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List: postgresql-general
Subject: Re: [HACKERS] [BUGS] Server crash while trying to read expression
From: Heikki Linnakangas <heikki.linnakangas () enterprisedb ! com>
Date: 2010-06-30 18:14:11
Message-ID: 4C2B8973.3050005 () enterprisedb ! com
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On 23/06/10 21:36, Robert Haas wrote:
> On Mon, Jun 21, 2010 at 7:50 PM, Heikki Linnakangas
> <heikki.linnakangas@enterprisedb.com> wrote:
>> On 15/06/10 10:31, Heikki Linnakangas wrote:
>>>
>>> You could avoid changing the meaning of fn_expr by putting the check in
>>> the parse analysis phase, into transformFuncCall(). That would feel
>>> safer at least for back-branches.
>>
>> Here's a patch using that approach.
>>
>> I grepped through PostgreSQL and pgadmin source code to find the system
>> columns where valid node-strings are stored:
>>
>> pg_index.indexprs
>> pg_index.indprep
>> pg_attrdef.adbin
>> pg_proc.proargdefaults
>> pg_constraint.conbin
>>
>> Am I missing anything?
>
> I think that pg_type.typdefaultbin is used by pg_dump.
Yep, added that.
> pg_rewrite.ev_qual, pg_rewrite.ev_action, pg_trigger.tgqual also
> contain nodeToString() output but I didn't have any luck using them
> with pg_get_expr() so maybe they don't need to be included.
I left them out.
> The only other thing I notice is that, obviously, the FIXME comment
> needs to be FIXMEd before commit.
Fixed.
> I'd still be in favor of inserting at least some basic error checks
> into readfuncs.c, though just in HEAD. The restrictions implemented
> here seem adequate to prevent a security vulnerability, but superusers
> can still invoke those functions manually, and while superusers can
> clearly crash the system in any number of ways, that doesn't seem (to
> me) like an adequate justification for ignoring the return value of
> strtok(). YMMV, of course.
Agreed. I'll do that as a separate patch.
Thanks for the review!
--
Heikki Linnakangas
EnterpriseDB http://www.enterprisedb.com
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