Move ssl/t1_ext.c to ssl/statem/extensions_cust.c

Brings all the extensions code together.

Reviewed-by: Rich Salz <rsalz@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/3139)

1 files changed, 277 insertions, 0 deletions

diff --git a/ssl/statem/extensions_cust.c b/ssl/statem/extensions_cust.c
new file mode 100644
index 0000000000..374fe1e55e
--- /dev/null
+++ b/ssl/statem/extensions_cust.c
@@ -0,0 +1,277 @@
+/*
+ * Copyright 2014-2016 The OpenSSL Project Authors. All Rights Reserved.
+ *
+ * Licensed under the OpenSSL license (the "License").  You may not use
+ * this file except in compliance with the License.  You can obtain a copy
+ * in the file LICENSE in the source distribution or at
+ * https://www.openssl.org/source/license.html
+ */
+
+/* Custom extension utility functions */
+
+#include <openssl/ct.h>
+#include "../ssl_locl.h"
+
+/* Find a custom extension from the list. */
+static custom_ext_method *custom_ext_find(const custom_ext_methods *exts,
+                                          unsigned int ext_type)
+{
+    size_t i;
+    custom_ext_method *meth = exts->meths;
+    for (i = 0; i < exts->meths_count; i++, meth++) {
+        if (ext_type == meth->ext_type)
+            return meth;
+    }
+    return NULL;
+}
+
+/*
+ * Initialise custom extensions flags to indicate neither sent nor received.
+ */
+void custom_ext_init(custom_ext_methods *exts)
+{
+    size_t i;
+    custom_ext_method *meth = exts->meths;
+    for (i = 0; i < exts->meths_count; i++, meth++)
+        meth->ext_flags = 0;
+}
+
+/* Pass received custom extension data to the application for parsing. */
+int custom_ext_parse(SSL *s, int server,
+                     unsigned int ext_type,
+                     const unsigned char *ext_data, size_t ext_size, int *al)
+{
+    custom_ext_methods *exts = server ? &s->cert->srv_ext : &s->cert->cli_ext;
+    custom_ext_method *meth;
+    meth = custom_ext_find(exts, ext_type);
+    /* If not found return success */
+    if (!meth)
+        return 1;
+    if (!server) {
+        /*
+         * If it's ServerHello we can't have any extensions not sent in
+         * ClientHello.
+         */
+        if (!(meth->ext_flags & SSL_EXT_FLAG_SENT)) {
+            *al = TLS1_AD_UNSUPPORTED_EXTENSION;
+            return 0;
+        }
+    }
+    /* If already present it's a duplicate */
+    if (meth->ext_flags & SSL_EXT_FLAG_RECEIVED) {
+        *al = TLS1_AD_DECODE_ERROR;
+        return 0;
+    }
+    meth->ext_flags |= SSL_EXT_FLAG_RECEIVED;
+    /* If no parse function set return success */
+    if (!meth->parse_cb)
+        return 1;
+
+    return meth->parse_cb(s, ext_type, ext_data, ext_size, al, meth->parse_arg);
+}
+
+/*
+ * Request custom extension data from the application and add to the return
+ * buffer.
+ */
+int custom_ext_add(SSL *s, int server, WPACKET *pkt, int *al)
+{
+    custom_ext_methods *exts = server ? &s->cert->srv_ext : &s->cert->cli_ext;
+    custom_ext_method *meth;
+    size_t i;
+
+    for (i = 0; i < exts->meths_count; i++) {
+        const unsigned char *out = NULL;
+        size_t outlen = 0;
+
+        meth = exts->meths + i;
+
+        if (server) {
+            /*
+             * For ServerHello only send extensions present in ClientHello.
+             */
+            if (!(meth->ext_flags & SSL_EXT_FLAG_RECEIVED))
+                continue;
+            /* If callback absent for server skip it */
+            if (!meth->add_cb)
+                continue;
+        }
+        if (meth->add_cb) {
+            int cb_retval = 0;
+            cb_retval = meth->add_cb(s, meth->ext_type,
+                                     &out, &outlen, al, meth->add_arg);
+            if (cb_retval < 0)
+                return 0;       /* error */
+            if (cb_retval == 0)
+                continue;       /* skip this extension */
+        }
+
+        if (!WPACKET_put_bytes_u16(pkt, meth->ext_type)
+                || !WPACKET_start_sub_packet_u16(pkt)
+                || (outlen > 0 && !WPACKET_memcpy(pkt, out, outlen))
+                || !WPACKET_close(pkt)) {
+            *al = SSL_AD_INTERNAL_ERROR;
+            return 0;
+        }
+        /*
+         * We can't send duplicates: code logic should prevent this.
+         */
+        OPENSSL_assert(!(meth->ext_flags & SSL_EXT_FLAG_SENT));
+        /*
+         * Indicate extension has been sent: this is both a sanity check to
+         * ensure we don't send duplicate extensions and indicates that it is
+         * not an error if the extension is present in ServerHello.
+         */
+        meth->ext_flags |= SSL_EXT_FLAG_SENT;
+        if (meth->free_cb)
+            meth->free_cb(s, meth->ext_type, out, meth->add_arg);
+    }
+    return 1;
+}
+
+/* Copy table of custom extensions */
+int custom_exts_copy(custom_ext_methods *dst, const custom_ext_methods *src)
+{
+    if (src->meths_count) {
+        dst->meths =
+            OPENSSL_memdup(src->meths,
+                           sizeof(custom_ext_method) * src->meths_count);
+        if (dst->meths == NULL)
+            return 0;
+        dst->meths_count = src->meths_count;
+    }
+    return 1;
+}
+
+void custom_exts_free(custom_ext_methods *exts)
+{
+    OPENSSL_free(exts->meths);
+}
+
+/* Set callbacks for a custom extension. */
+static int custom_ext_meth_add(custom_ext_methods *exts,
+                               unsigned int ext_type,
+                               custom_ext_add_cb add_cb,
+                               custom_ext_free_cb free_cb,
+                               void *add_arg,
+                               custom_ext_parse_cb parse_cb, void *parse_arg)
+{
+    custom_ext_method *meth, *tmp;
+    /*
+     * Check application error: if add_cb is not set free_cb will never be
+     * called.
+     */
+    if (!add_cb && free_cb)
+        return 0;
+    /*
+     * Don't add if extension supported internally, but make exception
+     * for extension types that previously were not supported, but now are.
+     */
+    if (SSL_extension_supported(ext_type) &&
+        ext_type != TLSEXT_TYPE_signed_certificate_timestamp)
+        return 0;
+    /* Extension type must fit in 16 bits */
+    if (ext_type > 0xffff)
+        return 0;
+    /* Search for duplicate */
+    if (custom_ext_find(exts, ext_type))
+        return 0;
+    tmp = OPENSSL_realloc(exts->meths,
+                          (exts->meths_count + 1) * sizeof(custom_ext_method));
+
+    if (tmp == NULL)
+        return 0;
+
+    exts->meths = tmp;
+    meth = exts->meths + exts->meths_count;
+    memset(meth, 0, sizeof(*meth));
+    meth->parse_cb = parse_cb;
+    meth->add_cb = add_cb;
+    meth->free_cb = free_cb;
+    meth->ext_type = ext_type;
+    meth->add_arg = add_arg;
+    meth->parse_arg = parse_arg;
+    exts->meths_count++;
+    return 1;
+}
+
+/* Return true if a client custom extension exists, false otherwise */
+int SSL_CTX_has_client_custom_ext(const SSL_CTX *ctx, unsigned int ext_type)
+{
+    return custom_ext_find(&ctx->cert->cli_ext, ext_type) != NULL;
+}
+
+/* Application level functions to add custom extension callbacks */
+int SSL_CTX_add_client_custom_ext(SSL_CTX *ctx, unsigned int ext_type,
+                                  custom_ext_add_cb add_cb,
+                                  custom_ext_free_cb free_cb,
+                                  void *add_arg,
+                                  custom_ext_parse_cb parse_cb, void *parse_arg)
+{
+#ifndef OPENSSL_NO_CT
+    /*
+     * We don't want applications registering callbacks for SCT extensions
+     * whilst simultaneously using the built-in SCT validation features, as
+     * these two things may not play well together.
+     */
+    if (ext_type == TLSEXT_TYPE_signed_certificate_timestamp &&
+        SSL_CTX_ct_is_enabled(ctx))
+        return 0;
+#endif
+    return custom_ext_meth_add(&ctx->cert->cli_ext, ext_type, add_cb,
+                               free_cb, add_arg, parse_cb, parse_arg);
+}
+
+int SSL_CTX_add_server_custom_ext(SSL_CTX *ctx, unsigned int ext_type,
+                                  custom_ext_add_cb add_cb,
+                                  custom_ext_free_cb free_cb,
+                                  void *add_arg,
+                                  custom_ext_parse_cb parse_cb, void *parse_arg)
+{
+    return custom_ext_meth_add(&ctx->cert->srv_ext, ext_type,
+                               add_cb, free_cb, add_arg, parse_cb, parse_arg);
+}
+
+int SSL_extension_supported(unsigned int ext_type)
+{
+    switch (ext_type) {
+        /* Internally supported extensions. */
+    case TLSEXT_TYPE_application_layer_protocol_negotiation:
+#ifndef OPENSSL_NO_EC
+    case TLSEXT_TYPE_ec_point_formats:
+    case TLSEXT_TYPE_supported_groups:
+    case TLSEXT_TYPE_key_share:
+#endif
+#ifndef OPENSSL_NO_NEXTPROTONEG
+    case TLSEXT_TYPE_next_proto_neg:
+#endif
+    case TLSEXT_TYPE_padding:
+    case TLSEXT_TYPE_renegotiate:
+    case TLSEXT_TYPE_server_name:
+    case TLSEXT_TYPE_session_ticket:
+    case TLSEXT_TYPE_signature_algorithms:
+#ifndef OPENSSL_NO_SRP
+    case TLSEXT_TYPE_srp:
+#endif
+#ifndef OPENSSL_NO_OCSP
+    case TLSEXT_TYPE_status_request:
+#endif
+#ifndef OPENSSL_NO_CT
+    case TLSEXT_TYPE_signed_certificate_timestamp:
+#endif
+#ifndef OPENSSL_NO_SRTP
+    case TLSEXT_TYPE_use_srtp:
+#endif
+    case TLSEXT_TYPE_encrypt_then_mac:
+    case TLSEXT_TYPE_supported_versions:
+    case TLSEXT_TYPE_extended_master_secret:
+    case TLSEXT_TYPE_psk_kex_modes:
+    case TLSEXT_TYPE_cookie:
+    case TLSEXT_TYPE_early_data:
+    case TLSEXT_TYPE_certificate_authorities:
+    case TLSEXT_TYPE_psk:
+        return 1;
+    default:
+        return 0;
+    }
+}