From a20d1cebb98bba75f2e34fddc768dd8712c1bded Mon Sep 17 00:00:00 2001 From: Theodore Ts'o Date: Mon, 3 May 2021 15:37:33 -0400 Subject: jbd2: fix portability problems caused by unaligned accesses This commit applies the e2fsck/recovery.c portions of commit 1e0c8ca7c08a ("e2fsck: fix portability problems caused by unaligned accesses) from the e2fsprogs git tree. The on-disk format for the ext4 journal can have unaigned 32-bit integers. This can happen when replaying a journal using a obsolete checksum format (which was never popularly used, since the v3 format replaced v2 while the metadata checksum feature was being stablized). Signed-off-by: Theodore Ts'o --- fs/jbd2/recovery.c | 22 +++++++++++----------- 1 file changed, 11 insertions(+), 11 deletions(-) diff --git a/fs/jbd2/recovery.c b/fs/jbd2/recovery.c index d47a0d96bf30..4c4209262437 100644 --- a/fs/jbd2/recovery.c +++ b/fs/jbd2/recovery.c @@ -196,7 +196,7 @@ static int jbd2_descriptor_block_csum_verify(journal_t *j, void *buf) static int count_tags(journal_t *journal, struct buffer_head *bh) { char * tagp; - journal_block_tag_t * tag; + journal_block_tag_t tag; int nr = 0, size = journal->j_blocksize; int tag_bytes = journal_tag_bytes(journal); @@ -206,14 +206,14 @@ static int count_tags(journal_t *journal, struct buffer_head *bh) tagp = &bh->b_data[sizeof(journal_header_t)]; while ((tagp - bh->b_data + tag_bytes) <= size) { - tag = (journal_block_tag_t *) tagp; + memcpy(&tag, tagp, sizeof(tag)); nr++; tagp += tag_bytes; - if (!(tag->t_flags & cpu_to_be16(JBD2_FLAG_SAME_UUID))) + if (!(tag.t_flags & cpu_to_be16(JBD2_FLAG_SAME_UUID))) tagp += 16; - if (tag->t_flags & cpu_to_be16(JBD2_FLAG_LAST_TAG)) + if (tag.t_flags & cpu_to_be16(JBD2_FLAG_LAST_TAG)) break; } @@ -433,9 +433,9 @@ static int jbd2_commit_block_csum_verify(journal_t *j, void *buf) } static int jbd2_block_tag_csum_verify(journal_t *j, journal_block_tag_t *tag, + journal_block_tag3_t *tag3, void *buf, __u32 sequence) { - journal_block_tag3_t *tag3 = (journal_block_tag3_t *)tag; __u32 csum32; __be32 seq; @@ -496,7 +496,7 @@ static int do_one_pass(journal_t *journal, while (1) { int flags; char * tagp; - journal_block_tag_t * tag; + journal_block_tag_t tag; struct buffer_head * obh; struct buffer_head * nbh; @@ -613,8 +613,8 @@ static int do_one_pass(journal_t *journal, <= journal->j_blocksize - descr_csum_size) { unsigned long io_block; - tag = (journal_block_tag_t *) tagp; - flags = be16_to_cpu(tag->t_flags); + memcpy(&tag, tagp, sizeof(tag)); + flags = be16_to_cpu(tag.t_flags); io_block = next_log_block++; wrap(journal, next_log_block); @@ -632,7 +632,7 @@ static int do_one_pass(journal_t *journal, J_ASSERT(obh != NULL); blocknr = read_tag_block(journal, - tag); + &tag); /* If the block has been * revoked, then we're all done @@ -647,8 +647,8 @@ static int do_one_pass(journal_t *journal, /* Look for block corruption */ if (!jbd2_block_tag_csum_verify( - journal, tag, obh->b_data, - be32_to_cpu(tmp->h_sequence))) { + journal, &tag, (journal_block_tag3_t *)tagp, + obh->b_data, be32_to_cpu(tmp->h_sequence))) { brelse(obh); success = -EFSBADCRC; printk(KERN_ERR "JBD2: Invalid " -- cgit v1.2.3