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authorEric Dumazet <edumazet@google.com>2013-01-10 16:18:47 +0000
committerDavid S. Miller <davem@davemloft.net>2013-01-10 22:49:30 -0800
commit7b514a886ba50e3b99295b00805f0d5ad750ca66 (patch)
tree188f1e2fc24e4ef03d1a8d60d88566a96d0aaaf3 /net
parentcb59c87dbc8be2ffa692c50bd22f89025ba7a342 (diff)
tcp: accept RST without ACK flag
commit c3ae62af8e755 (tcp: should drop incoming frames without ACK flag set) added a regression on the handling of RST messages. RST should be allowed to come even without ACK bit set. We validate the RST by checking the exact sequence, as requested by RFC 793 and 5961 3.2, in tcp_validate_incoming() Reported-by: Eric Wong <normalperson@yhbt.net> Signed-off-by: Eric Dumazet <edumazet@google.com> Acked-by: Neal Cardwell <ncardwell@google.com> Tested-by: Eric Wong <normalperson@yhbt.net> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
-rw-r--r--net/ipv4/tcp_input.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index a28e4db8a95..18f97ca76b0 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -5543,7 +5543,7 @@ slow_path:
if (len < (th->doff << 2) || tcp_checksum_complete_user(sk, skb))
goto csum_error;
- if (!th->ack)
+ if (!th->ack && !th->rst)
goto discard;
/*
@@ -5988,7 +5988,7 @@ int tcp_rcv_state_process(struct sock *sk, struct sk_buff *skb,
goto discard;
}
- if (!th->ack)
+ if (!th->ack && !th->rst)
goto discard;
if (!tcp_validate_incoming(sk, skb, th, 0))