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Validate ACK for TCP RST packets.

v0.7.x
whitequark 2016-12-26 13:10:39 +00:00
parent f468f47959
commit 83f886826f
1 changed files with 49 additions and 0 deletions
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49
src/socket/tcp.rs
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@ -274,6 +274,23 @@ impl<'a> TcpSocket<'a> {
return Err(Error::Malformed)
}
(State::Listen, TcpRepr { ack_number: None, .. }) => (),
// A reset received in response to initial SYN is acceptable if it acknowledges
// the initial SYN.
(State::SynSent, TcpRepr { control: TcpControl::Rst, ack_number: None, .. }) => {
net_trace!("tcp:{}:{}: unacceptable RST (expecting RST|ACK) \
in response to initial SYN",
self.local_endpoint, self.remote_endpoint);
return Err(Error::Malformed)
}
(State::SynSent, TcpRepr {
control: TcpControl::Rst, ack_number: Some(ack_number), ..
}) => {
if ack_number != self.local_seq_no {
net_trace!("tcp:{}:{}: unacceptable RST|ACK in response to initial SYN",
self.local_endpoint, self.remote_endpoint);
return Err(Error::Malformed)
}
}
// Every packet after the initial SYN must be an acknowledgement.
(_, TcpRepr { ack_number: None, .. }) => {
net_trace!("tcp:{}:{}: expecting an ACK",
@ -648,6 +665,38 @@ mod test {
}, Err(Error::Malformed));
}
#[test]
fn test_no_ack_syn_sent_rst() {
let mut s = socket();
s.state = State::SynSent;
s.local_endpoint = LOCAL_END;
s.remote_endpoint = REMOTE_END;
s.local_seq_no = LOCAL_SEQ;
send!(s, TcpRepr {
control: TcpControl::Rst,
seq_number: REMOTE_SEQ,
ack_number: None,
..SEND_TEMPL
}, Err(Error::Malformed));
}
#[test]
fn test_bad_ack_syn_sent_rst() {
let mut s = socket();
s.state = State::SynSent;
s.local_endpoint = LOCAL_END;
s.remote_endpoint = REMOTE_END;
s.local_seq_no = LOCAL_SEQ;
send!(s, TcpRepr {
control: TcpControl::Rst,
seq_number: REMOTE_SEQ,
ack_number: Some(1234),
..SEND_TEMPL
}, Err(Error::Malformed));
}
#[test]
fn test_bad_ack_established() {
let mut s = socket();