Re: [PATCH 3/8] Add support for a generic wal reading facility dubbed XLogReader

Andres Freund <andres@2ndquadrant.com> writes:
> On Tuesday, October 30, 2012 03:20:03 PM Alvaro Herrera wrote:
>> Am I the only one who finds this rather bizarre?  Maybe this was okay
>> when xlog data would only come from WAL files stored in the data
>> directory at recovery, but if we're now receiving these from a remote
>> sender over the network I wonder if we should be protecting against
>> malicious senders.  (This is not related to this patch anyway.)

> You can't use a CRC against malicous users anyway, its not cryptographically 
> secure in any meaning of the word,

More to the point, if a bad guy has got control of your WAL stream,
crashing the startup process with a ridiculous length word is several
orders of magnitude less than the worst thing he can find to do to you.
So the above argument seems completely nonsensical to me.  Anybody who's
worried about that type of scenario is better advised to be setting up
SSL to ensure that the stream is coming from the server they think it's
coming from.

			regards, tom lane