Convert HelloVerifyRequest construction to WPACKET
We actually construct a HelloVerifyRequest in two places with common code
pulled into a single function. This one commit handles both places.
Reviewed-by: Rich Salz <rsalz@openssl.org>
diff --git a/ssl/d1_lib.c b/ssl/d1_lib.c
index 043057f..f34818b 100644
--- a/ssl/d1_lib.c
+++ b/ssl/d1_lib.c
@@ -437,8 +437,8 @@
unsigned char cookie[DTLS1_COOKIE_LENGTH];
unsigned char seq[SEQ_NUM_SIZE];
const unsigned char *data;
- unsigned char *p, *buf;
- unsigned long reclen, fragoff, fraglen, msglen;
+ unsigned char *buf;
+ unsigned long fragoff, fraglen, msglen;
unsigned int rectype, versmajor, msgseq, msgtype, clientvers, cookielen;
BIO *rbio, *wbio;
BUF_MEM *bufm;
@@ -680,6 +680,10 @@
}
if (next == LISTEN_SEND_VERIFY_REQUEST) {
+ WPACKET wpkt;
+ unsigned int version;
+ size_t wreclen;
+
/*
* There was no cookie in the ClientHello so we need to send a
* HelloVerifyRequest. If this fails we do not worry about trying
@@ -703,60 +707,76 @@
return -1;
}
- p = &buf[DTLS1_RT_HEADER_LENGTH];
- msglen = dtls_raw_hello_verify_request(p + DTLS1_HM_HEADER_LENGTH,
- cookie, cookielen);
-
- *p++ = DTLS1_MT_HELLO_VERIFY_REQUEST;
-
- /* Message length */
- l2n3(msglen, p);
-
- /* Message sequence number is always 0 for a HelloVerifyRequest */
- s2n(0, p);
-
- /*
- * We never fragment a HelloVerifyRequest, so fragment offset is 0
- * and fragment length is message length
- */
- l2n3(0, p);
- l2n3(msglen, p);
-
- /* Set reclen equal to length of whole handshake message */
- reclen = msglen + DTLS1_HM_HEADER_LENGTH;
-
- /* Add the record header */
- p = buf;
-
- *(p++) = SSL3_RT_HANDSHAKE;
/*
* Special case: for hello verify request, client version 1.0 and we
* haven't decided which version to use yet send back using version
* 1.0 header: otherwise some clients will ignore it.
*/
- if (s->method->version == DTLS_ANY_VERSION) {
- *(p++) = DTLS1_VERSION >> 8;
- *(p++) = DTLS1_VERSION & 0xff;
- } else {
- *(p++) = s->version >> 8;
- *(p++) = s->version & 0xff;
+ version = (s->method->version == DTLS_ANY_VERSION) ? DTLS1_VERSION
+ : s->version;
+
+ /* Construct the record and message headers */
+ if (!WPACKET_init(&wpkt, s->init_buf)
+ || !WPACKET_put_bytes_u8(&wpkt, SSL3_RT_HANDSHAKE)
+ || !WPACKET_put_bytes_u16(&wpkt, version)
+ /*
+ * Record sequence number is always the same as in the
+ * received ClientHello
+ */
+ || !WPACKET_memcpy(&wpkt, seq, SEQ_NUM_SIZE)
+ /* End of record, start sub packet for message */
+ || !WPACKET_start_sub_packet_u16(&wpkt)
+ /* Message type */
+ || !WPACKET_put_bytes_u8(&wpkt,
+ DTLS1_MT_HELLO_VERIFY_REQUEST)
+ /*
+ * Message length - doesn't follow normal TLS convention:
+ * the length isn't the last thing in the message header.
+ * We'll need to fill this in later when we know the
+ * length. Set it to zero for now
+ */
+ || !WPACKET_put_bytes_u24(&wpkt, 0)
+ /*
+ * Message sequence number is always 0 for a
+ * HelloVerifyRequest
+ */
+ || !WPACKET_put_bytes_u16(&wpkt, 0)
+ /*
+ * We never fragment a HelloVerifyRequest, so fragment
+ * offset is 0
+ */
+ || !WPACKET_put_bytes_u24(&wpkt, 0)
+ /*
+ * Fragment length is the same as message length, but
+ * this *is* the last thing in the message header so we
+ * can just start a sub-packet. No need to come back
+ * later for this one.
+ */
+ || !WPACKET_start_sub_packet_u24(&wpkt)
+ /* Create the actual HelloVerifyRequest body */
+ || !dtls_raw_hello_verify_request(&wpkt, cookie, cookielen)
+ /* Close message body */
+ || !WPACKET_close(&wpkt)
+ /* Close record body */
+ || !WPACKET_close(&wpkt)
+ || !WPACKET_get_total_written(&wpkt, &wreclen)
+ || !WPACKET_finish(&wpkt)) {
+ SSLerr(SSL_F_DTLSV1_LISTEN, ERR_R_INTERNAL_ERROR);
+ WPACKET_cleanup(&wpkt);
+ /* This is fatal */
+ return -1;
}
/*
- * Record sequence number is always the same as in the received
- * ClientHello
+ * Fix up the message len in the message header. Its the same as the
+ * fragment len which has been filled in by WPACKET, so just copy
+ * that. Destination for the message len is after the record header
+ * plus one byte for the message content type. The source is the
+ * last 3 bytes of the message header
*/
- memcpy(p, seq, SEQ_NUM_SIZE);
- p += SEQ_NUM_SIZE;
-
- /* Length */
- s2n(reclen, p);
-
- /*
- * Set reclen equal to length of whole record including record
- * header
- */
- reclen += DTLS1_RT_HEADER_LENGTH;
+ memcpy(&buf[DTLS1_RT_HEADER_LENGTH + 1],
+ &buf[DTLS1_RT_HEADER_LENGTH + DTLS1_HM_HEADER_LENGTH - 3],
+ 3);
if (s->msg_callback)
s->msg_callback(1, 0, SSL3_RT_HEADER, buf,
@@ -778,7 +798,7 @@
BIO_ADDR_free(tmpclient);
tmpclient = NULL;
- if (BIO_write(wbio, buf, reclen) < (int)reclen) {
+ if (BIO_write(wbio, buf, wreclen) < (int)wreclen) {
if (BIO_should_retry(wbio)) {
/*
* Non-blocking IO...but we're stateless, so we're just
