Merge branch 'smack-for-4.21-a' of https://github.com/cschaufler/next-smack into next-smack

From Casey.

"I have two Smack patches for 4.21. One Jose's patch adds
missing documentation and Zoran's fleshes out the access checks
on keyrings."

Documentation/admin-guide/LSM/Smack.rst

@@ -818,6 +818,10 @@ Smack supports some mount options:
 	specifies a label to which all labels set on the
 	filesystem must have read access. Not yet enforced.
 
+  smackfstransmute=label:
+	behaves exactly like smackfsroot except that it also
+	sets the transmute flag on the root of the mount
+
 These mount options apply to all file system types.
 
 Smack auditing

security/smack/smack_lsm.c

@@ -4333,6 +4333,12 @@ static int smack_key_permission(key_ref_t key_ref,
 	int request = 0;
 	int rc;
 
+	/*
+	 * Validate requested permissions
+	 */
+	if (perm & ~KEY_NEED_ALL)
+		return -EINVAL;
+
 	keyp = key_ref_to_ptr(key_ref);
 	if (keyp == NULL)
 		return -EINVAL;
@@ -4356,10 +4362,10 @@ static int smack_key_permission(key_ref_t key_ref,
 	ad.a.u.key_struct.key = keyp->serial;
 	ad.a.u.key_struct.key_desc = keyp->description;
 #endif
-	if (perm & KEY_NEED_READ)
-		request = MAY_READ;
+	if (perm & (KEY_NEED_READ | KEY_NEED_SEARCH | KEY_NEED_VIEW))
+		request |= MAY_READ;
 	if (perm & (KEY_NEED_WRITE | KEY_NEED_LINK | KEY_NEED_SETATTR))
-		request = MAY_WRITE;
+		request |= MAY_WRITE;
 	rc = smk_access(tkp, keyp->security, request, &ad);
 	rc = smk_bu_note("key access", tkp, keyp->security, request, rc);
 	return rc;