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* [PATCH] ocfs2: Fix shift-out-of-bounds UBSAN bug in ocfs2_verify_volume()
@ 2024-08-16 13:41 qasdev
  2024-08-18 11:43 ` Heming Zhao
  0 siblings, 1 reply; 5+ messages in thread
From: qasdev @ 2024-08-16 13:41 UTC (permalink / raw)
  To: mark, jlbec, joseph.qi; +Cc: ocfs2-devel, linux-kernel

From ad1ca2fd2ecf4eb7ec2c76fcbbf34639f0ad87ca Mon Sep 17 00:00:00 2001
From: Qasim Ijaz <qasdev00@gmail.com>
Date: Fri, 16 Aug 2024 02:30:25 +0100
Subject: [PATCH] ocfs2: Fix shift-out-of-bounds UBSAN bug in
 ocfs2_verify_volume()

This patch addresses a shift-out-of-bounds error in the 
ocfs2_verify_volume() function, identified by UBSAN. The bug was triggered 
by an invalid s_clustersize_bits value (e.g., 1548), which caused the 
expression "1 << le32_to_cpu(di->id2.i_super.s_clustersize_bits)" 
to exceed the limits of a 32-bit integer, 
leading to an out-of-bounds shift.

Reported-by: syzbot <syzbot+f3fff775402751ebb471@syzkaller.appspotmail.com>
Closes: https://syzkaller.appspot.com/bug?extid=f3fff775402751ebb471
Tested-by: syzbot <syzbot+f3fff775402751ebb471@syzkaller.appspotmail.com>
Signed-off-by: Qasim Ijaz <qasdev00@gmail.com>
---
 fs/ocfs2/super.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/fs/ocfs2/super.c b/fs/ocfs2/super.c
index afee70125ae3..1e43cdca7f40 100644
--- a/fs/ocfs2/super.c
+++ b/fs/ocfs2/super.c
@@ -2357,8 +2357,12 @@ static int ocfs2_verify_volume(struct ocfs2_dinode *di,
 			     (unsigned long long)bh->b_blocknr);
 		} else if (le32_to_cpu(di->id2.i_super.s_clustersize_bits) < 12 ||
 			    le32_to_cpu(di->id2.i_super.s_clustersize_bits) > 20) {
-			mlog(ML_ERROR, "bad cluster size found: %u\n",
-			     1 << le32_to_cpu(di->id2.i_super.s_clustersize_bits));
+			if (le32_to_cpu(di->id2.i_super.s_clustersize_bits) < 32)
+				mlog(ML_ERROR, "bad cluster size found: %u\n",
+				     1 << le32_to_cpu(di->id2.i_super.s_clustersize_bits));
+			else
+				mlog(ML_ERROR, "invalid cluster size bit value: %u\n",
+				     le32_to_cpu(di->id2.i_super.s_clustersize_bits));
 		} else if (!le64_to_cpu(di->id2.i_super.s_root_blkno)) {
 			mlog(ML_ERROR, "bad root_blkno: 0\n");
 		} else if (!le64_to_cpu(di->id2.i_super.s_system_dir_blkno)) {
-- 
2.30.2

^ permalink raw reply	[flat|nested] 5+ messages in thread

end of thread, other threads:[~2024-08-20  1:12 UTC | newest]

Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2024-08-16 13:41 [PATCH] ocfs2: Fix shift-out-of-bounds UBSAN bug in ocfs2_verify_volume() qasdev
2024-08-18 11:43 ` Heming Zhao
2024-08-19  2:52   ` Joseph Qi
2024-08-20  1:03     ` [PATCH v2] " qasdev
2024-08-20  1:12       ` Joseph Qi

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