1 files changed, 17 insertions, 8 deletions

diff --git a/net/dccp/proto.c b/net/dccp/proto.c
index a06b5641287a..4e3266e4d7c3 100644
--- a/net/dccp/proto.c
+++ b/net/dccp/proto.c
@@ -191,6 +191,9 @@ int dccp_init_sock(struct sock *sk, const __u8 ctl_sock_initialized)
 	struct dccp_sock *dp = dccp_sk(sk);
 	struct inet_connection_sock *icsk = inet_csk(sk);
 
+	pr_warn_once("DCCP is deprecated and scheduled to be removed in 2025, "
+		     "please contact the netdev mailing list\n");
+
 	icsk->icsk_rto		= DCCP_TIMEOUT_INIT;
 	icsk->icsk_syn_retries	= sysctl_dccp_request_retries;
 	sk->sk_state		= DCCP_CLOSED;
@@ -359,7 +362,7 @@ __poll_t dccp_poll(struct file *file, struct socket *sock,
 
 EXPORT_SYMBOL_GPL(dccp_poll);
 
-int dccp_ioctl(struct sock *sk, int cmd, unsigned long arg)
+int dccp_ioctl(struct sock *sk, int cmd, int *karg)
 {
 	int rc = -ENOTCONN;
 
@@ -370,17 +373,17 @@ int dccp_ioctl(struct sock *sk, int cmd, unsigned long arg)
 
 	switch (cmd) {
 	case SIOCOUTQ: {
-		int amount = sk_wmem_alloc_get(sk);
+		*karg = sk_wmem_alloc_get(sk);
 		/* Using sk_wmem_alloc here because sk_wmem_queued is not used by DCCP and
 		 * always 0, comparably to UDP.
 		 */
 
-		rc = put_user(amount, (int __user *)arg);
+		rc = 0;
 	}
 		break;
 	case SIOCINQ: {
 		struct sk_buff *skb;
-		unsigned long amount = 0;
+		*karg = 0;
 
 		skb = skb_peek(&sk->sk_receive_queue);
 		if (skb != NULL) {
@@ -388,9 +391,9 @@ int dccp_ioctl(struct sock *sk, int cmd, unsigned long arg)
 			 * We will only return the amount of this packet since
 			 * that is all that will be read.
 			 */
-			amount = skb->len;
+			*karg = skb->len;
 		}
-		rc = put_user(amount, (int __user *)arg);
+		rc = 0;
 	}
 		break;
 	default:
@@ -627,7 +630,7 @@ static int do_dccp_getsockopt(struct sock *sk, int level, int optname,
 		return dccp_getsockopt_service(sk, len,
 					       (__be32 __user *)optval, optlen);
 	case DCCP_SOCKOPT_GET_CUR_MPS:
-		val = dp->dccps_mss_cache;
+		val = READ_ONCE(dp->dccps_mss_cache);
 		break;
 	case DCCP_SOCKOPT_AVAILABLE_CCIDS:
 		return ccid_getsockopt_builtin_ccids(sk, len, optval, optlen);
@@ -736,7 +739,7 @@ int dccp_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
 
 	trace_dccp_probe(sk, len);
 
-	if (len > dp->dccps_mss_cache)
+	if (len > READ_ONCE(dp->dccps_mss_cache))
 		return -EMSGSIZE;
 
 	lock_sock(sk);
@@ -769,6 +772,12 @@ int dccp_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
 		goto out_discard;
 	}
 
+	/* We need to check dccps_mss_cache after socket is locked. */
+	if (len > dp->dccps_mss_cache) {
+		rc = -EMSGSIZE;
+		goto out_discard;
+	}
+
 	skb_reserve(skb, sk->sk_prot->max_header);
 	rc = memcpy_from_msg(skb_put(skb, len), msg, len);
 	if (rc != 0)