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authorTheodore Ts'o <tytso@mit.edu>2017-03-25 17:22:47 -0400
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2017-03-30 09:44:06 +0200
commit35637b59f6759d3c79d881490aaca2dc73173bf5 (patch)
tree77aa2a5fdd7cd79275286319331514cd84110e89
parent26512e52106d8050bcf710e62badbcb120c34841 (diff)
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ext4: lock the xattr block before checksuming it
commit dac7a4b4b1f664934e8b713f529b629f67db313c upstream. We must lock the xattr block before calculating or verifying the checksum in order to avoid spurious checksum failures. https://bugzilla.kernel.org/show_bug.cgi?id=193661 Reported-by: Colin Ian King <colin.king@canonical.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--fs/ext4/xattr.c65
1 files changed, 31 insertions, 34 deletions
diff --git a/fs/ext4/xattr.c b/fs/ext4/xattr.c
index c40bd55b6400..7b5a683defe6 100644
--- a/fs/ext4/xattr.c
+++ b/fs/ext4/xattr.c
@@ -131,31 +131,26 @@ static __le32 ext4_xattr_block_csum(struct inode *inode,
}
static int ext4_xattr_block_csum_verify(struct inode *inode,
- sector_t block_nr,
- struct ext4_xattr_header *hdr)
+ struct buffer_head *bh)
{
- if (ext4_has_metadata_csum(inode->i_sb) &&
- (hdr->h_checksum != ext4_xattr_block_csum(inode, block_nr, hdr)))
- return 0;
- return 1;
-}
-
-static void ext4_xattr_block_csum_set(struct inode *inode,
- sector_t block_nr,
- struct ext4_xattr_header *hdr)
-{
- if (!ext4_has_metadata_csum(inode->i_sb))
- return;
+ struct ext4_xattr_header *hdr = BHDR(bh);
+ int ret = 1;
- hdr->h_checksum = ext4_xattr_block_csum(inode, block_nr, hdr);
+ if (ext4_has_metadata_csum(inode->i_sb)) {
+ lock_buffer(bh);
+ ret = (hdr->h_checksum == ext4_xattr_block_csum(inode,
+ bh->b_blocknr, hdr));
+ unlock_buffer(bh);
+ }
+ return ret;
}
-static inline int ext4_handle_dirty_xattr_block(handle_t *handle,
- struct inode *inode,
- struct buffer_head *bh)
+static void ext4_xattr_block_csum_set(struct inode *inode,
+ struct buffer_head *bh)
{
- ext4_xattr_block_csum_set(inode, bh->b_blocknr, BHDR(bh));
- return ext4_handle_dirty_metadata(handle, inode, bh);
+ if (ext4_has_metadata_csum(inode->i_sb))
+ BHDR(bh)->h_checksum = ext4_xattr_block_csum(inode,
+ bh->b_blocknr, BHDR(bh));
}
static inline const struct xattr_handler *
@@ -233,7 +228,7 @@ ext4_xattr_check_block(struct inode *inode, struct buffer_head *bh)
if (BHDR(bh)->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC) ||
BHDR(bh)->h_blocks != cpu_to_le32(1))
return -EFSCORRUPTED;
- if (!ext4_xattr_block_csum_verify(inode, bh->b_blocknr, BHDR(bh)))
+ if (!ext4_xattr_block_csum_verify(inode, bh))
return -EFSBADCRC;
error = ext4_xattr_check_names(BFIRST(bh), bh->b_data + bh->b_size,
bh->b_data);
@@ -615,23 +610,22 @@ ext4_xattr_release_block(handle_t *handle, struct inode *inode,
}
}
+ ext4_xattr_block_csum_set(inode, bh);
/*
* Beware of this ugliness: Releasing of xattr block references
* from different inodes can race and so we have to protect
* from a race where someone else frees the block (and releases
* its journal_head) before we are done dirtying the buffer. In
* nojournal mode this race is harmless and we actually cannot
- * call ext4_handle_dirty_xattr_block() with locked buffer as
+ * call ext4_handle_dirty_metadata() with locked buffer as
* that function can call sync_dirty_buffer() so for that case
* we handle the dirtying after unlocking the buffer.
*/
if (ext4_handle_valid(handle))
- error = ext4_handle_dirty_xattr_block(handle, inode,
- bh);
+ error = ext4_handle_dirty_metadata(handle, inode, bh);
unlock_buffer(bh);
if (!ext4_handle_valid(handle))
- error = ext4_handle_dirty_xattr_block(handle, inode,
- bh);
+ error = ext4_handle_dirty_metadata(handle, inode, bh);
if (IS_SYNC(inode))
ext4_handle_sync(handle);
dquot_free_block(inode, EXT4_C2B(EXT4_SB(inode->i_sb), 1));
@@ -860,13 +854,14 @@ ext4_xattr_block_set(handle_t *handle, struct inode *inode,
ext4_xattr_cache_insert(ext4_mb_cache,
bs->bh);
}
+ ext4_xattr_block_csum_set(inode, bs->bh);
unlock_buffer(bs->bh);
if (error == -EFSCORRUPTED)
goto bad_block;
if (!error)
- error = ext4_handle_dirty_xattr_block(handle,
- inode,
- bs->bh);
+ error = ext4_handle_dirty_metadata(handle,
+ inode,
+ bs->bh);
if (error)
goto cleanup;
goto inserted;
@@ -964,10 +959,11 @@ inserted:
ce->e_reusable = 0;
ea_bdebug(new_bh, "reusing; refcount now=%d",
ref);
+ ext4_xattr_block_csum_set(inode, new_bh);
unlock_buffer(new_bh);
- error = ext4_handle_dirty_xattr_block(handle,
- inode,
- new_bh);
+ error = ext4_handle_dirty_metadata(handle,
+ inode,
+ new_bh);
if (error)
goto cleanup_dquot;
}
@@ -1017,11 +1013,12 @@ getblk_failed:
goto getblk_failed;
}
memcpy(new_bh->b_data, s->base, new_bh->b_size);
+ ext4_xattr_block_csum_set(inode, new_bh);
set_buffer_uptodate(new_bh);
unlock_buffer(new_bh);
ext4_xattr_cache_insert(ext4_mb_cache, new_bh);
- error = ext4_handle_dirty_xattr_block(handle,
- inode, new_bh);
+ error = ext4_handle_dirty_metadata(handle, inode,
+ new_bh);
if (error)
goto cleanup;
}