This updated version includes the suggestions of Nagendra Modadugu.
--- ssl/d1_both.c 2007-10-17 23:17:49.000000000 +0200
+++ ssl/d1_both.c 2009-03-23 19:39:10.000000000 +0100
@@ -136,7 +136,6 @@
static void dtls1_set_message_header_int(SSL *s, unsigned char mt,
unsigned long len, unsigned short seq_num, unsigned long frag_off,
unsigned long frag_len);
-static int dtls1_retransmit_buffered_messages(SSL *s);
static long dtls1_get_message_fragment(SSL *s, int st1, int stn,
long max, int *ok);
@@ -942,8 +941,21 @@
return dtls1_retransmit_buffered_messages(s) ;
}
+int
+dtls1_get_queue_priority(unsigned short seq, int is_ccs)
+ {
+ /* The index of the retransmission queue actually is the message
sequence number,
+ * since the queue only contains messages of a single handshake.
However, the
+ * ChangeCipherSpec has no message sequence number and so using only
the sequence
+ * will result in the CCS and Finished having the same index. To
prevent this,
+ * the sequence number is multiplied by 2. In case of a CCS 1 is
subtracted.
+ * This does not only differ CSS and Finished, it also maintains the
order of the
+ * index (important for priority queues) and fits in the unsigned
short variable.
+ */
+ return seq * 2 - is_ccs;
+ }
-static int
+int
dtls1_retransmit_buffered_messages(SSL *s)
{
pqueue sent = s->d1->sent_messages;
@@ -957,8 +969,9 @@
for ( item = pqueue_next(&iter); item != NULL; item =
pqueue_next(&iter))
{
frag = (hm_fragment *)item->data;
- if ( dtls1_retransmit_message(s, frag->msg_header.seq, 0,
&found)
<= 0 &&
- found)
+ if ( dtls1_retransmit_message(s,
+ dtls1_get_queue_priority(frag->msg_header.seq,
frag-
>msg_header.is_ccs),
+ 0, &found) <= 0 && found)
{
fprintf(stderr, "dtls1_retransmit_message() failed\n");
return -1;
@@ -974,7 +987,6 @@
pitem *item;
hm_fragment *frag;
PQ_64BIT seq64;
- unsigned int epoch = s->d1->w_epoch;
/* this function is called immediately after a message has
* been serialized */
@@ -988,7 +1000,6 @@
{
OPENSSL_assert(s->d1->w_msg_hdr.msg_len +
DTLS1_CCS_HEADER_LENGTH <= (unsigned int)s->init_num);
- epoch++;
}
else
{
@@ -1003,9 +1014,19 @@
frag->msg_header.frag_len = s->d1->w_msg_hdr.msg_len;
frag->msg_header.is_ccs = is_ccs;
+ /* save current state*/
+ frag->msg_header.saved_retransmit_state.enc_write_ctx = s-
>enc_write_ctx;
+ frag->msg_header.saved_retransmit_state.write_hash = s->write_hash;
+ frag->msg_header.saved_retransmit_state.compress = s->compress;
+ frag->msg_header.saved_retransmit_state.session = s->session;
+ frag->msg_header.saved_retransmit_state.epoch = s->d1->w_epoch;
+
pq_64bit_init(&seq64);
- pq_64bit_assign_word(&seq64, epoch<<16 | frag->msg_header.seq);
+ pq_64bit_assign_word(&seq64,
+
dtls1_get_queue_priority(frag->msg_header.seq,
+
frag->msg_header.is_ccs));
+
item = pitem_new(seq64, frag);
pq_64bit_free(&seq64);
if ( item == NULL)
@@ -1034,6 +1055,8 @@
hm_fragment *frag ;
unsigned long header_length;
PQ_64BIT seq64;
+ struct dtls1_retransmit_state saved_state;
+ unsigned char save_write_sequence[8];
/*
OPENSSL_assert(s->init_num == 0);
@@ -1069,9 +1092,45 @@
frag->msg_header.msg_len, frag->msg_header.seq, 0,
frag->msg_header.frag_len);
+ /* save current state */
+ saved_state.enc_write_ctx = s->enc_write_ctx;
+ saved_state.write_hash = s->write_hash;
+ saved_state.compress = s->compress;
+ saved_state.session = s->session;
+ saved_state.epoch = s->d1->w_epoch;
+ saved_state.epoch = s->d1->w_epoch;
+
s->d1->retransmitting = 1;
+
+ /* restore state in which the message was originally sent */
+ s->enc_write_ctx = frag-
>msg_header.saved_retransmit_state.enc_write_ctx;
+ s->write_hash = frag->msg_header.saved_retransmit_state.write_hash;
+ s->compress = frag->msg_header.saved_retransmit_state.compress;
+ s->session = frag->msg_header.saved_retransmit_state.session;
+ s->d1->w_epoch = frag->msg_header.saved_retransmit_state.epoch;
+
+ if (frag->msg_header.saved_retransmit_state.epoch ==
saved_state.epoch - 1)
+ {
+ memcpy(save_write_sequence, s->s3->write_sequence,
sizeof(s->s3-
>write_sequence));
+ memcpy(s->s3->write_sequence, s->d1->last_write_sequence,
sizeof(s-
>s3->write_sequence));
+ }
+
ret = dtls1_do_write(s, frag->msg_header.is_ccs ?
- SSL3_RT_CHANGE_CIPHER_SPEC : SSL3_RT_HANDSHAKE);
+ SSL3_RT_CHANGE_CIPHER_SPEC :
SSL3_RT_HANDSHAKE);
+
+ /* restore current state */
+ s->enc_write_ctx = saved_state.enc_write_ctx;
+ s->write_hash = saved_state.write_hash;
+ s->compress = saved_state.compress;
+ s->session = saved_state.session;
+ s->d1->w_epoch = saved_state.epoch;
+
+ if (frag->msg_header.saved_retransmit_state.epoch ==
saved_state.epoch - 1)
+ {
+ memcpy(s->d1->last_write_sequence, s->s3->write_sequence,
sizeof(s-
>s3->write_sequence));
+ memcpy(s->s3->write_sequence, save_write_sequence,
sizeof(s->s3-
>write_sequence));
+ }
+
s->d1->retransmitting = 0;
(void)BIO_flush(SSL_get_wbio(s));
--- ssl/d1_pkt.c 2008-10-13 08:43:06.000000000 +0200
+++ ssl/d1_pkt.c 2009-03-23 19:45:04.000000000 +0100
@@ -942,7 +942,9 @@
n2s(p, seq);
n2l3(p, frag_off);
- dtls1_retransmit_message(s, seq, frag_off,
&found);
+ dtls1_retransmit_message(s,
+
dtls1_get_queue_priority(frag->msg_header.seq, 0),
+
frag_off, &found);
if ( ! found && SSL_in_init(s))
{
/* fprintf( stderr,"in init = %d\n",
SSL_in_init(s)); */
@@ -1035,6 +1037,16 @@
goto start;
}
+ /* If we are server, we may have a repeated FINISHED of the
+ * client here, then retransmit our CCS and FINISHED.
+ */
+ if (msg_hdr.type == SSL3_MT_FINISHED)
+ {
+ dtls1_retransmit_buffered_messages(s);
+ rr->length = 0;
+ goto start;
+ }
+
if (((s->state&SSL_ST_MASK) == SSL_ST_OK) &&
!(s->s3->flags & SSL3_FLAGS_NO_RENEGOTIATE_CIPHERS))
{
@@ -1758,6 +1770,7 @@
else
{
seq = s->s3->write_sequence;
+ memcpy(s->d1->last_write_sequence, seq, sizeof(s->s3-
>write_sequence));
s->d1->w_epoch++;
}
--- ssl/dtls1.h 2008-09-13 20:25:36.000000000 +0200
+++ ssl/dtls1.h 2009-03-23 19:31:39.000000000 +0100
@@ -101,6 +101,19 @@
PQ_64BIT max_seq_num; /* max record number seen so far */
} DTLS1_BITMAP;
+struct dtls1_retransmit_state
+ {
+ EVP_CIPHER_CTX *enc_write_ctx; /* cryptographic state */
+ const EVP_MD *write_hash; /* used for mac generation */
+#ifndef OPENSSL_NO_COMP
+ COMP_CTX *compress; /* compression */
+#else
+ char *compress;
+#endif
+ SSL_SESSION *session;
+ unsigned short epoch;
+ };
+
struct hm_header_st
{
unsigned char type;
@@ -109,6 +122,7 @@
unsigned long frag_off;
unsigned long frag_len;
unsigned int is_ccs;
+ struct dtls1_retransmit_state saved_retransmit_state;
};
struct ccs_header_st
@@ -168,6 +182,9 @@
unsigned short handshake_read_seq;
+ /* save last sequence number for retransmissions */
+ unsigned char last_write_sequence[8];
+
/* Received handshake records (processed and unprocessed) */
record_pqueue unprocessed_rcds;
record_pqueue processed_rcds;
--- ssl/ssl_locl.h 2009-01-05 15:43:07.000000000 +0100
+++ ssl/ssl_locl.h 2009-03-23 19:42:12.000000000 +0100
@@ -862,6 +862,8 @@
int dtls1_buffer_message(SSL *s, int ccs);
int dtls1_retransmit_message(SSL *s, unsigned short seq,
unsigned long frag_off, int *found);
+int dtls1_get_queue_priority(unsigned short seq, int is_ccs);
+int dtls1_retransmit_buffered_messages(SSL *s);
void dtls1_clear_record_buffer(SSL *s);
void dtls1_get_message_header(unsigned char *data, struct
hm_header_st *msg_hdr);
void dtls1_get_ccs_header(unsigned char *data, struct ccs_header_st
*ccs_hdr);
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