Re: remove redundant memset() call - Mailing list pgsql-hackers

From Bruce Momjian
Subject Re: remove redundant memset() call
Date
Msg-id Y0hjwacUauTMADIL@momjian.us
Whole thread Raw
In response to Re: remove redundant memset() call  (Zhihong Yu <zyu@yugabyte.com>)
Responses Re: remove redundant memset() call  (Nathan Bossart <nathandbossart@gmail.com>)
List pgsql-hackers
On Thu, Oct 13, 2022 at 12:12:35PM -0700, Zhihong Yu wrote:
> On Thu, Oct 13, 2022 at 12:10 PM Bruce Momjian <bruce@momjian.us> wrote:
> 
>     On Thu, Oct 13, 2022 at 10:55:08AM -0700, Zhihong Yu wrote:
>     > Hi,
>     > I was looking at combo_init in contrib/pgcrypto/px.c .
>     >
>     > There is a memset() call following palloc0() - the call is redundant.
>     >
>     > Please see the patch for the proposed change.
>     >
>     > Thanks
> 
>     > diff --git a/contrib/pgcrypto/px.c b/contrib/pgcrypto/px.c
>     > index 3b098c6151..d35ccca777 100644
>     > --- a/contrib/pgcrypto/px.c
>     > +++ b/contrib/pgcrypto/px.c
>     > @@ -203,7 +203,6 @@ combo_init(PX_Combo *cx, const uint8 *key, unsigned
>     klen,
>     >       if (klen > ks)
>     >               klen = ks;
>     >       keybuf = palloc0(ks);
>     > -     memset(keybuf, 0, ks);
>     >       memcpy(keybuf, key, klen);
>     > 
>     >       err = px_cipher_init(c, keybuf, klen, ivbuf);
> 
>     Uh, the memset() is ks length but the memcpy() is klen, and the above
>     test allows ks to be larger than klen.
> 
>     --
>       Bruce Momjian  <bruce@momjian.us>        https://momjian.us
>       EDB                                      https://enterprisedb.com
> 
>       Indecision is a decision.  Inaction is an action.  Mark Batterson
> 
> 
> Hi,
> the memory has been zero'ed out by palloc0().
> 
> memcpy is not relevant w.r.t. resetting memory.

Ah, good point.

-- 
  Bruce Momjian  <bruce@momjian.us>        https://momjian.us
  EDB                                      https://enterprisedb.com

  Indecision is a decision.  Inaction is an action.  Mark Batterson




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