linux-ext4 - [PATCH] jbd2: Make jbd2_handle_buffer_credits() handle reserved handles

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Date:   Fri, 15 Nov 2019 11:22:10 +0100
From:   Jan Kara <jack@...e.cz>
To:     Ted Tso <tytso@....edu>
Cc:     <linux-ext4@...r.kernel.org>, Eric Biggers <ebiggers@...nel.org>,
        Jan Kara <jack@...e.cz>
Subject: [PATCH] jbd2: Make jbd2_handle_buffer_credits() handle reserved handles

The helper jbd2_handle_buffer_credits() doesn't correctly handle reserved
handles which can lead to crashes. Fix it getting of journal pointer to
work for reserved handles as well.

Fixes: a9a8344ee171 ("ext4, jbd2: Provide accessor function for handle credits")
Reported-by: Eric Biggers <ebiggers@...nel.org>
Signed-off-by: Jan Kara <jack@...e.cz>
---
 include/linux/jbd2.h | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/include/linux/jbd2.h b/include/linux/jbd2.h
index 3115eeb44039..a23a3528e07a 100644
--- a/include/linux/jbd2.h
+++ b/include/linux/jbd2.h
@@ -1648,10 +1648,14 @@ static inline tid_t  jbd2_get_latest_transaction(journal_t *journal)
 	return tid;
 }
 
-
 static inline int jbd2_handle_buffer_credits(handle_t *handle)
 {
-	journal_t *journal = handle->h_transaction->t_journal;
+	journal_t *journal;
+
+	if (!handle->h_reserved)
+		journal = handle->h_transaction->t_journal;
+	else
+		journal = handle->h_journal;
 
 	return handle->h_total_credits -
 		DIV_ROUND_UP(handle->h_revoke_credits_requested,
-- 
2.16.4