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tcp: in SYN_SENT only accept SYNACK, discard everything else. 

THis would let FIN packets through, breaking the logic below.

Found with cargo-fuzz.
This commit is contained in:
Dario Nieuwenhuis 2021-10-04 23:39:43 +02:00
parent 947a69b8b2
commit 16abd60e9b
1 changed files with 11 additions and 18 deletions
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29
src/socket/tcp.rs
View File

@ -1355,24 +1355,6 @@ impl<'a> TcpSocket<'a> {
);
return Err(Error::Dropped);
}
// Any ACK in the SYN-SENT state must have the SYN flag set.
(
State::SynSent,
&TcpRepr {
control: TcpControl::None,
ack_number: Some(_),
..
},
) => {
net_debug!(
"{}:{}:{}: expecting a SYN|ACK",
self.meta.handle,
self.local_endpoint,
self.remote_endpoint
);
self.abort();
return Err(Error::Dropped);
}
// SYN|ACK in the SYN-SENT state must have the exact ACK number.
(
State::SynSent,
@ -1392,6 +1374,17 @@ impl<'a> TcpSocket<'a> {
return Err(Error::Dropped);
}
}
// Anything else in the SYN-SENT state is invalid.
(State::SynSent, _) => {
net_debug!(
"{}:{}:{}: expecting a SYN|ACK",
self.meta.handle,
self.local_endpoint,
self.remote_endpoint
);
self.abort();
return Err(Error::Dropped);
}
// Every acknowledgement must be for transmitted but unacknowledged data.
(
_,