On Fri, 2021-12-10 at 15:43 +0200, Heikki Linnakangas wrote: > ProcessStartupPacket() currently reads the first 4 bytes coming from the > client to decide what kind of a connection it is, and I believe a TLS > ClientHello message always begins with the same sequence of bytes, so it > would be easy to check for. > > You could use recv(.., MSG_PEEK | MSG_WAITALL) flags to leave the bytes > in the OS buffer. Not sure how portable that is, though. Alternatively, > you could stash them e.g. in a global variable and modify > secure_raw_read() to return those bytes first. > > Overall, doesn't seem very hard to me.
After further thought... Seems like sharing a port between implicit and explicit TLS will still allow a MITM to put bytes on the wire to try to attack the client-to-server communication, because they can craft the SSLRequest themselves and then hand it off to the real client. But they shouldn't be able to attack the server-to-client communication if the client is using implicit TLS, so it's still an overall improvement? I wonder if there are any other protocols out there doing this. --Jacob
