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Date: Sat, 07 Jan 2012 00:37:50 -0800 From: "Darrick J. Wong" <djwong@...ibm.com> To: Andreas Dilger <adilger.kernel@...ger.ca>, Theodore Tso <tytso@....edu>, "Darrick J. Wong" <djwong@...ibm.com> Cc: Sunil Mushran <sunil.mushran@...cle.com>, Amir Goldstein <amir73il@...il.com>, Andi Kleen <andi@...stfloor.org>, Mingming Cao <cmm@...ibm.com>, Joel Becker <jlbec@...lplan.org>, linux-ext4@...r.kernel.org, Coly Li <colyli@...il.com> Subject: [PATCH 46/51] e2fsck: Check descriptor block checksum when recovering journal Verify the descriptor block checksum when recovering a journal. Signed-off-by: Darrick J. Wong <djwong@...ibm.com> --- e2fsck/recovery.c | 39 ++++++++++++++++++++++++++++++++++++++- 1 files changed, 38 insertions(+), 1 deletions(-) diff --git a/e2fsck/recovery.c b/e2fsck/recovery.c index 60c8ceb..f76e7d8 100644 --- a/e2fsck/recovery.c +++ b/e2fsck/recovery.c @@ -174,6 +174,27 @@ static int jread(struct buffer_head **bhp, journal_t *journal, return 0; } +static int jbd2_descr_block_csum_verify(journal_t *j, + void *buf) +{ + struct journal_block_tail *tail; + __u32 provided, calculated; + + if (!JFS_HAS_INCOMPAT_FEATURE(j, JFS_FEATURE_INCOMPAT_CSUM_V2)) + return 1; + + tail = (struct journal_block_tail *)(buf + j->j_blocksize - + sizeof(struct journal_block_tail)); + provided = tail->t_checksum; + tail->t_checksum = 0; + calculated = ext2fs_crc32c_le(~0, j->j_superblock->s_uuid, + sizeof(j->j_superblock->s_uuid)); + calculated = ext2fs_crc32c_le(calculated, buf, j->j_blocksize); + tail->t_checksum = provided; + + provided = ext2fs_be32_to_cpu(provided); + return provided == calculated; +} /* * Count the number of in-use tags in a journal descriptor block. @@ -186,6 +207,9 @@ static int count_tags(journal_t *journal, struct buffer_head *bh) int nr = 0, size = journal->j_blocksize; int tag_bytes = journal_tag_bytes(journal); + if (JFS_HAS_INCOMPAT_FEATURE(journal, JFS_FEATURE_INCOMPAT_CSUM_V2)) + size -= sizeof(struct journal_block_tail); + tagp = &bh->b_data[sizeof(journal_header_t)]; while ((tagp - bh->b_data + tag_bytes) <= size) { @@ -364,6 +388,7 @@ static int do_one_pass(journal_t *journal, int blocktype; int tag_bytes = journal_tag_bytes(journal); __u32 crc32_sum = ~0; /* Transactional Checksums */ + int descr_csum_size = 0; /* Precompute the maximum metadata descriptors in a descriptor block */ int MAX_BLOCKS_PER_DESC; @@ -454,6 +479,18 @@ static int do_one_pass(journal_t *journal, switch(blocktype) { case JFS_DESCRIPTOR_BLOCK: + /* Verify checksum first */ + if (JFS_HAS_INCOMPAT_FEATURE(journal, + JFS_FEATURE_INCOMPAT_CSUM_V2)) + descr_csum_size = + sizeof(struct journal_block_tail); + if (descr_csum_size > 0 && + !jbd2_descr_block_csum_verify(journal, + bh->b_data)) { + err = -EIO; + goto failed; + } + /* If it is a valid descriptor block, replay it * in pass REPLAY; if journal_checksums enabled, then * calculate checksums in PASS_SCAN, otherwise, @@ -484,7 +521,7 @@ static int do_one_pass(journal_t *journal, tagp = &bh->b_data[sizeof(journal_header_t)]; while ((tagp - bh->b_data + tag_bytes) - <= journal->j_blocksize) { + <= journal->j_blocksize - descr_csum_size) { unsigned long io_block; tag = (journal_block_tag_t *) tagp; -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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