From patchwork Thu Aug 27 11:38:06 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Prasad Pandit X-Patchwork-Id: 11740577 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 99137722 for ; Thu, 27 Aug 2020 11:41:10 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id 2F55C2078A for ; Thu, 27 Aug 2020 11:41:10 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="EBn3IUtS" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 2F55C2078A Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Received: from localhost ([::1]:46986 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1kBGHF-0000HX-8z for patchwork-qemu-devel@patchwork.kernel.org; Thu, 27 Aug 2020 07:41:09 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:42076) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kBGGY-0007it-I9 for qemu-devel@nongnu.org; Thu, 27 Aug 2020 07:40:26 -0400 Received: from us-smtp-delivery-1.mimecast.com ([205.139.110.120]:59815 helo=us-smtp-1.mimecast.com) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1kBGGS-0005tZ-1g for qemu-devel@nongnu.org; Thu, 27 Aug 2020 07:40:26 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1598528418; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding; bh=jOm04fHcXIfQRdrxPnd54zDgfa1WG07n38J3lSXxtU0=; b=EBn3IUtSXP2kMUZrp4pwM3EUDyX5VMlfEpsR9qJ6yozwhlVCTzesgOU8FxAWXONNtucreL RZ93M7lUVzh8sQOJClzmuhMcLOfUwccRSVYlgAE5oE30Z7tu7bnTaYckT6D765w8Yd5c7Q GskPp4PgzEwizwvgnJzRmZTtCrgamRU= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-4-HomIeHsqOiusVUpu1IIjfg-1; Thu, 27 Aug 2020 07:40:13 -0400 X-MC-Unique: HomIeHsqOiusVUpu1IIjfg-1 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 595E91DDFF; Thu, 27 Aug 2020 11:40:12 +0000 (UTC) Received: from localhost.localdomain (ovpn-112-91.phx2.redhat.com [10.3.112.91]) by smtp.corp.redhat.com (Postfix) with ESMTPS id A058B1972A; Thu, 27 Aug 2020 11:40:09 +0000 (UTC) From: P J P To: John Snow Subject: [PATCH] fdc: check null block pointer before blk_pwrite Date: Thu, 27 Aug 2020 17:08:06 +0530 Message-Id: <20200827113806.1850687-1-ppandit@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=ppandit@redhat.com X-Mimecast-Spam-Score: 0.001 X-Mimecast-Originator: redhat.com Received-SPF: pass client-ip=205.139.110.120; envelope-from=ppandit@redhat.com; helo=us-smtp-1.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/08/27 00:13:19 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] [fuzzy] X-Spam_score_int: -30 X-Spam_score: -3.1 X-Spam_bar: --- X-Spam_report: (-3.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.959, 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_H2=-0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Ruhr-University , QEMU Developers , qemu-block@nongnu.org, Prasad J Pandit Errors-To: qemu-devel-bounces+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Sender: "Qemu-devel" From: Prasad J Pandit While transferring data via fdctrl_write_data(), check that current drive does not have a null block pointer. Avoid null pointer dereference. -> https://ruhr-uni-bochum.sciebo.de/s/NNWP2GfwzYKeKwE?path=%2Ffdc_nullptr1 ==1658854==Hint: address points to the zero page. #0 blk_inc_in_flight block/block-backend.c:1327 #1 blk_prw block/block-backend.c:1299 #2 blk_pwrite block/block-backend.c:1464 #3 fdctrl_write_data hw/block/fdc.c:2418 #4 fdctrl_write hw/block/fdc.c:962 #5 portio_write ioport.c:205 #6 memory_region_write_accessor memory.c:483 #7 access_with_adjusted_size memory.c:544 #8 memory_region_dispatch_write memory.c:1476 Reported-by: Ruhr-University Signed-off-by: Prasad J Pandit --- hw/block/fdc.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/hw/block/fdc.c b/hw/block/fdc.c index e9ed3eef45..dedadac68a 100644 --- a/hw/block/fdc.c +++ b/hw/block/fdc.c @@ -2419,7 +2419,8 @@ static void fdctrl_write_data(FDCtrl *fdctrl, uint32_t value) if (pos == FD_SECTOR_LEN - 1 || fdctrl->data_pos == fdctrl->data_len) { cur_drv = get_cur_drv(fdctrl); - if (blk_pwrite(cur_drv->blk, fd_offset(cur_drv), fdctrl->fifo, + if (cur_drv->blk + && blk_pwrite(cur_drv->blk, fd_offset(cur_drv), fdctrl->fifo, BDRV_SECTOR_SIZE, 0) < 0) { FLOPPY_DPRINTF("error writing sector %d\n", fd_sector(cur_drv));