From: "Darrick J. Wong" Subject: [PATCH 44/51] e2fsck: Check journal superblock checksum prior to recovery Date: Sat, 07 Jan 2012 00:37:38 -0800 Message-ID: <20120107083738.25788.94839.stgit@elm3c44.beaverton.ibm.com> References: <20120107083256.25788.41238.stgit@elm3c44.beaverton.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Cc: Sunil Mushran , Amir Goldstein , Andi Kleen , Mingming Cao , Joel Becker , linux-ext4@vger.kernel.org, Coly Li To: Andreas Dilger , Theodore Tso , "Darrick J. Wong" Return-path: Received: from e37.co.us.ibm.com ([32.97.110.158]:49144 "EHLO e37.co.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752879Ab2AGIi3 (ORCPT ); Sat, 7 Jan 2012 03:38:29 -0500 Received: from /spool/local by e37.co.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Sat, 7 Jan 2012 01:38:28 -0700 Received: from d03av03.boulder.ibm.com (d03av03.boulder.ibm.com [9.17.195.169]) by d03relay05.boulder.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id q078be3Y035764 for ; Sat, 7 Jan 2012 01:37:40 -0700 Received: from d03av03.boulder.ibm.com (loopback [127.0.0.1]) by d03av03.boulder.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id q078bdav013420 for ; Sat, 7 Jan 2012 01:37:40 -0700 In-Reply-To: <20120107083256.25788.41238.stgit@elm3c44.beaverton.ibm.com> Sender: linux-ext4-owner@vger.kernel.org List-ID: Ensure that the journal superblock passes checksum before recovering the filesystem. Signed-off-by: Darrick J. Wong --- e2fsck/journal.c | 59 ++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 files changed, 59 insertions(+), 0 deletions(-) diff --git a/e2fsck/journal.c b/e2fsck/journal.c index 915b8bb..2ac2e54 100644 --- a/e2fsck/journal.c +++ b/e2fsck/journal.c @@ -40,6 +40,53 @@ static int bh_count = 0; */ #undef USE_INODE_IO +/* Checksumming functions */ +int e2fsck_journal_verify_csum_type(journal_t *j, journal_superblock_t *jsb) +{ + if (!JFS_HAS_INCOMPAT_FEATURE(j, JFS_FEATURE_INCOMPAT_CSUM_V2)) + return 1; + + return jsb->s_checksum_type == JBD2_CRC32C_CHKSUM; +} + +static __u32 e2fsck_journal_sb_csum(journal_t *j, journal_superblock_t *jsb) +{ + __u32 crc, old_crc; + + old_crc = jsb->s_checksum; + jsb->s_checksum = 0; + crc = ext2fs_crc32c_le(~0, (unsigned char *)jsb, + sizeof(journal_superblock_t)); + jsb->s_checksum = old_crc; + + return crc; +} + +int e2fsck_journal_sb_csum_verify(journal_t *j, journal_superblock_t *jsb) +{ + __u32 provided, calculated; + + if (!JFS_HAS_INCOMPAT_FEATURE(j, JFS_FEATURE_INCOMPAT_CSUM_V2)) + return 1; + + provided = ext2fs_be32_to_cpu(jsb->s_checksum); + calculated = e2fsck_journal_sb_csum(j, jsb); + + return provided == calculated; +} + +errcode_t e2fsck_journal_sb_csum_set(journal_t *j, journal_superblock_t *jsb) +{ + __u32 crc; + + if (!JFS_HAS_INCOMPAT_FEATURE(j, JFS_FEATURE_INCOMPAT_CSUM_V2)) + return 0; + + crc = e2fsck_journal_sb_csum(j, jsb); + jsb->s_checksum = ext2fs_cpu_to_be32(crc); + return 0; +} + /* Kernel compatibility functions for handling the journal. These allow us * to use the recovery.c file virtually unchanged from the kernel, so we * don't have to do much to keep kernel and user recovery in sync. @@ -560,6 +607,15 @@ static errcode_t e2fsck_journal_load(journal_t *journal) if (JFS_HAS_RO_COMPAT_FEATURE(journal, ~JFS_KNOWN_ROCOMPAT_FEATURES)) return EXT2_ET_RO_UNSUPP_FEATURE; + /* Checksum v1 and v2 are mutually exclusive features. */ + if (JFS_HAS_INCOMPAT_FEATURE(journal, JFS_FEATURE_INCOMPAT_CSUM_V2) && + JFS_HAS_COMPAT_FEATURE(journal, JFS_FEATURE_COMPAT_CHECKSUM)) + return EXT2_ET_CORRUPT_SUPERBLOCK; + + if (!e2fsck_journal_verify_csum_type(journal, jsb) || + !e2fsck_journal_sb_csum_verify(journal, jsb)) + return EXT2_ET_CORRUPT_SUPERBLOCK; + /* We have now checked whether we know enough about the journal * format to be able to proceed safely, so any other checks that * fail we should attempt to recover from. */ @@ -627,6 +683,7 @@ static void e2fsck_journal_reset_super(e2fsck_t ctx, journal_superblock_t *jsb, for (i = 0; i < 4; i ++) new_seq ^= u.val[i]; jsb->s_sequence = htonl(new_seq); + e2fsck_journal_sb_csum_set(journal, jsb); mark_buffer_dirty(journal->j_sb_buffer); ll_rw_block(WRITE, 1, &journal->j_sb_buffer); @@ -667,6 +724,7 @@ static void e2fsck_journal_release(e2fsck_t ctx, journal_t *journal, jsb->s_sequence = htonl(journal->j_transaction_sequence); if (reset) jsb->s_start = 0; /* this marks the journal as empty */ + e2fsck_journal_sb_csum_set(journal, jsb); mark_buffer_dirty(journal->j_sb_buffer); } brelse(journal->j_sb_buffer); @@ -843,6 +901,7 @@ static errcode_t recover_ext3_journal(e2fsck_t ctx) ctx->fs->super->s_state |= EXT2_ERROR_FS; ext2fs_mark_super_dirty(ctx->fs); journal->j_superblock->s_errno = 0; + e2fsck_journal_sb_csum_set(journal, journal->j_superblock); mark_buffer_dirty(journal->j_sb_buffer); }