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 Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id EFED5C3DA6D for ; Tue, 20 May 2025 10:05:03 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1uHJpl-0008Ab-Mw; Tue, 20 May 2025 06:04:29 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1uHJpk-0008AE-7Y for qemu-devel@nongnu.org; Tue, 20 May 2025 06:04:28 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1uHJph-0000En-Ec for qemu-devel@nongnu.org; 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Tue, 20 May 2025 10:04:10 +0000 (UTC) Received: from redhat.com (unknown [10.45.226.86]) by mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 5851E30001AA; Tue, 20 May 2025 10:04:07 +0000 (UTC) Date: Tue, 20 May 2025 12:04:05 +0200 From: Kevin Wolf To: gerben@altlinux.org Cc: qemu-block@nongnu.org, hreitz@redhat.com, qemu-devel@nongnu.org, sdl.qemu@linuxtesting.org Subject: Re: [PATCH v2] qemu-img: fix offset calculation in bench Message-ID: References: <20250506141410.100119-1-gerben@altlinux.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250506141410.100119-1-gerben@altlinux.org> X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.4 Received-SPF: pass client-ip=170.10.129.124; envelope-from=kwolf@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -31 X-Spam_score: -3.2 X-Spam_bar: --- X-Spam_report: (-3.2 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.13, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H5=-1, RCVD_IN_MSPIKE_WL=-0.01, RCVD_IN_VALIDITY_CERTIFIED_BLOCKED=0.001, RCVD_IN_VALIDITY_RPBL_BLOCKED=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=unavailable autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Am 06.05.2025 um 16:13 hat gerben@altlinux.org geschrieben: > From: Denis Rastyogin > > This error was discovered by fuzzing qemu-img. > > The current offset calculation leads to an EIO error > in block/block-backend.c: blk_check_byte_request(): > > if (offset > len || len - offset < bytes) { > return -EIO; > } > > This triggers the error message: > "qemu-img: Failed request: Input/output error". > > Example of the issue: > offset: 260076 > len: 260096 > bytes: 4096 > > This fix ensures that offset remains within a valid range. > > Signed-off-by: Denis Rastyogin > --- > qemu-img.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/qemu-img.c b/qemu-img.c > index 76ac5d3028..e64acfafb3 100644 > --- a/qemu-img.c > +++ b/qemu-img.c > @@ -4488,10 +4488,10 @@ static void bench_cb(void *opaque, int ret) > */ > b->in_flight++; > b->offset += b->step; > - if (b->image_size == 0) { > + if (b->image_size - b->bufsize <= 0) { The result of b->image_size - b->bufsize is unsigned, so this doesn't do what it looks like. I'm replacing it with b->image_size <= b->bufsize. > b->offset = 0; > } else { > - b->offset %= b->image_size; > + b->offset %= b->image_size - b->bufsize; > } > if (b->write) { > acb = blk_aio_pwritev(b->blk, offset, b->qiov, 0, bench_cb, b); Thanks, applied to the block branch. Kevin