linux-kernel - [PATCH] ocfs2: pass u64 to ocfs2_truncate

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Message-ID: <tencent_B22CA96C8896C0E9FEEFD2CCAC795A6E500A@qq.com>
Date: Wed,  9 Oct 2024 23:05:41 +0800
From: Edward Adam Davis <eadavis@...com>
To: syzbot+81092778aac03460d6b7@...kaller.appspotmail.com
Cc: jlbec@...lplan.org,
	joseph.qi@...ux.alibaba.com,
	linux-kernel@...r.kernel.org,
	mark@...heh.com,
	ocfs2-devel@...ts.linux.dev,
	syzkaller-bugs@...glegroups.com
Subject: [PATCH] ocfs2: pass u64 to ocfs2_truncate_inline maybe overflow

Syzbot reported a kernel BUG in ocfs2_truncate_inline.
There are two reasons for this: first, the parameter value passed is greater
than UINT_MAX, second, the start and end parameters of ocfs2_truncate_inline
are "unsigned int".

So, we need to add a sanity check for offset and len in ocfs2_fallocate, if
they are greater than UINT_MAX return -EFBIG.

Reported-and-tested-by: syzbot+81092778aac03460d6b7@...kaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=81092778aac03460d6b7
Signed-off-by: Edward Adam Davis <eadavis@...com>
---
 fs/ocfs2/file.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/fs/ocfs2/file.c b/fs/ocfs2/file.c
index ad131a2fc58e..ed26ec8ac6b6 100644
--- a/fs/ocfs2/file.c
+++ b/fs/ocfs2/file.c
@@ -2117,6 +2117,9 @@ static long ocfs2_fallocate(struct file *file, int mode, loff_t offset,
 			return ret;
 	}
 
+	if (offset > UINT_MAX || offset + len > UINT_MAX)
+		return -EFBIG;
+
 	if (mode & FALLOC_FL_PUNCH_HOLE)
 		cmd = OCFS2_IOC_UNRESVSP64;
 
-- 
2.43.0