PR: 2458

Submitted by: Robin Seggelmann <seggelmann@fh-muenster.de>
Reviewed by: steve

Don't change state when answering DTLS ClientHello.

diff --git a/ssl/d1_both.c b/ssl/d1_both.c
index 2569bb7d679b8844629a4f44338856c47574b58c..c195159967f5f45504484526695e588ae253109b 100644 (file)
--- a/ssl/d1_both.c
+++ b/ssl/d1_both.c
@@ -464,7 +464,10 @@ again:
 
        memset(msg_hdr, 0x00, sizeof(struct hm_header_st));
 
-       s->d1->handshake_read_seq++;
+       /* Don't change sequence numbers while listening */
+       if (!s->d1->listen)
+               s->d1->handshake_read_seq++;
+
        /* we just read a handshake message from the other side:
         * this means that we don't need to retransmit of the
         * buffered messages.  
@@ -813,9 +816,11 @@ dtls1_get_message_fragment(SSL *s, int st1, int stn, long max, int *ok)
 
        /* 
         * if this is a future (or stale) message it gets buffered
-        * (or dropped)--no further processing at this time 
+        * (or dropped)--no further processing at this time
+        * While listening, we accept seq 1 (ClientHello with cookie)
+        * although we're still expecting seq 0 (ClientHello)
         */
-       if ( msg_hdr.seq != s->d1->handshake_read_seq)
+       if (msg_hdr.seq != s->d1->handshake_read_seq && !(s->d1->listen && msg_hdr.seq == 1))
                return dtls1_process_out_of_seq_message(s, &msg_hdr, ok);
 
        len = msg_hdr.msg_len;
@@ -1322,7 +1327,8 @@ unsigned char *
 dtls1_set_message_header(SSL *s, unsigned char *p, unsigned char mt,
                        unsigned long len, unsigned long frag_off, unsigned long frag_len)
        {
-       if ( frag_off == 0)
+       /* Don't change sequence numbers while listening */
+       if (frag_off == 0 && !s->d1->listen)
                {
                s->d1->handshake_write_seq = s->d1->next_handshake_write_seq;
                s->d1->next_handshake_write_seq++;

diff --git a/ssl/d1_srvr.c b/ssl/d1_srvr.c
index 301ceda7a578e990b74a7d51b823cb441264ab68..27ca887dc851c896ff672670a09dc61d9cea7de8 100644 (file)
--- a/ssl/d1_srvr.c
+++ b/ssl/d1_srvr.c
@@ -278,6 +278,12 @@ int dtls1_accept(SSL *s)
                                {
                                ret = 2;
                                s->d1->listen = 0;
+                               /* Set expected sequence numbers
+                                * to continue the handshake.
+                                */
+                               s->d1->handshake_read_seq = 2;
+                               s->d1->handshake_write_seq = 1;
+                               s->d1->next_handshake_write_seq = 1;
                                goto end;
                                }
                        
@@ -736,9 +742,6 @@ int dtls1_send_hello_verify_request(SSL *s)
                /* number of bytes to write */
                s->init_num=p-buf;
                s->init_off=0;
-
-               /* buffer the message to handle re-xmits */
-               dtls1_buffer_message(s, 0);
                }
 
        /* s->state = DTLS1_ST_SW_HELLO_VERIFY_REQUEST_B */