Horton

Re: glibc qsort() vulnerability

Nathan Bossart <nathandbossart@gmail.com>

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From: Nathan Bossart <nathandbossart@gmail.com>
To: Mats Kindahl <mats@timescale.com>
Cc: Tom Lane <tgl@sss.pgh.pa.us>, Andres Freund <andres@anarazel.de>, Thomas Munro <thomas.munro@gmail.com>, Heikki Linnakangas <hlinnaka@iki.fi>, pgsql-hackers@lists.postgresql.org
Date: 2024-02-12T15:57:15Z
Lists: pgsql-hackers

Commits

Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →

  1. Use new overflow-safe integer comparison functions.

  2. Introduce overflow-safe integer comparison functions.

  3. Replace calls to pg_qsort() with the qsort() macro.

  4. Switch over to using our own qsort() all the time, as has been proposed

On Sun, Feb 11, 2024 at 03:44:42PM +0100, Mats Kindahl wrote:
> On Sat, Feb 10, 2024 at 9:53 PM Nathan Bossart <nathandbossart@gmail.com>
> wrote:
>> and I think we should expand on some of the commentary in int.h.
>> For example, the comment at the top of int.h seems very tailored to the
>> existing functions and should probably be adjusted.
> 
> 
> I rewrote the beginning to the following, does that look good?
> 
>  * int.h
>  *  Routines to perform signed and unsigned integer arithmetics, including
>  *  comparisons, in an overflow-safe way.
> 
> 
> 
>> And the "comparison
>> routines for integers" comment might benefit from some additional details
>> about the purpose and guarantees of the new functions.
>>
> 
> I expanded that into the following. WDYT?
> 
> /*------------------------------------------------------------------------
>  * Comparison routines for integers.
>  *
>  * These routines are used to implement comparison functions for, e.g.,
>  * qsort(). They are designed to be efficient and not risk overflows in
>  * internal computations that could cause strange results, such as INT_MIN >
>  * INT_MAX if you just return "lhs - rhs".
>  *------------------------------------------------------------------------

LGTM.  I might editorialize a bit before committing, but I think your
proposed wording illustrates the thrust of the change.

-- 
Nathan Bossart
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