xt_ipp2p: don't search haystack if it's empty

All the search functions have a positive minimum packet length.

Signed-off-by: Jeremy Sowden <jeremy@azazel.net>

diff --git a/extensions/xt_ipp2p.c b/extensions/xt_ipp2p.c
index 8fb1b79bb4145bb50dc8410cfc57295cb3de8da7..4e0fbb675c76323dec53eee4fcfd524cd22aee82 100644 (file)
--- a/extensions/xt_ipp2p.c
+++ b/extensions/xt_ipp2p.c
@@ -842,14 +842,17 @@ ipp2p_mt(const struct sk_buff *skb, struct xt_action_param *par)
                if (tcph->syn) return 0;  /* if SYN bit is set bail out */
                if (tcph->rst) return 0;  /* if RST bit is set bail out */
 
-               haystack += tcph->doff * 4; /* get TCP-Header-Size */
                if (tcph->doff * 4 > hlen) {
                        if (info->debug)
                                pr_info("TCP header indicated packet larger than it is\n");
-                       hlen = 0;
-               } else {
-                       hlen -= tcph->doff * 4;
+                       return 0;
                }
+               if (tcph->doff * 4 == hlen)
+                       return 0;
+
+               haystack += tcph->doff * 4; /* get TCP-Header-Size */
+               hlen     -= tcph->doff * 4;
+
                while (matchlist[i].command) {
                        if ((info->cmd & matchlist[i].command) == matchlist[i].command &&
                            hlen > matchlist[i].packet_len)
@@ -875,14 +878,16 @@ ipp2p_mt(const struct sk_buff *skb, struct xt_action_param *par)
        {
                const struct udphdr *udph = (const void *)ip + ip_hdrlen(skb);
 
-               haystack += sizeof(*udph);
                if (sizeof(*udph) > hlen) {
                        if (info->debug)
                                pr_info("UDP header indicated packet larger than it is\n");
-                       hlen = 0;
-               } else {
-                       hlen -= sizeof(*udph);
+                       return 0;
                }
+               if (sizeof(*udph) == hlen)
+                       return 0;
+
+               haystack += sizeof(*udph);
+               hlen     -= sizeof(*udph);
 
                while (udp_list[i].command) {
                        if ((info->cmd & udp_list[i].command) == udp_list[i].command &&