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authorTheodore Ts'o <tytso@mit.edu>2018-06-17 02:21:45 +0200
committerTheodore Ts'o <tytso@mit.edu>2018-06-17 02:21:45 +0200
commite09463f220ca9a1a1ecfda84fcda658f99a1f12a (patch)
tree09dae2d5509c2e2aa36cd621cc81e94e9abbacd2
parentext4: never move the system.data xattr out of the inode body (diff)
downloadlinux-e09463f220ca9a1a1ecfda84fcda658f99a1f12a.tar.xz
linux-e09463f220ca9a1a1ecfda84fcda658f99a1f12a.zip
jbd2: don't mark block as modified if the handle is out of credits
Do not set the b_modified flag in block's journal head should not until after we're sure that jbd2_journal_dirty_metadat() will not abort with an error due to there not being enough space reserved in the jbd2 handle. Otherwise, future attempts to modify the buffer may lead a large number of spurious errors and warnings. This addresses CVE-2018-10883. https://bugzilla.kernel.org/show_bug.cgi?id=200071 Signed-off-by: Theodore Ts'o <tytso@mit.edu> Cc: stable@kernel.org
-rw-r--r--fs/jbd2/transaction.c9
1 files changed, 8 insertions, 1 deletions
diff --git a/fs/jbd2/transaction.c b/fs/jbd2/transaction.c
index 51dd68e67b0f..c0b66a7a795b 100644
--- a/fs/jbd2/transaction.c
+++ b/fs/jbd2/transaction.c
@@ -1361,6 +1361,13 @@ int jbd2_journal_dirty_metadata(handle_t *handle, struct buffer_head *bh)
if (jh->b_transaction == transaction &&
jh->b_jlist != BJ_Metadata) {
jbd_lock_bh_state(bh);
+ if (jh->b_transaction == transaction &&
+ jh->b_jlist != BJ_Metadata)
+ pr_err("JBD2: assertion failure: h_type=%u "
+ "h_line_no=%u block_no=%llu jlist=%u\n",
+ handle->h_type, handle->h_line_no,
+ (unsigned long long) bh->b_blocknr,
+ jh->b_jlist);
J_ASSERT_JH(jh, jh->b_transaction != transaction ||
jh->b_jlist == BJ_Metadata);
jbd_unlock_bh_state(bh);
@@ -1380,11 +1387,11 @@ int jbd2_journal_dirty_metadata(handle_t *handle, struct buffer_head *bh)
* of the transaction. This needs to be done
* once a transaction -bzzz
*/
- jh->b_modified = 1;
if (handle->h_buffer_credits <= 0) {
ret = -ENOSPC;
goto out_unlock_bh;
}
+ jh->b_modified = 1;
handle->h_buffer_credits--;
}