From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <gdb-patches-return-59495-listarch-gdb-patches=sources.redhat.com@sourceware.org>
Received: (qmail 27550 invoked by alias); 24 Oct 2008 18:43:46 -0000
Received: (qmail 27541 invoked by uid 22791); 24 Oct 2008 18:43:45 -0000
X-Spam-Check-By: sourceware.org
Received: from NaN.false.org (HELO nan.false.org) (208.75.86.248)     by sourceware.org (qpsmtpd/0.31) with ESMTP; Fri, 24 Oct 2008 18:43:06 +0000
Received: from nan.false.org (localhost [127.0.0.1]) 	by nan.false.org (Postfix) with ESMTP id 8960A10812; 	Fri, 24 Oct 2008 18:43:03 +0000 (GMT)
Received: from caradoc.them.org (209.195.188.212.nauticom.net [209.195.188.212]) 	by nan.false.org (Postfix) with ESMTP id 64A30106D8; 	Fri, 24 Oct 2008 18:43:03 +0000 (GMT)
Received: from drow by caradoc.them.org with local (Exim 4.69) 	(envelope-from <drow@caradoc.them.org>) 	id 1KtRcj-00026D-BZ; Fri, 24 Oct 2008 14:43:01 -0400
Date: Fri, 24 Oct 2008 18:43:00 -0000
From: Daniel Jacobowitz <drow@false.org>
To: Doug Evans <dje@google.com>
Cc: gdb-patches@sourceware.org
Subject: Re: [commit] dwarf2read.c (typename_concat): avoid segv
Message-ID: <20081024184301.GA7759@caradoc.them.org>
Mail-Followup-To: Doug Evans <dje@google.com>, gdb-patches@sourceware.org
References: <20081024182614.58B191C7947@localhost>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20081024182614.58B191C7947@localhost>
User-Agent: Mutt/1.5.17 (2008-05-11)
X-IsSubscribed: yes
Mailing-List: contact gdb-patches-help@sourceware.org; run by ezmlm
Precedence: bulk
List-Id: <gdb-patches.sourceware.org>
List-Subscribe: <mailto:gdb-patches-subscribe@sourceware.org>
List-Archive: <http://sourceware.org/ml/gdb-patches/>
List-Post: <mailto:gdb-patches@sourceware.org>
List-Help: <mailto:gdb-patches-help@sourceware.org>, <http://sourceware.org/ml/#faqs>
Sender: gdb-patches-owner@sourceware.org
X-SW-Source: 2008-10/txt/msg00611.txt.bz2

On Fri, Oct 24, 2008 at 11:26:14AM -0700, Doug Evans wrote:
> Hi. I checked in the following as obvious.
> Running a large app with many shared libs under gdb -r caused gdb to segv.

Shouldn't this be in the affected caller?  I thought we wouldn't reach
here if prefix or suffix are NULL.

>    if (obs == NULL)
>      {
>        char *retval = xmalloc (strlen (prefix) + MAX_SEP_LEN + strlen (suffix) + 1);
> -      retval[0] = '\0';
> -      
> -      if (prefix)
> -	{
> -	  strcpy (retval, prefix);
> -	  strcat (retval, sep);
> -	}
> -      if (suffix)
> -	strcat (retval, suffix);
> -      
> +      strcpy (retval, prefix);
> +      strcat (retval, sep);
> +      strcat (retval, suffix);
>        return retval;
>      }
>    else

If NULL values are valid, this change is definitely not correct.
You've changed a NULL prefix and "foo" suffix from "foo" to "::foo".

-- 
Daniel Jacobowitz
CodeSourcery