Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S265959AbUFIU5A (ORCPT ); Wed, 9 Jun 2004 16:57:00 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S266168AbUFIU4g (ORCPT ); Wed, 9 Jun 2004 16:56:36 -0400 Received: from smtp1.pp.htv.fi ([213.243.153.34]:53645 "EHLO smtp1.pp.htv.fi") by vger.kernel.org with ESMTP id S265959AbUFIUzx (ORCPT ); Wed, 9 Jun 2004 16:55:53 -0400 Subject: Re: [PATCH] ALSA: Remove subsystem-specific malloc (1/8) From: Pekka Enberg To: arjanv@redhat.com Cc: Chris Wright , linux-kernel@vger.kernel.org, tiwai@suse.de In-Reply-To: <1086812486.2810.21.camel@laptop.fenrus.com> References: <200406082124.i58LOuOL016163@melkki.cs.helsinki.fi> <20040609113455.U22989@build.pdx.osdl.net> <1086812001.13026.63.camel@cherry> <1086812486.2810.21.camel@laptop.fenrus.com> Content-Type: text/plain Message-Id: <1086814663.13026.70.camel@cherry> Mime-Version: 1.0 X-Mailer: Ximian Evolution 1.4.6 Date: Wed, 09 Jun 2004 23:57:43 +0300 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1653 Lines: 56 On Wed, 2004-06-09 at 23:21, Arjan van de Ven wrote: > how about making sure n*size doesn't overflow an int in this function? > We had a few security holes due to that happening a while ago; might as > well prevent it from happening entirely Sure. Pekka diff -urN linux-2.6.6/include/linux/slab.h kcalloc-2.6.6/include/linux/slab.h --- linux-2.6.6/include/linux/slab.h 2004-06-09 22:56:11.874249056 +0300 +++ kcalloc-2.6.6/include/linux/slab.h 2004-06-09 23:03:10.597593432 +0300 @@ -95,6 +95,7 @@ return __kmalloc(size, flags); } +extern void *kcalloc(size_t, size_t, int); extern void kfree(const void *); extern unsigned int ksize(const void *); diff -urN linux-2.6.6/mm/slab.c kcalloc-2.6.6/mm/slab.c --- linux-2.6.6/mm/slab.c 2004-06-09 22:59:13.081701336 +0300 +++ kcalloc-2.6.6/mm/slab.c 2004-06-09 23:50:06.592497136 +0300 @@ -2332,6 +2332,25 @@ EXPORT_SYMBOL(kmem_cache_free); /** + * kcalloc - allocate memory for an array. The memory is set to zero. + * @n: number of elements. + * @size: element size. + * @flags: the type of memory to allocate. + */ +void *kcalloc(size_t n, size_t size, int flags) +{ + if (n != 0 && size > INT_MAX / n) + return NULL; + + void *ret = kmalloc(n * size, flags); + if (ret) + memset(ret, 0, n * size); + return ret; +} + +EXPORT_SYMBOL(kcalloc); + +/** * kfree - free previously allocated memory * @objp: pointer returned by kmalloc. * - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/