Return-Path: Received: from mx1.redhat.com ([209.132.183.28]:56526 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729306AbeIYVwI (ORCPT ); Tue, 25 Sep 2018 17:52:08 -0400 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 1F2073081256 for ; Tue, 25 Sep 2018 15:44:03 +0000 (UTC) Subject: Re: [PATCH] getnetconfig.c: fix a BAD_FREE (CWE-763) To: Zhi Li , linux-nfs@vger.kernel.org References: <1537863212-1389-1-git-send-email-yieli@redhat.com> From: Steve Dickson Message-ID: <00c09492-70b0-0891-1f3c-318e8b787781@RedHat.com> Date: Tue, 25 Sep 2018 11:44:02 -0400 MIME-Version: 1.0 In-Reply-To: <1537863212-1389-1-git-send-email-yieli@redhat.com> Content-Type: text/plain; charset=utf-8 Sender: linux-nfs-owner@vger.kernel.org List-ID: On 9/25/18 4:13 AM, Zhi Li wrote: > Signed-off-by: Zhi Li > --- > > https://bugzilla.redhat.com/show_bug.cgi?id=1631614 > > src/getnetconfig.c | 17 +++++++++-------- > 1 file changed, 9 insertions(+), 8 deletions(-) > > diff --git a/src/getnetconfig.c b/src/getnetconfig.c > index d67d97d..869556d 100644 > --- a/src/getnetconfig.c > +++ b/src/getnetconfig.c > @@ -681,6 +681,7 @@ struct netconfig *ncp; > { > struct netconfig *p; > char *tmp; > + char *t; > u_int i; > > if ((tmp=malloc(MAXNETCONFIGLINE)) == NULL) > @@ -700,12 +701,12 @@ struct netconfig *ncp; > */ > *p = *ncp; > p->nc_netid = (char *)strcpy(tmp,ncp->nc_netid); > - tmp = strchr(tmp, 0) + 1; > - p->nc_protofmly = (char *)strcpy(tmp,ncp->nc_protofmly); > - tmp = strchr(tmp, 0) + 1; > - p->nc_proto = (char *)strcpy(tmp,ncp->nc_proto); > - tmp = strchr(tmp, 0) + 1; > - p->nc_device = (char *)strcpy(tmp,ncp->nc_device); > + t = strchr(tmp, 0) + 1; > + p->nc_protofmly = (char *)strcpy(t,ncp->nc_protofmly); > + t = strchr(t, 0) + 1; > + p->nc_proto = (char *)strcpy(t,ncp->nc_proto); > + t = strchr(t, 0) + 1; > + p->nc_device = (char *)strcpy(t,ncp->nc_device); > p->nc_lookups = (char **)malloc((size_t)(p->nc_nlookups+1) * sizeof(char *)); > if (p->nc_lookups == NULL) { > free(p->nc_netid); Ok... I see why tmp original value needs to be maintained to do the free()... but I'm wondering why the freeing of p->nc_netid is needed... it appears to me it is part of tmp string... so when tmp is freed won't p->nc_netid be freed as well? steved. > @@ -714,8 +715,8 @@ struct netconfig *ncp; > return(NULL); > } > for (i=0; i < p->nc_nlookups; i++) { > - tmp = strchr(tmp, 0) + 1; > - p->nc_lookups[i] = (char *)strcpy(tmp,ncp->nc_lookups[i]); > + t = strchr(t, 0) + 1; > + p->nc_lookups[i] = (char *)strcpy(t,ncp->nc_lookups[i]); > } > return(p); > } >