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Message-ID: <tencent_15CA920ADD9ADDCA19654FBE8DB5A5B88D07@qq.com>
From: Edward Adam Davis <eadavis@qq.com>
To: pmenzel@molgen.mpg.de
Cc: netdev@vger.kernel.org,
	eadavis@qq.com,
	johan.hedberg@gmail.com,
	linux-bluetooth@vger.kernel.org,
	linux-kernel@vger.kernel.org,
	luiz.dentz@gmail.com,
	marcel@holtmann.org,
	syzbot+d4ecae01a53fd9b42e7d@syzkaller.appspotmail.com,
	syzkaller-bugs@googlegroups.com
Subject: [PATCH] net/socket: Ensure length of input socket option param >= sizeof(int)
Date: Tue,  9 Apr 2024 20:15:53 +0800
In-Reply-To: <234da60a-709f-4430-b594-386b7c2b65f5@molgen.mpg.de>
References: <234da60a-709f-4430-b594-386b7c2b65f5@molgen.mpg.de>
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The optlen value passed by syzbot to _sys_setsockopt() is 2, which results in
only 2 bytes being allocated when allocating memory to kernel_optval, and the
optval size passed when calling the function copy_from_sockptr() is 4 bytes.
Here, optlen is determined uniformly in the entry function __sys_setsockopt(). 
If its value is less than 4, the parameter is considered invalid.

Reported-by: syzbot+837ba09d9db969068367@syzkaller.appspotmail.com
Reported-by: syzbot+b71011ec0a23f4d15625@syzkaller.appspotmail.com
Reported-by: syzbot+d4ecae01a53fd9b42e7d@syzkaller.appspotmail.com
Signed-off-by: Edward Adam Davis <eadavis@qq.com>
---
 net/socket.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/net/socket.c b/net/socket.c
index e5f3af49a8b6..ac8fd4f6ebfe 100644
--- a/net/socket.c
+++ b/net/socket.c
@@ -2327,6 +2327,9 @@ int __sys_setsockopt(int fd, int level, int optname, char __user *user_optval,
 	int err, fput_needed;
 	struct socket *sock;
 
+	if (optlen < sizeof(int))
+		return -EINVAL;
+
 	sock = sockfd_lookup_light(fd, &err, &fput_needed);
 	if (!sock)
 		return err;
-- 
2.43.0