Cipso: cipso_v4_optptr enter infinite loop

in for(),if((optlen > 0) && (optptr[1] == 0)), enter infinite loop.

Test: receive a packet which the ip length > 20 and the first byte of ip option is 0, produce this issue

Signed-off-by: yujuan.qi <yujuan.qi@mediatek.com>
Acked-by: Paul Moore <paul@paul-moore.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/ipv4/cipso_ipv4.c b/net/ipv4/cipso_ipv4.c
index c4c6e1969ed0606ff9fb4ea46609f75b249e589b..2ae8f54cb32148f2499f78ecbf29259db36bd207 100644 (file)
--- a/net/ipv4/cipso_ipv4.c
+++ b/net/ipv4/cipso_ipv4.c
@@ -1523,9 +1523,17 @@ unsigned char *cipso_v4_optptr(const struct sk_buff *skb)
        int taglen;
 
        for (optlen = iph->ihl*4 - sizeof(struct iphdr); optlen > 0; ) {
-               if (optptr[0] == IPOPT_CIPSO)
+               switch (optptr[0]) {
+               case IPOPT_CIPSO:
                        return optptr;
-               taglen = optptr[1];
+               case IPOPT_END:
+                       return NULL;
+               case IPOPT_NOOP:
+                       taglen = 1;
+                       break;
+               default:
+                       taglen = optptr[1];
+               }
                optlen -= taglen;
                optptr += taglen;
        }