linux-kernel - [PATCH] jfs: validate max amount of blocks before allocation.

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]

Message-Id: <20230722142401.71257-1-halip0503@gmail.com>
Date:   Sat, 22 Jul 2023 17:24:01 +0300
From:   Aleksei Filippov <halip0503@...il.com>
To:     shaggy@...nel.org, gregkh@...uxfoundation.org
Cc:     jfs-discussion@...ts.sourceforge.net, linux-kernel@...r.kernel.org,
        Alexei Filippov <halip0503@...il.com>,
        syzbot+5f088f29593e6b4c8db8@...kaller.appspotmail.com
Subject: [PATCH] jfs: validate max amount of blocks before allocation.

From: Alexei Filippov <halip0503@...il.com>

The lack of checking bmp->db_max_freebud in extBalloc() can lead to
shift out of bounds, so this patch prevents undefined behavior,
because bmp->db_max_freebud == -1 only if there
is no free space.

Signed-off-by: Aleksei Filippov <halip0503@...il.com>
Reported-and-tested-by: syzbot+5f088f29593e6b4c8db8@...kaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?id=01abadbd6ae6a08b1f1987aa61554c6b3ac19ff2
---
 fs/jfs/jfs_extent.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/fs/jfs/jfs_extent.c b/fs/jfs/jfs_extent.c
index ae99a7e232ee..a82751e6c47f 100644
--- a/fs/jfs/jfs_extent.c
+++ b/fs/jfs/jfs_extent.c
@@ -311,6 +311,11 @@ extBalloc(struct inode *ip, s64 hint, s64 * nblocks, s64 * blkno)
 	 * blocks in the map. in that case, we'll start off with the
 	 * maximum free.
 	 */
+
+	/* give up if no space left */
+	if (bmp->db_maxfreebud == -1)
+		return -ENOSPC;
+
 	max = (s64) 1 << bmp->db_maxfreebud;
 	if (*nblocks >= max && *nblocks > nbperpage)
 		nb = nblks = (max > nbperpage) ? max : nbperpage;
-- 
2.25.1