Convert dtls1_get_record to CBS.

ok miod@, input + ok jsing@

1 files changed, 28 insertions, 21 deletions

diff --git a/lib/libssl/d1_pkt.c b/lib/libssl/d1_pkt.c
index 68571c8fd06..1ff664370b4 100644
--- a/lib/libssl/d1_pkt.c
+++ b/lib/libssl/d1_pkt.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: d1_pkt.c,v 1.43 2015/07/18 22:28:53 doug Exp $ */
+/* $OpenBSD: d1_pkt.c,v 1.44 2015/07/18 22:36:55 doug Exp $ */
 /*
  * DTLS implementation written by Nagendra Modadugu
  * (nagendra@cs.stanford.edu) for the OpenSSL project 2005.
@@ -124,6 +124,7 @@
 #include <openssl/evp.h>
 
 #include "pqueue.h"
+#include "bytestring.h"
 
 /* mod 128 saturating subtract of two 64-bit values in big-endian order */
 static int
@@ -464,11 +465,9 @@ err:
 int
 dtls1_get_record(SSL *s)
 {
-	int ssl_major, ssl_minor;
 	int i, n;
 	SSL3_RECORD *rr;
 	unsigned char *p = NULL;
-	unsigned short version;
 	DTLS1_BITMAP *bitmap;
 	unsigned int is_next_epoch;
 
@@ -494,6 +493,10 @@ again:
 	/* check if we have the header */
 	if ((s->rstate != SSL_ST_READ_BODY) ||
 		(s->packet_length < DTLS1_RT_HEADER_LENGTH)) {
+		CBS header, seq_no;
+		uint16_t epoch, len, ssl_version;
+		uint8_t type;
+
 		n = ssl3_read_n(s, DTLS1_RT_HEADER_LENGTH, s->s3->rbuf.len, 0);
 		/* read timeout is handled by dtls1_read_bytes */
 		if (n <= 0)
@@ -505,35 +508,39 @@ again:
 
 		s->rstate = SSL_ST_READ_BODY;
 
-		p = s->packet;
+		CBS_init(&header, s->packet, s->packet_length);
 
 		/* Pull apart the header into the DTLS1_RECORD */
-		rr->type= *(p++);
-		ssl_major= *(p++);
-		ssl_minor= *(p++);
-		version = (ssl_major << 8)|ssl_minor;
+		if (!CBS_get_u8(&header, &type))
+			goto again;
+		if (!CBS_get_u16(&header, &ssl_version))
+			goto again;
 
 		/* sequence number is 64 bits, with top 2 bytes = epoch */
-		n2s(p, rr->epoch);
+		if (!CBS_get_u16(&header, &epoch) ||
+		    !CBS_get_bytes(&header, &seq_no, 6))
+			goto again;
 
-		memcpy(&(s->s3->read_sequence[2]), p, 6);
-		p += 6;
+		if (!CBS_write_bytes(&seq_no, &(s->s3->read_sequence[2]),
+		    sizeof(s->s3->read_sequence) - 2, NULL))
+			goto again;
+		if (!CBS_get_u16(&header, &len))
+			goto again;
 
-		n2s(p, rr->length);
+		rr->type = type;
+		rr->epoch = epoch;
+		rr->length = len;
 
-		/* Lets check version */
-		if (!s->first_packet) {
-			if (version != s->version)
-				/* unexpected version, silently discard */
-				goto again;
-		}
+		/* unexpected version, silently discard */
+		if (!s->first_packet && ssl_version != s->version)
+			goto again;
 
-		if ((version & 0xff00) != (s->version & 0xff00))
-			/* wrong version, silently discard record */
+		/* wrong version, silently discard record */
+		if ((ssl_version & 0xff00) != (s->version & 0xff00))
 			goto again;
 
+		/* record too long, silently discard it */
 		if (rr->length > SSL3_RT_MAX_ENCRYPTED_LENGTH)
-			/* record too long, silently discard it */
 			goto again;
 
 		/* now s->rstate == SSL_ST_READ_BODY */