Re: char 0x00 - Mailing list pgsql-docs

From Brett Okken
Subject Re: char 0x00
Date
Msg-id CANBJVOEO5GVXVrucPK9iUpr9CgODsZ_cwFsBoDOs8O50=eqRBQ@mail.gmail.com
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In response to Re: char 0x00  (Tom Lane <tgl@sss.pgh.pa.us>)
Responses Re: char 0x00  (Dave Cramer <davecramer@gmail.com>)
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Dave, any thoughts on best way to reproduce Vladimir’s described workflow in a way that is consumable by the postgresql team?

On Thu, Mar 26, 2020 at 10:21 AM Tom Lane <tgl@sss.pgh.pa.us> wrote:
Brett Okken <brett.okken.os@gmail.com> writes:
> Using a client and server encoding of SQL_ASCII makes it possible to get
> 0x00 into a text value column when using a bind variable.

Having looked at the code again, I flat out don't believe you.
textin is certainly not going to read past a nul character,
and textrecv goes through pg_client_to_server (via pq_getmsgtext),
which AFAICS is careful in all code paths to reject nuls.

If I'm missing something, I'd really like to see a concrete example,
because this would be a bug, and it'd suggest that somebody's managed
to reopen CVE-2006-2313.  If we're missing nul rejection in some code
path, then we're probably not doing encoding validation at all.

                        regards, tom lane

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