[PATCH] Add reallocarray function.

[Dennis Wölfing]

On 10.04.2017 17:18, Zack Weinberg wrote:
> On Mon, Apr 10, 2017 at 11:00 AM, Dennis Wölfing <denniswoelfing@gmx.de> wrote:
>> The reallocarray function is an extension from OpenBSD.  It is an
>> integer-overflow-safe replacement for realloc(p, X*Y) and
>> malloc(X*Y) (realloc(NULL, X*Y)).  It can therefore help in preventing
>> certain security issues in code.
>>
>> This is an updated version of a patch originally submitted by Rüdiger
>> Sonderfeld in May 2014.
>> See <https://sourceware.org/ml/libc-alpha/2014-05/msg00481.html>.
> 
> I agree in principle with adding this function.  I skimmed the patch
> and it seems to be mostly the Right Thing.  I do have two concerns:
> 
> * There do not appear to be any uses of the internal aliases
> __libc_reallocarray and __reallocarray.  Have you audited glibc itself
> for places that should use reallocarray?  If you haven't, would you be
> willing to do that?  This will determine whether we actually need
> those aliases.

I have not yet checked where glibc itself should use reallocarray but I
will do so.

> * Please add documentation for reallocarray.  It belongs in
> manual/memory.texi, in the "Changing Block Size" section.  This is the
> place to explain when and why one should use reallocarray instead of
> realloc.

Ok, I will look into this.