Remove NPN support.

NPN was never standardised and the last draft expired in October 2012.
ALPN was standardised in July 2014 and has been supported in LibreSSL
since December 2014. NPN has also been removed from Chromium in May 2016.

TLS clients and servers that try to use/enable NPN will fail gracefully and
fallback to the default protocol, since it will essentially appear that the
otherside does not support NPN. At some point in the future we will
actually remove the NPN related symbols entirely.

ok bcook@ beck@ doug@

1 files changed, 3 insertions, 110 deletions

diff --git a/lib/libssl/t1_lib.c b/lib/libssl/t1_lib.c
index 3e5133ab54c..911e8d3f4e2 100644
--- a/lib/libssl/t1_lib.c
+++ b/lib/libssl/t1_lib.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: t1_lib.c,v 1.127 2017/08/12 02:55:22 jsing Exp $ */
+/* $OpenBSD: t1_lib.c,v 1.128 2017/08/12 21:03:08 jsing Exp $ */
 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
  * All rights reserved.
  *
@@ -779,16 +779,6 @@ skip_ext:
 			i2d_X509_EXTENSIONS(s->internal->tlsext_ocsp_exts, &ret);
 	}
 
-	if (s->ctx->internal->next_proto_select_cb &&
-	    !S3I(s)->tmp.finish_md_len) {
-		/* The client advertises an emtpy extension to indicate its
-		 * support for Next Protocol Negotiation */
-		if ((size_t)(limit - ret) < 4)
-			return NULL;
-		s2n(TLSEXT_TYPE_next_proto_neg, ret);
-		s2n(0, ret);
-	}
-
 	if (s->internal->alpn_client_proto_list != NULL &&
 	    S3I(s)->tmp.finish_md_len == 0) {
 		if ((size_t)(limit - ret) <
@@ -868,7 +858,6 @@ ssl_add_serverhello_tlsext(SSL *s, unsigned char *p, unsigned char *limit)
 {
 	int extdatalen = 0;
 	unsigned char *ret = p;
-	int next_proto_neg_seen;
 	size_t len;
 	CBB cbb;
 
@@ -949,26 +938,6 @@ ssl_add_serverhello_tlsext(SSL *s, unsigned char *p, unsigned char *limit)
 		ret += sizeof(cryptopro_ext);
 	}
 
-	next_proto_neg_seen = S3I(s)->next_proto_neg_seen;
-	S3I(s)->next_proto_neg_seen = 0;
-	if (next_proto_neg_seen && s->ctx->internal->next_protos_advertised_cb) {
-		const unsigned char *npa;
-		unsigned int npalen;
-		int r;
-
-		r = s->ctx->internal->next_protos_advertised_cb(s, &npa, &npalen,
-		    s->ctx->internal->next_protos_advertised_cb_arg);
-		if (r == SSL_TLSEXT_ERR_OK) {
-			if ((size_t)(limit - ret) < 4 + npalen)
-				return NULL;
-			s2n(TLSEXT_TYPE_next_proto_neg, ret);
-			s2n(npalen, ret);
-			memcpy(ret, npa, npalen);
-			ret += npalen;
-			S3I(s)->next_proto_neg_seen = 1;
-		}
-	}
-
 	if (S3I(s)->alpn_selected != NULL) {
 		const unsigned char *selected = S3I(s)->alpn_selected;
 		unsigned int len = S3I(s)->alpn_selected_len;
@@ -1070,7 +1039,6 @@ ssl_parse_clienthello_tlsext(SSL *s, unsigned char **p, unsigned char *d,
 	s->internal->servername_done = 0;
 	s->tlsext_status_type = -1;
 	S3I(s)->renegotiate_seen = 0;
-	S3I(s)->next_proto_neg_seen = 0;
 	free(S3I(s)->alpn_selected);
 	S3I(s)->alpn_selected = NULL;
 	s->internal->srtp_profile = NULL;
@@ -1227,36 +1195,13 @@ ssl_parse_clienthello_tlsext(SSL *s, unsigned char **p, unsigned char *d,
  			 	*/
 				s->tlsext_status_type = -1;
 			}
-		}
-		else if (type == TLSEXT_TYPE_next_proto_neg &&
-		    S3I(s)->tmp.finish_md_len == 0 &&
-		    S3I(s)->alpn_selected == NULL) {
-			/* We shouldn't accept this extension on a
-			 * renegotiation.
-			 *
-			 * s->internal->new_session will be set on renegotiation, but we
-			 * probably shouldn't rely that it couldn't be set on
-			 * the initial renegotation too in certain cases (when
-			 * there's some other reason to disallow resuming an
-			 * earlier session -- the current code won't be doing
-			 * anything like that, but this might change).
-
-			 * A valid sign that there's been a previous handshake
-			 * in this connection is if S3I(s)->tmp.finish_md_len >
-			 * 0.  (We are talking about a check that will happen
-			 * in the Hello protocol round, well before a new
-			 * Finished message could have been computed.) */
-			S3I(s)->next_proto_neg_seen = 1;
-		}
-		else if (type ==
+		} else if (type ==
 		    TLSEXT_TYPE_application_layer_protocol_negotiation &&
 		    s->ctx->internal->alpn_select_cb != NULL &&
 		    S3I(s)->tmp.finish_md_len == 0) {
 			if (tls1_alpn_handle_client_hello(s, data,
 			    size, al) != 1)
 				return (0);
-			/* ALPN takes precedence over NPN. */
-			S3I(s)->next_proto_neg_seen = 0;
 		}
 
 		/* session ticket processed earlier */
@@ -1293,25 +1238,6 @@ err:
 	return 0;
 }
 
-/*
- * ssl_next_proto_validate validates a Next Protocol Negotiation block. No
- * elements of zero length are allowed and the set of elements must exactly fill
- * the length of the block.
- */
-static char
-ssl_next_proto_validate(const unsigned char *d, unsigned int len)
-{
-	CBS npn, value;
-
-	CBS_init(&npn, d, len);
-	while (CBS_len(&npn) > 0) {
-		if (!CBS_get_u8_length_prefixed(&npn, &value) ||
-		    CBS_len(&value) == 0)
-			return 0;
-	}
-	return 1;
-}
-
 int
 ssl_parse_serverhello_tlsext(SSL *s, unsigned char **p, size_t n, int *al)
 {
@@ -1323,7 +1249,6 @@ ssl_parse_serverhello_tlsext(SSL *s, unsigned char **p, size_t n, int *al)
 	CBS cbs;
 
 	S3I(s)->renegotiate_seen = 0;
-	S3I(s)->next_proto_neg_seen = 0;
 	free(S3I(s)->alpn_selected);
 	S3I(s)->alpn_selected = NULL;
 
@@ -1375,39 +1300,7 @@ ssl_parse_serverhello_tlsext(SSL *s, unsigned char **p, size_t n, int *al)
 			}
 			/* Set flag to expect CertificateStatus message */
 			s->internal->tlsext_status_expected = 1;
-		}
-		else if (type == TLSEXT_TYPE_next_proto_neg &&
-		    S3I(s)->tmp.finish_md_len == 0) {
-			unsigned char *selected;
-			unsigned char selected_len;
-
-			/* We must have requested it. */
-			if (s->ctx->internal->next_proto_select_cb == NULL) {
-				*al = TLS1_AD_UNSUPPORTED_EXTENSION;
-				return 0;
-			}
-			/* The data must be valid */
-			if (!ssl_next_proto_validate(data, size)) {
-				*al = TLS1_AD_DECODE_ERROR;
-				return 0;
-			}
-			if (s->ctx->internal->next_proto_select_cb(s, &selected,
-			    &selected_len, data, size,
-			    s->ctx->internal->next_proto_select_cb_arg) !=
-			    SSL_TLSEXT_ERR_OK) {
-				*al = TLS1_AD_INTERNAL_ERROR;
-				return 0;
-			}
-			s->internal->next_proto_negotiated = malloc(selected_len);
-			if (!s->internal->next_proto_negotiated) {
-				*al = TLS1_AD_INTERNAL_ERROR;
-				return 0;
-			}
-			memcpy(s->internal->next_proto_negotiated, selected, selected_len);
-			s->internal->next_proto_negotiated_len = selected_len;
-			S3I(s)->next_proto_neg_seen = 1;
-		}
-		else if (type ==
+		} else if (type ==
 		    TLSEXT_TYPE_application_layer_protocol_negotiation) {
 			unsigned int len;