4.9-stable review patch. If anyone has any objections, please let me know.
------------------ From: Theodore Ts'o <ty...@mit.edu> commit e09463f220ca9a1a1ecfda84fcda658f99a1f12a upstream. 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 <ty...@mit.edu> Cc: sta...@kernel.org Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org> --- fs/jbd2/transaction.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) --- a/fs/jbd2/transaction.c +++ b/fs/jbd2/transaction.c @@ -1353,6 +1353,13 @@ int jbd2_journal_dirty_metadata(handle_t 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); @@ -1372,11 +1379,11 @@ int jbd2_journal_dirty_metadata(handle_t * 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--; }
