From: Ilpo Järvinen Date: Wed, 8 Oct 2008 18:34:06 +0000 (-0700) Subject: tcp: fix length used for checksum in a reset X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=52cd5750e81ec8d213949fa7c0d2e08907bf498b;p=GitHub%2FLineageOS%2Fandroid_kernel_motorola_exynos9610.git tcp: fix length used for checksum in a reset While looking for some common code I came across difference in checksum calculation between tcp_v6_send_(reset|ack) I couldn't explain. I checked both v4 and v6 and found out that both seem to have the same "feature". I couldn't find anything in rfc nor anywhere else which would state that md5 option should be ignored like it was in case of reset so I came to a conclusion that this is probably a genuine bug. I suspect that addition of md5 just was fooled by the excessive copy-paste code in those functions and the reset part was never tested well enough to find out the problem. Signed-off-by: Ilpo Järvinen Signed-off-by: David S. Miller --- diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c index 24ffc5e1d3da..ba46769c6e97 100644 --- a/net/ipv4/tcp_ipv4.c +++ b/net/ipv4/tcp_ipv4.c @@ -589,7 +589,7 @@ static void tcp_v4_send_reset(struct sock *sk, struct sk_buff *skb) #endif arg.csum = csum_tcpudp_nofold(ip_hdr(skb)->daddr, ip_hdr(skb)->saddr, /* XXX */ - sizeof(struct tcphdr), IPPROTO_TCP, 0); + arg.iov[0].iov_len, IPPROTO_TCP, 0); arg.csumoffset = offsetof(struct tcphdr, check) / 2; arg.flags = (sk && inet_sk(sk)->transparent) ? IP_REPLY_ARG_NOSRCCHECK : 0; diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c index 424d9c4a67ac..e8b0fdd9edb8 100644 --- a/net/ipv6/tcp_ipv6.c +++ b/net/ipv6/tcp_ipv6.c @@ -1012,14 +1012,14 @@ static void tcp_v6_send_reset(struct sock *sk, struct sk_buff *skb) } #endif - buff->csum = csum_partial((char *)t1, sizeof(*t1), 0); + buff->csum = csum_partial((char *)t1, tot_len, 0); memset(&fl, 0, sizeof(fl)); ipv6_addr_copy(&fl.fl6_dst, &ipv6_hdr(skb)->saddr); ipv6_addr_copy(&fl.fl6_src, &ipv6_hdr(skb)->daddr); t1->check = csum_ipv6_magic(&fl.fl6_src, &fl.fl6_dst, - sizeof(*t1), IPPROTO_TCP, + tot_len, IPPROTO_TCP, buff->csum); fl.proto = IPPROTO_TCP;