[PATCH v2] net: check the return value of the copy_from_sockptr

[Qianqiang Liu]

We must check the return value of the copy_from_sockptr. Otherwise, it
may cause some weird issues.

Fixes: 33f339a1ba54e ("bpf, net: Fix a potential race in do_sock_getsockopt()")
Signed-off-by: Qianqiang Liu <qianqiang.liu@xxxxxxx>
---
Changes from v1:
Add a fix tag

---
 net/socket.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/net/socket.c b/net/socket.c
index 0a2bd22ec105..6b9a414d01d5 100644
--- a/net/socket.c
+++ b/net/socket.c
@@ -2370,8 +2370,11 @@ int do_sock_getsockopt(struct socket *sock, bool compat, int level,
 	if (err)
 		return err;
 
-	if (!compat)
-		copy_from_sockptr(&max_optlen, optlen, sizeof(int));
+	if (!compat) {
+		err = copy_from_sockptr(&max_optlen, optlen, sizeof(int));
+		if (err)
+			return -EFAULT;
+	}
 
 	ops = READ_ONCE(sock->ops);
 	if (level == SOL_SOCKET) {
-- 
2.39.2