From: Martijn van Duren <openbsd+tech@list.imperialat.at>
Subject: Re: smtpd: use memcpy() in xmemdup
To: Omar Polo <op@omarpolo.com>, tech@openbsd.org
Date: Mon, 16 Mar 2026 08:48:18 +0100

OK martijn@

On 3/15/26 17:19, Omar Polo wrote:
> Unsure why it's memmove() since the two pointers cannot overlap by construction.
> xmemdup() was added by eric@ back in 2012, and it seems he took the existing
> memmove that used to be in IMSG_BATCH_APPEND handling in mta.c, which was also
> "wrong", since a memcpy() would suffice.  I haven't dig earlier in the history.
> (c.f. 591e1804eb on src.git or mta.c revision 1.141..1.142)
> 
> ok?
> 
> diff /home/op/w/smtpd
> path + /home/op/w/smtpd
> commit - 6965f4adac1ec8b9b9fcb3516ed56fae271049dc
> blob - 948bb06e9a1ef43ab28919e45d8f95703351ca71
> file + util.c
> --- util.c
> +++ util.c
> @@ -95,7 +95,7 @@ xmemdup(const void *ptr, size_t size)
>  	if ((r = malloc(size)) == NULL)
>  		fatal("malloc");
>  
> -	memmove(r, ptr, size);
> +	memcpy(r, ptr, size);
>  
>  	return (r);
>  }
>