From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2EC87C18E5A for ; Tue, 10 Mar 2020 12:14:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 052F8246A2 for ; Tue, 10 Mar 2020 12:14:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1583842464; bh=bEhWoDM7ps0zyNDOlrnx2a1ZEwiVCTIx3byAPh8nRh0=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=KI1CxiDuwdK73VTveoexFxo7CPeCMphEGQoHEe61jO5TudP9tQeUFl9GHQ9nBiW/I id6gjgtc80oA/lu65FS/5xg5Dh3sSXOJuAfPBVmAxRWYbA6iQdHkdIkeUSWbD449b0 MJYpsbt5uJbzKEAzie/QqLFnB8mpcs0xWOJ2Aqkg= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726271AbgCJMOX (ORCPT ); Tue, 10 Mar 2020 08:14:23 -0400 Received: from mail.kernel.org ([198.145.29.99]:54150 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726224AbgCJMOX (ORCPT ); Tue, 10 Mar 2020 08:14:23 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 00EC02468C; Tue, 10 Mar 2020 12:14:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1583842462; bh=bEhWoDM7ps0zyNDOlrnx2a1ZEwiVCTIx3byAPh8nRh0=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=IoZsxsSaTjPdCjnPxr5oeJz7uBoT4nMSuMA7d7llQlDCFBw1FL4Oh+ZJu6oRNNDL4 3B+3uAMbcSWsPqcQNFsLs18Ms4O2v3Mdltiyvd+boWpscLgBlSpWYAB8X/I0rPL7MH IGvbMI+CCFoi56mhDdL5Ipujjp0x2r01HQvzKdcc= Date: Tue, 10 Mar 2020 13:14:20 +0100 From: Greg KH To: yangerkun Cc: Sasha Levin , herbert@gondor.apana.org.au, stable@vger.kernel.org, linux-crypto@vger.kernel.org Subject: Re: [PATCH 4.4.y v2] crypto: algif_skcipher - use ZERO_OR_NULL_PTR in skcipher_recvmsg_async Message-ID: <20200310121420.GG3106483@kroah.com> References: <20200305085755.22730-1-yangerkun@huawei.com> <20200306133941.GQ21491@sasha-vm> <8bb5b0d7-4232-14cb-49c7-a3cc348645ae@huawei.com> <20200308001945.GT21491@sasha-vm> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: Sender: linux-crypto-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-crypto@vger.kernel.org On Mon, Mar 09, 2020 at 09:27:16AM +0800, yangerkun wrote: > > > On 2020/3/8 8:19, Sasha Levin wrote: > > On Sat, Mar 07, 2020 at 09:49:25AM +0800, yangerkun wrote: > > > > > > > > > On 2020/3/6 21:39, Sasha Levin wrote: > > > > On Thu, Mar 05, 2020 at 04:57:55PM +0800, yangerkun wrote: > > > > > Nowdays, we trigger a oops: > > > > > ... > > > > > kasan: GPF could be caused by NULL-ptr deref or user memory > > > > > accessgeneral protection fault: 0000 [#1] SMP KASAN > > > > > ... > > > > > Call Trace: > > > > > [] skcipher_recvmsg_async+0x3f1/0x1400 > > > > > x86/../crypto/algif_skcipher.c:543 > > > > > [] skcipher_recvmsg+0x93/0x7f0 > > > > > x86/../crypto/algif_skcipher.c:723 > > > > > [] sock_recvmsg_nosec > > > > > x86/../net/socket.c:702 [inline] > > > > > [] sock_recvmsg x86/../net/socket.c:710 [inline] > > > > > [] sock_recvmsg+0x94/0xc0 x86/../net/socket.c:705 > > > > > [] sock_read_iter+0x27b/0x3a0 x86/../net/socket.c:787 > > > > > [] aio_run_iocb+0x21b/0x7a0 x86/../fs/aio.c:1520 > > > > > [] io_submit_one x86/../fs/aio.c:1630 [inline] > > > > > [] do_io_submit+0x6b9/0x10b0 x86/../fs/aio.c:1688 > > > > > [] SYSC_io_submit x86/../fs/aio.c:1713 [inline] > > > > > [] SyS_io_submit+0x2d/0x40 x86/../fs/aio.c:1710 > > > > > [] tracesys_phase2+0x90/0x95 > > > > > > > > > > In skcipher_recvmsg_async, we use '!sreq->tsg' to determine does we > > > > > calloc fail. However, kcalloc may return ZERO_SIZE_PTR, and with this, > > > > > the latter sg_init_table will trigger the bug. Fix it be use > > > > > ZERO_OF_NULL_PTR. > > > > > > > > > > This function was introduced with ' commit a596999b7ddf ("crypto: > > > > > algif - change algif_skcipher to be asynchronous")', and has > > > > > been removed > > > > > with 'commit e870456d8e7c ("crypto: algif_skcipher - overhaul memory > > > > > management")'. > > > > > > > > > > Reported-by: Hulk Robot > > > > > Signed-off-by: yangerkun > > > > > --- > > > > > crypto/algif_skcipher.c | 2 +- > > > > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > > > > > > > v1->v2: > > > > > update the commit message > > > > > > > > > > diff --git a/crypto/algif_skcipher.c b/crypto/algif_skcipher.c > > > > > index d12782dc9683..9bd4691cc5c5 100644 > > > > > --- a/crypto/algif_skcipher.c > > > > > +++ b/crypto/algif_skcipher.c > > > > > @@ -538,7 +538,7 @@ static int skcipher_recvmsg_async(struct > > > > > socket *sock, struct msghdr *msg, > > > > > lock_sock(sk); > > > > > tx_nents = skcipher_all_sg_nents(ctx); > > > > > sreq->tsg = kcalloc(tx_nents, sizeof(*sg), GFP_KERNEL); > > > > > - if (unlikely(!sreq->tsg)) > > > > > + if (unlikely(ZERO_OR_NULL_PTR(sreq->tsg))) > > > > > > > > I'm a bit confused: kcalloc() will return ZERO_SIZE_PTR for allocations > > > > that ask for 0 bytes, but here we ask for "sizeof(*sg)" bytes, which is > > > > guaranteed to be more than 0, no? > > > > > > Actually, the size need to calloc is (tx_nents * sizeof(*sg)), and > > > tx_nents is 0. > > > > Makes sense. This is also needed on 4.9, right? > > Yes! Thanks for checking it! Now queued up,t hanks. greg k-h