cifs: Use after free in debug code

This debug code dereferences "old_iface" after it was already freed by the call to release_iface(). Re-order the debugging to avoid this issue. Fixes: b54034a ("cifs: during reconnect, update interface if necessary") Cc: [email protected] # 5.19+ Reviewed-by: Paulo Alcantara (SUSE) <[email protected]> Signed-off-by: Dan Carpenter <[email protected]> Signed-off-by: Steve French <[email protected]>
ammarfaizi2 · Nov 19, 2022 · f391d6e · f391d6e
1 parent 926028a
commit f391d6e
Showing 1 changed file with 2 additions and 2 deletions.
diff --git a/fs/cifs/sess.c b/fs/cifs/sess.c
@@ -302,14 +302,14 @@ cifs_chan_update_iface(struct cifs_ses *ses, struct TCP_Server_Info *server)
 
 	/* now drop the ref to the current iface */
 	if (old_iface && iface) {
-		kref_put(&old_iface->refcount, release_iface);
 		cifs_dbg(FYI, "replacing iface: %pIS with %pIS\n",
 			 &old_iface->sockaddr,
 			 &iface->sockaddr);
-	} else if (old_iface) {
 		kref_put(&old_iface->refcount, release_iface);
+	} else if (old_iface) {
 		cifs_dbg(FYI, "releasing ref to iface: %pIS\n",
 			 &old_iface->sockaddr);
+		kref_put(&old_iface->refcount, release_iface);
 	} else {
 		WARN_ON(!iface);
 		cifs_dbg(FYI, "adding new iface: %pIS\n", &iface->sockaddr);