1 files changed, 261 insertions, 0 deletions

diff --git a/src/lib/libssl/ssl_tlsext.c b/src/lib/libssl/ssl_tlsext.c
new file mode 100644
index 0000000000..18ac98103a
--- /dev/null
+++ b/src/lib/libssl/ssl_tlsext.c
@@ -0,0 +1,261 @@
+/* $OpenBSD: ssl_tlsext.c,v 1.1 2017/07/16 18:14:37 jsing Exp $ */
+/*
+ * Copyright (c) 2016, 2017 Joel Sing <jsing@openbsd.org>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#include "ssl_locl.h"
+
+#include "bytestring.h"
+#include "ssl_tlsext.h"
+
+/*
+ * Server Name Indication - RFC 6066, section 3.
+ */
+int
+tlsext_sni_clienthello_needs(SSL *s)
+{
+        return (s->tlsext_hostname != NULL);
+}
+
+int
+tlsext_sni_clienthello_build(SSL *s, CBB *cbb)
+{
+        CBB server_name_list, host_name;
+
+        if (!CBB_add_u16_length_prefixed(cbb, &server_name_list))
+                return 0;
+        if (!CBB_add_u8(&server_name_list, TLSEXT_NAMETYPE_host_name))
+                return 0;
+        if (!CBB_add_u16_length_prefixed(&server_name_list, &host_name))
+                return 0;
+        if (!CBB_add_bytes(&host_name, (const uint8_t *)s->tlsext_hostname,
+            strlen(s->tlsext_hostname)))
+                return 0;
+        if (!CBB_flush(cbb))
+                return 0;
+
+        return 1;
+}
+
+int
+tlsext_sni_clienthello_parse(SSL *s, CBS *cbs, int *alert)
+{
+        CBS server_name_list, host_name;
+        uint8_t name_type;
+
+        if (!CBS_get_u16_length_prefixed(cbs, &server_name_list))
+                goto err;
+
+        /*
+         * RFC 6066 section 3 forbids multiple host names with the same type.
+         * Additionally, only one type (host_name) is specified.
+         */
+        if (!CBS_get_u8(&server_name_list, &name_type))
+                goto err;
+        if (name_type != TLSEXT_NAMETYPE_host_name)
+                goto err;
+
+        if (!CBS_get_u16_length_prefixed(&server_name_list, &host_name))
+                goto err;
+        if (CBS_len(&host_name) == 0 ||
+            CBS_len(&host_name) > TLSEXT_MAXLEN_host_name ||
+            CBS_contains_zero_byte(&host_name)) {
+                *alert = TLS1_AD_UNRECOGNIZED_NAME;
+                return 0;
+        }
+
+        if (s->internal->hit) {
+                if (s->session->tlsext_hostname == NULL) {
+                        *alert = TLS1_AD_UNRECOGNIZED_NAME;
+                        return 0;
+                }
+                if (!CBS_mem_equal(&host_name, s->session->tlsext_hostname,
+                    strlen(s->session->tlsext_hostname))) {
+                        *alert = TLS1_AD_UNRECOGNIZED_NAME;
+                        return 0;
+                }
+        } else {
+                if (s->session->tlsext_hostname != NULL)
+                        goto err;
+                if (!CBS_strdup(&host_name, &s->session->tlsext_hostname)) {
+                        *alert = TLS1_AD_INTERNAL_ERROR;
+                        return 0;
+                }
+        }
+
+        if (CBS_len(&server_name_list) != 0)
+                goto err;
+        if (CBS_len(cbs) != 0)
+                goto err;
+
+        return 1;
+
+ err:
+        *alert = SSL_AD_DECODE_ERROR;
+        return 0;
+}
+
+int
+tlsext_sni_serverhello_needs(SSL *s)
+{
+        return (s->session->tlsext_hostname != NULL);
+}
+
+int
+tlsext_sni_serverhello_build(SSL *s, CBB *cbb)
+{
+        return 1;
+}
+
+int
+tlsext_sni_serverhello_parse(SSL *s, CBS *cbs, int *alert)
+{
+        if (s->tlsext_hostname == NULL || CBS_len(cbs) != 0) {
+                *alert = TLS1_AD_UNRECOGNIZED_NAME;
+                return 0;
+        }
+
+        return 1;
+}
+
+struct tls_extension {
+        uint16_t type;
+        int (*clienthello_needs)(SSL *s);
+        int (*clienthello_build)(SSL *s, CBB *cbb);
+        int (*clienthello_parse)(SSL *s, CBS *cbs, int *alert);
+        int (*serverhello_needs)(SSL *s);
+        int (*serverhello_build)(SSL *s, CBB *cbb);
+        int (*serverhello_parse)(SSL *s, CBS *cbs, int *alert);
+};
+
+static struct tls_extension tls_extensions[] = {
+        {
+                .type = TLSEXT_TYPE_server_name,
+                .clienthello_needs = tlsext_sni_clienthello_needs,
+                .clienthello_build = tlsext_sni_clienthello_build,
+                .clienthello_parse = tlsext_sni_clienthello_parse,
+                .serverhello_needs = tlsext_sni_serverhello_needs,
+                .serverhello_build = tlsext_sni_serverhello_build,
+                .serverhello_parse = tlsext_sni_serverhello_parse,
+        },
+};
+
+#define N_TLS_EXTENSIONS (sizeof(tls_extensions) / sizeof(*tls_extensions))
+
+int
+tlsext_clienthello_build(SSL *s, CBB *cbb)
+{
+        struct tls_extension *tlsext;
+        CBB extension_data;
+        size_t i;
+
+        memset(&extension_data, 0, sizeof(extension_data));
+
+        for (i = 0; i < N_TLS_EXTENSIONS; i++) {
+                tlsext = &tls_extensions[i];
+
+                if (!tlsext->clienthello_needs(s))
+                        continue;
+                
+                if (!CBB_add_u16(cbb, tlsext->type))
+                        return 0;
+                if (!CBB_add_u16_length_prefixed(cbb, &extension_data))
+                        return 0;
+                if (!tls_extensions[i].clienthello_build(s, &extension_data))
+                        return 0;
+                if (!CBB_flush(cbb))
+                        return 0;
+        }
+
+        return 1;
+}
+
+int
+tlsext_clienthello_parse_one(SSL *s, CBS *cbs, uint16_t type, int *alert)
+{
+        struct tls_extension *tlsext;
+        size_t i;
+
+        for (i = 0; i < N_TLS_EXTENSIONS; i++) {
+                tlsext = &tls_extensions[i];
+
+                if (tlsext->type != type)
+                        continue;
+                if (!tlsext->clienthello_parse(s, cbs, alert))
+                        return 0;
+                if (CBS_len(cbs) != 0) {
+                        *alert = SSL_AD_DECODE_ERROR;
+                        return 0;
+                }
+
+                return 1;
+        }
+
+        /* Not found. */
+        return 2;
+}
+
+int
+tlsext_serverhello_build(SSL *s, CBB *cbb)
+{
+        struct tls_extension *tlsext;
+        CBB extension_data;
+        size_t i;
+
+        memset(&extension_data, 0, sizeof(extension_data));
+
+        for (i = 0; i < N_TLS_EXTENSIONS; i++) {
+                tlsext = &tls_extensions[i];
+
+                if (!tlsext->serverhello_needs(s))
+                        continue;
+                
+                if (!CBB_add_u16(cbb, tlsext->type))
+                        return 0;
+                if (!CBB_add_u16_length_prefixed(cbb, &extension_data))
+                        return 0;
+                if (!tlsext->serverhello_build(s, &extension_data))
+                        return 0;
+                if (!CBB_flush(cbb))
+                        return 0;
+        }
+
+        return 1;
+}
+
+int
+tlsext_serverhello_parse_one(SSL *s, CBS *cbs, uint16_t type, int *alert)
+{
+        struct tls_extension *tlsext;
+        size_t i;
+
+        for (i = 0; i < N_TLS_EXTENSIONS; i++) {
+                tlsext = &tls_extensions[i];
+
+                if (tlsext->type != type)
+                        continue;
+                if (!tlsext->serverhello_parse(s, cbs, alert))
+                        return 0;
+                if (CBS_len(cbs) != 0) {
+                        *alert = SSL_AD_DECODE_ERROR;
+                        return 0;
+                }
+
+                return 1;
+        }
+
+        /* Not found. */
+        return 2;
+}