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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,
	linux-audit@redhat.com,
	audit@vger.kernel.org
Subject: [PATCH v39 08/42] LSM: Use lsmblob in security_ipc_getsecid
Date: Fri, 15 Dec 2023 14:16:02 -0800
Message-ID: <20231215221636.105680-9-casey@schaufler-ca.com>
In-Reply-To: <20231215221636.105680-1-casey@schaufler-ca.com>
References: <20231215221636.105680-1-casey@schaufler-ca.com>
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There may be more than one LSM that provides IPC data for auditing.
Change security_ipc_getsecid() to fill in a lsmblob structure instead
of the u32 secid.  Change the name to security_ipc_getlsmblob() to
reflect the change.  The audit data structure containing the secid
will be updated later, so there is a bit of scaffolding here.

Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: John Johansen <john.johansen@canonical.com>
Acked-by: Stephen Smalley <stephen.smalley.work@gmail.com>
Acked-by: Paul Moore <paul@paul-moore.com>
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Cc: linux-audit@redhat.com
Cc: audit@vger.kernel.org
---
 include/linux/lsm_hook_defs.h |  4 ++--
 include/linux/security.h      | 18 +++++++++++++++---
 kernel/auditsc.c              |  3 +--
 security/security.c           | 14 +++++++-------
 security/selinux/hooks.c      |  9 ++++++---
 security/smack/smack_lsm.c    | 17 ++++++++++-------
 6 files changed, 41 insertions(+), 24 deletions(-)

diff --git a/include/linux/lsm_hook_defs.h b/include/linux/lsm_hook_defs.h
index 52d090d1957c..d69332031270 100644
--- a/include/linux/lsm_hook_defs.h
+++ b/include/linux/lsm_hook_defs.h
@@ -234,8 +234,8 @@ LSM_HOOK(void, LSM_RET_VOID, task_to_inode, struct task_struct *p,
 	 struct inode *inode)
 LSM_HOOK(int, 0, userns_create, const struct cred *cred)
 LSM_HOOK(int, 0, ipc_permission, struct kern_ipc_perm *ipcp, short flag)
-LSM_HOOK(void, LSM_RET_VOID, ipc_getsecid, struct kern_ipc_perm *ipcp,
-	 u32 *secid)
+LSM_HOOK(void, LSM_RET_VOID, ipc_getlsmblob, struct kern_ipc_perm *ipcp,
+	 struct lsmblob *blob)
 LSM_HOOK(int, 0, msg_msg_alloc_security, struct msg_msg *msg)
 LSM_HOOK(void, LSM_RET_VOID, msg_msg_free_security, struct msg_msg *msg)
 LSM_HOOK(int, 0, msg_queue_alloc_security, struct kern_ipc_perm *perm)
diff --git a/include/linux/security.h b/include/linux/security.h
index 029cf071148b..2ca118960234 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -289,6 +289,17 @@ static inline bool lsmblob_is_set(struct lsmblob *blob)
 	return !!memcmp(blob, &empty, sizeof(*blob));
 }
 
+/**
+ * lsmblob_init - initialize a lsmblob structure
+ * @blob: Pointer to the data to initialize
+ *
+ * Set all secid for all modules to the specified value.
+ */
+static inline void lsmblob_init(struct lsmblob *blob)
+{
+	memset(blob, 0, sizeof(*blob));
+}
+
 #ifdef CONFIG_SECURITY
 
 int call_blocking_lsm_notifier(enum lsm_event event, void *data);
@@ -487,7 +498,7 @@ int security_task_prctl(int option, unsigned long arg2, unsigned long arg3,
 void security_task_to_inode(struct task_struct *p, struct inode *inode);
 int security_create_user_ns(const struct cred *cred);
 int security_ipc_permission(struct kern_ipc_perm *ipcp, short flag);
-void security_ipc_getsecid(struct kern_ipc_perm *ipcp, u32 *secid);
+void security_ipc_getlsmblob(struct kern_ipc_perm *ipcp, struct lsmblob *blob);
 int security_msg_msg_alloc(struct msg_msg *msg);
 void security_msg_msg_free(struct msg_msg *msg);
 int security_msg_queue_alloc(struct kern_ipc_perm *msq);
@@ -1299,9 +1310,10 @@ static inline int security_ipc_permission(struct kern_ipc_perm *ipcp,
 	return 0;
 }
 
-static inline void security_ipc_getsecid(struct kern_ipc_perm *ipcp, u32 *secid)
+static inline void security_ipc_getlsmblob(struct kern_ipc_perm *ipcp,
+					   struct lsmblob *blob)
 {
-	*secid = 0;
+	lsmblob_init(blob);
 }
 
 static inline int security_msg_msg_alloc(struct msg_msg *msg)
diff --git a/kernel/auditsc.c b/kernel/auditsc.c
index 52b4697d938c..89d490db0494 100644
--- a/kernel/auditsc.c
+++ b/kernel/auditsc.c
@@ -2638,8 +2638,7 @@ void __audit_ipc_obj(struct kern_ipc_perm *ipcp)
 	context->ipc.gid = ipcp->gid;
 	context->ipc.mode = ipcp->mode;
 	context->ipc.has_perm = 0;
-	/* stacking scaffolding */
-	security_ipc_getsecid(ipcp, &context->ipc.oblob.scaffold.secid);
+	security_ipc_getlsmblob(ipcp, &context->ipc.oblob);
 	context->type = AUDIT_IPC;
 }
 
diff --git a/security/security.c b/security/security.c
index 4b78bface040..b82245d55f66 100644
--- a/security/security.c
+++ b/security/security.c
@@ -3595,17 +3595,17 @@ int security_ipc_permission(struct kern_ipc_perm *ipcp, short flag)
 }
 
 /**
- * security_ipc_getsecid() - Get the sysv ipc object's secid
+ * security_ipc_getlsmblob() - Get the sysv ipc object LSM data
  * @ipcp: ipc permission structure
- * @secid: secid pointer
+ * @blob: pointer to lsm information
  *
- * Get the secid associated with the ipc object.  In case of failure, @secid
- * will be set to zero.
+ * Get the lsm information associated with the ipc object.
  */
-void security_ipc_getsecid(struct kern_ipc_perm *ipcp, u32 *secid)
+
+void security_ipc_getlsmblob(struct kern_ipc_perm *ipcp, struct lsmblob *blob)
 {
-	*secid = 0;
-	call_void_hook(ipc_getsecid, ipcp, secid);
+	lsmblob_init(blob);
+	call_void_hook(ipc_getlsmblob, ipcp, blob);
 }
 
 /**
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index 83ce496e8ef6..f15991ef6ca8 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -6266,10 +6266,13 @@ static int selinux_ipc_permission(struct kern_ipc_perm *ipcp, short flag)
 	return ipc_has_perm(ipcp, av);
 }
 
-static void selinux_ipc_getsecid(struct kern_ipc_perm *ipcp, u32 *secid)
+static void selinux_ipc_getlsmblob(struct kern_ipc_perm *ipcp,
+				   struct lsmblob *blob)
 {
 	struct ipc_security_struct *isec = selinux_ipc(ipcp);
-	*secid = isec->sid;
+	blob->selinux.secid = isec->sid;
+	/* stacking scaffolding */
+	blob->scaffold.secid = isec->sid;
 }
 
 static void selinux_d_instantiate(struct dentry *dentry, struct inode *inode)
@@ -7165,7 +7168,7 @@ static struct security_hook_list selinux_hooks[] __ro_after_init = {
 	LSM_HOOK_INIT(userns_create, selinux_userns_create),
 
 	LSM_HOOK_INIT(ipc_permission, selinux_ipc_permission),
-	LSM_HOOK_INIT(ipc_getsecid, selinux_ipc_getsecid),
+	LSM_HOOK_INIT(ipc_getlsmblob, selinux_ipc_getlsmblob),
 
 	LSM_HOOK_INIT(msg_queue_associate, selinux_msg_queue_associate),
 	LSM_HOOK_INIT(msg_queue_msgctl, selinux_msg_queue_msgctl),
diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
index a4ace6ea2ab0..b00f4f44f9c5 100644
--- a/security/smack/smack_lsm.c
+++ b/security/smack/smack_lsm.c
@@ -3396,16 +3396,19 @@ static int smack_ipc_permission(struct kern_ipc_perm *ipp, short flag)
 }
 
 /**
- * smack_ipc_getsecid - Extract smack security id
+ * smack_ipc_getlsmblob - Extract smack security data
  * @ipp: the object permissions
- * @secid: where result will be saved
+ * @blob: where result will be saved
  */
-static void smack_ipc_getsecid(struct kern_ipc_perm *ipp, u32 *secid)
+static void smack_ipc_getlsmblob(struct kern_ipc_perm *ipp,
+				 struct lsmblob *blob)
 {
-	struct smack_known **blob = smack_ipc(ipp);
-	struct smack_known *iskp = *blob;
+	struct smack_known **iskpp = smack_ipc(ipp);
+	struct smack_known *iskp = *iskpp;
 
-	*secid = iskp->smk_secid;
+	blob->smack.skp = iskp;
+	/* stacking scaffolding */
+	blob->scaffold.secid = iskp->smk_secid;
 }
 
 /**
@@ -5109,7 +5112,7 @@ static struct security_hook_list smack_hooks[] __ro_after_init = {
 	LSM_HOOK_INIT(task_to_inode, smack_task_to_inode),
 
 	LSM_HOOK_INIT(ipc_permission, smack_ipc_permission),
-	LSM_HOOK_INIT(ipc_getsecid, smack_ipc_getsecid),
+	LSM_HOOK_INIT(ipc_getlsmblob, smack_ipc_getlsmblob),
 
 	LSM_HOOK_INIT(msg_msg_alloc_security, smack_msg_msg_alloc_security),
 
-- 
2.41.0