From patchwork Mon May 25 11:50:49 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Tetsuhiro Kohada X-Patchwork-Id: 11568727 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 CCC11739 for ; Mon, 25 May 2020 11:51:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id AC5A72071A for ; Mon, 25 May 2020 11:51:17 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="CcPulbWU" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2390370AbgEYLvO (ORCPT ); Mon, 25 May 2020 07:51:14 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49798 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388697AbgEYLvN (ORCPT ); Mon, 25 May 2020 07:51:13 -0400 Received: from mail-pl1-x644.google.com (mail-pl1-x644.google.com [IPv6:2607:f8b0:4864:20::644]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9797CC061A0E; Mon, 25 May 2020 04:51:13 -0700 (PDT) Received: by mail-pl1-x644.google.com with SMTP id u22so7403814plq.12; Mon, 25 May 2020 04:51:13 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=+cV+B94asZZ/7gT7USNnklXwNK87VKFcwbJZH4mw41Q=; b=CcPulbWUhsMWJd8cKUtnAZWfZh9/f7CReyfLbH8MwtcaTC3X5vDxUj11vNQog6a/b6 OcTyOCEsGm9tHLRxyEXd1LCwW4tii6cKei9tBikm6owtgQ4RVLtV5Rqj9Pogm8icMx92 q7LBIT/RPsSRwEWWuLkLVQbFWqN6IeiEJzW3FzJe0fDufJdT9ki1UQEyrXatWYFzVLd+ EsM/HyiXBGA104/3grNN1r89OLJn4ZMB1AKNhLNdzSmcK6HK+9jr2Y4N+iLoA6/4VfXP +MsWDtxv1WAZRa2fgb+/4A1NYNbQf4g5bUkgnMZ1Y023PC3dAiZ1BE9697QN4TBePlB6 mMKg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=+cV+B94asZZ/7gT7USNnklXwNK87VKFcwbJZH4mw41Q=; b=BBLRBEavCqc6XA2Qb0n0Xzhbx0UTNmN2rYd1Z6xVn39X+S63zf6OrueuAFq25Kc/lw 1eJR8WSG0ZRYPIMlvPmSdAHqPNUgXsBpWk3xuUMssNa23uoo/Ssv2hN2snOlBqtuj7AJ iCbZ9l7w54hw50lg1Dt+yCFsxo5jF7i/DYbf0lCopU7ceH1F8nLqprESymkWD1YUX/eC k2SdUYsXnFs27NH+gMb11FXqMhJAoqk1okKHfiuv6VAG4/42DG5HZCpK0dRVvTTTnrqR mSup3mAudGcTVzsgCFu3hoCve3+irFBSQiPhMJHNR/xvMt+GhMtw0ClOq6YFGr/Xs5rF /1IA== X-Gm-Message-State: AOAM532lghFzmd10twwn25mAUOEQcLLJWTh+04HkM2LjDOXf3apF2lws Q9Bj0wUuhwLHzl/cKlgZUPY= X-Google-Smtp-Source: ABdhPJyznXDdIEvvNy2XZQ+GLuctI3UJZVPyQl+Exhs3fOoLBYqz7TRxNdmlq41EUxTpWkdYzkeNnA== X-Received: by 2002:a17:90a:2a03:: with SMTP id i3mr20245504pjd.29.1590407473115; Mon, 25 May 2020 04:51:13 -0700 (PDT) Received: from dc803.flets-west.jp ([2404:7a87:83e0:f800:b9cb:9f91:3c10:565c]) by smtp.gmail.com with ESMTPSA id h16sm13017537pfq.56.2020.05.25.04.51.10 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 25 May 2020 04:51:12 -0700 (PDT) From: Tetsuhiro Kohada To: kohada.t2@gmail.com Cc: kohada.tetsuhiro@dc.mitsubishielectric.co.jp, mori.takahiro@ab.mitsubishielectric.co.jp, motai.hirotaka@aj.mitsubishielectric.co.jp, Namjae Jeon , Sungjong Seo , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH 2/4] exfat: separate the boot sector analysis Date: Mon, 25 May 2020 20:50:49 +0900 Message-Id: <20200525115052.19243-2-kohada.t2@gmail.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200525115052.19243-1-kohada.t2@gmail.com> References: <20200525115052.19243-1-kohada.t2@gmail.com> MIME-Version: 1.0 Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org Separate the boot sector analysis to read_boot_sector(). Furthermore, add a strict consistency check, because overlapping areas can cause serious corruption. Signed-off-by: Tetsuhiro Kohada --- fs/exfat/exfat_raw.h | 1 + fs/exfat/super.c | 96 +++++++++++++++++++++++--------------------- 2 files changed, 52 insertions(+), 45 deletions(-) diff --git a/fs/exfat/exfat_raw.h b/fs/exfat/exfat_raw.h index b373dc4e099f..65f884785192 100644 --- a/fs/exfat/exfat_raw.h +++ b/fs/exfat/exfat_raw.h @@ -15,6 +15,7 @@ #define VOL_CLEAN 0x0000 #define VOL_DIRTY 0x0002 +#define ERR_MEDIUM 0x0004 #define EXFAT_EOF_CLUSTER 0xFFFFFFFFu #define EXFAT_BAD_CLUSTER 0xFFFFFFF7u diff --git a/fs/exfat/super.c b/fs/exfat/super.c index e60d28e73ff0..95909b4d5e75 100644 --- a/fs/exfat/super.c +++ b/fs/exfat/super.c @@ -366,25 +366,20 @@ static int exfat_read_root(struct inode *inode) return 0; } -static struct boot_sector *exfat_read_boot_with_logical_sector( - struct super_block *sb) +static int exfat_calibrate_blocksize(struct super_block *sb, int logical_sect) { struct exfat_sb_info *sbi = EXFAT_SB(sb); - struct boot_sector *p_boot = (struct boot_sector *)sbi->boot_bh->b_data; - unsigned short logical_sect = 0; - - logical_sect = 1 << p_boot->sect_size_bits; if (!is_power_of_2(logical_sect) || logical_sect < 512 || logical_sect > 4096) { exfat_err(sb, "bogus logical sector size %u", logical_sect); - return NULL; + return -EIO; } if (logical_sect < sb->s_blocksize) { exfat_err(sb, "logical sector size too small for device (logical sector size = %u)", logical_sect); - return NULL; + return -EIO; } if (logical_sect > sb->s_blocksize) { @@ -394,24 +389,20 @@ static struct boot_sector *exfat_read_boot_with_logical_sector( if (!sb_set_blocksize(sb, logical_sect)) { exfat_err(sb, "unable to set blocksize %u", logical_sect); - return NULL; + return -EIO; } sbi->boot_bh = sb_bread(sb, 0); if (!sbi->boot_bh) { exfat_err(sb, "unable to read boot sector (logical sector size = %lu)", sb->s_blocksize); - return NULL; + return -EIO; } - - p_boot = (struct boot_sector *)sbi->boot_bh->b_data; } - return p_boot; + return 0; } -/* mount the file system volume */ -static int __exfat_fill_super(struct super_block *sb) +static int exfat_read_boot_sector(struct super_block *sb) { - int ret; struct boot_sector *p_boot; struct exfat_sb_info *sbi = EXFAT_SB(sb); @@ -424,51 +415,36 @@ static int __exfat_fill_super(struct super_block *sb) exfat_err(sb, "unable to read boot sector"); return -EIO; } - - /* PRB is read */ p_boot = (struct boot_sector *)sbi->boot_bh->b_data; /* check the validity of BOOT */ if (le16_to_cpu((p_boot->signature)) != BOOT_SIGNATURE) { exfat_err(sb, "invalid boot record signature"); - ret = -EINVAL; - goto free_bh; - } - - - /* check logical sector size */ - p_boot = exfat_read_boot_with_logical_sector(sb); - if (!p_boot) { - ret = -EIO; - goto free_bh; + return -EINVAL; } /* - * res_zero field must be filled with zero to prevent mounting + * must_be_zero field must be filled with zero to prevent mounting * from FAT volume. */ - if (memchr_inv(p_boot->must_be_zero, 0, - sizeof(p_boot->must_be_zero))) { - ret = -EINVAL; - goto free_bh; - } + if (memchr_inv(p_boot->must_be_zero, 0, sizeof(p_boot->must_be_zero))) + return -EINVAL; - p_boot = (struct boot_sector *)p_boot; - if (!p_boot->num_fats) { + if (p_boot->num_fats != 1 && p_boot->num_fats != 2) { exfat_err(sb, "bogus number of FAT structure"); - ret = -EINVAL; - goto free_bh; + return -EINVAL; } sbi->sect_per_clus = 1 << p_boot->sect_per_clus_bits; sbi->sect_per_clus_bits = p_boot->sect_per_clus_bits; - sbi->cluster_size_bits = sbi->sect_per_clus_bits + sb->s_blocksize_bits; + sbi->cluster_size_bits = p_boot->sect_per_clus_bits + + p_boot->sect_size_bits; sbi->cluster_size = 1 << sbi->cluster_size_bits; sbi->num_FAT_sectors = le32_to_cpu(p_boot->fat_length); sbi->FAT1_start_sector = le32_to_cpu(p_boot->fat_offset); - sbi->FAT2_start_sector = p_boot->num_fats == 1 ? - sbi->FAT1_start_sector : - sbi->FAT1_start_sector + sbi->num_FAT_sectors; + sbi->FAT2_start_sector = le32_to_cpu(p_boot->fat_offset); + if (p_boot->num_fats == 2) + sbi->FAT2_start_sector += sbi->num_FAT_sectors; sbi->data_start_sector = le32_to_cpu(p_boot->clu_offset); sbi->num_sectors = le64_to_cpu(p_boot->vol_length); /* because the cluster index starts with 2 */ @@ -483,15 +459,45 @@ static int __exfat_fill_super(struct super_block *sb) sbi->clu_srch_ptr = EXFAT_FIRST_CLUSTER; sbi->used_clusters = EXFAT_CLUSTERS_UNTRACKED; - if (le16_to_cpu(p_boot->vol_flags) & VOL_DIRTY) { - sbi->vol_flag |= VOL_DIRTY; - exfat_warn(sb, "Volume was not properly unmounted. Some data may be corrupt. Please run fsck."); + /* check consistencies */ + if (sbi->num_FAT_sectors << p_boot->sect_size_bits < + sbi->num_clusters * 4) { + exfat_err(sb, "bogus fat length"); + return -EINVAL; + } + if (sbi->data_start_sector < + sbi->FAT1_start_sector + sbi->num_FAT_sectors * p_boot->num_fats) { + exfat_err(sb, "bogus data start sector"); + return -EINVAL; } + if (sbi->vol_flag & VOL_DIRTY) + exfat_warn(sb, "Volume was not properly unmounted. Some data may be corrupt. Please run fsck."); + if (sbi->vol_flag & ERR_MEDIUM) + exfat_warn(sb, "Medium has reported failures. Some data may be lost."); /* exFAT file size is limited by a disk volume size */ sb->s_maxbytes = (u64)(sbi->num_clusters - EXFAT_RESERVED_CLUSTERS) << sbi->cluster_size_bits; + /* check logical sector size */ + if (exfat_calibrate_blocksize(sb, 1 << p_boot->sect_size_bits)) + return -EIO; + + return 0; +} + +/* mount the file system volume */ +static int __exfat_fill_super(struct super_block *sb) +{ + int ret; + struct exfat_sb_info *sbi = EXFAT_SB(sb); + + ret = exfat_read_boot_sector(sb); + if (ret) { + exfat_err(sb, "failed to read boot sector"); + goto free_bh; + } + ret = exfat_create_upcase_table(sb); if (ret) { exfat_err(sb, "failed to load upcase table");