tcp_recvmsg: Fix application bug induced races with MSG_PEEK and copied_seq.

589a54dc · Alexey Kuznetsov · David S. Miller · d283ad89 · 589a54dc
Commit 589a54dc authored May 21, 2002 by Alexey Kuznetsov Committed by David S. Miller May 21, 2002
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net/ipv4/tcp.c net/ipv4/tcp.c +6 -0

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--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -1674,6 +1674,12 @@ int tcp_recvmsg(struct sock *sk, struct msghdr *msg,
 				}
 			}
 		}
+		if ((flags & MSG_PEEK) && peek_seq != tp->copied_seq) {
+			if (net_ratelimit())
+				printk(KERN_DEBUG "TCP(%s:%d): Application bug, race in MSG_PEEK.\n",
+				       current->comm, current->pid);
+			peek_seq = tp->copied_seq;
+		}
 		continue;
 	found_ok_skb: