From 5c8428513dc0e53af847b5435f58c94237d1cc3d Mon Sep 17 00:00:00 2001 From: "Darrick J. Wong" Date: Thu, 2 Aug 2012 20:47:46 -0400 Subject: [PATCH] e2fsck: check descriptor block checksum when recovering journal Verify the descriptor block checksum when recovering a journal. Signed-off-by: Darrick J. Wong Signed-off-by: Theodore Ts'o --- e2fsck/recovery.c | 39 ++++++++++++++++++++++++++++++++++++++- 1 file changed, 38 insertions(+), 1 deletion(-) diff --git a/e2fsck/recovery.c b/e2fsck/recovery.c index 8bf4401..208e1cb 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) { @@ -362,6 +386,7 @@ 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; @@ -452,6 +477,18 @@ 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, @@ -482,7 +519,7 @@ 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 long io_block; tag = (journal_block_tag_t *) tagp; -- 1.8.3.1