Commit a4896e11 authored Oct 17, 2015 by Lukas Czerner Committed by Greg Kroah-Hartman May 20, 2017

ext4: fix potential use after free in __ext4_journal_stop



commit 6934da9238da947628be83635e365df41064b09b upstream.

There is a use-after-free possibility in __ext4_journal_stop() in the
case that we free the handle in the first jbd2_journal_stop() because
we're referencing handle->h_err afterwards. This was introduced in
9705acd63b125dee8b15c705216d7186daea4625 and it is wrong. Fix it by
storing the handle->h_err value beforehand and avoid referencing
potentially freed handle.

Fixes: 9705acd63b125dee8b15c705216d7186daea4625
Signed-off-by: Lukas Czerner <lczerner@redhat.com>
Reviewed-by: Andreas Dilger <adilger@dilger.ca>
Signed-off-by: Amit Pundir <amit.pundir@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

parent 7da78079

fs/ext4/ext4_jbd2.c

+3 −3

Original line number	Diff line number	Diff line
		@@ -88,13 +88,13 @@ int __ext4_journal_stop(const char where, unsigned int line, handle_t handle)
		return 0;
		}

		err = handle->h_err;
		if (!handle->h_transaction) {
		err = jbd2_journal_stop(handle);
		return handle->h_err ? handle->h_err : err;
		rc = jbd2_journal_stop(handle);
		return err ? err : rc;
		}

		sb = handle->h_transaction->t_journal->j_private;
		err = handle->h_err;
		rc = jbd2_journal_stop(handle);

		if (!err)