[Top][All Lists]
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
[Qemu-devel] PATCH: Fix edge case bug in VNC server TLS auth
From: |
Daniel P. Berrange |
Subject: |
[Qemu-devel] PATCH: Fix edge case bug in VNC server TLS auth |
Date: |
Thu, 12 Feb 2009 12:24:00 +0000 |
User-agent: |
Mutt/1.4.1i |
Just discovered a nasty little edge case bug in the VNC server TLS auth
code. In the case where the TLS handshake does *not* block on I/O, QEMU
sends the next 'start sub-auth' message twice. This seriously confuses
the VNC client :-) Fortunately the chances of the handshake not blocking
are close to zero for a TCP socket, which is why it has not been noticed
thus far. Even with both client & server on localhost, I can only hit the
bug 1 time in 20.
NB, the diff context here is not too informative. If you look at the
full code you'll see that a few lines early we called vnc_start_tls()
which called vnc_continue_handshake() which called the method
start_auth_vencrypt_subauth(). Hence, fixing the bug, just involves
removing the 2nd bogus call to start_auth_vencrypt_subauth() as per
this patch.
Signed-off-by: Daniel P. Berrange <address@hidden>
Daniel
diff -r da9abc900b0e vnc.c
--- a/vnc.c Tue Feb 10 18:46:57 2009 +0000
+++ b/vnc.c Wed Feb 11 17:31:25 2009 +0000
@@ -2049,14 +2049,6 @@ static int protocol_client_vencrypt_auth
VNC_DEBUG("Failed to complete TLS\n");
return 0;
}
-
- if (vs->wiremode == VNC_WIREMODE_TLS) {
- VNC_DEBUG("Starting VeNCrypt subauth\n");
- return start_auth_vencrypt_subauth(vs);
- } else {
- VNC_DEBUG("TLS handshake blocked\n");
- return 0;
- }
}
return 0;
}
--
|: Red Hat, Engineering, London -o- http://people.redhat.com/berrange/ :|
|: http://libvirt.org -o- http://virt-manager.org -o- http://ovirt.org :|
|: http://autobuild.org -o- http://search.cpan.org/~danberr/ :|
|: GnuPG: 7D3B9505 -o- F3C9 553F A1DA 4AC2 5648 23C1 B3DF F742 7D3B 9505 :|
[Prev in Thread] |
Current Thread |
[Next in Thread] |
- [Qemu-devel] PATCH: Fix edge case bug in VNC server TLS auth,
Daniel P. Berrange <=