1 files changed, 44 insertions, 23 deletions

diff --git a/net/sctp/socket.c b/net/sctp/socket.c
index b029757..3204a9b 100644
--- a/net/sctp/socket.c
+++ b/net/sctp/socket.c
@@ -84,8 +84,8 @@
 /* Forward declarations for internal helper functions. */
 static int sctp_writeable(struct sock *sk);
 static void sctp_wfree(struct sk_buff *skb);
-static int sctp_wait_for_sndbuf(struct sctp_association *, long *timeo_p,
-				size_t msg_len);
+static int sctp_wait_for_sndbuf(struct sctp_association *asoc, long *timeo_p,
+				size_t msg_len, struct sock **orig_sk);
 static int sctp_wait_for_packet(struct sock *sk, int *err, long *timeo_p);
 static int sctp_wait_for_connect(struct sctp_association *, long *timeo_p);
 static int sctp_wait_for_accept(struct sock *sk, long timeo);
@@ -1970,9 +1970,16 @@ static int sctp_sendmsg(struct sock *sk, struct msghdr *msg, size_t msg_len)
 
 	timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT);
 	if (!sctp_wspace(asoc)) {
-		err = sctp_wait_for_sndbuf(asoc, &timeo, msg_len);
-		if (err)
+		/* sk can be changed by peel off when waiting for buf. */
+		err = sctp_wait_for_sndbuf(asoc, &timeo, msg_len, &sk);
+		if (err) {
+			if (err == -ESRCH) {
+				/* asoc is already dead. */
+				new_asoc = NULL;
+				err = -EPIPE;
+			}
 			goto out_free;
+		}
 	}
 
 	/* If an address is passed with the sendto/sendmsg call, it is used
@@ -3133,9 +3140,9 @@ static int sctp_setsockopt_mappedv4(struct sock *sk, char __user *optval, unsign
  */
 static int sctp_setsockopt_maxseg(struct sock *sk, char __user *optval, unsigned int optlen)
 {
+	struct sctp_sock *sp = sctp_sk(sk);
 	struct sctp_assoc_value params;
 	struct sctp_association *asoc;
-	struct sctp_sock *sp = sctp_sk(sk);
 	int val;
 
 	if (optlen == sizeof(int)) {
@@ -3151,26 +3158,35 @@ static int sctp_setsockopt_maxseg(struct sock *sk, char __user *optval, unsigned
 		if (copy_from_user(&params, optval, optlen))
 			return -EFAULT;
 		val = params.assoc_value;
-	} else
+	} else {
 		return -EINVAL;
+	}
 
-	if ((val != 0) && ((val < 8) || (val > SCTP_MAX_CHUNK_LEN)))
-		return -EINVAL;
+	if (val) {
+		int min_len, max_len;
 
-	asoc = sctp_id2assoc(sk, params.assoc_id);
-	if (!asoc && params.assoc_id && sctp_style(sk, UDP))
-		return -EINVAL;
+		min_len = SCTP_DEFAULT_MINSEGMENT - sp->pf->af->net_header_len;
+		min_len -= sizeof(struct sctphdr) +
+			   sizeof(struct sctp_data_chunk);
+
+		max_len = SCTP_MAX_CHUNK_LEN - sizeof(struct sctp_data_chunk);
 
+		if (val < min_len || val > max_len)
+			return -EINVAL;
+	}
+
+	asoc = sctp_id2assoc(sk, params.assoc_id);
 	if (asoc) {
 		if (val == 0) {
-			val = asoc->pathmtu;
-			val -= sp->pf->af->net_header_len;
+			val = asoc->pathmtu - sp->pf->af->net_header_len;
 			val -= sizeof(struct sctphdr) +
-					sizeof(struct sctp_data_chunk);
+			       sizeof(struct sctp_data_chunk);
 		}
 		asoc->user_frag = val;
 		asoc->frag_point = sctp_frag_point(asoc, asoc->pathmtu);
 	} else {
+		if (params.assoc_id && sctp_style(sk, UDP))
+			return -EINVAL;
 		sp->user_frag = val;
 	}
 
@@ -5015,12 +5031,6 @@ int sctp_do_peeloff(struct sock *sk, sctp_assoc_t id, struct socket **sockp)
 	if (!asoc)
 		return -EINVAL;
 
-	/* If there is a thread waiting on more sndbuf space for
-	 * sending on this asoc, it cannot be peeled.
-	 */
-	if (waitqueue_active(&asoc->wait))
-		return -EBUSY;
-
 	/* An association cannot be branched off from an already peeled-off
 	 * socket, nor is this supported for tcp style sockets.
 	 */
@@ -7989,7 +7999,7 @@ void sctp_sock_rfree(struct sk_buff *skb)
 
 /* Helper function to wait for space in the sndbuf.  */
 static int sctp_wait_for_sndbuf(struct sctp_association *asoc, long *timeo_p,
-				size_t msg_len)
+				size_t msg_len, struct sock **orig_sk)
 {
 	struct sock *sk = asoc->base.sk;
 	int err = 0;
@@ -8006,10 +8016,11 @@ static int sctp_wait_for_sndbuf(struct sctp_association *asoc, long *timeo_p,
 	for (;;) {
 		prepare_to_wait_exclusive(&asoc->wait, &wait,
 					  TASK_INTERRUPTIBLE);
+		if (asoc->base.dead)
+			goto do_dead;
 		if (!*timeo_p)
 			goto do_nonblock;
-		if (sk->sk_err || asoc->state >= SCTP_STATE_SHUTDOWN_PENDING ||
-		    asoc->base.dead)
+		if (sk->sk_err || asoc->state >= SCTP_STATE_SHUTDOWN_PENDING)
 			goto do_error;
 		if (signal_pending(current))
 			goto do_interrupted;
@@ -8022,11 +8033,17 @@ static int sctp_wait_for_sndbuf(struct sctp_association *asoc, long *timeo_p,
 		release_sock(sk);
 		current_timeo = schedule_timeout(current_timeo);
 		lock_sock(sk);
+		if (sk != asoc->base.sk) {
+			release_sock(sk);
+			sk = asoc->base.sk;
+			lock_sock(sk);
+		}
 
 		*timeo_p = current_timeo;
 	}
 
 out:
+	*orig_sk = sk;
 	finish_wait(&asoc->wait, &wait);
 
 	/* Release the association's refcnt.  */
@@ -8034,6 +8051,10 @@ out:
 
 	return err;
 
+do_dead:
+	err = -ESRCH;
+	goto out;
+
 do_error:
 	err = -EPIPE;
 	goto out;