From e65e227f28bf274abf4b46f656c0cb94e7428560 Mon Sep 17 00:00:00 2001
From: lyq140 <34637052+lyq140@users.noreply.github.com>
Date: Wed, 1 Aug 2018 12:03:24 +0800
Subject: [PATCH] ripd: null check the key string

This fix a crash of  null pointer.
when we don't add a key string or delete it,
the key is not null but key string is null,
so the code have to return.

Signed-off-by: lyq140 <34637052+lyq140@users.noreply.github.com>
---
 ripd/ripd.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/ripd/ripd.c b/ripd/ripd.c
index 90dc7808eb..fa1188d625 100644
--- a/ripd/ripd.c
+++ b/ripd/ripd.c
@@ -902,7 +902,7 @@ static int rip_auth_md5(struct rip_packet *packet, struct sockaddr_in *from,
 			return 0;
 
 		key = key_lookup_for_accept(keychain, md5->keyid);
-		if (key == NULL)
+		if (key == NULL || key->string == NULL)
 			return 0;
 
 		strncpy(auth_str, key->string, RIP_AUTH_MD5_SIZE);