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Subject: [PATCH v5 35/38] SELinux: Abstract use of ipc security blobs
To:     James Morris <jmorris@namei.org>,
        LSM <linux-security-module@vger.kernel.org>,
        LKLM <linux-kernel@vger.kernel.org>,
        SE Linux <selinux@tycho.nsa.gov>
Cc:     John Johansen <john.johansen@canonical.com>,
        Kees Cook <keescook@chromium.org>,
        Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>,
        Paul Moore <paul@paul-moore.com>,
        "linux-fsdevel@vger.kernel.org" <linux-fsdevel@vger.kernel.org>,
        Stephen Smalley <sds@tycho.nsa.gov>,
        Alexey Dobriyan <adobriyan@gmail.com>,
        =?UTF-8?Q?Micka=c3=abl_Sala=c3=bcn?= <mic@digikod.net>,
        Salvatore Mesoraca <s.mesoraca16@gmail.com>
References: <50db058a-7dde-441b-a7f9-f6837fe8b69f@schaufler-ca.com>
From:   Casey Schaufler <casey@schaufler-ca.com>
Message-ID: <2b9fa6ed-c7b9-49a3-c4e2-957ef1d31243@schaufler-ca.com>
Date:   Mon, 26 Nov 2018 15:54:31 -0800
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Sender: linux-kernel-owner@vger.kernel.org
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Don't use the ipc->security pointer directly.
Don't use the msg_msg->security pointer directly.
Provide helper functions that provides the security blob pointers.

Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
---
 security/selinux/hooks.c          | 18 +++++++++---------
 security/selinux/include/objsec.h | 13 +++++++++++++
 2 files changed, 22 insertions(+), 9 deletions(-)

diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index f0e7ac26f3a9..1e56b036018a 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -5889,7 +5889,7 @@ static int ipc_has_perm(struct kern_ipc_perm *ipc_perms,
 	struct common_audit_data ad;
 	u32 sid = current_sid();
 
-	isec = ipc_perms->security;
+	isec = selinux_ipc(ipc_perms);
 
 	ad.type = LSM_AUDIT_DATA_IPC;
 	ad.u.ipc_id = ipc_perms->key;
@@ -5946,7 +5946,7 @@ static int selinux_msg_queue_associate(struct kern_ipc_perm *msq, int msqflg)
 	struct common_audit_data ad;
 	u32 sid = current_sid();
 
-	isec = msq->security;
+	isec = selinux_ipc(msq);
 
 	ad.type = LSM_AUDIT_DATA_IPC;
 	ad.u.ipc_id = msq->key;
@@ -5995,8 +5995,8 @@ static int selinux_msg_queue_msgsnd(struct kern_ipc_perm *msq, struct msg_msg *m
 	u32 sid = current_sid();
 	int rc;
 
-	isec = msq->security;
-	msec = msg->security;
+	isec = selinux_ipc(msq);
+	msec = selinux_msg_msg(msg);
 
 	/*
 	 * First time through, need to assign label to the message
@@ -6043,8 +6043,8 @@ static int selinux_msg_queue_msgrcv(struct kern_ipc_perm *msq, struct msg_msg *m
 	u32 sid = task_sid(target);
 	int rc;
 
-	isec = msq->security;
-	msec = msg->security;
+	isec = selinux_ipc(msq);
+	msec = selinux_msg_msg(msg);
 
 	ad.type = LSM_AUDIT_DATA_IPC;
 	ad.u.ipc_id = msq->key;
@@ -6097,7 +6097,7 @@ static int selinux_shm_associate(struct kern_ipc_perm *shp, int shmflg)
 	struct common_audit_data ad;
 	u32 sid = current_sid();
 
-	isec = shp->security;
+	isec = selinux_ipc(shp);
 
 	ad.type = LSM_AUDIT_DATA_IPC;
 	ad.u.ipc_id = shp->key;
@@ -6194,7 +6194,7 @@ static int selinux_sem_associate(struct kern_ipc_perm *sma, int semflg)
 	struct common_audit_data ad;
 	u32 sid = current_sid();
 
-	isec = sma->security;
+	isec = selinux_ipc(sma);
 
 	ad.type = LSM_AUDIT_DATA_IPC;
 	ad.u.ipc_id = sma->key;
@@ -6280,7 +6280,7 @@ static int selinux_ipc_permission(struct kern_ipc_perm *ipcp, short flag)
 
 static void selinux_ipc_getsecid(struct kern_ipc_perm *ipcp, u32 *secid)
 {
-	struct ipc_security_struct *isec = ipcp->security;
+	struct ipc_security_struct *isec = selinux_ipc(ipcp);
 	*secid = isec->sid;
 }
 
diff --git a/security/selinux/include/objsec.h b/security/selinux/include/objsec.h
index 562fad58c56b..539cacf4a572 100644
--- a/security/selinux/include/objsec.h
+++ b/security/selinux/include/objsec.h
@@ -26,6 +26,7 @@
 #include <linux/in.h>
 #include <linux/spinlock.h>
 #include <linux/lsm_hooks.h>
+#include <linux/msg.h>
 #include <net/net_namespace.h>
 #include "flask.h"
 #include "avc.h"
@@ -175,4 +176,16 @@ static inline struct inode_security_struct *selinux_inode(
 	return inode->i_security + selinux_blob_sizes.lbs_inode;
 }
 
+static inline struct msg_security_struct *selinux_msg_msg(
+						const struct msg_msg *msg_msg)
+{
+	return msg_msg->security;
+}
+
+static inline struct ipc_security_struct *selinux_ipc(
+						const struct kern_ipc_perm *ipc)
+{
+	return ipc->security;
+}
+
 #endif /* _SELINUX_OBJSEC_H_ */
-- 
2.14.5