From: Patrick McHardy Date: Wed, 29 Nov 2006 04:10:21 +0000 (-0800) Subject: [NETFILTER]: ipt_REJECT: fix memory corruption X-Git-Tag: v2.6.19~4^2~1 X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=af443b6d90de17f7630621269cf0610d9d772670;p=linux-2.6 [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: Patrick McHardy Signed-off-by: David S. Miller --- diff --git a/net/ipv4/netfilter/ipt_REJECT.c b/net/ipv4/netfilter/ipt_REJECT.c index ad0312d0e4..264763adc3 100644 --- a/net/ipv4/netfilter/ipt_REJECT.c +++ b/net/ipv4/netfilter/ipt_REJECT.c @@ -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);