
+
TEST_F(audit_layout1, read_file)
{
struct audit_records records;
--
2.51.0
^ permalink raw reply related
* [PATCH v6 3/6] samples/landlock: Add LANDLOCK_ADD_RULE_NO_INHERIT to landlock-sandboxer
From: Justin Suess @ 2025-12-21 19:42 UTC (permalink / raw)
To: Mickaël Salaün
Cc: Tingmao Wang, Günther Noack, Justin Suess, Jan Kara,
Abhinav Saxena, linux-security-module
In-Reply-To: <20251221194301.247484-1-utilityemal77@gmail.com>
Adds support to landlock-sandboxer with environment variable
LL_FS_NO_INHERIT, which can be tagged on any filesystem object to
suppress access right inheritance.
Cc: Tingmao Wang <m@maowtm.org>
Signed-off-by: Justin Suess <utilityemal77@gmail.com>
---
Notes:
v4..v6 changes:
* None
v3..v4 changes:
* Modified LL_FS_R(O/W)_NO_INHERIT variables to a single variable
to allow access rule combination. (credit to Tingmao Wang)
v2..v3 changes:
* Minor formatting fixes
samples/landlock/sandboxer.c | 13 ++++++++++++-
1 file changed, 12 insertions(+), 1 deletion(-)
diff --git a/samples/landlock/sandboxer.c b/samples/landlock/sandboxer.c
index 07dc0013ff19..852ffa413c75 100644
--- a/samples/landlock/sandboxer.c
+++ b/samples/landlock/sandboxer.c
@@ -60,6 +60,7 @@ static inline int landlock_restrict_self(const int ruleset_fd,
#define ENV_FS_RW_NAME "LL_FS_RW"
#define ENV_FS_QUIET_NAME "LL_FS_QUIET"
#define ENV_FS_QUIET_ACCESS_NAME "LL_FS_QUIET_ACCESS"
+#define ENV_FS_NO_INHERIT_NAME "LL_FS_NO_INHERIT"
#define ENV_TCP_BIND_NAME "LL_TCP_BIND"
#define ENV_TCP_CONNECT_NAME "LL_TCP_CONNECT"
#define ENV_NET_QUIET_NAME "LL_NET_QUIET"
@@ -383,6 +384,7 @@ static const char help[] =
"but to test audit we can set " ENV_FORCE_LOG_NAME "=1\n"
ENV_FS_QUIET_NAME " and " ENV_NET_QUIET_NAME ", both optional, can then be used "
"to make access to some denied paths or network ports not trigger audit logging.\n"
+ ENV_FS_NO_INHERIT_NAME " can be used to suppress access right propagation (ABI >= 8).\n"
ENV_FS_QUIET_ACCESS_NAME " and " ENV_NET_QUIET_ACCESS_NAME " can be used to specify "
"which accesses should be quieted (defaults to all):\n"
"* " ENV_FS_QUIET_ACCESS_NAME ": file system accesses to quiet\n"
@@ -430,6 +432,7 @@ int main(const int argc, char *const argv[], char *const *const envp)
};
bool quiet_supported = true;
+ bool no_inherit_supported = true;
int supported_restrict_flags = LANDLOCK_RESTRICT_SELF_LOG_NEW_EXEC_ON;
int set_restrict_flags = 0;
@@ -517,8 +520,9 @@ int main(const int argc, char *const argv[], char *const *const envp)
LANDLOCK_ABI_LAST, abi);
__attribute__((fallthrough));
case 7:
- /* Don't add quiet flags for ABI < 8 later on. */
+ /* Don't add quiet/no_inherit flags for ABI < 8 later on. */
quiet_supported = false;
+ no_inherit_supported = false;
__attribute__((fallthrough));
case LANDLOCK_ABI_LAST:
@@ -605,6 +609,13 @@ int main(const int argc, char *const argv[], char *const *const envp)
goto err_close_ruleset;
}
+ /* Don't require this env to be present. */
+ if (no_inherit_supported && getenv(ENV_FS_NO_INHERIT_NAME)) {
+ if (populate_ruleset_fs(ENV_FS_NO_INHERIT_NAME, ruleset_fd, 0,
+ LANDLOCK_ADD_RULE_NO_INHERIT))
+ goto err_close_ruleset;
+ }
+
if (populate_ruleset_net(ENV_TCP_BIND_NAME, ruleset_fd,
LANDLOCK_ACCESS_NET_BIND_TCP, 0)) {
goto err_close_ruleset;
--
2.51.0
^ permalink raw reply related
* [PATCH v6 2/6] landlock: Implement LANDLOCK_ADD_RULE_NO_INHERIT userspace api
From: Justin Suess @ 2025-12-21 19:42 UTC (permalink / raw)
To: Mickaël Salaün
Cc: Tingmao Wang, Günther Noack, Justin Suess, Jan Kara,
Abhinav Saxena, linux-security-module
In-Reply-To: <20251221194301.247484-1-utilityemal77@gmail.com>
Implements the syscall side flag handling and kernel api headers for the
LANDLOCK_ADD_RULE_NO_INHERIT flag.
Signed-off-by: Justin Suess <utilityemal77@gmail.com>
---
Notes:
v5..v6 changes:
* None
v4..v5 changes:
* Moved syscall handling to this patch and moved out flag definition
to allow independent build.
v3..v4 changes:
* Changed documentation to reflect protections now apply to VFS root
instead of the mountpoint.
v2..v3 changes:
* Extended documentation for flag inheritance suppression on
LANDLOCK_ADD_RULE_NO_INHERIT.
* Extended the flag validation rules in the syscall.
* Added mention of no inherit in empty rules in add_rule_path_beneath
as per Tingmao Wang's suggestion.
* Added check for useless no-inherit flag in networking rules.
security/landlock/ruleset.c | 19 ++++++++++++++++++-
security/landlock/syscalls.c | 16 ++++++++++++----
2 files changed, 30 insertions(+), 5 deletions(-)
diff --git a/security/landlock/ruleset.c b/security/landlock/ruleset.c
index a58af26db201..adc965de8e4e 100644
--- a/security/landlock/ruleset.c
+++ b/security/landlock/ruleset.c
@@ -254,8 +254,13 @@ static int insert_rule(struct landlock_ruleset *const ruleset,
return -EINVAL;
if (WARN_ON_ONCE(this->layers[0].level != 0))
return -EINVAL;
+ /* Merge the flags into the rules */
this->layers[0].access |= (*layers)[0].access;
this->layers[0].flags.quiet |= (*layers)[0].flags.quiet;
+ this->layers[0].flags.no_inherit |=
+ (*layers)[0].flags.no_inherit;
+ this->layers[0].flags.has_no_inherit_descendant |=
+ (*layers)[0].flags.has_no_inherit_descendant;
return 0;
}
@@ -314,7 +319,10 @@ int landlock_insert_rule(struct landlock_ruleset *const ruleset,
.level = 0,
.flags = {
.quiet = !!(flags & LANDLOCK_ADD_RULE_QUIET),
- },
+ .no_inherit = !!(flags & LANDLOCK_ADD_RULE_NO_INHERIT),
+ .has_no_inherit_descendant =
+ !!(flags & LANDLOCK_ADD_RULE_NO_INHERIT),
+ }
} };
build_check_layer();
@@ -661,9 +669,18 @@ bool landlock_unmask_layers(const struct landlock_rule *const rule,
unsigned long access_bit;
bool is_empty;
+ /* Skip layers that already have no inherit flags. */
+ if (rule_flags &&
+ (rule_flags->no_inherit_masks & layer_bit))
+ continue;
+
/* Collect rule flags for each layer. */
if (rule_flags && layer->flags.quiet)
rule_flags->quiet_masks |= layer_bit;
+ if (rule_flags && layer->flags.no_inherit)
+ rule_flags->no_inherit_masks |= layer_bit;
+ if (rule_flags && layer->flags.has_no_inherit_descendant)
+ rule_flags->no_inherit_desc_masks |= layer_bit;
/*
* Records in @layer_masks which layer grants access to each requested
diff --git a/security/landlock/syscalls.c b/security/landlock/syscalls.c
index 5cf1183bb596..cffe7d944ae5 100644
--- a/security/landlock/syscalls.c
+++ b/security/landlock/syscalls.c
@@ -352,7 +352,7 @@ static int add_rule_path_beneath(struct landlock_ruleset *const ruleset,
/*
* Informs about useless rule: empty allowed_access (i.e. deny rules)
* are ignored in path walks. However, the rule is not useless if it
- * is there to hold a quiet flag
+ * is there to hold a quiet or no inherit flag.
*/
if (!flags && !path_beneath_attr.allowed_access)
return -ENOMSG;
@@ -407,6 +407,10 @@ static int add_rule_net_port(struct landlock_ruleset *ruleset,
if (flags & LANDLOCK_ADD_RULE_QUIET && !ruleset->quiet_masks.net)
return -EINVAL;
+ /* No inherit is always useless for this scope */
+ if (flags & LANDLOCK_ADD_RULE_NO_INHERIT)
+ return -EINVAL;
+
/* Denies inserting a rule with port greater than 65535. */
if (net_port_attr.port > U16_MAX)
return -EINVAL;
@@ -424,7 +428,7 @@ static int add_rule_net_port(struct landlock_ruleset *ruleset,
* @rule_type: Identify the structure type pointed to by @rule_attr:
* %LANDLOCK_RULE_PATH_BENEATH or %LANDLOCK_RULE_NET_PORT.
* @rule_attr: Pointer to a rule (matching the @rule_type).
- * @flags: Must be 0 or %LANDLOCK_ADD_RULE_QUIET.
+ * @flags: Must be 0 or %LANDLOCK_ADD_RULE_QUIET and/or %LANDLOCK_ADD_RULE_NO_INHERIT.
*
* This system call enables to define a new rule and add it to an existing
* ruleset.
@@ -462,8 +466,12 @@ SYSCALL_DEFINE4(landlock_add_rule, const int, ruleset_fd,
if (!is_initialized())
return -EOPNOTSUPP;
-
- if (flags && flags != LANDLOCK_ADD_RULE_QUIET)
+ /* Checks flag existence */
+ if (flags & ~(LANDLOCK_ADD_RULE_QUIET | LANDLOCK_ADD_RULE_NO_INHERIT))
+ return -EINVAL;
+ /* No inherit may only apply on path_beneath rules. */
+ if ((flags & LANDLOCK_ADD_RULE_NO_INHERIT) &&
+ rule_type != LANDLOCK_RULE_PATH_BENEATH)
return -EINVAL;
/* Gets and checks the ruleset. */
--
2.51.0
^ permalink raw reply related
* [PATCH v6 1/6] landlock: Implement LANDLOCK_ADD_RULE_NO_INHERIT
From: Justin Suess @ 2025-12-21 19:42 UTC (permalink / raw)
To: Mickaël Salaün
Cc: Tingmao Wang, Günther Noack, Justin Suess, Jan Kara,
Abhinav Saxena, linux-security-module
In-Reply-To: <20251221194301.247484-1-utilityemal77@gmail.com>
Implements a flag to prevent access grant inheritance within the filesystem
hierarchy for landlock rules.
If a landlock rule on an inode has this flag, any access grants on parent
inodes will be ignored. Moreover, operations that involve altering the
ancestors of the subject with LANDLOCK_ADD_RULE_NO_INHERIT will be
denied up to the VFS root.
Signed-off-by: Justin Suess <utilityemal77@gmail.com>
Cc: Tingmao Wang <m@maowtm.org>
Cc: Mickaël Salaün <mic@digikod.net>
---
Notes:
v5..v6 changes:
* Retain existing documentation for path traversal in
is_access_to_paths_allowed.
* Change conditional for path walk in is_access_to_paths_allowed
removing possibility of infinite loop and renamed constant.
* Remove (now) redundant mnt_root parameter from
collect_domain_accesses.
* Change path parameter to a dentry for
deny_no_inherit_topology_change because only the dentry was needed.
* Minor documentation fixes.
v4..v5 changes:
* Centralized path walking logic with landlock_walk_path_up.
* Removed redundant functions in fs.c, and streamlined core
logic, removing ~120 lines of code.
* Removed mark_no_inherit_ancestors, replacing with direct flag
setting in append_fs_rule.
* Removed micro-optimization of skipping ancestor processing
when all layers have no_inherit, as it complicated the code
significantly for little gain.
v3..v4 changes:
* Rebased on v6 of Tingmao Wang's "quiet flag" series.
* Removed unnecessary mask_no_inherit_descendant_layers and related
code at Tingmao Wang's suggestion, simplifying patch.
* Updated to use new disconnected directory handling.
* Improved WARN_ON_ONCE usage. (Thanks Tingmao Wang!)
* Removed redundant loop for single-layer rulesets (again thanks Tingmao
Wang!)
* Protections now apply up to the VFS root, not just the mountpoint.
* Indentation fixes.
* Removed redundant flag marker blocked_flag_masks.
v2..v3 changes:
* Parent directory topology protections now work by lazily
inserting blank rules on parent inodes if they do not
exist. This replaces the previous xarray implementation
with simplified logic.
* Added an optimization to skip further processing if all layers
collected have no inherit.
* Added support to block flag inheritance.
include/uapi/linux/landlock.h | 29 ++++
security/landlock/fs.c | 250 ++++++++++++++++++++++++++--------
security/landlock/ruleset.h | 28 +++-
3 files changed, 250 insertions(+), 57 deletions(-)
diff --git a/include/uapi/linux/landlock.h b/include/uapi/linux/landlock.h
index d4f47d20361a..239cdab66f14 100644
--- a/include/uapi/linux/landlock.h
+++ b/include/uapi/linux/landlock.h
@@ -127,10 +127,39 @@ struct landlock_ruleset_attr {
* allowed_access in the passed in rule_attr. When this flag is
* present, the caller is also allowed to pass in an empty
* allowed_access.
+ * %LANDLOCK_ADD_RULE_NO_INHERIT
+ * When set on a rule being added to a ruleset, this flag disables the
+ * inheritance of access rights and flags from parent objects.
+ *
+ * This flag currently applies only to filesystem rules. Adding it to
+ * non-filesystem rules will return -EINVAL, unless future extensions
+ * of Landlock define other hierarchical object types.
+ *
+ * By default, Landlock filesystem rules inherit allowed accesses from
+ * ancestor directories: if a parent directory grants certain rights,
+ * those rights also apply to its children. A rule marked with
+ * LANDLOCK_ADD_RULE_NO_INHERIT stops this propagation at the directory
+ * covered by the rule. Descendants of that directory continue to inherit
+ * normally unless they also have rules using this flag.
+ *
+ * If a regular file is marked with this flag, it will not inherit any
+ * access rights from its parent directories; only the accesses explicitly
+ * allowed by the rule will apply to that file.
+ *
+ * This flag also enforces parent-directory restrictions: rename, rmdir,
+ * link, and other operations that would change the directory's immediate
+ * parent subtree are denied up to the VFS root. This prevents
+ * sandboxed processes from manipulating the filesystem hierarchy to evade
+ * restrictions (e.g., via sandbox-restart attacks).
+ *
+ * In addition, this flag blocks the inheritance of rule flags
+ * (such as the quiet flag) from parent directories to the object covered
+ * by this rule.
*/
/* clang-format off */
#define LANDLOCK_ADD_RULE_QUIET (1U << 0)
+#define LANDLOCK_ADD_RULE_NO_INHERIT (1U << 1)
/* clang-format on */
/**
diff --git a/security/landlock/fs.c b/security/landlock/fs.c
index 3320d88d8c36..fd0efd1adb8d 100644
--- a/security/landlock/fs.c
+++ b/security/landlock/fs.c
@@ -317,6 +317,43 @@ static struct landlock_object *get_inode_object(struct inode *const inode)
LANDLOCK_ACCESS_FS_IOCTL_DEV)
/* clang-format on */
+/**
+ * enum landlock_walk_result - Result codes for landlock_walk_path_up()
+ * @LANDLOCK_WALK_CONTINUE: Path is now neither the real root nor an internal mount point.
+ * @LANDLOCK_WALK_STOP_REAL_ROOT: Path has reached the real VFS root.
+ * @LANDLOCK_WALK_INTERNAL: Path has reached an internal mount point.
+ */
+enum landlock_walk_result {
+ LANDLOCK_WALK_CONTINUE,
+ LANDLOCK_WALK_STOP_REAL_ROOT,
+ LANDLOCK_WALK_INTERNAL,
+};
+
+static enum landlock_walk_result landlock_walk_path_up(struct path *const path)
+{
+ while (path->dentry == path->mnt->mnt_root) {
+ if (!follow_up(path))
+ return LANDLOCK_WALK_STOP_REAL_ROOT;
+ }
+
+ if (unlikely(IS_ROOT(path->dentry))) {
+ if (likely(path->mnt->mnt_flags & MNT_INTERNAL))
+ return LANDLOCK_WALK_INTERNAL;
+ dput(path->dentry);
+ path->dentry = dget(path->mnt->mnt_root);
+ return LANDLOCK_WALK_CONTINUE;
+ }
+
+ struct dentry *const parent = dget_parent(path->dentry);
+
+ dput(path->dentry);
+ path->dentry = parent;
+ return LANDLOCK_WALK_CONTINUE;
+}
+
+static const struct landlock_rule *find_rule(const struct landlock_ruleset *const domain,
+ const struct dentry *const dentry);
+
/*
* @path: Should have been checked by get_path_from_fd().
*/
@@ -344,6 +381,48 @@ int landlock_append_fs_rule(struct landlock_ruleset *const ruleset,
return PTR_ERR(id.key.object);
mutex_lock(&ruleset->lock);
err = landlock_insert_rule(ruleset, id, access_rights, flags);
+ if (err || !(flags & LANDLOCK_ADD_RULE_NO_INHERIT))
+ goto out_unlock;
+
+ /* Create ancestor rules and set has_no_inherit_descendant flags */
+ struct path walker = *path;
+
+ path_get(&walker);
+ while (landlock_walk_path_up(&walker) == LANDLOCK_WALK_CONTINUE) {
+ struct landlock_rule *ancestor_rule;
+
+ if (WARN_ON_ONCE(!walker.dentry || d_is_negative(walker.dentry))) {
+ err = -EIO;
+ break;
+ }
+
+ ancestor_rule = (struct landlock_rule *)find_rule(ruleset, walker.dentry);
+ if (!ancestor_rule) {
+ struct landlock_id ancestor_id = {
+ .type = LANDLOCK_KEY_INODE,
+ .key.object = get_inode_object(d_backing_inode(walker.dentry)),
+ };
+
+ if (IS_ERR(ancestor_id.key.object)) {
+ err = PTR_ERR(ancestor_id.key.object);
+ break;
+ }
+ err = landlock_insert_rule(ruleset, ancestor_id, 0, 0);
+ landlock_put_object(ancestor_id.key.object);
+ if (err)
+ break;
+
+ ancestor_rule = (struct landlock_rule *)
+ find_rule(ruleset, walker.dentry);
+ }
+ if (WARN_ON_ONCE(!ancestor_rule || ancestor_rule->num_layers != 1)) {
+ err = -EIO;
+ break;
+ }
+ ancestor_rule->layers[0].flags.has_no_inherit_descendant = true;
+ }
+ path_put(&walker);
+out_unlock:
mutex_unlock(&ruleset->lock);
/*
* No need to check for an error because landlock_insert_rule()
@@ -855,6 +934,7 @@ static bool is_access_to_paths_allowed(
*/
while (true) {
const struct landlock_rule *rule;
+ enum landlock_walk_result walk_res;
/*
* If at least all accesses allowed on the destination are
@@ -913,47 +993,25 @@ static bool is_access_to_paths_allowed(
/* Stops when a rule from each layer grants access. */
if (allowed_parent1 && allowed_parent2)
break;
+ /* Otherwise, keep walking up to the root. */
+ walk_res = landlock_walk_path_up(&walker_path);
-jump_up:
- if (walker_path.dentry == walker_path.mnt->mnt_root) {
- if (follow_up(&walker_path)) {
- /* Ignores hidden mount points. */
- goto jump_up;
- } else {
- /*
- * Stops at the real root. Denies access
- * because not all layers have granted access.
- */
- break;
- }
- }
-
- if (unlikely(IS_ROOT(walker_path.dentry))) {
- if (likely(walker_path.mnt->mnt_flags & MNT_INTERNAL)) {
- /*
- * Stops and allows access when reaching disconnected root
- * directories that are part of internal filesystems (e.g. nsfs,
- * which is reachable through /proc/<pid>/ns/<namespace>).
- */
- allowed_parent1 = true;
- allowed_parent2 = true;
- break;
- }
-
+ if (walk_res == LANDLOCK_WALK_INTERNAL) {
/*
- * We reached a disconnected root directory from a bind mount.
- * Let's continue the walk with the mount point we missed.
+ * Stops and allows access when reaching disconnected root
+ * directories that are part of internal filesystems (e.g. nsfs,
+ * which is reachable through /proc/<pid>/ns/<namespace>).
*/
- dput(walker_path.dentry);
- walker_path.dentry = walker_path.mnt->mnt_root;
- dget(walker_path.dentry);
- } else {
- struct dentry *const parent_dentry =
- dget_parent(walker_path.dentry);
-
- dput(walker_path.dentry);
- walker_path.dentry = parent_dentry;
+ allowed_parent1 = true;
+ allowed_parent2 = true;
+ break;
}
+ /*
+ * Stops at the real root. Denies access
+ * because not all layers have granted access
+ */
+ else if (walk_res == LANDLOCK_WALK_STOP_REAL_ROOT)
+ break;
}
path_put(&walker_path);
@@ -1050,8 +1108,8 @@ static access_mask_t maybe_remove(const struct dentry *const dentry)
* collect_domain_accesses - Walk through a file path and collect accesses
*
* @domain: Domain to check against.
- * @mnt_root: Last directory to check.
- * @dir: Directory to start the walk from.
+ * @mnt_root: Last path element to check.
+ * @dir: Directory path to start the walk from.
* @layer_masks_dom: Where to store the collected accesses.
*
* This helper is useful to begin a path walk from the @dir directory to a
@@ -1073,29 +1131,31 @@ static access_mask_t maybe_remove(const struct dentry *const dentry)
*/
static bool collect_domain_accesses(
const struct landlock_ruleset *const domain,
- const struct dentry *const mnt_root, struct dentry *dir,
+ const struct path *const dir,
layer_mask_t (*const layer_masks_dom)[LANDLOCK_NUM_ACCESS_FS],
struct collected_rule_flags *const rule_flags)
{
unsigned long access_dom;
bool ret = false;
+ struct path walker;
- if (WARN_ON_ONCE(!domain || !mnt_root || !dir || !layer_masks_dom))
+ if (WARN_ON_ONCE(!domain || !dir || !layer_masks_dom))
return true;
- if (is_nouser_or_private(dir))
+ if (is_nouser_or_private(dir->dentry))
return true;
access_dom = landlock_init_layer_masks(domain, LANDLOCK_MASK_ACCESS_FS,
layer_masks_dom,
LANDLOCK_KEY_INODE);
- dget(dir);
+ walker = *dir;
+ path_get(&walker);
while (true) {
- struct dentry *parent_dentry;
+ enum landlock_walk_result walk_res;
/* Gets all layers allowing all domain accesses. */
if (landlock_unmask_layers(
- find_rule(domain, dir), access_dom, layer_masks_dom,
+ find_rule(domain, walker.dentry), access_dom, layer_masks_dom,
ARRAY_SIZE(*layer_masks_dom), rule_flags)) {
/*
* Stops when all handled accesses are allowed by at
@@ -1104,22 +1164,71 @@ static bool collect_domain_accesses(
ret = true;
break;
}
-
/*
* Stops at the mount point or the filesystem root for a disconnected
* directory.
*/
- if (dir == mnt_root || unlikely(IS_ROOT(dir)))
+ if (walker.dentry == dir->mnt->mnt_root && walker.mnt == dir->mnt)
+ break;
+ walk_res = landlock_walk_path_up(&walker);
+ if (walk_res != LANDLOCK_WALK_CONTINUE)
break;
-
- parent_dentry = dget_parent(dir);
- dput(dir);
- dir = parent_dentry;
}
- dput(dir);
+ path_put(&walker);
return ret;
}
+/**
+ * deny_no_inherit_topology_change - deny topology changes on sealed paths
+ * @subject: Subject performing the operation (contains the domain).
+ * @path: Path whose dentry is the target of the topology modification.
+ *
+ * Checks whether any domain layers are sealed against topology changes at
+ * @path. If so, emit an audit record and return -EACCES. Otherwise return 0.
+ */
+static int deny_no_inherit_topology_change(const struct landlock_cred_security *subject,
+ struct dentry *const dcache_entry)
+{
+ layer_mask_t sealed_layers = 0;
+ layer_mask_t override_layers = 0;
+ const struct landlock_rule *rule;
+ u32 layer_index;
+ unsigned long audit_layer_index;
+
+ if (WARN_ON_ONCE(!subject || !dcache_entry || d_is_negative(dcache_entry)))
+ return 0;
+
+ rule = find_rule(subject->domain, dcache_entry);
+ if (!rule)
+ return 0;
+
+ for (layer_index = 0; layer_index < rule->num_layers; layer_index++) {
+ const struct landlock_layer *layer = &rule->layers[layer_index];
+ layer_mask_t layer_bit = BIT_ULL(layer->level - 1);
+
+ if (layer->flags.no_inherit ||
+ layer->flags.has_no_inherit_descendant)
+ sealed_layers |= layer_bit;
+ else
+ override_layers |= layer_bit;
+ }
+
+ sealed_layers &= ~override_layers;
+ if (!sealed_layers)
+ return 0;
+
+ audit_layer_index = __ffs((unsigned long)sealed_layers);
+ landlock_log_denial(subject, &(struct landlock_request) {
+ .type = LANDLOCK_REQUEST_FS_CHANGE_TOPOLOGY,
+ .audit = {
+ .type = LSM_AUDIT_DATA_DENTRY,
+ .u.dentry = dcache_entry,
+ },
+ .layer_plus_one = audit_layer_index + 1,
+ });
+ return -EACCES;
+}
+
/**
* current_check_refer_path - Check if a rename or link action is allowed
*
@@ -1206,6 +1315,15 @@ static int current_check_refer_path(struct dentry *const old_dentry,
access_request_parent2 =
get_mode_access(d_backing_inode(old_dentry)->i_mode);
if (removable) {
+ int err = deny_no_inherit_topology_change(subject, old_dentry);
+
+ if (err)
+ return err;
+ if (exchange) {
+ err = deny_no_inherit_topology_change(subject, new_dentry);
+ if (err)
+ return err;
+ }
access_request_parent1 |= maybe_remove(old_dentry);
access_request_parent2 |= maybe_remove(new_dentry);
}
@@ -1248,12 +1366,13 @@ static int current_check_refer_path(struct dentry *const old_dentry,
old_dentry->d_parent;
/* new_dir->dentry is equal to new_dentry->d_parent */
- allow_parent1 = collect_domain_accesses(subject->domain, mnt_dir.dentry,
- old_parent,
+ allow_parent1 = collect_domain_accesses(subject->domain,
+ &(struct path){ .mnt = new_dir->mnt,
+ .dentry = old_parent },
&layer_masks_parent1,
&rule_flags_parent1);
- allow_parent2 = collect_domain_accesses(subject->domain, mnt_dir.dentry,
- new_dir->dentry,
+ allow_parent2 = collect_domain_accesses(subject->domain,
+ new_dir,
&layer_masks_parent2,
&rule_flags_parent2);
if (allow_parent1 && allow_parent2)
@@ -1602,12 +1721,31 @@ static int hook_path_symlink(const struct path *const dir,
static int hook_path_unlink(const struct path *const dir,
struct dentry *const dentry)
{
+ const struct landlock_cred_security *const subject =
+ landlock_get_applicable_subject(current_cred(), any_fs, NULL);
+ int err;
+
+ if (subject) {
+ err = deny_no_inherit_topology_change(subject, dentry);
+ if (err)
+ return err;
+ }
return current_check_access_path(dir, LANDLOCK_ACCESS_FS_REMOVE_FILE);
}
static int hook_path_rmdir(const struct path *const dir,
struct dentry *const dentry)
{
+ const struct landlock_cred_security *const subject =
+ landlock_get_applicable_subject(current_cred(), any_fs, NULL);
+ int err;
+
+ if (subject) {
+ err = deny_no_inherit_topology_change(subject, dentry);
+ if (err)
+ return err;
+ }
+
return current_check_access_path(dir, LANDLOCK_ACCESS_FS_REMOVE_DIR);
}
diff --git a/security/landlock/ruleset.h b/security/landlock/ruleset.h
index eb60db646422..c0a9b33e68b2 100644
--- a/security/landlock/ruleset.h
+++ b/security/landlock/ruleset.h
@@ -40,6 +40,20 @@ struct landlock_layer {
* down the file hierarchy.
*/
bool quiet:1;
+ /**
+ * @no_inherit: Prevents this rule from inheriting access rights
+ * from ancestor inodes. Only used for filesystem rules.
+ */
+ bool no_inherit:1;
+ /**
+ * @has_no_inherit_descendant: Marker to indicate that this layer
+ * has at least one descendant directory with a rule having the
+ * no_inherit flag. Only used for filesystem rules.
+ * This "flag" is not set by the user, but by Landlock on
+ * parent directories of rules when the child rule has
+ * a rule with the no_inherit flag to deny topology changes.
+ */
+ bool has_no_inherit_descendant:1;
} flags;
/**
* @access: Bitfield of allowed actions on the kernel object. They are
@@ -49,13 +63,25 @@ struct landlock_layer {
};
/**
- * struct collected_rule_flags - Hold accumulated flags for each layer.
+ * struct collected_rule_flags - Hold accumulated flags and their markers for each layer.
*/
struct collected_rule_flags {
/**
* @quiet_masks: Layers for which the quiet flag is effective.
*/
layer_mask_t quiet_masks;
+ /**
+ * @no_inherit_masks: Layers for which the no_inherit flag is effective.
+ */
+ layer_mask_t no_inherit_masks;
+ /**
+ * @no_inherit_desc_masks: Layers for which the
+ * has_no_inherit_descendant tag is effective.
+ * This is not a flag itself, but a marker set on ancestors
+ * of rules with the no_inherit flag to deny topology changes
+ * in the direct parent path.
+ */
+ layer_mask_t no_inherit_desc_masks;
};
/**
--
2.51.0
^ permalink raw reply related
* [PATCH v6 0/6] Implement LANDLOCK_ADD_RULE_NO_INHERIT
From: Justin Suess @ 2025-12-21 19:42 UTC (permalink / raw)
To: Mickaël Salaün
Cc: Tingmao Wang, Günther Noack, Justin Suess, Jan Kara,
Abhinav Saxena, linux-security-module
Hi,
This is version 6 of the LANDLOCK_ADD_RULE_NO_INHERIT series, which
implements a new flag to suppress inheritance of access rights and
flags from parent objects.
This version of the series focuses again on simplification and
cleanup.
Behavior of the flag is identical to the previous patch.
This series is rebased on v7 of Tingmao Wang's "quiet flag" series.
Previous patch summary:
The new flag enables policies where a parent directory needs broader
access than its children. For example, a sandbox may permit read-write
access to /home/user but still prohibit writes to ~/.bashrc or
~/.ssh, even though they are nested beneath the parent. Today this is
not possible because access rights always propagate from parent to
child inodes.
When a rule is added with LANDLOCK_ADD_RULE_NO_INHERIT:
* access rights on parent inodes are ignored for that inode and its
descendants; and
* operations that reparent, rename, or remove the tagged inode or
its ancestors (via rename, rmdir, link) are denied up to the VFS
root; and
* parent flags do not propagate below a NO_INHERIT rule.
These parent-directory restrictions help mitigate sandbox-restart
attacks: a sandboxed process could otherwise move a protected
directory before exit, causing the next sandbox instance to apply its
policy to the wrong path.
Changes since v5:
1. Retain existing documentation for path traversal in
is_access_to_paths_allowed.
2. Change conditional for path walk in is_access_to_paths_allowed
removing possibility of infinite loop and renamed constant.
3. Remove (now) redundant mnt_root parameter from
collect_domain_accesses.
4. Change path parameter to a dentry for
deny_no_inherit_topology_change because only the dentry was needed.
5. Remove duplicated tree diagram comment from selftests.
6. Minor documentation fixes.
Credit to Tingmao Wang for pointing out 1, 2, 3, 4, and 6.
Changes since v4:
1. Trimmed 120 lines from core implementation in fs.c.
2. Centralized path traversal logic with a helper function
landlock_walk_path_up.
3. Fixed bug in test on applying LANDLOCK_ADD_RULE_NO_INHERIT on
a file, giving it valid access rights.
4. Restructured commits to allow independent builds.
5. Adds userspace API documentation for the flag.
Changes since v3:
1. Trimmed core implementation in fs.c by removing redundant functions.
2. Fixed placement/inclusion of prototypes.
3. Added 4 new selftests for bind mount cases.
4. Protections now apply up to the VFS root instead of the mountpoint
root.
Links:
v1:
https://lore.kernel.org/linux-security-module/20251105180019.1432367-1-utilityemal77@gmail.com/
v2:
https://lore.kernel.org/linux-security-module/20251120222346.1157004-1-utilityemal77@gmail.com/
v3:
https://lore.kernel.org/linux-security-module/20251126122039.3832162-1-utilityemal77@gmail.com/
v4:
https://lore.kernel.org/linux-security-module/20251207015132.800576-1-utilityemal77@gmail.com/
v5:
https://lore.kernel.org/linux-security-module/20251214170548.408142-1-utilityemal77@gmail.com/
quiet-flag v6:
https://lore.kernel.org/linux-security-module/cover.1765040503.git.m@maowtm.org/
Example usage:
# LL_FS_RO="/a/b/c" LL_FS_RW="/" LL_FS_NO_INHERIT="/a/b/c"
landlock-sandboxer sh
# touch /a/b/c/fi # denied; / RW does not inherit
# rmdir /a/b/c # denied by ancestor protections
# mv /a /bad # denied
# mkdir /a/good; touch /a/good/fi # allowed; unrelated path
All tests added by this series, and all other existing landlock tests,
are passing. This patch was also validated through checkpatch.pl.
Special thanks to Tingmao Wang and Mickaël Salaün for your valuable
feedback.
Thank you for your time and review.
Regards,
Justin Suess
Justin Suess (6):
landlock: Implement LANDLOCK_ADD_RULE_NO_INHERIT
landlock: Implement LANDLOCK_ADD_RULE_NO_INHERIT userspace api
samples/landlock: Add LANDLOCK_ADD_RULE_NO_INHERIT to
landlock-sandboxer
selftests/landlock: Implement selftests for
LANDLOCK_ADD_RULE_NO_INHERIT
landlock: Implement KUnit test for LANDLOCK_ADD_RULE_NO_INHERIT
landlock: Add documentation for LANDLOCK_ADD_RULE_NO_INHERIT
Documentation/userspace-api/landlock.rst | 17 +
include/uapi/linux/landlock.h | 29 +
samples/landlock/sandboxer.c | 13 +-
security/landlock/fs.c | 250 ++++++--
security/landlock/ruleset.c | 108 +++-
security/landlock/ruleset.h | 28 +-
security/landlock/syscalls.c | 16 +-
tools/testing/selftests/landlock/fs_test.c | 704 +++++++++++++++++++++
8 files changed, 1102 insertions(+), 63 deletions(-)
base-commit: 1c618dbb98a3d2346940bddc890a49a5cd7dcbdc
--
2.51.0
^ permalink raw reply
* [PATCH v2] ima: Fix stack-out-of-bounds in is_bprm_creds_for_exec()
From: Chris J Arges @ 2025-12-21 18:01 UTC (permalink / raw)
To: zohar, roberto.sassu
Cc: kernel-team, Chris J Arges, Dmitry Kasatkin, Eric Snowberg,
Paul Moore, James Morris, Serge E. Hallyn,
Mickaël Salaün, Kees Cook, linux-integrity,
linux-security-module, linux-kernel
In-Reply-To: <20251219195456.912190-1-carges@cloudflare.com>
KASAN reported a stack-out-of-bounds access in ima_appraise_measurement
from is_bprm_creds_for_exec:
BUG: KASAN: stack-out-of-bounds in ima_appraise_measurement+0x12dc/0x16a0
Read of size 1 at addr ffffc9000160f940 by task sudo/550
The buggy address belongs to stack of task sudo/550
and is located at offset 24 in frame:
ima_appraise_measurement+0x0/0x16a0
This frame has 2 objects:
[48, 56) 'file'
[80, 148) 'hash'
This is caused by using container_of on the *file pointer. This offset
calculation is what triggers the stack-out-of-bounds error.
In order to fix this, pass in a bprm_is_check boolean which can be set
depending on how process_measurement is called. If the caller has a
linux_binprm pointer and the function is BPRM_CHECK we can determine
is_check and set it then. Otherwise set it to false.
Fixes: 95b3cdafd7cb7 ("ima: instantiate the bprm_creds_for_exec() hook")
Signed-off-by: Chris J Arges <carges@cloudflare.com>
---
security/integrity/ima/ima.h | 4 ++--
security/integrity/ima/ima_appraise.c | 15 ++-------------
security/integrity/ima/ima_main.c | 18 +++++++++---------
3 files changed, 13 insertions(+), 24 deletions(-)
diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h
index e3d71d8d56e3..2c9e50c02634 100644
--- a/security/integrity/ima/ima.h
+++ b/security/integrity/ima/ima.h
@@ -441,7 +441,7 @@ int ima_check_blacklist(struct ima_iint_cache *iint,
int ima_appraise_measurement(enum ima_hooks func, struct ima_iint_cache *iint,
struct file *file, const unsigned char *filename,
struct evm_ima_xattr_data *xattr_value,
- int xattr_len, const struct modsig *modsig);
+ int xattr_len, const struct modsig *modsig, bool bprm_is_check);
int ima_must_appraise(struct mnt_idmap *idmap, struct inode *inode,
int mask, enum ima_hooks func);
void ima_update_xattr(struct ima_iint_cache *iint, struct file *file);
@@ -466,7 +466,7 @@ static inline int ima_appraise_measurement(enum ima_hooks func,
const unsigned char *filename,
struct evm_ima_xattr_data *xattr_value,
int xattr_len,
- const struct modsig *modsig)
+ const struct modsig *modsig, bool bprm_is_check)
{
return INTEGRITY_UNKNOWN;
}
diff --git a/security/integrity/ima/ima_appraise.c b/security/integrity/ima/ima_appraise.c
index 5149ff4fd50d..ea2079417318 100644
--- a/security/integrity/ima/ima_appraise.c
+++ b/security/integrity/ima/ima_appraise.c
@@ -470,17 +470,6 @@ int ima_check_blacklist(struct ima_iint_cache *iint,
return rc;
}
-static bool is_bprm_creds_for_exec(enum ima_hooks func, struct file *file)
-{
- struct linux_binprm *bprm;
-
- if (func == BPRM_CHECK) {
- bprm = container_of(&file, struct linux_binprm, file);
- return bprm->is_check;
- }
- return false;
-}
-
/*
* ima_appraise_measurement - appraise file measurement
*
@@ -492,7 +481,7 @@ static bool is_bprm_creds_for_exec(enum ima_hooks func, struct file *file)
int ima_appraise_measurement(enum ima_hooks func, struct ima_iint_cache *iint,
struct file *file, const unsigned char *filename,
struct evm_ima_xattr_data *xattr_value,
- int xattr_len, const struct modsig *modsig)
+ int xattr_len, const struct modsig *modsig, bool bprm_is_check)
{
static const char op[] = "appraise_data";
int audit_msgno = AUDIT_INTEGRITY_DATA;
@@ -514,7 +503,7 @@ int ima_appraise_measurement(enum ima_hooks func, struct ima_iint_cache *iint,
* of the script interpreter(userspace). Differentiate kernel and
* userspace enforced integrity audit messages.
*/
- if (is_bprm_creds_for_exec(func, file))
+ if (bprm_is_check)
audit_msgno = AUDIT_INTEGRITY_USERSPACE;
/* If reading the xattr failed and there's no modsig, error out. */
diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c
index 5770cf691912..36ce07063dc7 100644
--- a/security/integrity/ima/ima_main.c
+++ b/security/integrity/ima/ima_main.c
@@ -236,7 +236,7 @@ static void ima_file_free(struct file *file)
static int process_measurement(struct file *file, const struct cred *cred,
struct lsm_prop *prop, char *buf, loff_t size,
int mask, enum ima_hooks func,
- enum kernel_read_file_id read_id)
+ enum kernel_read_file_id read_id, bool bprm_is_check)
{
struct inode *real_inode, *inode = file_inode(file);
struct ima_iint_cache *iint = NULL;
@@ -426,7 +426,7 @@ static int process_measurement(struct file *file, const struct cred *cred,
inode_lock(inode);
rc = ima_appraise_measurement(func, iint, file,
pathname, xattr_value,
- xattr_len, modsig);
+ xattr_len, modsig, bprm_is_check);
inode_unlock(inode);
}
if (!rc)
@@ -493,14 +493,14 @@ static int ima_file_mmap(struct file *file, unsigned long reqprot,
if (reqprot & PROT_EXEC) {
ret = process_measurement(file, current_cred(), &prop, NULL,
- 0, MAY_EXEC, MMAP_CHECK_REQPROT, 0);
+ 0, MAY_EXEC, MMAP_CHECK_REQPROT, 0, false);
if (ret)
return ret;
}
if (prot & PROT_EXEC)
return process_measurement(file, current_cred(), &prop, NULL,
- 0, MAY_EXEC, MMAP_CHECK, 0);
+ 0, MAY_EXEC, MMAP_CHECK, 0, false);
return 0;
}
@@ -584,7 +584,7 @@ static int ima_bprm_check(struct linux_binprm *bprm)
security_current_getlsmprop_subj(&prop);
return process_measurement(bprm->file, current_cred(),
- &prop, NULL, 0, MAY_EXEC, BPRM_CHECK, 0);
+ &prop, NULL, 0, MAY_EXEC, BPRM_CHECK, 0, bprm->is_check);
}
/**
@@ -614,7 +614,7 @@ static int ima_creds_check(struct linux_binprm *bprm, const struct file *file)
security_current_getlsmprop_subj(&prop);
return process_measurement((struct file *)file, bprm->cred, &prop, NULL,
- 0, MAY_EXEC, CREDS_CHECK, 0);
+ 0, MAY_EXEC, CREDS_CHECK, 0, false);
}
/**
@@ -662,7 +662,7 @@ static int ima_file_check(struct file *file, int mask)
security_current_getlsmprop_subj(&prop);
return process_measurement(file, current_cred(), &prop, NULL, 0,
mask & (MAY_READ | MAY_WRITE | MAY_EXEC |
- MAY_APPEND), FILE_CHECK, 0);
+ MAY_APPEND), FILE_CHECK, 0, false);
}
static int __ima_inode_hash(struct inode *inode, struct file *file, char *buf,
@@ -881,7 +881,7 @@ static int ima_read_file(struct file *file, enum kernel_read_file_id read_id,
func = read_idmap[read_id] ?: FILE_CHECK;
security_current_getlsmprop_subj(&prop);
return process_measurement(file, current_cred(), &prop, NULL, 0,
- MAY_READ, func, 0);
+ MAY_READ, func, 0, false);
}
const int read_idmap[READING_MAX_ID] = {
@@ -925,7 +925,7 @@ static int ima_post_read_file(struct file *file, char *buf, loff_t size,
func = read_idmap[read_id] ?: FILE_CHECK;
security_current_getlsmprop_subj(&prop);
return process_measurement(file, current_cred(), &prop, buf, size,
- MAY_READ, func, read_id);
+ MAY_READ, func, read_id, false);
}
/**
--
2.43.0
^ permalink raw reply related
* [PATCH v7 9/9] selftests/landlock: Add tests for invalid use of quiet flag
From: Tingmao Wang @ 2025-12-21 15:20 UTC (permalink / raw)
To: Mickaël Salaün
Cc: Tingmao Wang, Günther Noack, Justin Suess, Jan Kara,
Abhinav Saxena, linux-security-module
In-Reply-To: <cover.1766330134.git.m@maowtm.org>
Signed-off-by: Tingmao Wang <m@maowtm.org>
---
Changes in v4:
- New patch
tools/testing/selftests/landlock/base_test.c | 57 ++++++++++++++++++++
1 file changed, 57 insertions(+)
diff --git a/tools/testing/selftests/landlock/base_test.c b/tools/testing/selftests/landlock/base_test.c
index b34b340c52a5..055d416508a0 100644
--- a/tools/testing/selftests/landlock/base_test.c
+++ b/tools/testing/selftests/landlock/base_test.c
@@ -526,4 +526,61 @@ TEST(cred_transfer)
EXPECT_EQ(EACCES, errno);
}
+TEST(useless_quiet_rule)
+{
+ struct landlock_ruleset_attr ruleset_attr = {
+ .handled_access_fs = LANDLOCK_ACCESS_FS_READ_DIR,
+ .quiet_access_fs = 0,
+ };
+ struct landlock_path_beneath_attr path_beneath_attr = {
+ .allowed_access = LANDLOCK_ACCESS_FS_READ_DIR,
+ };
+ int ruleset_fd, root_fd;
+
+ drop_caps(_metadata);
+ ruleset_fd =
+ landlock_create_ruleset(&ruleset_attr, sizeof(ruleset_attr), 0);
+ ASSERT_LE(0, ruleset_fd);
+
+ root_fd = open("/", O_PATH | O_CLOEXEC);
+ ASSERT_LE(0, root_fd);
+ path_beneath_attr.parent_fd = root_fd;
+ ASSERT_EQ(-1, landlock_add_rule(ruleset_fd, LANDLOCK_RULE_PATH_BENEATH,
+ &path_beneath_attr,
+ LANDLOCK_ADD_RULE_QUIET));
+ ASSERT_EQ(EINVAL, errno);
+
+ /* Check that the rule had not been added. */
+ ASSERT_EQ(0, close(root_fd));
+ enforce_ruleset(_metadata, ruleset_fd);
+ ASSERT_EQ(0, close(ruleset_fd));
+
+ ASSERT_EQ(-1, open("/", O_RDONLY | O_DIRECTORY | O_CLOEXEC));
+ ASSERT_EQ(EACCES, errno);
+}
+
+TEST(invalid_quiet_bits_1)
+{
+ struct landlock_ruleset_attr ruleset_attr = {
+ .handled_access_fs = LANDLOCK_ACCESS_FS_READ_DIR,
+ .quiet_access_fs = LANDLOCK_ACCESS_FS_WRITE_FILE,
+ };
+
+ ASSERT_EQ(-1, landlock_create_ruleset(&ruleset_attr,
+ sizeof(ruleset_attr), 0));
+ ASSERT_EQ(EINVAL, errno);
+}
+
+TEST(invalid_quiet_bits_2)
+{
+ struct landlock_ruleset_attr ruleset_attr = {
+ .handled_access_fs = LANDLOCK_ACCESS_FS_READ_DIR,
+ .quiet_access_fs = 1ULL << 63,
+ };
+
+ ASSERT_EQ(-1, landlock_create_ruleset(&ruleset_attr,
+ sizeof(ruleset_attr), 0));
+ ASSERT_EQ(EINVAL, errno);
+}
+
TEST_HARNESS_MAIN
--
2.52.0
^ permalink raw reply related
* [PATCH v7 8/9] selftests/landlock: Add tests for quiet flag with scope
From: Tingmao Wang @ 2025-12-21 15:20 UTC (permalink / raw)
To: Mickaël Salaün
Cc: Tingmao Wang, Günther Noack, Justin Suess, Jan Kara,
Abhinav Saxena, linux-security-module
In-Reply-To: <cover.1766330134.git.m@maowtm.org>
Enhance scoped_audit.connect_to_child and audit_flags.signal to test
interaction with various quiet flag settings.
Signed-off-by: Tingmao Wang <m@maowtm.org>
---
Changes in v4:
- New patch
tools/testing/selftests/landlock/audit_test.c | 25 ++++--
.../landlock/scoped_abstract_unix_test.c | 77 ++++++++++++++++---
2 files changed, 87 insertions(+), 15 deletions(-)
diff --git a/tools/testing/selftests/landlock/audit_test.c b/tools/testing/selftests/landlock/audit_test.c
index 4417cdedeadd..818ce485ecd9 100644
--- a/tools/testing/selftests/landlock/audit_test.c
+++ b/tools/testing/selftests/landlock/audit_test.c
@@ -289,30 +289,42 @@ FIXTURE(audit_flags)
FIXTURE_VARIANT(audit_flags)
{
const int restrict_flags;
+ const __u64 quiet_scoped;
};
/* clang-format off */
FIXTURE_VARIANT_ADD(audit_flags, default) {
/* clang-format on */
.restrict_flags = 0,
+ .quiet_scoped = 0,
};
/* clang-format off */
FIXTURE_VARIANT_ADD(audit_flags, same_exec_off) {
/* clang-format on */
.restrict_flags = LANDLOCK_RESTRICT_SELF_LOG_SAME_EXEC_OFF,
+ .quiet_scoped = 0,
};
/* clang-format off */
FIXTURE_VARIANT_ADD(audit_flags, subdomains_off) {
/* clang-format on */
.restrict_flags = LANDLOCK_RESTRICT_SELF_LOG_SUBDOMAINS_OFF,
+ .quiet_scoped = 0,
};
/* clang-format off */
FIXTURE_VARIANT_ADD(audit_flags, cross_exec_on) {
/* clang-format on */
.restrict_flags = LANDLOCK_RESTRICT_SELF_LOG_NEW_EXEC_ON,
+ .quiet_scoped = 0,
+};
+
+/* clang-format off */
+FIXTURE_VARIANT_ADD(audit_flags, signal_quieted) {
+ /* clang-format on */
+ .restrict_flags = 0,
+ .quiet_scoped = LANDLOCK_SCOPE_SIGNAL,
};
FIXTURE_SETUP(audit_flags)
@@ -356,12 +368,16 @@ TEST_F(audit_flags, signal)
pid_t child;
struct audit_records records;
__u64 deallocated_dom = 2;
+ bool expect_audit = !(variant->restrict_flags &
+ LANDLOCK_RESTRICT_SELF_LOG_SAME_EXEC_OFF) &&
+ !(variant->quiet_scoped & LANDLOCK_SCOPE_SIGNAL);
child = fork();
ASSERT_LE(0, child);
if (child == 0) {
const struct landlock_ruleset_attr ruleset_attr = {
.scoped = LANDLOCK_SCOPE_SIGNAL,
+ .quiet_scoped = variant->quiet_scoped,
};
int ruleset_fd;
@@ -378,8 +394,7 @@ TEST_F(audit_flags, signal)
EXPECT_EQ(-1, kill(getppid(), 0));
EXPECT_EQ(EPERM, errno);
- if (variant->restrict_flags &
- LANDLOCK_RESTRICT_SELF_LOG_SAME_EXEC_OFF) {
+ if (!expect_audit) {
EXPECT_EQ(-EAGAIN, matches_log_signal(
_metadata, self->audit_fd,
getppid(), self->domain_id));
@@ -406,8 +421,7 @@ TEST_F(audit_flags, signal)
/* Makes sure there is no superfluous logged records. */
EXPECT_EQ(0, audit_count_records(self->audit_fd, &records));
- if (variant->restrict_flags &
- LANDLOCK_RESTRICT_SELF_LOG_SAME_EXEC_OFF) {
+ if (!expect_audit) {
EXPECT_EQ(0, records.access);
} else {
EXPECT_EQ(1, records.access);
@@ -431,8 +445,7 @@ TEST_F(audit_flags, signal)
WEXITSTATUS(status) != EXIT_SUCCESS)
_metadata->exit_code = KSFT_FAIL;
- if (variant->restrict_flags &
- LANDLOCK_RESTRICT_SELF_LOG_SAME_EXEC_OFF) {
+ if (!expect_audit) {
EXPECT_EQ(-EAGAIN,
matches_log_domain_deallocated(self->audit_fd, 0,
&deallocated_dom));
diff --git a/tools/testing/selftests/landlock/scoped_abstract_unix_test.c b/tools/testing/selftests/landlock/scoped_abstract_unix_test.c
index 2cdf1ba07016..1415ab351941 100644
--- a/tools/testing/selftests/landlock/scoped_abstract_unix_test.c
+++ b/tools/testing/selftests/landlock/scoped_abstract_unix_test.c
@@ -293,6 +293,45 @@ FIXTURE_TEARDOWN_PARENT(scoped_audit)
EXPECT_EQ(0, audit_cleanup(-1, NULL));
}
+FIXTURE_VARIANT(scoped_audit)
+{
+ const __u64 scoped;
+ const __u64 quiet_scoped;
+};
+
+// clang-format off
+FIXTURE_VARIANT_ADD(scoped_audit, no_quiet)
+{
+ // clang-format on
+ .scoped = LANDLOCK_SCOPE_ABSTRACT_UNIX_SOCKET,
+ .quiet_scoped = 0,
+};
+
+// clang-format off
+FIXTURE_VARIANT_ADD(scoped_audit, quiet_abstract_socket)
+{
+ // clang-format on
+ .scoped = LANDLOCK_SCOPE_ABSTRACT_UNIX_SOCKET,
+ .quiet_scoped = LANDLOCK_SCOPE_ABSTRACT_UNIX_SOCKET,
+};
+
+// clang-format off
+FIXTURE_VARIANT_ADD(scoped_audit, quiet_abstract_socket_2)
+{
+ // clang-format on
+ .scoped = LANDLOCK_SCOPE_ABSTRACT_UNIX_SOCKET | LANDLOCK_SCOPE_SIGNAL,
+ .quiet_scoped = LANDLOCK_SCOPE_ABSTRACT_UNIX_SOCKET |
+ LANDLOCK_SCOPE_SIGNAL,
+};
+
+// clang-format off
+FIXTURE_VARIANT_ADD(scoped_audit, quiet_unrelated)
+{
+ // clang-format on
+ .scoped = LANDLOCK_SCOPE_ABSTRACT_UNIX_SOCKET | LANDLOCK_SCOPE_SIGNAL,
+ .quiet_scoped = LANDLOCK_SCOPE_SIGNAL,
+};
+
/* python -c 'print(b"\0selftests-landlock-abstract-unix-".hex().upper())' */
#define ABSTRACT_SOCKET_PATH_PREFIX \
"0073656C6674657374732D6C616E646C6F636B2D61627374726163742D756E69782D"
@@ -308,6 +347,13 @@ TEST_F(scoped_audit, connect_to_child)
char buf;
int dgram_client;
struct audit_records records;
+ int ruleset_fd;
+ const struct landlock_ruleset_attr ruleset_attr = {
+ .scoped = variant->scoped,
+ .quiet_scoped = variant->quiet_scoped,
+ };
+ bool should_audit =
+ !(variant->quiet_scoped & LANDLOCK_SCOPE_ABSTRACT_UNIX_SOCKET);
/* Makes sure there is no superfluous logged records. */
EXPECT_EQ(0, audit_count_records(self->audit_fd, &records));
@@ -345,7 +391,14 @@ TEST_F(scoped_audit, connect_to_child)
EXPECT_EQ(0, close(pipe_child[1]));
EXPECT_EQ(0, close(pipe_parent[0]));
- create_scoped_domain(_metadata, LANDLOCK_SCOPE_ABSTRACT_UNIX_SOCKET);
+ ruleset_fd =
+ landlock_create_ruleset(&ruleset_attr, sizeof(ruleset_attr), 0);
+ ASSERT_LE(0, ruleset_fd)
+ {
+ TH_LOG("Failed to create a ruleset: %s", strerror(errno));
+ }
+ enforce_ruleset(_metadata, ruleset_fd);
+ EXPECT_EQ(0, close(ruleset_fd));
/* Signals that the parent is in a domain, if any. */
ASSERT_EQ(1, write(pipe_parent[1], ".", 1));
@@ -360,14 +413,20 @@ TEST_F(scoped_audit, connect_to_child)
EXPECT_EQ(-1, err_dgram);
EXPECT_EQ(EPERM, errno);
- EXPECT_EQ(
- 0,
- audit_match_record(
- self->audit_fd, AUDIT_LANDLOCK_ACCESS,
- REGEX_LANDLOCK_PREFIX
- " blockers=scope\\.abstract_unix_socket path=" ABSTRACT_SOCKET_PATH_PREFIX
- "[0-9A-F]\\+$",
- NULL));
+ if (should_audit) {
+ EXPECT_EQ(
+ 0,
+ audit_match_record(
+ self->audit_fd, AUDIT_LANDLOCK_ACCESS,
+ REGEX_LANDLOCK_PREFIX
+ " blockers=scope\\.abstract_unix_socket path=" ABSTRACT_SOCKET_PATH_PREFIX
+ "[0-9A-F]\\+$",
+ NULL));
+ }
+
+ /* No other logs */
+ EXPECT_EQ(0, audit_count_records(self->audit_fd, &records));
+ EXPECT_EQ(0, records.access);
ASSERT_EQ(1, write(pipe_parent[1], ".", 1));
EXPECT_EQ(0, close(dgram_client));
--
2.52.0
^ permalink raw reply related
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