* Re: [PATCH RFC 2/3] LSM: Enforce exclusive hooks
From: Paul Moore @ 2026-04-24 1:19 UTC (permalink / raw)
To: Casey Schaufler, casey, linux-security-module
Cc: jmorris, serge, keescook, john.johansen, penguin-kernel,
stephen.smalley.work, selinux
In-Reply-To: <20260225192143.14448-3-casey@schaufler-ca.com>
On Feb 25, 2026 Casey Schaufler <casey@schaufler-ca.com> wrote:
>
> If an LSM hook is marked as exclusive via LSM_FLAG_EXCLUSIVE
> in lsm_hook_defs.h it will not be added to the set of hooks to
> be executed if an different LSM has already registered an
> exclusive hook.
>
> Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
> ---
> include/linux/security.h | 2 ++
> security/lsm_init.c | 66 ++++++++++++++++++++++++++++++++++++++++
> 2 files changed, 68 insertions(+)
>
> diff --git a/include/linux/security.h b/include/linux/security.h
> index 83a646d72f6f..e3c137a1b30a 100644
> --- a/include/linux/security.h
> +++ b/include/linux/security.h
> @@ -2404,4 +2404,6 @@ static inline void security_initramfs_populated(void)
> }
> #endif /* CONFIG_SECURITY */
>
> +extern u64 lsm_exclusive_hooks;
We already have the 'lsm_exclusive' variable in lsm_init.c, don't create
another variable that does the same thing. If the scope of the existing
variable isn't what you need, change that.
Although to be honest, I'm not in love with what you're doing with the
variable anyway, more on that later in the review.
> #endif /* ! __LINUX_SECURITY_H */
> diff --git a/security/lsm_init.c b/security/lsm_init.c
> index 05bd52e6b1f2..dc3c84387a7e 100644
> --- a/security/lsm_init.c
> +++ b/security/lsm_init.c
> @@ -356,6 +356,70 @@ static int __init lsm_static_call_init(struct security_hook_list *hl)
> return -ENOSPC;
> }
>
> +/*
> + * Hooks that are restricted to use by a single security module.
> + *
> + * Secmark hooks have not been converted from secids to lsm_props
> + * due to space limitations in packet headers.
If this is a general purpose mechanism for all types of LSM hooks, please
don't put commentary in here about a single class of hook.
If this only reason for doing all of this is for secmark, just fix
secmark instead of going through all of this trouble.
> + * Conversions from a secid to a secctx are restricted to the
> + * single security module. All cases where there may be multiple
> + * modules providing the input data have been converted to use
> + * a lsm_prop instead of a secid.
Okay, yes, the paragraph above is true, I'm just not sure why it is
important here?
> + */
> +struct lsm_exclusive {
> + struct lsm_static_call *name;
> + char *namestr;
> + u32 flags;
> +};
> +
> +static __initdata struct lsm_exclusive lsm_exclusive_set[] = {
> +#define LSM_HOOK(RET, DEFAULT, FLAGS, NAME, ...) \
> + { .name = static_calls_table.NAME, .flags = FLAGS, .namestr = "" #NAME "" , },
> +#include <linux/lsm_hook_defs.h>
> +#undef LSM_HOOK
> +};
> +u64 lsm_exclusive_hooks;
> +EXPORT_SYMBOL(lsm_exclusive_hooks);
Unless I missed something, we really shouldn't need to export this, why
did you need EXPORT_SYMBOL() here?
> +/**
> + * lsm_exclusive_hook_denial - Check if exclusive hook is in use
> + * @hook: the hook to check
> + *
> + * Check if the hook in question is restricted to a single using LSM,
> + * and if the LSM providing single LSM hooks is defined.
> + *
> + * Returns true if the hook is exclusive and they are already provided,
> + * false otherwise.
> + */
> +static bool __init lsm_exclusive_hook_denial(struct security_hook_list *hook)
> +{
> + int i;
> +
> + if (lsm_exclusive_hooks == hook->lsmid->id)
> + return false;
> +
> + for (i = 0; i < ARRAY_SIZE(lsm_exclusive_set); i++) {
> + if (!(lsm_exclusive_set[i].flags & LSM_FLAG_EXCLUSIVE))
> + continue;
The logic on this looks a bit odd. What is wrong with something like the
pseduo code below?
for (i = 0; ARRAY_SIZE(lsm_hooks); i++) {
if (lsm_hooks[i] == hook) {
if (lsm_hooks[i].flags & LSM_FLAG_EXCLUSIVE)
return true;
else
return false;
}
}
> + if (hook->scalls == lsm_exclusive_set[i].name) {
> + if (lsm_exclusive_hooks) {
> + if (lsm_debug)
> + lsm_pr("%s denied for %s.\n",
> + lsm_exclusive_set[i].namestr,
> + hook->lsmid->name);
The lsm_pr_dbg() macro exists for this very reason.
> + return true;
> + }
> + if (lsm_debug)
> + lsm_pr("Exclusive hooks limited to %s.\n",
> + hook->lsmid->name);
Same as above.
> + lsm_exclusive_hooks = hook->lsmid->id;
> + break;
> + }
> + }
> + return false;
> +}
>
> /**
> * security_add_hooks - Add a LSM's hooks to the LSM framework's hook lists
> * @hooks: LSM hooks to add
> @@ -371,6 +435,8 @@ void __init security_add_hooks(struct security_hook_list *hooks, int count,
>
> for (i = 0; i < count; i++) {
> hooks[i].lsmid = lsmid;
> + if (lsm_exclusive_hook_denial(&hooks[i]))
> + continue;
> if (lsm_static_call_init(&hooks[i]))
> panic("exhausted LSM callback slots with LSM %s\n",
> lsmid->name);
I don't think we'd want to simply skip over a hook registration if the
LSM doesn't have access to an exclusive hook. At the very least it risks
unexpected behavior in the LSM and at the worst it prevents the LSM from
properly enforcing it's security policy. There is a reason we have the
panic() call in the existing code if we are not able to register a hook.
The simpliest solution here would be to panic, like we do today.
However, if you want to get fancy and enable LSMs to optionally adjust
their behavior to cope with the loss of a hook callback (I'm looking at
your patch 3/3 now), come up with a mechanism to report back to the LSM
that one or more of the callbacks were not registered. One quick thought
would be to return a non-zero error code and add an indicator/bool/flag
to the security_hook_list that would be set by security_add_hooks().
--
paul-moore.com
^ permalink raw reply
* Re: [PATCH RFC 3/3] LSM: Reserve use of secmarks
From: Paul Moore @ 2026-04-24 1:19 UTC (permalink / raw)
To: Casey Schaufler, casey, linux-security-module
Cc: jmorris, serge, keescook, john.johansen, penguin-kernel,
stephen.smalley.work, selinux
In-Reply-To: <20260225192143.14448-4-casey@schaufler-ca.com>
On Feb 25, 2026 Casey Schaufler <casey@schaufler-ca.com> wrote:
>
> Use of "exclusive" LSM hooks are limited to the first LSM registering
> them. These hooks include those use to process network secmarks.
> The hooks required to process secmarks are flagged with LSM_FLAG_EXCLUSIVE
> in their definitions. This includes secid_to_secctx and secctx_to_secid,
> which are used by netfilter.
>
> The various LSMs that use secmarks are updated to detect whether
> they are providing exclusive hooks, and to eschew the use of secmarks
> if they are not.
>
> SELinux has a peculiar behavior in that it may decide that it
> must have network controls, but only after policy is loaded.
> This patch includes a warning should policy capability alwaysnetwork
> be set when another LSM holds the exclusive hooks. It has been
> suggested that SELinux would consider this a fatal condition, in
> which case a panic might be a favored, if draconian, option.
>
> Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
> ---
> include/linux/lsm_hook_defs.h | 12 +++++------
> include/linux/security.h | 1 +
> security/apparmor/lsm.c | 24 ++++++++++++++++------
> security/security.c | 15 ++++++++++++++
> security/selinux/hooks.c | 35 ++++++++++++++++++++++++--------
> security/selinux/ss/services.c | 3 +++
> security/smack/smack_lsm.c | 6 ++++--
> security/smack/smack_netfilter.c | 6 ++++++
> 8 files changed, 80 insertions(+), 22 deletions(-)
...
> diff --git a/include/linux/security.h b/include/linux/security.h
> index e3c137a1b30a..638436b9b748 100644
> --- a/include/linux/security.h
> +++ b/include/linux/security.h
> @@ -326,6 +326,7 @@ int unregister_blocking_lsm_notifier(struct notifier_block *nb);
> extern int security_init(void);
> extern int early_security_init(void);
> extern u64 lsm_name_to_attr(const char *name);
> +extern u32 lsm_secmark_from_skb(struct sk_buff *skb, const u64 lsmid);
>
> /* Security operations */
> int security_binder_set_context_mgr(const struct cred *mgr);
> diff --git a/security/apparmor/lsm.c b/security/apparmor/lsm.c
> index a87cd60ed206..2ce0d9a73973 100644
> --- a/security/apparmor/lsm.c
> +++ b/security/apparmor/lsm.c
> @@ -1511,9 +1511,11 @@ static int apparmor_socket_shutdown(struct socket *sock, int how)
> static int apparmor_socket_sock_rcv_skb(struct sock *sk, struct sk_buff *skb)
> {
> struct aa_sk_ctx *ctx = aa_sock(sk);
> + u32 secmark;
> int error;
>
> - if (!skb->secmark)
> + secmark = lsm_secmark_from_skb(skb, LSM_ID_APPARMOR);
> + if (!secmark)
> return 0;
>
> /*
...
> diff --git a/security/security.c b/security/security.c
> index 25e7cfc96f20..754b16004677 100644
> --- a/security/security.c
> +++ b/security/security.c
> @@ -4509,6 +4509,21 @@ void security_inet_conn_established(struct sock *sk,
> }
> EXPORT_SYMBOL(security_inet_conn_established);
>
> +/**
> + * lsm_secmark_from_skb - secid for the specified LSM from the packet
> + * @skb: the packet
> + * @lsm: which LSM is asking
> + *
> + * If the specified LSM has use of the secmark, return its value.
> + * Otherwise, return the invalid secid 0.
> + */
> +u32 lsm_secmark_from_skb(struct sk_buff *skb, const u64 lsmid)
> +{
> + if (lsmid == lsm_exclusive_hooks)
> + return skb->secmark;
> + return 0;
> +}
Ooof. Not a fan. A better way to handle this would be to like I
mentioned in my comments on patch 2/3: have the LSM detect that it lost
the LSM_FLAG_EXCLUSIVE battle at callback registration time and do
whatever adjustments are necessary at init time. In a number of cases I
believe that simply not registering the callback will be sufficient.
If the only way to solve this is via runtime checks like this,
unfortunately my answer is going to be "no".
... and of course the proper way to solve this for secmark is to just
do the idr/xarray conversion for secmarks so every LSM can have their
own secmark. Yes, it does require some work, but to be honest I think
you've spent more time avoiding that work then it would be to just do
it. I'm growing increasing inclined to simply state that this is the
only solution I'm going to accept.
--
paul-moore.com
^ permalink raw reply
* Re: [RFC PATCH v2 1/4] security: ima: call ima_init() again at late_initcall_sync for defered TPM
From: Paul Moore @ 2026-04-24 1:27 UTC (permalink / raw)
To: Mimi Zohar, roberto.sassu
Cc: Yeoreum Yun, Jonathan McDowell, linux-security-module,
linux-kernel, linux-integrity, linux-arm-kernel, kvmarm, jmorris,
serge, dmitry.kasatkin, eric.snowberg, jarkko, jgg, sudeep.holla,
maz, oupton, joey.gouly, suzuki.poulose, yuzenghui,
catalin.marinas, will, noodles, sebastianene
In-Reply-To: <aephL3MzYoqFGaT5@e129823.arm.com>
On Thu, Apr 23, 2026 at 2:13 PM Yeoreum Yun <yeoreum.yun@arm.com> wrote:
>
> Sounds good. Once the patch is posted, I’ll review it as well.
> Sorry again for the noise, and thanks for your patience ;)
My apologies for not getting a chance to look at this patchset sooner.
This seems like an obvious, perhaps even stupid, question, but I have
to ask: if IMA can be properly initialized via late_initcall_sync(),
why not simply do the initialization in late_initcall_sync() and drop
the late_initcall() initialization?
Does any IMA functionality suffer if initialization waits until
late_initcall_sync()? If so, it seems non-critical if waiting until
_sync() is acceptable, as it appears in these patches/comments.
--
paul-moore.com
^ permalink raw reply
* Re: [RFC PATCH v2 1/4] security: ima: call ima_init() again at late_initcall_sync for defered TPM
From: Yeoreum Yun @ 2026-04-24 5:57 UTC (permalink / raw)
To: Paul Moore
Cc: Mimi Zohar, roberto.sassu, Jonathan McDowell,
linux-security-module, linux-kernel, linux-integrity,
linux-arm-kernel, kvmarm, jmorris, serge, dmitry.kasatkin,
eric.snowberg, jarkko, jgg, sudeep.holla, maz, oupton, joey.gouly,
suzuki.poulose, yuzenghui, catalin.marinas, will, noodles,
sebastianene
In-Reply-To: <CAHC9VhRQWHEWQ5NzOPiu8jtYv6UsRm8WVS4fd74AbkOcAd4y_g@mail.gmail.com>
Hi Paul,
> On Thu, Apr 23, 2026 at 2:13 PM Yeoreum Yun <yeoreum.yun@arm.com> wrote:
> >
> > Sounds good. Once the patch is posted, I’ll review it as well.
> > Sorry again for the noise, and thanks for your patience ;)
>
> My apologies for not getting a chance to look at this patchset sooner.
>
> This seems like an obvious, perhaps even stupid, question, but I have
> to ask: if IMA can be properly initialized via late_initcall_sync(),
> why not simply do the initialization in late_initcall_sync() and drop
> the late_initcall() initialization?
>
> Does any IMA functionality suffer if initialization waits until
> late_initcall_sync()? If so, it seems non-critical if waiting until
> _sync() is acceptable, as it appears in these patches/comments.
This is the way first patch did, and here is some discussion for this
(Might you have seen, but in case of you missed):
- https://lore.kernel.org/all/a6a0e15286c983d720de227c6827adbe976c5b9b.camel@linux.ibm.com/
Thanks.
--
Sincerely,
Yeoreum Yun
^ permalink raw reply
* Re: [PATCH v3] evm: terminate and bound the evm_xattrs read buffer
From: Roberto Sassu @ 2026-04-24 8:13 UTC (permalink / raw)
To: Pengpeng Hou, Mimi Zohar
Cc: Roberto Sassu, Dmitry Kasatkin, Eric Snowberg, Paul Moore,
James Morris, Serge Hallyn, linux-integrity,
linux-security-module, linux-kernel
In-Reply-To: <20260424070101.1-evm-v3-pengpeng@iscas.ac.cn>
On Thu, 2026-04-23 at 23:30 +0800, Pengpeng Hou wrote:
> evm_read_xattrs() allocates size + 1 bytes, fills them from the list of
> enabled xattrs, and then passes strlen(temp) to
> simple_read_from_buffer(). When no configured xattrs are enabled, the
> fill loop stores nothing and temp[0] remains uninitialized, so strlen()
> reads beyond initialized memory.
>
> Explicitly terminate the buffer after allocation, use snprintf() for
> each formatted line, and pass the accumulated length, without risk of
> truncation, to simple_read_from_buffer().
>
> Fixes: fa516b66a1bf ("EVM: Allow runtime modification of the set of verified xattrs")
> Signed-off-by: Pengpeng Hou <pengpeng@iscas.ac.cn>
Reviewed-by: Roberto Sassu <roberto.sassu@huawei.com>
Thanks
Roberto
> ---
> Changes since v2:
> - adjust the changelog wording to mention why the accumulated length is
> safe
> - add the blank line after the allocation error path
> - add a comment explaining why snprintf() cannot truncate in the fill loop
>
> diff --git a/security/integrity/evm/evm_secfs.c b/security/integrity/evm/evm_secfs.c
> index acd840461902..4baf5e23bc97 100644
> --- a/security/integrity/evm/evm_secfs.c
> +++ b/security/integrity/evm/evm_secfs.c
> @@ -127,8 +127,8 @@ static ssize_t evm_read_xattrs(struct file *filp, char __user *buf,
> size_t count, loff_t *ppos)
> {
> char *temp;
> - int offset = 0;
> - ssize_t rc, size = 0;
> + size_t offset = 0, size = 0;
> + ssize_t rc;
> struct xattr_list *xattr;
>
> if (*ppos != 0)
> @@ -151,16 +151,22 @@ static ssize_t evm_read_xattrs(struct file *filp, char __user *buf,
> return -ENOMEM;
> }
>
> + temp[size] = '\0';
> +
> + /*
> + * No truncation possible: size is computed over the same enabled
> + * xattrs under xattr_list_mutex, so offset never exceeds size.
> + */
> list_for_each_entry(xattr, &evm_config_xattrnames, list) {
> if (!xattr->enabled)
> continue;
>
> - sprintf(temp + offset, "%s\n", xattr->name);
> - offset += strlen(xattr->name) + 1;
> + offset += snprintf(temp + offset, size + 1 - offset, "%s\n",
> + xattr->name);
> }
>
> mutex_unlock(&xattr_list_mutex);
> - rc = simple_read_from_buffer(buf, count, ppos, temp, strlen(temp));
> + rc = simple_read_from_buffer(buf, count, ppos, temp, offset);
>
> kfree(temp);
>
^ permalink raw reply
* [PATCH] ima: Fix sigv3 signature handling for EVM_IMA_XATTR_DIGSIG
From: Kamlesh Kumar @ 2026-04-24 11:39 UTC (permalink / raw)
To: zohar, stefanb
Cc: linux-integrity, linux-security-module, linux-kernel,
Kamlesh Kumar
ima_get_hash_algo() only recognizes version 2 signatures when the xattr
type is EVM_IMA_XATTR_DIGSIG. Since sigv3 signatures also use
EVM_IMA_XATTR_DIGSIG as the xattr type, version 3 must be accepted as
well to correctly determine the hash algorithm.
Additionally, ima_validate_rule() does not include IMA_SIGV3_REQUIRED in
the allowed flags bitmask for MODULE_CHECK, KEXEC_KERNEL_CHECK, and
KEXEC_INITRAMFS_CHECK hook functions. As a result, policy rules with
"appraise_type=sigv3" are rejected for these functions.
Add version 3 to the accepted versions in ima_get_hash_algo() for
EVM_IMA_XATTR_DIGSIG, and add IMA_SIGV3_REQUIRED to the allowed flags
for MODULE_CHECK, KEXEC_KERNEL_CHECK, and KEXEC_INITRAMFS_CHECK in
ima_validate_rule().
Signed-off-by: Kamlesh Kumar <kam@juniper.net>
---
security/integrity/ima/ima_appraise.c | 5 +++--
security/integrity/ima/ima_policy.c | 3 ++-
2 files changed, 5 insertions(+), 3 deletions(-)
diff --git a/security/integrity/ima/ima_appraise.c b/security/integrity/ima/ima_appraise.c
index de963b9f3634..2dd231567710 100644
--- a/security/integrity/ima/ima_appraise.c
+++ b/security/integrity/ima/ima_appraise.c
@@ -195,8 +195,9 @@ enum hash_algo ima_get_hash_algo(const struct evm_ima_xattr_data *xattr_value,
return sig->hash_algo;
case EVM_IMA_XATTR_DIGSIG:
sig = (typeof(sig))xattr_value;
- if (sig->version != 2 || xattr_len <= sizeof(*sig)
- || sig->hash_algo >= HASH_ALGO__LAST)
+ if ((sig->version != 2 && sig->version != 3) ||
+ xattr_len <= sizeof(*sig) ||
+ sig->hash_algo >= HASH_ALGO__LAST)
return ima_hash_algo;
return sig->hash_algo;
case IMA_XATTR_DIGEST_NG:
diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c
index f7f940a76922..b1c010e8eb13 100644
--- a/security/integrity/ima/ima_policy.c
+++ b/security/integrity/ima/ima_policy.c
@@ -1313,7 +1313,8 @@ static bool ima_validate_rule(struct ima_rule_entry *entry)
IMA_GID | IMA_EGID |
IMA_FGROUP | IMA_DIGSIG_REQUIRED |
IMA_PERMIT_DIRECTIO | IMA_MODSIG_ALLOWED |
- IMA_CHECK_BLACKLIST | IMA_VALIDATE_ALGOS))
+ IMA_CHECK_BLACKLIST | IMA_VALIDATE_ALGOS |
+ IMA_SIGV3_REQUIRED))
return false;
break;
base-commit: 82bbd447199ff1441031d2eaf9afe041550cf525
--
2.34.1
^ permalink raw reply related
* [RFC PATCH v3 0/4] Fix IMA + TPM initialisation ordering issue
From: Jonathan McDowell @ 2026-04-24 13:23 UTC (permalink / raw)
To: linux-security-module, linux-kernel, linux-integrity,
linux-arm-kernel, kvmarm
Cc: paul, jmorris, serge, zohar, roberto.sassu, dmitry.kasatkin,
eric.snowberg, jarkko, jgg, sudeep.holla, maz, oupton, joey.gouly,
suzuki.poulose, yuzenghui, catalin.marinas, will, noodles,
sebastianene, Yeoreum Yun
This is a slight reworking of the series from Yeoreum Yun, adding
functionality for IMA initialisation during the late_initcall_sync
stage. This solves the situation where the TPM is not fully registered
at the point IMA wants to initialise, avoiding a failure to correctly
extend TPM measurements from IMA. This has been observed on both Arm
FF-A and SPI attached TPM setups.
As part of this series we also revert the original changes made to the
FF-A driver to try and solve this problem.
(I have left Yeoreum credited in all the diffs except my rework of the
IMA piece. Yeoreum, please yell if you're not happy with this.)
Patch history
=============
from v2 to v3:
- Drop ff-a/pKVM diff (this seems to have a separate set of
discussion)
- Rework IMA delayed initialisation to avoid delaying when unnecessary
- Ensure IMA log clearly indicates when we've initialised late
from v1 to v2:
- add notifier to make ffa-driver pkvm initialised.
- modify to try initailisation again when IMA coudln't find proper TPM device.
- https://lore.kernel.org/all/20260417175759.3191279-1-yeoreum.yun@arm.com/#t
Jonathan McDowell (1):
security: ima: call ima_init() again at late_initcall_sync for defered
TPM
Yeoreum Yun (3):
lsm: Allow LSMs to register for late_initcall_sync init
Revert "tpm: tpm_crb_ffa: try to probe tpm_crb_ffa when it's built-in"
Revert "firmware: arm_ffa: Change initcall level of ffa_init() to
rootfs_initcall"
drivers/char/tpm/tpm_crb_ffa.c | 19 ++----------
drivers/firmware/arm_ffa/driver.c | 2 +-
include/linux/lsm_hooks.h | 2 ++
security/integrity/ima/ima.h | 3 +-
security/integrity/ima/ima_init.c | 25 ++++++++-------
security/integrity/ima/ima_main.c | 37 ++++++++++++++++++++---
security/integrity/ima/ima_template_lib.c | 3 +-
security/lsm_init.c | 13 ++++++--
8 files changed, 67 insertions(+), 37 deletions(-)
--
2.53.0
^ permalink raw reply
* [RFC PATCH v3 1/4] lsm: Allow LSMs to register for late_initcall_sync init
From: Jonathan McDowell @ 2026-04-24 13:24 UTC (permalink / raw)
To: linux-security-module, linux-kernel, linux-integrity,
linux-arm-kernel, kvmarm
Cc: paul, jmorris, serge, zohar, roberto.sassu, dmitry.kasatkin,
eric.snowberg, jarkko, jgg, sudeep.holla, maz, oupton, joey.gouly,
suzuki.poulose, yuzenghui, catalin.marinas, will, noodles,
sebastianene, Yeoreum Yun
In-Reply-To: <cover.1777036497.git.noodles@meta.com>
From: Yeoreum Yun <yeoreum.yun@arm.com>
There are situations where LSMs have dependencies that might mean they
want to be initialised later in the boot process, to ensure those
dependencies are available. In particular there are some TPM setups (Arm
FF-A devices, SPI attached TPMs) required by IMA which are not
guaranteed to be initialised for regular initcall_late.
Add an initcall_late_sync option that can be used in these situations.
[noodles: Split out from actual IMA changes]
Signed-off-by: Yeoreum Yun <yeoreum.yun@arm.com>
Signed-off-by: Jonathan McDowell <noodles@meta.com>
---
include/linux/lsm_hooks.h | 2 ++
security/lsm_init.c | 13 +++++++++++--
2 files changed, 13 insertions(+), 2 deletions(-)
diff --git a/include/linux/lsm_hooks.h b/include/linux/lsm_hooks.h
index d48bf0ad26f4..88fe105b7f00 100644
--- a/include/linux/lsm_hooks.h
+++ b/include/linux/lsm_hooks.h
@@ -166,6 +166,7 @@ enum lsm_order {
* @initcall_fs: LSM callback for fs_initcall setup, optional
* @initcall_device: LSM callback for device_initcall() setup, optional
* @initcall_late: LSM callback for late_initcall() setup, optional
+ * @initcall_late_sync: LSM callback for late_initcall_sync() setup, optional
*/
struct lsm_info {
const struct lsm_id *id;
@@ -181,6 +182,7 @@ struct lsm_info {
int (*initcall_fs)(void);
int (*initcall_device)(void);
int (*initcall_late)(void);
+ int (*initcall_late_sync)(void);
};
#define DEFINE_LSM(lsm) \
diff --git a/security/lsm_init.c b/security/lsm_init.c
index 573e2a7250c4..4e5c59beb82a 100644
--- a/security/lsm_init.c
+++ b/security/lsm_init.c
@@ -547,13 +547,22 @@ device_initcall(security_initcall_device);
* security_initcall_late - Run the LSM late initcalls
*/
static int __init security_initcall_late(void)
+{
+ return lsm_initcall(late);
+}
+late_initcall(security_initcall_late);
+
+/**
+ * security_initcall_late_sync - Run the LSM late initcalls sync
+ */
+static int __init security_initcall_late_sync(void)
{
int rc;
- rc = lsm_initcall(late);
+ rc = lsm_initcall(late_sync);
lsm_pr_dbg("all enabled LSMs fully activated\n");
call_blocking_lsm_notifier(LSM_STARTED_ALL, NULL);
return rc;
}
-late_initcall(security_initcall_late);
+late_initcall_sync(security_initcall_late_sync);
--
2.53.0
^ permalink raw reply related
* [RFC PATCH v3 2/4] security: ima: call ima_init() again at late_initcall_sync for defered TPM
From: Jonathan McDowell @ 2026-04-24 13:24 UTC (permalink / raw)
To: linux-security-module, linux-kernel, linux-integrity,
linux-arm-kernel, kvmarm
Cc: paul, jmorris, serge, zohar, roberto.sassu, dmitry.kasatkin,
eric.snowberg, jarkko, jgg, sudeep.holla, maz, oupton, joey.gouly,
suzuki.poulose, yuzenghui, catalin.marinas, will, noodles,
sebastianene, Yeoreum Yun
In-Reply-To: <cover.1777036497.git.noodles@meta.com>
From: Jonathan McDowell <noodles@meta.com>
The Linux IMA (Integrity Measurement Architecture) subsystem used for
secure boot, file integrity, or remote attestation cannot be a loadable
module for few reasons listed below:
o Boot-Time Integrity: IMA’s main role is to measure and appraise files
before they are used. This includes measuring critical system files
during early boot (e.g., init, init scripts, login binaries). If IMA
were a module, it would be loaded too late to cover those.
o TPM Dependency: IMA integrates tightly with the TPM to record
measurements into PCRs. The TPM must be initialized early (ideally
before init_ima()), which aligns with IMA being built-in.
o Security Model: IMA is part of a Trusted Computing Base (TCB). Making
it a module would weaken the security model, as a potentially
compromised system could delay or tamper with its initialization.
IMA must be built-in to ensure it starts measuring from the earliest
possible point in boot which inturn implies TPM must be initialised and
ready to use before IMA.
Unfortunately some TPM drivers (such as Arm FF-A, or SPI attached TPM
devices) are not reliably available during the initcall_late stage,
resulting in a log error:
ima: No TPM chip found, activating TPM-bypass!
and no measurements into the TPM by IMA. We can avoid this by doing IMA
init in the initcall_late_sync stage, after the drivers have completed
their init + registration.
Rather than do this everywhere, and needlessly delay the initialisation
of IMA when there is no need to do so, we continue to try to initialise
at the earlier stage, only deferring to the later point if the TPM is
not available yet.
Signed-off-by: Jonathan McDowell <noodles@meta.com>
---
security/integrity/ima/ima.h | 3 +-
security/integrity/ima/ima_init.c | 25 ++++++++-------
security/integrity/ima/ima_main.c | 37 ++++++++++++++++++++---
security/integrity/ima/ima_template_lib.c | 3 +-
4 files changed, 50 insertions(+), 18 deletions(-)
diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h
index 89ebe98ffc5e..b3677b403a5a 100644
--- a/security/integrity/ima/ima.h
+++ b/security/integrity/ima/ima.h
@@ -65,6 +65,7 @@ extern struct ima_algo_desc *ima_algo_array __ro_after_init;
extern int ima_appraise;
extern struct tpm_chip *ima_tpm_chip;
extern const char boot_aggregate_name[];
+extern const char boot_aggregate_late_name[];
/* IMA event related data */
struct ima_event_data {
@@ -257,7 +258,7 @@ static inline void ima_measure_kexec_event(const char *event_name) {}
extern bool ima_canonical_fmt;
/* Internal IMA function definitions */
-int ima_init(void);
+int ima_init_core(bool late);
int ima_fs_init(void);
int ima_add_template_entry(struct ima_template_entry *entry, int violation,
const char *op, struct inode *inode,
diff --git a/security/integrity/ima/ima_init.c b/security/integrity/ima/ima_init.c
index a2f34f2d8ad7..5f335834a9bb 100644
--- a/security/integrity/ima/ima_init.c
+++ b/security/integrity/ima/ima_init.c
@@ -22,6 +22,7 @@
/* name for boot aggregate entry */
const char boot_aggregate_name[] = "boot_aggregate";
+const char boot_aggregate_late_name[] = "boot_aggregate_late";
struct tpm_chip *ima_tpm_chip;
/* Add the boot aggregate to the IMA measurement list and extend
@@ -39,17 +40,17 @@ struct tpm_chip *ima_tpm_chip;
* a different value.) Violations add a zero entry to the measurement
* list and extend the aggregate PCR value with ff...ff's.
*/
-static int __init ima_add_boot_aggregate(void)
+static int __init ima_add_boot_aggregate(bool late)
{
static const char op[] = "add_boot_aggregate";
const char *audit_cause = "ENOMEM";
struct ima_template_entry *entry;
struct ima_iint_cache tmp_iint, *iint = &tmp_iint;
- struct ima_event_data event_data = { .iint = iint,
- .filename = boot_aggregate_name };
+ struct ima_event_data event_data = { .iint = iint };
struct ima_max_digest_data hash;
struct ima_digest_data *hash_hdr = container_of(&hash.hdr,
struct ima_digest_data, hdr);
+ const char *filename;
int result = -ENOMEM;
int violation = 0;
@@ -59,6 +60,12 @@ static int __init ima_add_boot_aggregate(void)
iint->ima_hash->algo = ima_hash_algo;
iint->ima_hash->length = hash_digest_size[ima_hash_algo];
+ if (late)
+ filename = boot_aggregate_late_name;
+ else
+ filename = boot_aggregate_name;
+ event_data.filename = filename;
+
/*
* With TPM 2.0 hash agility, TPM chips could support multiple TPM
* PCR banks, allowing firmware to configure and enable different
@@ -86,7 +93,7 @@ static int __init ima_add_boot_aggregate(void)
}
result = ima_store_template(entry, violation, NULL,
- boot_aggregate_name,
+ filename,
CONFIG_IMA_MEASURE_PCR_IDX);
if (result < 0) {
ima_free_template_entry(entry);
@@ -95,7 +102,7 @@ static int __init ima_add_boot_aggregate(void)
}
return 0;
err_out:
- integrity_audit_msg(AUDIT_INTEGRITY_PCR, NULL, boot_aggregate_name, op,
+ integrity_audit_msg(AUDIT_INTEGRITY_PCR, NULL, filename, op,
audit_cause, result, 0);
return result;
}
@@ -115,14 +122,10 @@ void __init ima_load_x509(void)
}
#endif
-int __init ima_init(void)
+int __init ima_init_core(bool late)
{
int rc;
- ima_tpm_chip = tpm_default_chip();
- if (!ima_tpm_chip)
- pr_info("No TPM chip found, activating TPM-bypass!\n");
-
rc = integrity_init_keyring(INTEGRITY_KEYRING_IMA);
if (rc)
return rc;
@@ -140,7 +143,7 @@ int __init ima_init(void)
rc = ima_init_digests();
if (rc != 0)
return rc;
- rc = ima_add_boot_aggregate(); /* boot aggregate must be first entry */
+ rc = ima_add_boot_aggregate(late); /* boot aggregate must be first entry */
if (rc != 0)
return rc;
diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c
index 1d6229b156fb..0b93a286c0d3 100644
--- a/security/integrity/ima/ima_main.c
+++ b/security/integrity/ima/ima_main.c
@@ -1237,7 +1237,7 @@ static int ima_kernel_module_request(char *kmod_name)
#endif /* CONFIG_INTEGRITY_ASYMMETRIC_KEYS */
-static int __init init_ima(void)
+static int __init init_ima(bool late)
{
int error;
@@ -1247,10 +1247,26 @@ static int __init init_ima(void)
return 0;
}
+ /*
+ * If we found the TPM during our first attempt, or we know there's no
+ * TPM, nothing further to do
+ */
+ if (late && (ima_tpm_chip || !IS_ENABLED(CONFIG_TCG_TPM)))
+ return 0;
+
+ ima_tpm_chip = tpm_default_chip();
+ if (!ima_tpm_chip && !late && IS_ENABLED(CONFIG_TCG_TPM)) {
+ pr_debug("TPM not available, will try later\n");
+ return -EPROBE_DEFER;
+ }
+
+ if (!ima_tpm_chip)
+ pr_info("No TPM chip found, activating TPM-bypass!\n");
+
ima_appraise_parse_cmdline();
ima_init_template_list();
hash_setup(CONFIG_IMA_DEFAULT_HASH);
- error = ima_init();
+ error = ima_init_core(late);
if (error && strcmp(hash_algo_name[ima_hash_algo],
CONFIG_IMA_DEFAULT_HASH) != 0) {
@@ -1258,7 +1274,7 @@ static int __init init_ima(void)
hash_algo_name[ima_hash_algo], CONFIG_IMA_DEFAULT_HASH);
hash_setup_done = 0;
hash_setup(CONFIG_IMA_DEFAULT_HASH);
- error = ima_init();
+ error = ima_init_core(late);
}
if (error)
@@ -1274,6 +1290,16 @@ static int __init init_ima(void)
return error;
}
+static int __init init_ima_late(void)
+{
+ return init_ima(false);
+}
+
+static int __init init_ima_late_sync(void)
+{
+ return init_ima(true);
+}
+
static struct security_hook_list ima_hooks[] __ro_after_init = {
LSM_HOOK_INIT(bprm_check_security, ima_bprm_check),
LSM_HOOK_INIT(bprm_creds_for_exec, ima_bprm_creds_for_exec),
@@ -1319,6 +1345,7 @@ DEFINE_LSM(ima) = {
.init = init_ima_lsm,
.order = LSM_ORDER_LAST,
.blobs = &ima_blob_sizes,
- /* Start IMA after the TPM is available */
- .initcall_late = init_ima,
+ /* Ensure we start IMA after the TPM is available */
+ .initcall_late = init_ima_late,
+ .initcall_late_sync = init_ima_late_sync,
};
diff --git a/security/integrity/ima/ima_template_lib.c b/security/integrity/ima/ima_template_lib.c
index 0e627eac9c33..8a89236f926c 100644
--- a/security/integrity/ima/ima_template_lib.c
+++ b/security/integrity/ima/ima_template_lib.c
@@ -363,7 +363,8 @@ int ima_eventdigest_init(struct ima_event_data *event_data,
goto out;
}
- if ((const char *)event_data->filename == boot_aggregate_name) {
+ if ((const char *)event_data->filename == boot_aggregate_name ||
+ (const char *)event_data->filename == boot_aggregate_late_name) {
if (ima_tpm_chip) {
hash.hdr.algo = HASH_ALGO_SHA1;
result = ima_calc_boot_aggregate(hash_hdr);
--
2.53.0
^ permalink raw reply related
* [RFC PATCH v3 3/4] Revert "tpm: tpm_crb_ffa: try to probe tpm_crb_ffa when it's built-in"
From: Jonathan McDowell @ 2026-04-24 13:24 UTC (permalink / raw)
To: linux-security-module, linux-kernel, linux-integrity,
linux-arm-kernel, kvmarm
Cc: paul, jmorris, serge, zohar, roberto.sassu, dmitry.kasatkin,
eric.snowberg, jarkko, jgg, sudeep.holla, maz, oupton, joey.gouly,
suzuki.poulose, yuzenghui, catalin.marinas, will, noodles,
sebastianene, Yeoreum Yun
In-Reply-To: <cover.1777036497.git.noodles@meta.com>
From: Yeoreum Yun <yeoreum.yun@arm.com>
This reverts commit 746d9e9f62a6e8ba0eba2b83fc61cfe7fa8797ce.
Now that IMA will retry in the late_initcall_sync level if the TPM is
not available at first, this change is no longer required.
Signed-off-by: Yeoreum Yun <yeoreum.yun@arm.com>
Signed-off-by: Jonathan McDowell <noodles@meta.com>
---
drivers/char/tpm/tpm_crb_ffa.c | 19 +++----------------
1 file changed, 3 insertions(+), 16 deletions(-)
diff --git a/drivers/char/tpm/tpm_crb_ffa.c b/drivers/char/tpm/tpm_crb_ffa.c
index 99f1c1e5644b..05f19c0ebf82 100644
--- a/drivers/char/tpm/tpm_crb_ffa.c
+++ b/drivers/char/tpm/tpm_crb_ffa.c
@@ -123,7 +123,6 @@ struct tpm_crb_ffa {
};
static struct tpm_crb_ffa *tpm_crb_ffa;
-static struct ffa_driver tpm_crb_ffa_driver;
static int tpm_crb_ffa_to_linux_errno(int errno)
{
@@ -177,23 +176,13 @@ static int tpm_crb_ffa_to_linux_errno(int errno)
*/
int tpm_crb_ffa_init(void)
{
- int ret = 0;
-
- if (!IS_MODULE(CONFIG_TCG_ARM_CRB_FFA)) {
- ret = ffa_register(&tpm_crb_ffa_driver);
- if (ret) {
- tpm_crb_ffa = ERR_PTR(-ENODEV);
- return ret;
- }
- }
-
if (!tpm_crb_ffa)
- ret = -ENOENT;
+ return -ENOENT;
if (IS_ERR_VALUE(tpm_crb_ffa))
- ret = -ENODEV;
+ return -ENODEV;
- return ret;
+ return 0;
}
EXPORT_SYMBOL_GPL(tpm_crb_ffa_init);
@@ -405,9 +394,7 @@ static struct ffa_driver tpm_crb_ffa_driver = {
.id_table = tpm_crb_ffa_device_id,
};
-#ifdef MODULE
module_ffa_driver(tpm_crb_ffa_driver);
-#endif
MODULE_AUTHOR("Arm");
MODULE_DESCRIPTION("TPM CRB FFA driver");
--
2.53.0
^ permalink raw reply related
* [RFC PATCH v3 4/4] Revert "firmware: arm_ffa: Change initcall level of ffa_init() to rootfs_initcall"
From: Jonathan McDowell @ 2026-04-24 13:24 UTC (permalink / raw)
To: linux-security-module, linux-kernel, linux-integrity,
linux-arm-kernel, kvmarm
Cc: paul, jmorris, serge, zohar, roberto.sassu, dmitry.kasatkin,
eric.snowberg, jarkko, jgg, sudeep.holla, maz, oupton, joey.gouly,
suzuki.poulose, yuzenghui, catalin.marinas, will, noodles,
sebastianene, Yeoreum Yun
In-Reply-To: <cover.1777036497.git.noodles@meta.com>
From: Yeoreum Yun <yeoreum.yun@arm.com>
This reverts commit 0e0546eabcd6c19765a8dbf5b5db3723e7b0ea75, which was
added to address ordering issues with the IMA LSM initialisation where
the TPM would not be fully ready by the time IMA wanted it. This has
been resolved within IMA by retrying setup during late_initcall_sync if
the TPM is not available at first.
Signed-off-by: Yeoreum Yun <yeoreum.yun@arm.com>
Signed-off-by: Jonathan McDowell <noodles@meta.com>
---
drivers/firmware/arm_ffa/driver.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/firmware/arm_ffa/driver.c b/drivers/firmware/arm_ffa/driver.c
index f2f94d4d533e..01547c5c0e38 100644
--- a/drivers/firmware/arm_ffa/driver.c
+++ b/drivers/firmware/arm_ffa/driver.c
@@ -2106,7 +2106,7 @@ static int __init ffa_init(void)
kfree(drv_info);
return ret;
}
-rootfs_initcall(ffa_init);
+module_init(ffa_init);
static void __exit ffa_exit(void)
{
--
2.53.0
^ permalink raw reply related
* Re: [PATCH v2 0/4] Firmware LSM hook
From: Jason Gunthorpe @ 2026-04-24 14:19 UTC (permalink / raw)
To: Leon Romanovsky
Cc: Paul Moore, Roberto Sassu, KP Singh, Matt Bobrowski,
Alexei Starovoitov, Daniel Borkmann, John Fastabend,
Andrii Nakryiko, Martin KaFai Lau, Eduard Zingerman, Song Liu,
Yonghong Song, Stanislav Fomichev, Hao Luo, Jiri Olsa, Shuah Khan,
Saeed Mahameed, Itay Avraham, Dave Jiang, Jonathan Cameron, bpf,
linux-kernel, linux-kselftest, linux-rdma, Chiara Meiohas,
Maher Sanalla, linux-security-module
In-Reply-To: <20260423140950.GE172828@unreal>
On Thu, Apr 23, 2026 at 05:09:50PM +0300, Leon Romanovsky wrote:
> > > Leon mentioned that different firmware revisions would have different
> > > parameters for a given opcode, and that one would need to inspect
> > > those parameters to properly filter the command. Is that not true, or
> > > am I misreading or misunderstanding Leon's comments?
> >
> > They are ABI stable, so there will be rules about future changes that
> > old software can follow to ignore or reject future things it doesn't
> > understand.
>
> It is wishful thinking and applicable only to mlx5 devices. No one
> promises that other devices follow same ABI rules.
Well, I will definately kick them out of fwctl if they don't.
Jason
^ permalink raw reply
* Re: [PATCH v2 0/4] Firmware LSM hook
From: Jason Gunthorpe @ 2026-04-24 14:36 UTC (permalink / raw)
To: Paul Moore
Cc: Leon Romanovsky, Roberto Sassu, KP Singh, Matt Bobrowski,
Alexei Starovoitov, Daniel Borkmann, John Fastabend,
Andrii Nakryiko, Martin KaFai Lau, Eduard Zingerman, Song Liu,
Yonghong Song, Stanislav Fomichev, Hao Luo, Jiri Olsa, Shuah Khan,
Saeed Mahameed, Itay Avraham, Dave Jiang, Jonathan Cameron, bpf,
linux-kernel, linux-kselftest, linux-rdma, Chiara Meiohas,
Maher Sanalla, linux-security-module
In-Reply-To: <CAHC9VhQbpS9XpO6dWu7gOiX=ppjtAxnNBOFe6s5wjEZNpMRjgw@mail.gmail.com>
On Mon, Apr 20, 2026 at 08:58:09PM -0400, Paul Moore wrote:
> > > > > The access control point itself represents the requested
> > > > > operation. This is possible because the number of networking
> > > > > operations on a given packet is well defined and fairly limited; at a
> > > > > high level the packet is either being sent from the node, received by
> > > > > the node, or is passing through the node.
> > > >
> > > > I think we have the same split, fwctl send/recive analog is also very
> > > > limited.
> > >
> > > Sure, but I thought the goal was to enforce access controls on the
> > > firmware requests based on the opcodes/parameters contained within the
> > > firmware request blob/mailbox?
> >
> > Yes, that's the goal. It is the same as iptables being able to
> > identify that a send system call has a packet that is http or dns.
>
> I think we still have a disconnect here. A packet being a DNS or HTTP
> packet is different from an opcode. The opcode in the iptables isn't
> "DNS" or "HTTP" it is "INPUT", "OUTPUT", or "FORWARD".
I understand that
> Most LSMs will want to know who is initiating the firmware request
> (the subject), the requested operation/opcode (the action/verb), and
> the target of the request (the object, which in this case is likely
> the kernel or the device).
How is
system_u:object_r:httpd_packet_t:s0
A kernel or device? It is a label for packet contents. I also want a
label for packet contents.
> As I understand things, the action/verb is going to be the opcode
> within the firmware request. If you believe I'm wrong about this
> please help me understand why.
You could make that choice, I'm arguing we should not, and it should
be in the object side.
> > - op_X_t is the result of the classifier inspecting the RPC
> > packet. Admin tells the classifier to return op_X_t similar to
> > how --selctx does for iptables.
>
> I've tried to explain how this doesn't match with secmark, but I'm
> evidently doing a poor job.
Yeah, I don't get it at all, sorry. I fell you are making some very
nuanced distinction with HTTP being an object but the HTTP-equivilant
in fwctl is not an object, I can't follow it at all.
By that logic:
iptables -p 80 --string "GET"
Is an action, and it should get a unique action in the tuple.
> If you want to continue with the secmark comparisons it might be
> helpful to spend some time configuring secmark on a SELinux system,
> and writing policy for it, to see how it works.
I think I have a pretty good idea, you haven't said anything that
contradicts what I expect..
> certain action on an object. My concern with your example is that the
> object isn't what is actually being acted upon, it's the requested
> action.
Object is a label for the packet contents.
> The fwctl ioctl/API allows a user to act on a device, with the
> actual action being specified by the fwctl payload. From what I can
> see, the classifier's output is the action, not the object.
You can take that view, it is certainly one valid way to look at it.
But it is completely impractical.
I am arguing for the secmark like view where the content of the packet
decides the object label.
> > The same way secmark cannot pre-identify all the XXX_packet_t's.
>
> Once again, I think there is a disconnect or misunderstanding, on a
> SELinux system using secmark all of the packet types, e.g.
> "XXX_packet_t's", *are* pre-defined in the SELinux policy.
"Pre-defined" in a text files in user space controlled by the admin.
Admin can "pre-define" their fwctl ones too, what is the issue?
AFAICT the only debate here is you want to make fwctl's packet content
an action while allowing iptable's packet content to be an object.
Jason
^ permalink raw reply
* Re: [PATCH RFC 1/3] LSM: add a flags field to the LSM hook definitions
From: Casey Schaufler @ 2026-04-24 15:24 UTC (permalink / raw)
To: Paul Moore, linux-security-module
Cc: jmorris, serge, keescook, john.johansen, penguin-kernel,
stephen.smalley.work, selinux, Casey Schaufler
In-Reply-To: <c25833f447e6c00868b352cfea50d2b2@paul-moore.com>
On 4/23/2026 6:19 PM, Paul Moore wrote:
> On Feb 25, 2026 Casey Schaufler <casey@schaufler-ca.com> wrote:
>> Add a field for flags to the definition of LSM hooks. This allows
>> for hooks to be identified at system initialization for special
>> processing.
>>
>> Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
>> ---
>> include/linux/bpf_lsm.h | 2 +-
>> include/linux/lsm_hook_defs.h | 614 ++++++++++++++++++----------------
>> include/linux/lsm_hooks.h | 4 +-
>> kernel/bpf/bpf_lsm.c | 10 +-
>> security/bpf/hooks.c | 2 +-
>> security/security.c | 6 +-
>> 6 files changed, 331 insertions(+), 307 deletions(-)
>>
>> diff --git a/include/linux/bpf_lsm.h b/include/linux/bpf_lsm.h
>> index 643809cc78c3..d71ba8c87e79 100644
>> --- a/include/linux/bpf_lsm.h
>> +++ b/include/linux/bpf_lsm.h
>> @@ -14,7 +14,7 @@
>>
>> #ifdef CONFIG_BPF_LSM
>>
>> -#define LSM_HOOK(RET, DEFAULT, NAME, ...) \
>> +#define LSM_HOOK(RET, DEFAULT, FLAGS, NAME, ...) \
>> RET bpf_lsm_##NAME(__VA_ARGS__);
>> #include <linux/lsm_hook_defs.h>
>> #undef LSM_HOOK
>> diff --git a/include/linux/lsm_hook_defs.h b/include/linux/lsm_hook_defs.h
>> index 8c42b4bde09c..acda3a02da97 100644
>> --- a/include/linux/lsm_hook_defs.h
>> +++ b/include/linux/lsm_hook_defs.h
>> @@ -18,451 +18,475 @@
>> * The macro LSM_HOOK is used to define the data structures required by
>> * the LSM framework using the pattern:
>> *
>> - * LSM_HOOK(<return_type>, <default_value>, <hook_name>, args...)
>> + * LSM_HOOK(<return_type>, <default_value>, <flags>, <single>,
>> + * <hook_name>, args...)
>> *
>> * struct security_hook_heads {
>> - * #define LSM_HOOK(RET, DEFAULT, NAME, ...) struct hlist_head NAME;
>> + * #define LSM_HOOK(RET, DEFAULT, FLAGS, NAME, ...) struct hlist_head NAME;
>> * #include <linux/lsm_hook_defs.h>
>> * #undef LSM_HOOK
>> * };
>> */
>> -LSM_HOOK(int, 0, binder_set_context_mgr, const struct cred *mgr)
>> -LSM_HOOK(int, 0, binder_transaction, const struct cred *from,
>> +LSM_HOOK(int, 0, 0, binder_set_context_mgr, const struct cred *mgr)
>> +LSM_HOOK(int, 0, 0, binder_transaction, const struct cred *from,
>> const struct cred *to)
> I think adding a flag field to the LSM_HOOK() macro/definitions is a good
> and useful addition, but I'd prefer if we created a LSM_FLAG_NONE #define
> and used it here just so we could avoid the back-to-back 0's and do a bit
> of self-documentation.
I had LSM_FLAG_NONE initially, but removed it when I saw the amount of code
churn it introduced. I'm happy to put it back.
^ permalink raw reply
* Re: [RFC PATCH v3 4/4] Revert "firmware: arm_ffa: Change initcall level of ffa_init() to rootfs_initcall"
From: Sudeep Holla @ 2026-04-24 16:09 UTC (permalink / raw)
To: Jonathan McDowell
Cc: linux-security-module, linux-kernel, Sudeep Holla,
linux-integrity, linux-arm-kernel, kvmarm, paul, jmorris, serge,
zohar, roberto.sassu, dmitry.kasatkin, eric.snowberg, jarkko, jgg,
maz, oupton, joey.gouly, suzuki.poulose, yuzenghui,
catalin.marinas, will, noodles, sebastianene, Yeoreum Yun
In-Reply-To: <2e7b4dc552b45ddf14cc43bc449cbebb4ade0027.1777036497.git.noodles@meta.com>
On Fri, Apr 24, 2026 at 02:24:42PM +0100, Jonathan McDowell wrote:
> From: Yeoreum Yun <yeoreum.yun@arm.com>
>
> This reverts commit 0e0546eabcd6c19765a8dbf5b5db3723e7b0ea75, which was
> added to address ordering issues with the IMA LSM initialisation where
> the TPM would not be fully ready by the time IMA wanted it. This has
> been resolved within IMA by retrying setup during late_initcall_sync if
> the TPM is not available at first.
>
Reviewed-by: Sudeep Holla <sudeep.holla@kernel.org>
--
Regards,
Sudeep
^ permalink raw reply
* Re: [RFC PATCH v3 3/4] Revert "tpm: tpm_crb_ffa: try to probe tpm_crb_ffa when it's built-in"
From: Sudeep Holla @ 2026-04-24 16:10 UTC (permalink / raw)
To: Jonathan McDowell
Cc: linux-security-module, linux-kernel, Sudeep Holla,
linux-integrity, linux-arm-kernel, kvmarm, paul, jmorris, serge,
zohar, roberto.sassu, dmitry.kasatkin, eric.snowberg, jarkko, jgg,
maz, oupton, joey.gouly, suzuki.poulose, yuzenghui,
catalin.marinas, will, noodles, sebastianene, Yeoreum Yun
In-Reply-To: <f8d6dcbeb5bf2d4316989d05dcaae20225774d51.1777036497.git.noodles@meta.com>
On Fri, Apr 24, 2026 at 02:24:30PM +0100, Jonathan McDowell wrote:
> From: Yeoreum Yun <yeoreum.yun@arm.com>
>
> This reverts commit 746d9e9f62a6e8ba0eba2b83fc61cfe7fa8797ce.
>
> Now that IMA will retry in the late_initcall_sync level if the TPM is
> not available at first, this change is no longer required.
>
Acked-by: Sudeep Holla <sudeep.holla@kernel.org>
--
Regards,
Sudeep
^ permalink raw reply
* Re: [RFC PATCH v3 2/4] security: ima: call ima_init() again at late_initcall_sync for defered TPM
From: Yeoreum Yun @ 2026-04-24 16:55 UTC (permalink / raw)
To: Jonathan McDowell
Cc: linux-security-module, linux-kernel, linux-integrity,
linux-arm-kernel, kvmarm, paul, jmorris, serge, zohar,
roberto.sassu, dmitry.kasatkin, eric.snowberg, jarkko, jgg,
sudeep.holla, maz, oupton, joey.gouly, suzuki.poulose, yuzenghui,
catalin.marinas, will, noodles, sebastianene
In-Reply-To: <5552c20c6d6d2ae3bbb6b35124af5d98d2f79163.1777036497.git.noodles@meta.com>
> From: Jonathan McDowell <noodles@meta.com>
>
> The Linux IMA (Integrity Measurement Architecture) subsystem used for
> secure boot, file integrity, or remote attestation cannot be a loadable
> module for few reasons listed below:
>
> o Boot-Time Integrity: IMA’s main role is to measure and appraise files
> before they are used. This includes measuring critical system files
> during early boot (e.g., init, init scripts, login binaries). If IMA
> were a module, it would be loaded too late to cover those.
>
> o TPM Dependency: IMA integrates tightly with the TPM to record
> measurements into PCRs. The TPM must be initialized early (ideally
> before init_ima()), which aligns with IMA being built-in.
>
> o Security Model: IMA is part of a Trusted Computing Base (TCB). Making
> it a module would weaken the security model, as a potentially
> compromised system could delay or tamper with its initialization.
>
> IMA must be built-in to ensure it starts measuring from the earliest
> possible point in boot which inturn implies TPM must be initialised and
> ready to use before IMA.
>
> Unfortunately some TPM drivers (such as Arm FF-A, or SPI attached TPM
> devices) are not reliably available during the initcall_late stage,
> resulting in a log error:
>
> ima: No TPM chip found, activating TPM-bypass!
>
> and no measurements into the TPM by IMA. We can avoid this by doing IMA
> init in the initcall_late_sync stage, after the drivers have completed
> their init + registration.
>
> Rather than do this everywhere, and needlessly delay the initialisation
> of IMA when there is no need to do so, we continue to try to initialise
> at the earlier stage, only deferring to the later point if the TPM is
> not available yet.
>
> Signed-off-by: Jonathan McDowell <noodles@meta.com>
> ---
> security/integrity/ima/ima.h | 3 +-
> security/integrity/ima/ima_init.c | 25 ++++++++-------
> security/integrity/ima/ima_main.c | 37 ++++++++++++++++++++---
> security/integrity/ima/ima_template_lib.c | 3 +-
> 4 files changed, 50 insertions(+), 18 deletions(-)
>
> diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h
> index 89ebe98ffc5e..b3677b403a5a 100644
> --- a/security/integrity/ima/ima.h
> +++ b/security/integrity/ima/ima.h
> @@ -65,6 +65,7 @@ extern struct ima_algo_desc *ima_algo_array __ro_after_init;
> extern int ima_appraise;
> extern struct tpm_chip *ima_tpm_chip;
> extern const char boot_aggregate_name[];
> +extern const char boot_aggregate_late_name[];
>
> /* IMA event related data */
> struct ima_event_data {
> @@ -257,7 +258,7 @@ static inline void ima_measure_kexec_event(const char *event_name) {}
> extern bool ima_canonical_fmt;
>
> /* Internal IMA function definitions */
> -int ima_init(void);
> +int ima_init_core(bool late);
> int ima_fs_init(void);
> int ima_add_template_entry(struct ima_template_entry *entry, int violation,
> const char *op, struct inode *inode,
> diff --git a/security/integrity/ima/ima_init.c b/security/integrity/ima/ima_init.c
> index a2f34f2d8ad7..5f335834a9bb 100644
> --- a/security/integrity/ima/ima_init.c
> +++ b/security/integrity/ima/ima_init.c
> @@ -22,6 +22,7 @@
>
> /* name for boot aggregate entry */
> const char boot_aggregate_name[] = "boot_aggregate";
> +const char boot_aggregate_late_name[] = "boot_aggregate_late";
> struct tpm_chip *ima_tpm_chip;
>
> /* Add the boot aggregate to the IMA measurement list and extend
> @@ -39,17 +40,17 @@ struct tpm_chip *ima_tpm_chip;
> * a different value.) Violations add a zero entry to the measurement
> * list and extend the aggregate PCR value with ff...ff's.
> */
> -static int __init ima_add_boot_aggregate(void)
> +static int __init ima_add_boot_aggregate(bool late)
> {
> static const char op[] = "add_boot_aggregate";
> const char *audit_cause = "ENOMEM";
> struct ima_template_entry *entry;
> struct ima_iint_cache tmp_iint, *iint = &tmp_iint;
> - struct ima_event_data event_data = { .iint = iint,
> - .filename = boot_aggregate_name };
> + struct ima_event_data event_data = { .iint = iint };
> struct ima_max_digest_data hash;
> struct ima_digest_data *hash_hdr = container_of(&hash.hdr,
> struct ima_digest_data, hdr);
> + const char *filename;
> int result = -ENOMEM;
> int violation = 0;
>
> @@ -59,6 +60,12 @@ static int __init ima_add_boot_aggregate(void)
> iint->ima_hash->algo = ima_hash_algo;
> iint->ima_hash->length = hash_digest_size[ima_hash_algo];
>
> + if (late)
> + filename = boot_aggregate_late_name;
> + else
> + filename = boot_aggregate_name;
> + event_data.filename = filename;
> +
> /*
> * With TPM 2.0 hash agility, TPM chips could support multiple TPM
> * PCR banks, allowing firmware to configure and enable different
> @@ -86,7 +93,7 @@ static int __init ima_add_boot_aggregate(void)
> }
>
> result = ima_store_template(entry, violation, NULL,
> - boot_aggregate_name,
> + filename,
> CONFIG_IMA_MEASURE_PCR_IDX);
> if (result < 0) {
> ima_free_template_entry(entry);
> @@ -95,7 +102,7 @@ static int __init ima_add_boot_aggregate(void)
> }
> return 0;
> err_out:
> - integrity_audit_msg(AUDIT_INTEGRITY_PCR, NULL, boot_aggregate_name, op,
> + integrity_audit_msg(AUDIT_INTEGRITY_PCR, NULL, filename, op,
> audit_cause, result, 0);
> return result;
> }
> @@ -115,14 +122,10 @@ void __init ima_load_x509(void)
> }
> #endif
>
> -int __init ima_init(void)
> +int __init ima_init_core(bool late)
> {
> int rc;
>
> - ima_tpm_chip = tpm_default_chip();
> - if (!ima_tpm_chip)
> - pr_info("No TPM chip found, activating TPM-bypass!\n");
> -
> rc = integrity_init_keyring(INTEGRITY_KEYRING_IMA);
> if (rc)
> return rc;
> @@ -140,7 +143,7 @@ int __init ima_init(void)
> rc = ima_init_digests();
> if (rc != 0)
> return rc;
> - rc = ima_add_boot_aggregate(); /* boot aggregate must be first entry */
> + rc = ima_add_boot_aggregate(late); /* boot aggregate must be first entry */
> if (rc != 0)
> return rc;
>
> diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c
> index 1d6229b156fb..0b93a286c0d3 100644
> --- a/security/integrity/ima/ima_main.c
> +++ b/security/integrity/ima/ima_main.c
> @@ -1237,7 +1237,7 @@ static int ima_kernel_module_request(char *kmod_name)
>
> #endif /* CONFIG_INTEGRITY_ASYMMETRIC_KEYS */
>
> -static int __init init_ima(void)
> +static int __init init_ima(bool late)
> {
> int error;
>
> @@ -1247,10 +1247,26 @@ static int __init init_ima(void)
> return 0;
> }
>
> + /*
> + * If we found the TPM during our first attempt, or we know there's no
> + * TPM, nothing further to do
> + */
> + if (late && (ima_tpm_chip || !IS_ENABLED(CONFIG_TCG_TPM)))
> + return 0;
> +
> + ima_tpm_chip = tpm_default_chip();
> + if (!ima_tpm_chip && !late && IS_ENABLED(CONFIG_TCG_TPM)) {
> + pr_debug("TPM not available, will try later\n");
> + return -EPROBE_DEFER;
> + }
> +
> + if (!ima_tpm_chip)
> + pr_info("No TPM chip found, activating TPM-bypass!\n");
> +
> ima_appraise_parse_cmdline();
> ima_init_template_list();
> hash_setup(CONFIG_IMA_DEFAULT_HASH);
> - error = ima_init();
> + error = ima_init_core(late);
>
> if (error && strcmp(hash_algo_name[ima_hash_algo],
> CONFIG_IMA_DEFAULT_HASH) != 0) {
> @@ -1258,7 +1274,7 @@ static int __init init_ima(void)
> hash_algo_name[ima_hash_algo], CONFIG_IMA_DEFAULT_HASH);
> hash_setup_done = 0;
> hash_setup(CONFIG_IMA_DEFAULT_HASH);
> - error = ima_init();
> + error = ima_init_core(late);
> }
>
> if (error)
> @@ -1274,6 +1290,16 @@ static int __init init_ima(void)
> return error;
> }
>
> +static int __init init_ima_late(void)
> +{
> + return init_ima(false);
> +}
> +
> +static int __init init_ima_late_sync(void)
> +{
> + return init_ima(true);
> +}
> +
> static struct security_hook_list ima_hooks[] __ro_after_init = {
> LSM_HOOK_INIT(bprm_check_security, ima_bprm_check),
> LSM_HOOK_INIT(bprm_creds_for_exec, ima_bprm_creds_for_exec),
> @@ -1319,6 +1345,7 @@ DEFINE_LSM(ima) = {
> .init = init_ima_lsm,
> .order = LSM_ORDER_LAST,
> .blobs = &ima_blob_sizes,
> - /* Start IMA after the TPM is available */
> - .initcall_late = init_ima,
> + /* Ensure we start IMA after the TPM is available */
> + .initcall_late = init_ima_late,
> + .initcall_late_sync = init_ima_late_sync,
> };
> diff --git a/security/integrity/ima/ima_template_lib.c b/security/integrity/ima/ima_template_lib.c
> index 0e627eac9c33..8a89236f926c 100644
> --- a/security/integrity/ima/ima_template_lib.c
> +++ b/security/integrity/ima/ima_template_lib.c
> @@ -363,7 +363,8 @@ int ima_eventdigest_init(struct ima_event_data *event_data,
> goto out;
> }
>
> - if ((const char *)event_data->filename == boot_aggregate_name) {
> + if ((const char *)event_data->filename == boot_aggregate_name ||
> + (const char *)event_data->filename == boot_aggregate_late_name) {
> if (ima_tpm_chip) {
> hash.hdr.algo = HASH_ALGO_SHA1;
> result = ima_calc_boot_aggregate(hash_hdr);
> --
> 2.53.0
>
This looks good to me. Feel free to add:
Reviewed-by: Yeoreum Yun <yeoreum.yun@arm.com>
Thanks!
--
Sincerely,
Yeoreum Yun
^ permalink raw reply
* Re: [GIT PULL] AppArmor updates for 7.1
From: pr-tracker-bot @ 2026-04-24 18:32 UTC (permalink / raw)
To: John Johansen; +Cc: Linus Torvalds, open list:SECURITY SUBSYSTEM, LKLM
In-Reply-To: <1d7db151-f119-4270-aee7-b3fb568c47b2@canonical.com>
The pull request you sent on Thu, 23 Apr 2026 16:53:00 -0700:
> git://git.kernel.org/pub/scm/linux/kernel/git/jj/linux-apparmor tags/apparmor-pr-2026-04-23
has been merged into torvalds/linux.git:
https://git.kernel.org/torvalds/c/eefe0b9dee5db64ec87707c8e44f31851f257389
Thank you!
--
Deet-doot-dot, I am a bot.
https://korg.docs.kernel.org/prtracker.html
^ permalink raw reply
* Re: [RFC PATCH v1 01/11] security: add LSM blob and hooks for namespaces
From: Mickaël Salaün @ 2026-04-24 18:56 UTC (permalink / raw)
To: Paul Moore
Cc: Christian Brauner, Günther Noack, Serge E . Hallyn,
Justin Suess, Lennart Poettering, Mikhail Ivanov,
Nicolas Bouchinet, Shervin Oloumi, Tingmao Wang, kernel-team,
linux-fsdevel, linux-kernel, linux-security-module
In-Reply-To: <CAHC9VhT4Cd-FMYhaKgt6Gv-Suu7YJm7YbKZ-vdMwQV7EiWDryA@mail.gmail.com>
On Wed, Apr 22, 2026 at 08:19:59PM -0400, Paul Moore wrote:
> On Thu, Mar 12, 2026 at 6:05 AM Mickaël Salaün <mic@digikod.net> wrote:
> >
> > From: Christian Brauner <brauner@kernel.org>
> >
> > All namespace types now share the same ns_common infrastructure. Extend
> > this to include a security blob so LSMs can start managing namespaces
> > uniformly without having to add one-off hooks or security fields to
> > every individual namespace type.
> >
> > Add a ns_security pointer to ns_common and the corresponding lbs_ns
> > blob size to lsm_blob_sizes. Allocation and freeing hooks are called
> > from the common __ns_common_init() and __ns_common_free() paths so
> > every namespace type gets covered in one go. All information about the
> > namespace type and the appropriate casting helpers to get at the
> > containing namespace are available via ns_common making it
> > straightforward for LSMs to differentiate when they need to.
> >
> > A namespace_install hook is called from validate_ns() during setns(2)
> > giving LSMs a chance to enforce policy on namespace transitions.
> >
> > Individual namespace types can still have their own specialized security
> > hooks when needed. This is just the common baseline that makes it easy
> > to track and manage namespaces from the security side without requiring
> > every namespace type to reinvent the wheel.
> >
> > Cc: Günther Noack <gnoack@google.com>
> > Cc: Paul Moore <paul@paul-moore.com>
> > Cc: Serge E. Hallyn <serge@hallyn.com>
> > Signed-off-by: Christian Brauner <brauner@kernel.org>
> > Link: https://lore.kernel.org/r/20260216-work-security-namespace-v1-1-075c28758e1f@kernel.org
> > ---
> > include/linux/lsm_hook_defs.h | 3 ++
> > include/linux/lsm_hooks.h | 1 +
> > include/linux/ns/ns_common_types.h | 3 ++
> > include/linux/security.h | 20 ++++++++
> > kernel/nscommon.c | 12 +++++
> > kernel/nsproxy.c | 8 +++-
> > security/lsm_init.c | 2 +
> > security/security.c | 76 ++++++++++++++++++++++++++++++
> > 8 files changed, 124 insertions(+), 1 deletion(-)
>
> ...
>
> > diff --git a/kernel/nscommon.c b/kernel/nscommon.c
> > index bdc3c86231d3..de774e374f9d 100644
> > --- a/kernel/nscommon.c
> > +++ b/kernel/nscommon.c
> > @@ -77,6 +81,13 @@ int __ns_common_init(struct ns_common *ns, u32 ns_type, const struct proc_ns_ope
> > ret = proc_alloc_inum(&ns->inum);
> > if (ret)
> > return ret;
> > +
> > + ret = security_namespace_alloc(ns);
> > + if (ret) {
> > + proc_free_inum(ns->inum);
> > + return ret;
> > + }
>
> Since this is an RFC, I'll make the nitpicky comment that it would be
> better if the LSM hook is called security_namespace_init() instead of
> security_namespace_alloc(). This fits better with the convention of
> aligning with the caller's name, as well as to helps to indicate that
> the LSMs will be initializing the LSM state associated with the
> ns_common instance.
Looks good.
>
> > diff --git a/kernel/nsproxy.c b/kernel/nsproxy.c
> > index 259c4b4f1eeb..f0b30d1907e7 100644
> > --- a/kernel/nsproxy.c
> > +++ b/kernel/nsproxy.c
> > @@ -379,7 +379,13 @@ static int prepare_nsset(unsigned flags, struct nsset *nsset)
> >
> > static inline int validate_ns(struct nsset *nsset, struct ns_common *ns)
> > {
> > - return ns->ops->install(nsset, ns);
> > + int ret;
> > +
> > + ret = ns->ops->install(nsset, ns);
> > + if (ret)
> > + return ret;
> > +
> > + return security_namespace_install(nsset, ns);
> > }
>
> Do we also want a security_namespace_switch() called from within
> switch_task_namespaces()? Of course LSMs would not be able to fail or
> return an error at that point, but it seems reasonable that LSMs might
> want to update LSM state associated with the current task once the
> namespaces have been changed. This is similar to all the "_post_" LSM
> hooks we have for various operations in the VFS and network layers.
What cannot be infered from security_namespace_install()?
>
> I think we would want to pass both the task_struct and whichever
> nsproxy instance is not stored in the task_struct to the hook. I
> prefer placing the hook after the task_struct has been updated, but if
> anyone feels strongly that it should be the other way that's okay with
> me.
>
> > diff --git a/security/security.c b/security/security.c
> > index 67af9228c4e9..dcf073cac848 100644
> > --- a/security/security.c
> > +++ b/security/security.c
> > +/**
> > + * security_namespace_free() - Release LSM security data from a namespace
> > + * @ns: the namespace being freed
> > + *
> > + * Release security data attached to the namespace. Called before the
> > + * namespace structure is freed.
> > + *
> > + * Note: The namespace may be freed via kfree_rcu(). LSMs must use
> > + * RCU-safe freeing for any data that might be accessed by concurrent
> > + * RCU readers.
> > + */
> > +void security_namespace_free(struct ns_common *ns)
> > +{
> > + if (!ns->ns_security)
> > + return;
> > +
> > + call_void_hook(namespace_free, ns);
> > +
> > + kfree(ns->ns_security);
> > + ns->ns_security = NULL;
> > +}
>
> The "namespace may be freed via kfree_rcu()" comment in conjunction
> with the standard kfree() in the function above raises a red flag. Do
> we need to take an approach similar to
> security_inode_free()/inode_free_by_rcu() here?
I though at that too, but the key point is that once the namespace is
being freed it is not reachable, which is not the case for inode being
freed (i.e. because of path walks). So I think the current approach is
fine even if the comment might be a bit scary.
>
> --
> paul-moore.com
>
^ permalink raw reply
* Re: [RFC PATCH v1 01/11] security: add LSM blob and hooks for namespaces
From: Paul Moore @ 2026-04-24 19:28 UTC (permalink / raw)
To: Mickaël Salaün
Cc: Christian Brauner, Günther Noack, Serge E . Hallyn,
Justin Suess, Lennart Poettering, Mikhail Ivanov,
Nicolas Bouchinet, Shervin Oloumi, Tingmao Wang, kernel-team,
linux-fsdevel, linux-kernel, linux-security-module
In-Reply-To: <20260424.ein5Aiwah6Ai@digikod.net>
On Fri, Apr 24, 2026 at 2:56 PM Mickaël Salaün <mic@digikod.net> wrote:
> On Wed, Apr 22, 2026 at 08:19:59PM -0400, Paul Moore wrote:
> > On Thu, Mar 12, 2026 at 6:05 AM Mickaël Salaün <mic@digikod.net> wrote:
> > >
> > > From: Christian Brauner <brauner@kernel.org>
> > >
> > > All namespace types now share the same ns_common infrastructure. Extend
> > > this to include a security blob so LSMs can start managing namespaces
> > > uniformly without having to add one-off hooks or security fields to
> > > every individual namespace type.
> > >
> > > Add a ns_security pointer to ns_common and the corresponding lbs_ns
> > > blob size to lsm_blob_sizes. Allocation and freeing hooks are called
> > > from the common __ns_common_init() and __ns_common_free() paths so
> > > every namespace type gets covered in one go. All information about the
> > > namespace type and the appropriate casting helpers to get at the
> > > containing namespace are available via ns_common making it
> > > straightforward for LSMs to differentiate when they need to.
> > >
> > > A namespace_install hook is called from validate_ns() during setns(2)
> > > giving LSMs a chance to enforce policy on namespace transitions.
> > >
> > > Individual namespace types can still have their own specialized security
> > > hooks when needed. This is just the common baseline that makes it easy
> > > to track and manage namespaces from the security side without requiring
> > > every namespace type to reinvent the wheel.
> > >
> > > Cc: Günther Noack <gnoack@google.com>
> > > Cc: Paul Moore <paul@paul-moore.com>
> > > Cc: Serge E. Hallyn <serge@hallyn.com>
> > > Signed-off-by: Christian Brauner <brauner@kernel.org>
> > > Link: https://lore.kernel.org/r/20260216-work-security-namespace-v1-1-075c28758e1f@kernel.org
> > > ---
> > > include/linux/lsm_hook_defs.h | 3 ++
> > > include/linux/lsm_hooks.h | 1 +
> > > include/linux/ns/ns_common_types.h | 3 ++
> > > include/linux/security.h | 20 ++++++++
> > > kernel/nscommon.c | 12 +++++
> > > kernel/nsproxy.c | 8 +++-
> > > security/lsm_init.c | 2 +
> > > security/security.c | 76 ++++++++++++++++++++++++++++++
> > > 8 files changed, 124 insertions(+), 1 deletion(-)
...
> > > diff --git a/kernel/nsproxy.c b/kernel/nsproxy.c
> > > index 259c4b4f1eeb..f0b30d1907e7 100644
> > > --- a/kernel/nsproxy.c
> > > +++ b/kernel/nsproxy.c
> > > @@ -379,7 +379,13 @@ static int prepare_nsset(unsigned flags, struct nsset *nsset)
> > >
> > > static inline int validate_ns(struct nsset *nsset, struct ns_common *ns)
> > > {
> > > - return ns->ops->install(nsset, ns);
> > > + int ret;
> > > +
> > > + ret = ns->ops->install(nsset, ns);
> > > + if (ret)
> > > + return ret;
> > > +
> > > + return security_namespace_install(nsset, ns);
> > > }
> >
> > Do we also want a security_namespace_switch() called from within
> > switch_task_namespaces()? Of course LSMs would not be able to fail or
> > return an error at that point, but it seems reasonable that LSMs might
> > want to update LSM state associated with the current task once the
> > namespaces have been changed. This is similar to all the "_post_" LSM
> > hooks we have for various operations in the VFS and network layers.
>
> What cannot be infered from security_namespace_install()?
We don't actually know if the namespace is attached to a process until
we get to switch_task_namespaces().
Now that I'm looking at this again, why is the
security_namespace_install() call placed after the ns->ops->install()
call? From an access control perspective we want the LSM hook before
the namespace install, not after as in this patch. From an LSM state
update perspective we likely only care about when the namespace/nsset
is assigned to a process.
> > I think we would want to pass both the task_struct and whichever
> > nsproxy instance is not stored in the task_struct to the hook. I
> > prefer placing the hook after the task_struct has been updated, but if
> > anyone feels strongly that it should be the other way that's okay with
> > me.
> >
> > > diff --git a/security/security.c b/security/security.c
> > > index 67af9228c4e9..dcf073cac848 100644
> > > --- a/security/security.c
> > > +++ b/security/security.c
> > > +/**
> > > + * security_namespace_free() - Release LSM security data from a namespace
> > > + * @ns: the namespace being freed
> > > + *
> > > + * Release security data attached to the namespace. Called before the
> > > + * namespace structure is freed.
> > > + *
> > > + * Note: The namespace may be freed via kfree_rcu(). LSMs must use
> > > + * RCU-safe freeing for any data that might be accessed by concurrent
> > > + * RCU readers.
> > > + */
> > > +void security_namespace_free(struct ns_common *ns)
> > > +{
> > > + if (!ns->ns_security)
> > > + return;
> > > +
> > > + call_void_hook(namespace_free, ns);
> > > +
> > > + kfree(ns->ns_security);
> > > + ns->ns_security = NULL;
> > > +}
> >
> > The "namespace may be freed via kfree_rcu()" comment in conjunction
> > with the standard kfree() in the function above raises a red flag. Do
> > we need to take an approach similar to
> > security_inode_free()/inode_free_by_rcu() here?
>
> I though at that too, but the key point is that once the namespace is
> being freed it is not reachable, which is not the case for inode being
> freed (i.e. because of path walks). So I think the current approach is
> fine even if the comment might be a bit scary.
The comment in the code and your comment in this email thread don't
seem to align very well; one of those needs to be fixed in the next
revision ;)
--
paul-moore.com
^ permalink raw reply
* Re: [RFC PATCH v2 1/4] security: ima: call ima_init() again at late_initcall_sync for defered TPM
From: Paul Moore @ 2026-04-24 20:15 UTC (permalink / raw)
To: Yeoreum Yun, Mimi Zohar, roberto.sassu
Cc: Jonathan McDowell, linux-security-module, linux-kernel,
linux-integrity, linux-arm-kernel, kvmarm, jmorris, serge,
dmitry.kasatkin, eric.snowberg, jarkko, jgg, sudeep.holla, maz,
oupton, joey.gouly, suzuki.poulose, yuzenghui, catalin.marinas,
will, noodles, sebastianene
In-Reply-To: <aesGU8a3mbVzvteH@e129823.arm.com>
On Fri, Apr 24, 2026 at 1:57 AM Yeoreum Yun <yeoreum.yun@arm.com> wrote:
> > On Thu, Apr 23, 2026 at 2:13 PM Yeoreum Yun <yeoreum.yun@arm.com> wrote:
> > >
> > > Sounds good. Once the patch is posted, I’ll review it as well.
> > > Sorry again for the noise, and thanks for your patience ;)
> >
> > My apologies for not getting a chance to look at this patchset sooner.
> >
> > This seems like an obvious, perhaps even stupid, question, but I have
> > to ask: if IMA can be properly initialized via late_initcall_sync(),
> > why not simply do the initialization in late_initcall_sync() and drop
> > the late_initcall() initialization?
> >
> > Does any IMA functionality suffer if initialization waits until
> > late_initcall_sync()? If so, it seems non-critical if waiting until
> > _sync() is acceptable, as it appears in these patches/comments.
>
> This is the way first patch did, and here is some discussion for this
> (Might you have seen, but in case of you missed):
> - https://lore.kernel.org/all/a6a0e15286c983d720de227c6827adbe976c5b9b.camel@linux.ibm.com/
Thanks for the pointer.
Unfortunately, my concern remains the same: it's either "safe" to
initialize IMA at late_initcall_sync() or it isn't. Attempting to
initialize IMA twice seems both odd and wrong.
I understand the need to ensure that the TPM is available, but if it
isn't safe to wait to initialize IMA at late_initcall_sync() then it
would seem like this is a bad option and we need another mechanism to
synchronize IMA with TPM devices. If it is safe to initalize IMA in
late_initcall_sync(), just do that and be done with it.
I'm also guessing a two stage init process, e.g. some in
late_initcall() and some in late_initcall_sync(), doesn't make much
sense here, but that could be one other thing to consider if some IMA
tasks must be done in late_initcall().
--
paul-moore.com
^ permalink raw reply
* Re: [RFC PATCH v3 2/4] security: ima: call ima_init() again at late_initcall_sync for defered TPM
From: Mimi Zohar @ 2026-04-24 20:25 UTC (permalink / raw)
To: Jonathan McDowell, linux-security-module, linux-kernel,
linux-integrity, linux-arm-kernel, kvmarm
Cc: paul, jmorris, serge, roberto.sassu, dmitry.kasatkin,
eric.snowberg, jarkko, jgg, sudeep.holla, maz, oupton, joey.gouly,
suzuki.poulose, yuzenghui, catalin.marinas, will, noodles,
sebastianene, Yeoreum Yun
In-Reply-To: <5552c20c6d6d2ae3bbb6b35124af5d98d2f79163.1777036497.git.noodles@meta.com>
Thanks, Jonathan!
On Fri, 2026-04-24 at 14:24 +0100, Jonathan McDowell wrote:
> -static int __init init_ima(void)
> +static int __init init_ima(bool late)
> {
> int error;
>
> @@ -1247,10 +1247,26 @@ static int __init init_ima(void)
> return 0;
> }
>
> + /*
> + * If we found the TPM during our first attempt, or we know there's no
> + * TPM, nothing further to do
> + */
Perhaps it's just me, but the comment wording is a bit off. Could I change it
to: If we either found the TPM or knew there's no TPM during our first attempt,
nothing futher to do.
Otherwise the patch looks good.
Mimi
> + if (late && (ima_tpm_chip || !IS_ENABLED(CONFIG_TCG_TPM)))
> + return 0;
> +
> + ima_tpm_chip = tpm_default_chip();
> + if (!ima_tpm_chip && !late && IS_ENABLED(CONFIG_TCG_TPM)) {
> + pr_debug("TPM not available, will try later\n");
> + return -EPROBE_DEFER;
> + }
> +
> + if (!ima_tpm_chip)
> + pr_info("No TPM chip found, activating TPM-bypass!\n");
> +
^ permalink raw reply
* Re: [PATCH RFC 1/3] LSM: add a flags field to the LSM hook definitions
From: Paul Moore @ 2026-04-24 20:29 UTC (permalink / raw)
To: Casey Schaufler
Cc: linux-security-module, jmorris, serge, keescook, john.johansen,
penguin-kernel, stephen.smalley.work, selinux
In-Reply-To: <fadac326-d6cc-4d28-8ebe-b4ed3a06ddd0@schaufler-ca.com>
On Fri, Apr 24, 2026 at 11:24 AM Casey Schaufler <casey@schaufler-ca.com> wrote:
> On 4/23/2026 6:19 PM, Paul Moore wrote:
> > On Feb 25, 2026 Casey Schaufler <casey@schaufler-ca.com> wrote:
> >> Add a field for flags to the definition of LSM hooks. This allows
> >> for hooks to be identified at system initialization for special
> >> processing.
> >>
> >> Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
> >> ---
> >> include/linux/bpf_lsm.h | 2 +-
> >> include/linux/lsm_hook_defs.h | 614 ++++++++++++++++++----------------
> >> include/linux/lsm_hooks.h | 4 +-
> >> kernel/bpf/bpf_lsm.c | 10 +-
> >> security/bpf/hooks.c | 2 +-
> >> security/security.c | 6 +-
> >> 6 files changed, 331 insertions(+), 307 deletions(-)
> >>
> >> diff --git a/include/linux/bpf_lsm.h b/include/linux/bpf_lsm.h
> >> index 643809cc78c3..d71ba8c87e79 100644
> >> --- a/include/linux/bpf_lsm.h
> >> +++ b/include/linux/bpf_lsm.h
> >> @@ -14,7 +14,7 @@
> >>
> >> #ifdef CONFIG_BPF_LSM
> >>
> >> -#define LSM_HOOK(RET, DEFAULT, NAME, ...) \
> >> +#define LSM_HOOK(RET, DEFAULT, FLAGS, NAME, ...) \
> >> RET bpf_lsm_##NAME(__VA_ARGS__);
> >> #include <linux/lsm_hook_defs.h>
> >> #undef LSM_HOOK
> >> diff --git a/include/linux/lsm_hook_defs.h b/include/linux/lsm_hook_defs.h
> >> index 8c42b4bde09c..acda3a02da97 100644
> >> --- a/include/linux/lsm_hook_defs.h
> >> +++ b/include/linux/lsm_hook_defs.h
> >> @@ -18,451 +18,475 @@
> >> * The macro LSM_HOOK is used to define the data structures required by
> >> * the LSM framework using the pattern:
> >> *
> >> - * LSM_HOOK(<return_type>, <default_value>, <hook_name>, args...)
> >> + * LSM_HOOK(<return_type>, <default_value>, <flags>, <single>,
> >> + * <hook_name>, args...)
> >> *
> >> * struct security_hook_heads {
> >> - * #define LSM_HOOK(RET, DEFAULT, NAME, ...) struct hlist_head NAME;
> >> + * #define LSM_HOOK(RET, DEFAULT, FLAGS, NAME, ...) struct hlist_head NAME;
> >> * #include <linux/lsm_hook_defs.h>
> >> * #undef LSM_HOOK
> >> * };
> >> */
> >> -LSM_HOOK(int, 0, binder_set_context_mgr, const struct cred *mgr)
> >> -LSM_HOOK(int, 0, binder_transaction, const struct cred *from,
> >> +LSM_HOOK(int, 0, 0, binder_set_context_mgr, const struct cred *mgr)
> >> +LSM_HOOK(int, 0, 0, binder_transaction, const struct cred *from,
> >> const struct cred *to)
> > I think adding a flag field to the LSM_HOOK() macro/definitions is a good
> > and useful addition, but I'd prefer if we created a LSM_FLAG_NONE #define
> > and used it here just so we could avoid the back-to-back 0's and do a bit
> > of self-documentation.
>
> I had LSM_FLAG_NONE initially, but removed it when I saw the amount of code
> churn it introduced. I'm happy to put it back.
You're already touching every LSM_HOOK() definition to add a another
parameter, changing that parameter from 0 to LSM_FLAG_NONE shouldn't
make it that much worse.
--
paul-moore.com
^ permalink raw reply
* Re: [RFC PATCH v2 1/4] security: ima: call ima_init() again at late_initcall_sync for defered TPM
From: Mimi Zohar @ 2026-04-24 20:57 UTC (permalink / raw)
To: Paul Moore, Yeoreum Yun, roberto.sassu
Cc: Jonathan McDowell, linux-security-module, linux-kernel,
linux-integrity, linux-arm-kernel, kvmarm, jmorris, serge,
dmitry.kasatkin, eric.snowberg, jarkko, jgg, sudeep.holla, maz,
oupton, joey.gouly, suzuki.poulose, yuzenghui, catalin.marinas,
will, noodles, sebastianene
In-Reply-To: <CAHC9VhSaT_quKYnpFjAfqvL07JNbWMgM6c4pB9F46NHawX3DCA@mail.gmail.com>
On Fri, 2026-04-24 at 16:15 -0400, Paul Moore wrote:
> On Fri, Apr 24, 2026 at 1:57 AM Yeoreum Yun <yeoreum.yun@arm.com> wrote:
> > > On Thu, Apr 23, 2026 at 2:13 PM Yeoreum Yun <yeoreum.yun@arm.com> wrote:
> > > >
> > > > Sounds good. Once the patch is posted, I’ll review it as well.
> > > > Sorry again for the noise, and thanks for your patience ;)
> > >
> > > My apologies for not getting a chance to look at this patchset sooner.
> > >
> > > This seems like an obvious, perhaps even stupid, question, but I have
> > > to ask: if IMA can be properly initialized via late_initcall_sync(),
> > > why not simply do the initialization in late_initcall_sync() and drop
> > > the late_initcall() initialization?
> > >
> > > Does any IMA functionality suffer if initialization waits until
> > > late_initcall_sync()? If so, it seems non-critical if waiting until
> > > _sync() is acceptable, as it appears in these patches/comments.
> >
> > This is the way first patch did, and here is some discussion for this
> > (Might you have seen, but in case of you missed):
> > - https://lore.kernel.org/all/a6a0e15286c983d720de227c6827adbe976c5b9b.camel@linux.ibm.com/
>
> Thanks for the pointer.
>
> Unfortunately, my concern remains the same: it's either "safe" to
> initialize IMA at late_initcall_sync() or it isn't. Attempting to
> initialize IMA twice seems both odd and wrong.
Agreed. However, IMA should be initialized as soon as the TPM becomes
available, not delayed.
In patch 2/4 patch description, Jonathan describes the reasoning:
Unfortunately some TPM drivers (such as Arm FF-A, or SPI attached TPM
devices) are not reliably available during the initcall_late stage,
resulting in a log error:
ima: No TPM chip found, activating TPM-bypass!
and no measurements into the TPM by IMA. We can avoid this by doing IMA
init in the initcall_late_sync stage, after the drivers have completed
their init + registration.
Rather than do this everywhere, and needlessly delay the initialisation
of IMA when there is no need to do so, we continue to try to initialise
at the earlier stage, only deferring to the later point if the TPM is
not available yet.
>
> I understand the need to ensure that the TPM is available, but if it
> isn't safe to wait to initialize IMA at late_initcall_sync() then it
> would seem like this is a bad option and we need another mechanism to
> synchronize IMA with TPM devices. If it is safe to initalize IMA in
> late_initcall_sync(), just do that and be done with it.
Within the same initcall level there is no way of ordering the initialization.
Yeorum attempted to address the ordering issue in commit 0e0546eabcd6
("firmware: arm_ffa: Change initcall level of ffa_init() to rootfs_initcall"),
which is being reverted in this patch set.
Ordering within an initcall level needs to be fixed, but for now retrying at
late_initcall_sync works for some, hopefully most, cases.
>
> I'm also guessing a two stage init process, e.g. some in
> late_initcall() and some in late_initcall_sync(), doesn't make much
> sense here, but that could be one other thing to consider if some IMA
> tasks must be done in late_initcall().
Perhaps something to think about for the future.
Mimi
^ permalink raw reply
* Re: [PATCH v2 0/4] Firmware LSM hook
From: Paul Moore @ 2026-04-24 20:59 UTC (permalink / raw)
To: Jason Gunthorpe
Cc: Leon Romanovsky, Roberto Sassu, KP Singh, Matt Bobrowski,
Alexei Starovoitov, Daniel Borkmann, John Fastabend,
Andrii Nakryiko, Martin KaFai Lau, Eduard Zingerman, Song Liu,
Yonghong Song, Stanislav Fomichev, Hao Luo, Jiri Olsa, Shuah Khan,
Saeed Mahameed, Itay Avraham, Dave Jiang, Jonathan Cameron, bpf,
linux-kernel, linux-kselftest, linux-rdma, Chiara Meiohas,
Maher Sanalla, linux-security-module
In-Reply-To: <20260424143603.GB3611611@ziepe.ca>
On Fri, Apr 24, 2026 at 10:36 AM Jason Gunthorpe <jgg@ziepe.ca> wrote:
> On Mon, Apr 20, 2026 at 08:58:09PM -0400, Paul Moore wrote:
> > > > > > The access control point itself represents the requested
> > > > > > operation. This is possible because the number of networking
> > > > > > operations on a given packet is well defined and fairly limited; at a
> > > > > > high level the packet is either being sent from the node, received by
> > > > > > the node, or is passing through the node.
> > > > >
> > > > > I think we have the same split, fwctl send/recive analog is also very
> > > > > limited.
> > > >
> > > > Sure, but I thought the goal was to enforce access controls on the
> > > > firmware requests based on the opcodes/parameters contained within the
> > > > firmware request blob/mailbox?
> > >
> > > Yes, that's the goal. It is the same as iptables being able to
> > > identify that a send system call has a packet that is http or dns.
> >
> > I think we still have a disconnect here. A packet being a DNS or HTTP
> > packet is different from an opcode. The opcode in the iptables isn't
> > "DNS" or "HTTP" it is "INPUT", "OUTPUT", or "FORWARD".
>
> I understand that
>
> > Most LSMs will want to know who is initiating the firmware request
> > (the subject), the requested operation/opcode (the action/verb), and
> > the target of the request (the object, which in this case is likely
> > the kernel or the device).
>
> How is
> system_u:object_r:httpd_packet_t:s0
>
> A kernel or device?
It's not. It's one of two labels on a packet. I've cautioned you
about leaning too heavily on the secmark comparison as it falls apart
in a number of places, this is one of those places.
> It is a label for packet contents. I also want a label for packet contents.
According to your explanations, my understanding is that you want a
fwctl RPC operation. That is not the same as the secmark label
assigned by an iptables/nftables rule.
> > As I understand things, the action/verb is going to be the opcode
> > within the firmware request. If you believe I'm wrong about this
> > please help me understand why.
>
> You could make that choice, I'm arguing we should not, and it should
> be in the object side.
Okay, you believe I'm wrong, that's fine, but you need to provide a
(better) explanation for why I'm wrong and your approach is The Right
Way. Present your case, but please do it without referencing secmark
as that comparison is horribly broken at this point in the discussion.
> > > - op_X_t is the result of the classifier inspecting the RPC
> > > packet. Admin tells the classifier to return op_X_t similar to
> > > how --selctx does for iptables.
> >
> > I've tried to explain how this doesn't match with secmark, but I'm
> > evidently doing a poor job.
>
> Yeah, I don't get it at all, sorry. I fell you are making some very
> nuanced distinction with HTTP being an object but the HTTP-equivilant
> in fwctl is not an object, I can't follow it at all.
>
> By that logic:
>
> iptables -p 80 --string "GET"
>
> Is an action, and it should get a unique action in the tuple.
Let's both do ourselves a favor and drop the secmark comparisons; I
think it is only hurting things at this point. If we stick with the
secmark analogy I worry we are going to keep repeating the same things
to each other without making any forward progress.
> > If you want to continue with the secmark comparisons it might be
> > helpful to spend some time configuring secmark on a SELinux system,
> > and writing policy for it, to see how it works.
>
> I think I have a pretty good idea, you haven't said anything that
> contradicts what I expect..
Frankly, several comments, including in your last reply, indicate you
don't really grasp secmark, subject/verb/object, SELinux, or some
combination thereof ... and that's okay, you don't really need to
understand those details. Let's move past the failed secmark analogy
and return to the fwctl hooks, that's the ultimate goal.
> > certain action on an object. My concern with your example is that the
> > object isn't what is actually being acted upon, it's the requested
> > action.
>
> Object is a label for the packet contents.
>
> > The fwctl ioctl/API allows a user to act on a device, with the
> > actual action being specified by the fwctl payload. From what I can
> > see, the classifier's output is the action, not the object.
>
> You can take that view, it is certainly one valid way to look at it.
>
> But it is completely impractical.
Elaborate on that, because from what I can tell that is the valid way
to look at it from a subject/verb/object perspective.
> > > The same way secmark cannot pre-identify all the XXX_packet_t's.
> >
> > Once again, I think there is a disconnect or misunderstanding, on a
> > SELinux system using secmark all of the packet types, e.g.
> > "XXX_packet_t's", *are* pre-defined in the SELinux policy.
>
> "Pre-defined" in a text files in user space controlled by the admin.
That's not correct. It's kinda like saying the NIC driver sources are
simply "text files in user space controlled by the admin". The
SELinux secmark labels are defined in the SELinux policy sources which
must be compiled and loaded into the kernel before they are valid on a
running system. Policy must be written not only to define the secmark
labels, but also to define the access control rules which govern how
those packets are handled by the system. The iptables/nftables
command lines simply assign a secmark label to a packet; that's
important, but only a small part of the total equation.
--
paul-moore.com
^ permalink raw reply
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