From mboxrd@z Thu Jan 1 00:00:00 1970 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on inbox.vuxu.org X-Spam-Level: X-Spam-Status: No, score=-3.3 required=5.0 tests=MAILING_LIST_MULTI, RCVD_IN_DNSWL_MED,RCVD_IN_MSPIKE_H3,RCVD_IN_MSPIKE_WL autolearn=ham autolearn_force=no version=3.4.4 Received: (qmail 6877 invoked from network); 11 May 2021 07:33:21 -0000 Received: from mother.openwall.net (195.42.179.200) by inbox.vuxu.org with ESMTPUTF8; 11 May 2021 07:33:21 -0000 Received: (qmail 5554 invoked by uid 550); 11 May 2021 07:33:19 -0000 Mailing-List: contact musl-help@lists.openwall.com; run by ezmlm Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-ID: Reply-To: musl@lists.openwall.com Received: (qmail 5536 invoked from network); 11 May 2021 07:33:18 -0000 Date: Tue, 11 May 2021 09:33:06 +0200 From: Szabolcs Nagy To: David CARLIER , g@port70.net Cc: musl@lists.openwall.com Message-ID: <20210511073306.GQ2799122@port70.net> Mail-Followup-To: David CARLIER , g@port70.net, musl@lists.openwall.com References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Subject: Re: [musl] [PATCH 1/1] reallocarray casting overflow check explicitally * David CARLIER [2021-05-10 20:48:26 +0100]: > From 04e3caa580cfe501ad00d85d63040de329962823 Mon Sep 17 00:00:00 2001 > From: David Carlier > Date: Mon, 10 May 2021 20:45:12 +0100 > Subject: [PATCH] reallocarray overflow check cast to size_t > > --- > src/malloc/reallocarray.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/src/malloc/reallocarray.c b/src/malloc/reallocarray.c > index 4a6ebe46..2556c917 100644 > --- a/src/malloc/reallocarray.c > +++ b/src/malloc/reallocarray.c > @@ -4,7 +4,7 @@ > > void *reallocarray(void *ptr, size_t m, size_t n) > { > - if (n && m > -1 / n) { > + if (n && m > (size_t)-1 / n) { you need to explain this change more i think. the usual arithmetic conversion rules of c already convert both operands of / to size_t, unless size_t has lower conversion rank than signed int, but such a system would have problems because size_t was always promoted to int so you would need a lot more casts in musl (and other software) to avoid signed int overflow and negative arithmetics. > errno = ENOMEM; > return 0; > } > -- > 2.20.1 >