From patchwork Sat Sep 3 16:23:01 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: =?utf-8?q?Herv=C3=A9_Poussineau?= X-Patchwork-Id: 12965000 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 4ACFEECAAD4 for ; Sat, 3 Sep 2022 16:24:49 +0000 (UTC) Received: from localhost ([::1]:33706 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1oUVwu-000525-0k for qemu-devel@archiver.kernel.org; Sat, 03 Sep 2022 12:24:48 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:56452) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1oUVvQ-0003WY-P3; Sat, 03 Sep 2022 12:23:16 -0400 Received: from iserv.reactos.org ([2a01:4f8:1c17:5ae1::1]:39072) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1oUVvO-00064j-Lk; Sat, 03 Sep 2022 12:23:16 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=reactos.org ; s=25047; h=Content-Transfer-Encoding:Content-Type:MIME-Version:References: In-Reply-To:Message-Id:Date:Subject:Cc:To:From:Sender:Reply-To:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:List-Id:List-Help:List-Unsubscribe:List-Subscribe: List-Post:List-Owner:List-Archive; bh=WHv6pmGMYmsvVdtQ+Ffp1n10JkheWRlDlCVMBRmmniA=; b=PMXXDmBlD6TEOTIoQxM8r6ja9J 9GHxv93VB2whbQQX/g0FzugEvmPw9TSITb80Zj+433oYHLqtd8VuQQptqsZbJXsWmr0ScEMpBhwgM AKqp47QiUKyTOprn7ntiBZU4OpVrBIUpkp/TYylaXI8/o58aMhcBuAZZ/OKxYJHSWOZQ=; Received: by iserv.reactos.org with esmtpsa (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1oUVvK-0002VU-7U; Sat, 03 Sep 2022 16:23:10 +0000 From: =?utf-8?q?Herv=C3=A9_Poussineau?= To: Kevin Wolf , Hanna Reitz , qemu-block@nongnu.org Cc: qemu-devel@nongnu.org, =?utf-8?q?Herv=C3=A9_Poussineau?= Subject: [PATCH 1/2] vvfat: allow some writes to bootsector Date: Sat, 3 Sep 2022 18:23:01 +0200 Message-Id: <20220903162302.3176003-2-hpoussin@reactos.org> X-Mailer: git-send-email 2.36.2 In-Reply-To: <20220903162302.3176003-1-hpoussin@reactos.org> References: <20220903162302.3176003-1-hpoussin@reactos.org> MIME-Version: 1.0 Received-SPF: pass client-ip=2a01:4f8:1c17:5ae1::1; envelope-from=hpoussin@reactos.org; helo=iserv.reactos.org X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=ham 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" 'reserved1' field in bootsector is used to mark volume dirty, or need to verify. Allow writes to bootsector which only changes the 'reserved1' field. This fixes I/O errors on Windows guests. Resolves: https://bugs.launchpad.net/qemu/+bug/1889421 Signed-off-by: Hervé Poussineau --- block/vvfat.c | 18 +++++++++++++++++- 1 file changed, 17 insertions(+), 1 deletion(-) diff --git a/block/vvfat.c b/block/vvfat.c index d6dd919683d..35057a51c67 100644 --- a/block/vvfat.c +++ b/block/vvfat.c @@ -2993,11 +2993,27 @@ DLOG(checkpoint()); vvfat_close_current_file(s); + if (sector_num == s->offset_to_bootsector && nb_sectors == 1) { + /* + * Write on bootsector. Allow only changing the reserved1 field, + * used to mark volume dirtiness + */ + const unsigned char *initial = s->first_sectors + + s->offset_to_bootsector * 0x200; + for (i = 0; i < 0x200; i++) { + if (i != offsetof(bootsector_t, u.fat16.reserved1) && + initial[i] != buf[i]) { + fprintf(stderr, "Tried to write to protected bootsector\n"); + return -1; + } + } + return 0; + } + /* * Some sanity checks: * - do not allow writing to the boot sector */ - if (sector_num < s->offset_to_fat) return -1;