Smack: Abstract use of ipc security blobs

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 <[email protected]> Reviewed-by: Kees Cook <[email protected]> Signed-off-by: Kees Cook <[email protected]>
wangyan0507 · Jan 8, 2019 · 019bcca · 019bcca
1 parent 7c65382
commit 019bcca
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Showing 2 changed files with 20 additions and 5 deletions.
diff --git a/security/smack/smack.h b/security/smack/smack.h
@@ -24,6 +24,7 @@
 #include <linux/list.h>
 #include <linux/rculist.h>
 #include <linux/lsm_audit.h>
+#include <linux/msg.h>
 
 /*
  * Use IPv6 port labeling if IPv6 is enabled and secmarks
@@ -373,6 +374,16 @@ static inline struct inode_smack *smack_inode(const struct inode *inode)
 	return inode->i_security + smack_blob_sizes.lbs_inode;
 }
 
+static inline struct smack_known **smack_msg_msg(const struct msg_msg *msg)
+{
+	return (struct smack_known **)&msg->security;
+}
+
+static inline struct smack_known **smack_ipc(const struct kern_ipc_perm *ipc)
+{
+	return (struct smack_known **)&ipc->security;
+}
+
 /*
  * Is the directory transmuting?
  */

diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
@@ -2834,7 +2834,9 @@ static void smack_msg_msg_free_security(struct msg_msg *msg)
  */
 static struct smack_known *smack_of_ipc(struct kern_ipc_perm *isp)
 {
-	return (struct smack_known *)isp->security;
+	struct smack_known **blob = smack_ipc(isp);
+
+	return *blob;
 }
 
 /**
@@ -2845,9 +2847,9 @@ static struct smack_known *smack_of_ipc(struct kern_ipc_perm *isp)
  */
 static int smack_ipc_alloc_security(struct kern_ipc_perm *isp)
 {
-	struct smack_known *skp = smk_of_current();
+	struct smack_known **blob = smack_ipc(isp);
 
-	isp->security = skp;
+	*blob = smk_of_current();
 	return 0;
 }
 
@@ -3159,7 +3161,8 @@ static int smack_msg_queue_msgrcv(struct kern_ipc_perm *isp, struct msg_msg *msg
  */
 static int smack_ipc_permission(struct kern_ipc_perm *ipp, short flag)
 {
-	struct smack_known *iskp = ipp->security;
+	struct smack_known **blob = smack_ipc(ipp);
+	struct smack_known *iskp = *blob;
 	int may = smack_flags_to_may(flag);
 	struct smk_audit_info ad;
 	int rc;
@@ -3180,7 +3183,8 @@ static int smack_ipc_permission(struct kern_ipc_perm *ipp, short flag)
  */
 static void smack_ipc_getsecid(struct kern_ipc_perm *ipp, u32 *secid)
 {
-	struct smack_known *iskp = ipp->security;
+	struct smack_known **blob = smack_ipc(ipp);
+	struct smack_known *iskp = *blob;
 
 	*secid = iskp->smk_secid;
 }