Horton

Re: Avoid possible overflow (src/port/bsearch_arg.c)

Nathan Bossart <nathandbossart@gmail.com>

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From: Nathan Bossart <nathandbossart@gmail.com>
To: Ranier Vilela <ranier.vf@gmail.com>
Cc: Pg Hackers <pgsql-hackers@postgresql.org>
Date: 2024-10-08T21:28:37Z
Lists: pgsql-hackers 
On Tue, Oct 08, 2024 at 04:09:00PM -0300, Ranier Vilela wrote:
> The port function *bsearch_arg* mimics the C function
> *bsearch*.
> 
> The API signature is:
> void *
> bsearch_arg(const void *key, const void *base0,
> size_t nmemb, size_t size,
> int (*compar) (const void *, const void *, void *),
> void *arg)
> 
> So, the parameter *nmemb* is size_t.
> Therefore, a call with nmemb greater than INT_MAX is possible.
> 
> Internally the code uses the *int* type to iterate through the number of
> members, which makes overflow possible.

I traced this back to commit bfa2cee (v14), which both moved bsearch_arg()
to its current location and adjusted the style a bit.  Your patch looks
reasonable to me.

-- 
nathan

Commits

  1. Fix overflow in bsearch_arg() with more than INT_MAX elements

  2. Fix typos and grammar in comments and docs

  3. Move bsearch_arg to src/port