4.17-stable review patch. If anyone has any objections, please let me know.
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From: Theodore Ts'o tytso@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 tytso@mit.edu Cc: stable@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- fs/jbd2/transaction.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-)
--- a/fs/jbd2/transaction.c +++ b/fs/jbd2/transaction.c @@ -1363,6 +1363,13 @@ 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); @@ -1382,11 +1389,11 @@ 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--; }