Fix case where "-K 1" would cause a SSH_MSG_IGNORE packet to be sent

with the wrong encryption key ("bad packet length" symptom) while
key exchange was happening.

2 files changed, 9 insertions, 3 deletions

diff --git a/kex.h b/kex.h
index a3bdc7a..c89b0a3 100644
--- a/kex.h
+++ b/kex.h
@@ -52,8 +52,8 @@ struct KEXState {
 	unsigned sentkexinit : 1; /*set when we've sent/recv kexinit packet */
 	unsigned recvkexinit : 1;
 	unsigned firstfollows : 1; /* true when first_kex_packet_follows is set */
-	unsigned sentnewkeys : 1; /* set once we've send/recv'ed MSG_NEWKEYS*/
-	unsigned recvnewkeys : 1;
+	unsigned sentnewkeys : 1; /* set once we've send MSG_NEWKEYS (will be cleared once we have also received */
+	unsigned recvnewkeys : 1; /* set once we've received MSG_NEWKEYS (cleared once we have also sent */
 
 	unsigned donefirstkex : 1; /* Set to 1 after the first kex has completed,
 								  ie the transport layer has been set up */
diff --git a/packet.c b/packet.c
index 80eb177..349ed40 100644
--- a/packet.c
+++ b/packet.c
@@ -441,10 +441,16 @@ void encrypt_packet() {
 
 	TRACE(("encrypt_packet type is %d", packet_type))
 	
-	if (!ses.dataallowed && !packet_is_okay_kex(packet_type)) {
+	if ((!ses.dataallowed && !packet_is_okay_kex(packet_type))
+			|| ses.kexstate.sentnewkeys) {
 		/* During key exchange only particular packets are allowed.
 			Since this packet_type isn't OK we just enqueue it to send 
 			after the KEX, see maybe_flush_reply_queue */
+
+		/* We also enqueue packets here when we have sent a MSG_NEWKEYS
+		 * packet but are yet to received one. For simplicity we just switch
+		 * over all the keys at once. This is the 'ses.kexstate.sentnewkeys'
+		 * case. */
 		enqueue_reply_packet();
 		return;
 	}