Commit af443b6d authored by Patrick McHardy's avatar Patrick McHardy Committed by David S. Miller
Browse files

[NETFILTER]: ipt_REJECT: fix memory corruption



On devices with hard_header_len > LL_MAX_HEADER ip_route_me_harder()
reallocates the skb, leading to memory corruption when using the stale
tcph pointer to update the checksum.
Signed-off-by: default avatarPatrick McHardy <kaber@trash.net>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 2e47c264
......@@ -114,6 +114,14 @@ static void send_reset(struct sk_buff *oldskb, int hook)
tcph->window = 0;
tcph->urg_ptr = 0;
/* Adjust TCP checksum */
tcph->check = 0;
tcph->check = tcp_v4_check(tcph, sizeof(struct tcphdr),
nskb->nh.iph->saddr,
nskb->nh.iph->daddr,
csum_partial((char *)tcph,
sizeof(struct tcphdr), 0));
/* Set DF, id = 0 */
nskb->nh.iph->frag_off = htons(IP_DF);
nskb->nh.iph->id = 0;
......@@ -129,14 +137,8 @@ static void send_reset(struct sk_buff *oldskb, int hook)
if (ip_route_me_harder(&nskb, addr_type))
goto free_nskb;
/* Adjust TCP checksum */
nskb->ip_summed = CHECKSUM_NONE;
tcph->check = 0;
tcph->check = tcp_v4_check(tcph, sizeof(struct tcphdr),
nskb->nh.iph->saddr,
nskb->nh.iph->daddr,
csum_partial((char *)tcph,
sizeof(struct tcphdr), 0));
/* Adjust IP TTL */
nskb->nh.iph->ttl = dst_metric(nskb->dst, RTAX_HOPLIMIT);
......
Supports Markdown
0% or .
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment