Merge branch 'smack-for-4.9' of http://github.com/cschaufler/smack-next into next

security/smack/Kconfig

···
 	  This enables security marking of network packets using
 	  Smack labels.
 	  If you are unsure how to answer this question, answer N.
+
+config SECURITY_SMACK_APPEND_SIGNALS
+	bool "Treat delivering signals as an append operation"
+	depends on SECURITY_SMACK
+	default n
+	help
+	  Sending a signal has been treated as a write operation to the
+	  receiving process. If this option is selected, the delivery
+	  will be an append operation instead. This makes it possible
+	  to differentiate between delivering a network packet and
+	  delivering a signal in the Smack rules.
+	  If you are unsure how to answer this question, answer N.

security/smack/smack.h

···
 #define MAY_LOCK	0x00002000	/* Locks should be writes, but ... */
 #define MAY_BRINGUP	0x00004000	/* Report use of this rule */
 
+/*
+ * The policy for delivering signals is configurable.
+ * It is usually "write", but can be "append".
+ */
+#ifdef CONFIG_SECURITY_SMACK_APPEND_SIGNALS
+#define MAY_DELIVER	MAY_APPEND	/* Signal delivery requires append */
+#else
+#define MAY_DELIVER	MAY_WRITE	/* Signal delivery requires write */
+#endif
+
 #define SMACK_BRINGUP_ALLOW		1	/* Allow bringup mode */
 #define SMACK_UNCONFINED_SUBJECT	2	/* Allow unconfined label */
 #define SMACK_UNCONFINED_OBJECT		3	/* Allow unconfined label */

security/smack/smack_lsm.c

···
 
 	/* we don't log here as rc can be overriden */
 	skp = file->f_security;
-	rc = smk_access(skp, tkp, MAY_WRITE, NULL);
-	rc = smk_bu_note("sigiotask", skp, tkp, MAY_WRITE, rc);
+	rc = smk_access(skp, tkp, MAY_DELIVER, NULL);
+	rc = smk_bu_note("sigiotask", skp, tkp, MAY_DELIVER, rc);
 	if (rc != 0 && has_capability(tsk, CAP_MAC_OVERRIDE))
 		rc = 0;
 
 	smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_TASK);
 	smk_ad_setfield_u_tsk(&ad, tsk);
-	smack_log(skp->smk_known, tkp->smk_known, MAY_WRITE, rc, &ad);
+	smack_log(skp->smk_known, tkp->smk_known, MAY_DELIVER, rc, &ad);
 	return rc;
 }
 
···
 	 * can write the receiver.
 	 */
 	if (secid == 0) {
-		rc = smk_curacc(tkp, MAY_WRITE, &ad);
-		rc = smk_bu_task(p, MAY_WRITE, rc);
+		rc = smk_curacc(tkp, MAY_DELIVER, &ad);
+		rc = smk_bu_task(p, MAY_DELIVER, rc);
 		return rc;
 	}
 	/*
···
 	 * we can't take privilege into account.
 	 */
 	skp = smack_from_secid(secid);
-	rc = smk_access(skp, tkp, MAY_WRITE, &ad);
-	rc = smk_bu_note("USB signal", skp, tkp, MAY_WRITE, rc);
+	rc = smk_access(skp, tkp, MAY_DELIVER, &ad);
+	rc = smk_bu_note("USB signal", skp, tkp, MAY_DELIVER, rc);
 	return rc;
 }
 

security/smack/smackfs.c

···
 	if (count == 0 || count > SMK_LONGLABEL)
 		return -EINVAL;
 
-	data = kzalloc(count, GFP_KERNEL);
-	if (data == NULL)
-		return -ENOMEM;
-
-	if (copy_from_user(data, buf, count) != 0) {
-		rc = -EFAULT;
-		goto out_data;
-	}
+	data = memdup_user(buf, count);
+	if (IS_ERR(data))
+		return PTR_ERR(data);
 
 	cp = smk_parse_smack(data, count);
 	if (IS_ERR(cp)) {