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=-8.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=ham 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 1647CC10DCE for ; Fri, 6 Mar 2020 13:39:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E2E652084E for ; Fri, 6 Mar 2020 13:39:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1583501984; bh=DSzVN77wc9UBW6xxS8MhVz43+mLB9HuADYFSIrfj9Pc=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=kVZ4/1kHgi1wZfsxZP8PHLYZv7TWUgnX9p3qfH4yoigwZQ5e/1Y3WKhivR4eoasUD Z00e+qNWjUPsVhNt0PMOksuqdb9HhIUv+IrI3CESzmegasuKN8YeI3PpSAOHwSt1+P 3dJm7ywrEk1e4wVcZxKTNp4Eer1Ditabr7rZy10E= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726300AbgCFNjn (ORCPT ); Fri, 6 Mar 2020 08:39:43 -0500 Received: from mail.kernel.org ([198.145.29.99]:57336 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726090AbgCFNjn (ORCPT ); Fri, 6 Mar 2020 08:39:43 -0500 Received: from localhost (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (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 7E6CA2072D; Fri, 6 Mar 2020 13:39:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1583501982; bh=DSzVN77wc9UBW6xxS8MhVz43+mLB9HuADYFSIrfj9Pc=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=XDUlPD2INaUHFrx3pmh15B0gffkx5LXpn2S/2JXylCnTFn3ivok8nDnfCJlfWRG4W YHN1MxbjA6sYgczgs/YS2hsXiSnM9WN93iCpx1WBBgdfjJ0W6jnXGrH9vwXBzrQUsQ e4kgTUfIcOSKxg8dRiqG94jIrqtcRUI16Ep37lvk= Date: Fri, 6 Mar 2020 08:39:41 -0500 From: Sasha Levin To: yangerkun Cc: gregkh@linuxfoundation.org, 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: <20200306133941.GQ21491@sasha-vm> References: <20200305085755.22730-1-yangerkun@huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Disposition: inline In-Reply-To: <20200305085755.22730-1-yangerkun@huawei.com> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-crypto-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-crypto@vger.kernel.org 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? -- Thanks, Sasha