[04/13] Audit: maintain an lsmblob in audit_context

Message ID	20240825190048.13289-5-casey@schaufler-ca.com (mailing list archive)
State	Superseded
Delegated to:	Paul Moore
Headers	show Received: from sonic310-30.consmr.mail.ne1.yahoo.com (sonic310-30.consmr.mail.ne1.yahoo.com [66.163.186.211]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id B22963987D for <linux-security-module@vger.kernel.org>; Sun, 25 Aug 2024 19:02:43 +0000 (UTC) From: Casey Schaufler <casey@schaufler-ca.com> To: casey@schaufler-ca.com, paul@paul-moore.com, linux-security-module@vger.kernel.org Cc: jmorris@namei.org, serge@hallyn.com, keescook@chromium.org, john.johansen@canonical.com, penguin-kernel@i-love.sakura.ne.jp, stephen.smalley.work@gmail.com, linux-kernel@vger.kernel.org, mic@digikod.net Subject: [PATCH 04/13] Audit: maintain an lsmblob in audit_context Date: Sun, 25 Aug 2024 12:00:39 -0700 Message-ID: <20240825190048.13289-5-casey@schaufler-ca.com> In-Reply-To: <20240825190048.13289-1-casey@schaufler-ca.com> References: <20240825190048.13289-1-casey@schaufler-ca.com> Precedence: bulk MIME-Version: 1.0 Content-Transfer-Encoding: 8bit
Series	LSM: Move away from secids \| expand [00/13] LSM: Move away from secids [01/13] LSM: Add the lsmblob data structure. [02/13] LSM: Use lsmblob in security_audit_rule_match [03/13] LSM: Add lsmblob_to_secctx hook [04/13] Audit: maintain an lsmblob in audit_context [05/13] LSM: Use lsmblob in security_ipc_getsecid [06/13] Audit: Update shutdown LSM data [07/13] LSM: Use lsmblob in security_current_getsecid [08/13] LSM: Use lsmblob in security_inode_getsecid [09/13] Audit: use an lsmblob in audit_names [10/13] LSM: Create new security_cred_getlsmblob LSM hook [11/13] Audit: Change context data from secid to lsmblob [12/13] Netlabel: Use lsmblob for audit data [13/13] LSM: Remove lsmblob scaffolding

Message ID

20240825190048.13289-5-casey@schaufler-ca.com (mailing list archive)

State

Superseded

Delegated to:

Paul Moore

Headers

From: Casey Schaufler <casey@schaufler-ca.com>
To: casey@schaufler-ca.com,
	paul@paul-moore.com,
	linux-security-module@vger.kernel.org
Cc: jmorris@namei.org,
	serge@hallyn.com,
	keescook@chromium.org,
	john.johansen@canonical.com,
	penguin-kernel@i-love.sakura.ne.jp,
	stephen.smalley.work@gmail.com,
	linux-kernel@vger.kernel.org,
	mic@digikod.net
Subject: [PATCH 04/13] Audit: maintain an lsmblob in audit_context
Date: Sun, 25 Aug 2024 12:00:39 -0700
Message-ID: <20240825190048.13289-5-casey@schaufler-ca.com>
In-Reply-To: <20240825190048.13289-1-casey@schaufler-ca.com>
References: <20240825190048.13289-1-casey@schaufler-ca.com>
Precedence: bulk
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit

Series

LSM: Move away from secids | expand

Commit Message

Casey Schaufler Aug. 25, 2024, 7 p.m. UTC

Replace the secid value stored in struct audit_context with a struct
lsmblob. Change the code that uses this value to accommodate the
change. security_audit_rule_match() expects a lsmblob, so existing
scaffolding can be removed. A call to security_secid_to_secctx()
is changed to security_lsmblob_to_secctx().  The call to
security_ipc_getsecid() is scaffolded.

A new function lsmblob_is_set() is introduced to identify whether
an lsmblob contains a non-zero value.

Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
---
 include/linux/security.h | 13 +++++++++++++
 kernel/audit.h           |  3 ++-
 kernel/auditsc.c         | 19 ++++++++-----------
 3 files changed, 23 insertions(+), 12 deletions(-)

Comments

Georgia Garcia Aug. 27, 2024, 3:01 p.m. UTC | #1

On Sun, 2024-08-25 at 12:00 -0700, Casey Schaufler wrote:
> Replace the secid value stored in struct audit_context with a struct
> lsmblob. Change the code that uses this value to accommodate the
> change. security_audit_rule_match() expects a lsmblob, so existing
> scaffolding can be removed. A call to security_secid_to_secctx()
> is changed to security_lsmblob_to_secctx().  The call to
> security_ipc_getsecid() is scaffolded.
> 
> A new function lsmblob_is_set() is introduced to identify whether
> an lsmblob contains a non-zero value.
> 
> Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
> ---
>  include/linux/security.h | 13 +++++++++++++
>  kernel/audit.h           |  3 ++-
>  kernel/auditsc.c         | 19 ++++++++-----------
>  3 files changed, 23 insertions(+), 12 deletions(-)
> 
> diff --git a/include/linux/security.h b/include/linux/security.h
> index 457fafc32fb0..a0b23b6e8734 100644
> --- a/include/linux/security.h
> +++ b/include/linux/security.h
> @@ -277,6 +277,19 @@ static inline const char *kernel_load_data_id_str(enum kernel_load_data_id id)
>  	return kernel_load_data_str[id];
>  }
>  
> +/**
> + * lsmblob_is_set - report if there is a value in the lsmblob
> + * @blob: Pointer to the exported LSM data
> + *
> + * Returns true if there is a value set, false otherwise
> + */
> +static inline bool lsmblob_is_set(struct lsmblob *blob)
> +{
> +	const struct lsmblob empty = {};
> +
> +	return !!memcmp(blob, &empty, sizeof(*blob));
> +}
> +
>  #ifdef CONFIG_SECURITY
>  
>  int call_blocking_lsm_notifier(enum lsm_event event, void *data);
> diff --git a/kernel/audit.h b/kernel/audit.h
> index a60d2840559e..b1f2de4d4f1e 100644
> --- a/kernel/audit.h
> +++ b/kernel/audit.h
> @@ -11,6 +11,7 @@
>  
>  #include <linux/fs.h>
>  #include <linux/audit.h>
> +#include <linux/security.h>
>  #include <linux/skbuff.h>
>  #include <uapi/linux/mqueue.h>
>  #include <linux/tty.h>
> @@ -160,7 +161,7 @@ struct audit_context {
>  			kuid_t			uid;
>  			kgid_t			gid;
>  			umode_t			mode;
> -			u32			osid;
> +			struct lsmblob		oblob;
>  			int			has_perm;
>  			uid_t			perm_uid;
>  			gid_t			perm_gid;
> diff --git a/kernel/auditsc.c b/kernel/auditsc.c
> index 23adb15cae43..84f6e9356b8f 100644
> --- a/kernel/auditsc.c
> +++ b/kernel/auditsc.c
> @@ -724,9 +724,7 @@ static int audit_filter_rules(struct task_struct *tsk,
>  				/* Find ipc objects that match */
>  				if (!ctx || ctx->type != AUDIT_IPC)
>  					break;
> -				/* scaffolding */
> -				blob.scaffold.secid = ctx->ipc.osid;
> -				if (security_audit_rule_match(&blob,
> +				if (security_audit_rule_match(&ctx->ipc.oblob,
>  							      f->type, f->op,
>  							      f->lsm_rule))
>  					++result;
> @@ -1394,19 +1392,17 @@ static void show_special(struct audit_context *context, int *call_panic)
>  			audit_log_format(ab, " a%d=%lx", i,
>  				context->socketcall.args[i]);
>  		break; }
> -	case AUDIT_IPC: {
> -		u32 osid = context->ipc.osid;
> -
> +	case AUDIT_IPC:
>  		audit_log_format(ab, "ouid=%u ogid=%u mode=%#ho",
>  				 from_kuid(&init_user_ns, context->ipc.uid),
>  				 from_kgid(&init_user_ns, context->ipc.gid),
>  				 context->ipc.mode);
> -		if (osid) {
> +		if (lsmblob_is_set(&context->ipc.oblob)) {
>  			char *ctx = NULL;
>  			u32 len;
>  
> -			if (security_secid_to_secctx(osid, &ctx, &len)) {
> -				audit_log_format(ab, " osid=%u", osid);
> +			if (security_lsmblob_to_secctx(&context->ipc.oblob,
> +						       &ctx, &len)) {

Is there any reason to stop auditing secid when we fail to get the
security context?

>  				*call_panic = 1;
>  			} else {
>  				audit_log_format(ab, " obj=%s", ctx);
> @@ -1426,7 +1422,7 @@ static void show_special(struct audit_context *context, int *call_panic)
>  				context->ipc.perm_gid,
>  				context->ipc.perm_mode);
>  		}
> -		break; }
> +		break;
>  	case AUDIT_MQ_OPEN:
>  		audit_log_format(ab,
>  			"oflag=0x%x mode=%#ho mq_flags=0x%lx mq_maxmsg=%ld "
> @@ -2642,7 +2638,8 @@ void __audit_ipc_obj(struct kern_ipc_perm *ipcp)
>  	context->ipc.gid = ipcp->gid;
>  	context->ipc.mode = ipcp->mode;
>  	context->ipc.has_perm = 0;
> -	security_ipc_getsecid(ipcp, &context->ipc.osid);
> +	/* scaffolding */
> +	security_ipc_getsecid(ipcp, &context->ipc.oblob.scaffold.secid);
>  	context->type = AUDIT_IPC;
>  }
>

Georgia Garcia Aug. 27, 2024, 3:08 p.m. UTC | #2

On Tue, 2024-08-27 at 12:01 -0300, Georgia Garcia wrote:
> On Sun, 2024-08-25 at 12:00 -0700, Casey Schaufler wrote:
> > Replace the secid value stored in struct audit_context with a struct
> > lsmblob. Change the code that uses this value to accommodate the
> > change. security_audit_rule_match() expects a lsmblob, so existing
> > scaffolding can be removed. A call to security_secid_to_secctx()
> > is changed to security_lsmblob_to_secctx().  The call to
> > security_ipc_getsecid() is scaffolded.
> > 
> > A new function lsmblob_is_set() is introduced to identify whether
> > an lsmblob contains a non-zero value.
> > 
> > Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
> > ---
> >  include/linux/security.h | 13 +++++++++++++
> >  kernel/audit.h           |  3 ++-
> >  kernel/auditsc.c         | 19 ++++++++-----------
> >  3 files changed, 23 insertions(+), 12 deletions(-)
> > 
> > diff --git a/include/linux/security.h b/include/linux/security.h
> > index 457fafc32fb0..a0b23b6e8734 100644
> > --- a/include/linux/security.h
> > +++ b/include/linux/security.h
> > @@ -277,6 +277,19 @@ static inline const char *kernel_load_data_id_str(enum kernel_load_data_id id)
> >  	return kernel_load_data_str[id];
> >  }
> >  
> > +/**
> > + * lsmblob_is_set - report if there is a value in the lsmblob
> > + * @blob: Pointer to the exported LSM data
> > + *
> > + * Returns true if there is a value set, false otherwise
> > + */
> > +static inline bool lsmblob_is_set(struct lsmblob *blob)
> > +{
> > +	const struct lsmblob empty = {};
> > +
> > +	return !!memcmp(blob, &empty, sizeof(*blob));
> > +}
> > +
> >  #ifdef CONFIG_SECURITY
> >  
> >  int call_blocking_lsm_notifier(enum lsm_event event, void *data);
> > diff --git a/kernel/audit.h b/kernel/audit.h
> > index a60d2840559e..b1f2de4d4f1e 100644
> > --- a/kernel/audit.h
> > +++ b/kernel/audit.h
> > @@ -11,6 +11,7 @@
> >  
> >  #include <linux/fs.h>
> >  #include <linux/audit.h>
> > +#include <linux/security.h>
> >  #include <linux/skbuff.h>
> >  #include <uapi/linux/mqueue.h>
> >  #include <linux/tty.h>
> > @@ -160,7 +161,7 @@ struct audit_context {
> >  			kuid_t			uid;
> >  			kgid_t			gid;
> >  			umode_t			mode;
> > -			u32			osid;
> > +			struct lsmblob		oblob;
> >  			int			has_perm;
> >  			uid_t			perm_uid;
> >  			gid_t			perm_gid;
> > diff --git a/kernel/auditsc.c b/kernel/auditsc.c
> > index 23adb15cae43..84f6e9356b8f 100644
> > --- a/kernel/auditsc.c
> > +++ b/kernel/auditsc.c
> > @@ -724,9 +724,7 @@ static int audit_filter_rules(struct task_struct *tsk,
> >  				/* Find ipc objects that match */
> >  				if (!ctx || ctx->type != AUDIT_IPC)
> >  					break;
> > -				/* scaffolding */
> > -				blob.scaffold.secid = ctx->ipc.osid;
> > -				if (security_audit_rule_match(&blob,
> > +				if (security_audit_rule_match(&ctx->ipc.oblob,
> >  							      f->type, f->op,
> >  							      f->lsm_rule))
> >  					++result;
> > @@ -1394,19 +1392,17 @@ static void show_special(struct audit_context *context, int *call_panic)
> >  			audit_log_format(ab, " a%d=%lx", i,
> >  				context->socketcall.args[i]);
> >  		break; }
> > -	case AUDIT_IPC: {
> > -		u32 osid = context->ipc.osid;
> > -
> > +	case AUDIT_IPC:
> >  		audit_log_format(ab, "ouid=%u ogid=%u mode=%#ho",
> >  				 from_kuid(&init_user_ns, context->ipc.uid),
> >  				 from_kgid(&init_user_ns, context->ipc.gid),
> >  				 context->ipc.mode);
> > -		if (osid) {
> > +		if (lsmblob_is_set(&context->ipc.oblob)) {
> >  			char *ctx = NULL;
> >  			u32 len;
> >  
> > -			if (security_secid_to_secctx(osid, &ctx, &len)) {
> > -				audit_log_format(ab, " osid=%u", osid);
> > +			if (security_lsmblob_to_secctx(&context->ipc.oblob,
> > +						       &ctx, &len)) {
> 
> Is there any reason to stop auditing secid when we fail to get the
> security context?

Well, yes, if we're moving away from using secid for all LSMs, then it
doesn't make sense to audit it here anymore, so nevermind :)

> 
> >  				*call_panic = 1;
> >  			} else {
> >  				audit_log_format(ab, " obj=%s", ctx);
> > @@ -1426,7 +1422,7 @@ static void show_special(struct audit_context *context, int *call_panic)
> >  				context->ipc.perm_gid,
> >  				context->ipc.perm_mode);
> >  		}
> > -		break; }
> > +		break;
> >  	case AUDIT_MQ_OPEN:
> >  		audit_log_format(ab,
> >  			"oflag=0x%x mode=%#ho mq_flags=0x%lx mq_maxmsg=%ld "
> > @@ -2642,7 +2638,8 @@ void __audit_ipc_obj(struct kern_ipc_perm *ipcp)
> >  	context->ipc.gid = ipcp->gid;
> >  	context->ipc.mode = ipcp->mode;
> >  	context->ipc.has_perm = 0;
> > -	security_ipc_getsecid(ipcp, &context->ipc.osid);
> > +	/* scaffolding */
> > +	security_ipc_getsecid(ipcp, &context->ipc.oblob.scaffold.secid);
> >  	context->type = AUDIT_IPC;
> >  }
> >  
>

diff --git a/include/linux/security.h b/include/linux/security.h
index 457fafc32fb0..a0b23b6e8734 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -277,6 +277,19 @@  static inline const char *kernel_load_data_id_str(enum kernel_load_data_id id)
 	return kernel_load_data_str[id];
 }
 
+/**
+ * lsmblob_is_set - report if there is a value in the lsmblob
+ * @blob: Pointer to the exported LSM data
+ *
+ * Returns true if there is a value set, false otherwise
+ */
+static inline bool lsmblob_is_set(struct lsmblob *blob)
+{
+	const struct lsmblob empty = {};
+
+	return !!memcmp(blob, &empty, sizeof(*blob));
+}
+
 #ifdef CONFIG_SECURITY
 
 int call_blocking_lsm_notifier(enum lsm_event event, void *data);
diff --git a/kernel/audit.h b/kernel/audit.h
index a60d2840559e..b1f2de4d4f1e 100644
--- a/kernel/audit.h
+++ b/kernel/audit.h
@@ -11,6 +11,7 @@ 
 
 #include <linux/fs.h>
 #include <linux/audit.h>
+#include <linux/security.h>
 #include <linux/skbuff.h>
 #include <uapi/linux/mqueue.h>
 #include <linux/tty.h>
@@ -160,7 +161,7 @@  struct audit_context {
 			kuid_t			uid;
 			kgid_t			gid;
 			umode_t			mode;
-			u32			osid;
+			struct lsmblob		oblob;
 			int			has_perm;
 			uid_t			perm_uid;
 			gid_t			perm_gid;
diff --git a/kernel/auditsc.c b/kernel/auditsc.c
index 23adb15cae43..84f6e9356b8f 100644
--- a/kernel/auditsc.c
+++ b/kernel/auditsc.c
@@ -724,9 +724,7 @@  static int audit_filter_rules(struct task_struct *tsk,
 				/* Find ipc objects that match */
 				if (!ctx || ctx->type != AUDIT_IPC)
 					break;
-				/* scaffolding */
-				blob.scaffold.secid = ctx->ipc.osid;
-				if (security_audit_rule_match(&blob,
+				if (security_audit_rule_match(&ctx->ipc.oblob,
 							      f->type, f->op,
 							      f->lsm_rule))
 					++result;
@@ -1394,19 +1392,17 @@  static void show_special(struct audit_context *context, int *call_panic)
 			audit_log_format(ab, " a%d=%lx", i,
 				context->socketcall.args[i]);
 		break; }
-	case AUDIT_IPC: {
-		u32 osid = context->ipc.osid;
-
+	case AUDIT_IPC:
 		audit_log_format(ab, "ouid=%u ogid=%u mode=%#ho",
 				 from_kuid(&init_user_ns, context->ipc.uid),
 				 from_kgid(&init_user_ns, context->ipc.gid),
 				 context->ipc.mode);
-		if (osid) {
+		if (lsmblob_is_set(&context->ipc.oblob)) {
 			char *ctx = NULL;
 			u32 len;
 
-			if (security_secid_to_secctx(osid, &ctx, &len)) {
-				audit_log_format(ab, " osid=%u", osid);
+			if (security_lsmblob_to_secctx(&context->ipc.oblob,
+						       &ctx, &len)) {
 				*call_panic = 1;
 			} else {
 				audit_log_format(ab, " obj=%s", ctx);
@@ -1426,7 +1422,7 @@  static void show_special(struct audit_context *context, int *call_panic)
 				context->ipc.perm_gid,
 				context->ipc.perm_mode);
 		}
-		break; }
+		break;
 	case AUDIT_MQ_OPEN:
 		audit_log_format(ab,
 			"oflag=0x%x mode=%#ho mq_flags=0x%lx mq_maxmsg=%ld "
@@ -2642,7 +2638,8 @@  void __audit_ipc_obj(struct kern_ipc_perm *ipcp)
 	context->ipc.gid = ipcp->gid;
 	context->ipc.mode = ipcp->mode;
 	context->ipc.has_perm = 0;
-	security_ipc_getsecid(ipcp, &context->ipc.osid);
+	/* scaffolding */
+	security_ipc_getsecid(ipcp, &context->ipc.oblob.scaffold.secid);
 	context->type = AUDIT_IPC;
 }

[04/13] Audit: maintain an lsmblob in audit_context

Commit Message

Comments

Patch