Custom extension revision.

Use the same structure for client and server custom extensions.

Add utility functions in new file t1_ext.c.
Use new utility functions to handle custom server and client extensions
and remove a lot of code duplication.
Reviewed-by: Emilia Käsper <emilia@openssl.org>

1 files changed, 209 insertions, 0 deletions

diff --git a/ssl/t1_ext.c b/ssl/t1_ext.c
new file mode 100644
index 0000000000..ba6d3ded74
--- /dev/null
+++ b/ssl/t1_ext.c
@@ -0,0 +1,209 @@
+/* ssl/t1_ext.c */
+/* ====================================================================
+ * Copyright (c) 2014 The OpenSSL Project.  All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ *
+ * 3. All advertising materials mentioning features or use of this
+ *    software must display the following acknowledgment:
+ *    "This product includes software developed by the OpenSSL Project
+ *    for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
+ *
+ * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
+ *    endorse or promote products derived from this software without
+ *    prior written permission. For written permission, please contact
+ *    openssl-core@openssl.org.
+ *
+ * 5. Products derived from this software may not be called "OpenSSL"
+ *    nor may "OpenSSL" appear in their names without prior written
+ *    permission of the OpenSSL Project.
+ *
+ * 6. Redistributions of any form whatsoever must retain the following
+ *    acknowledgment:
+ *    "This product includes software developed by the OpenSSL Project
+ *    for use in the OpenSSL Toolkit (http://www.openssl.org/)"
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
+ * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE OpenSSL PROJECT OR
+ * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+ * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
+ * OF THE POSSIBILITY OF SUCH DAMAGE.
+ * ====================================================================
+ *
+ * This product includes cryptographic software written by Eric Young
+ * (eay@cryptsoft.com).  This product includes software written by Tim
+ * Hudson (tjh@cryptsoft.com).
+ *
+ */
+
+/* Custom extension utility functions */
+
+#include "ssl_locl.h"
+
+#ifndef OPENSSL_NO_TLSEXT
+
+/* Find a custom extension from the list */
+
+static custom_ext_method *custom_ext_find(custom_ext_methods *exts,
+						unsigned short 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;
+	}
+
+/* pass received custom extension data to the application for parsing */
+
+int custom_ext_parse(SSL *s, int server,
+			unsigned short ext_type,
+			const unsigned char *ext_data, 
+			unsigned short 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 or no parse function set, return success */
+	if (!meth || !meth->parse_cb)
+		return 1;
+
+	return meth->parse_cb(s, ext_type, ext_data, ext_size, al, meth->arg);
+	}
+
+/* request custom extension data from the application and add to the
+ * return buffer
+ */
+
+int custom_ext_add(SSL *s, int server,
+			unsigned char **pret,
+			unsigned char *limit,
+			int *al)
+	{
+	custom_ext_methods *exts = server ? &s->cert->srv_ext : &s->cert->cli_ext;
+	custom_ext_method *meth;
+	unsigned char *ret = *pret;
+	size_t i;
+
+	for (i = 0; i < exts->meths_count; i++)
+		{
+		const unsigned char *out = NULL;
+		unsigned short outlen = 0;
+		meth = exts->meths + i;
+
+		/* For servers no callback omits extension,
+		 * For clients it sends empty extension.
+		 */
+		if (server && !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->arg);
+			if (cb_retval == 0)
+				return 0; /* error */
+			if (cb_retval == -1)
+					continue; /* skip this extension */
+			}
+		if (4 > limit - ret || outlen > limit - ret - 4)
+			return 0;
+		s2n(meth->ext_type, ret);
+		s2n(outlen, ret);
+		if (outlen)
+			{
+			memcpy(ret, out, outlen);
+			ret += outlen;
+			}
+		}
+	*pret = ret;
+	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 = BUF_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)
+	{
+	if (exts->meths)
+		OPENSSL_free(exts->meths);
+	}
+
+/* Set callbacks for a custom extension */
+static int custom_ext_set(custom_ext_methods *exts,
+			unsigned short ext_type,
+			custom_ext_parse_cb parse_cb,
+			custom_ext_add_cb add_cb,
+			void *arg)
+	{
+	custom_ext_method *meth;
+	/* Search for duplicate */
+	if (custom_ext_find(exts, ext_type))
+		return 0;
+	exts->meths = OPENSSL_realloc(exts->meths,
+					(exts->meths_count + 1) * sizeof(custom_ext_method));
+
+	if (!exts->meths)
+		{
+		exts->meths_count = 0;
+		return 0;
+		}
+
+	meth = exts->meths + exts->meths_count;
+	meth->parse_cb = parse_cb;
+	meth->add_cb = add_cb;
+	meth->ext_type = ext_type;
+	meth->arg = arg;
+	exts->meths_count++;
+	return 1;
+	}
+
+/* Application level functions to add custom extension callbacks */
+
+int SSL_CTX_set_custom_cli_ext(SSL_CTX *ctx, unsigned short ext_type,
+			       custom_cli_ext_first_cb_fn fn1, 
+			       custom_cli_ext_second_cb_fn fn2, void *arg)
+	{
+	return custom_ext_set(&ctx->cert->cli_ext, ext_type, fn2, fn1, arg);
+	}
+
+int SSL_CTX_set_custom_srv_ext(SSL_CTX *ctx, unsigned short ext_type,
+			       custom_srv_ext_first_cb_fn fn1, 
+			       custom_srv_ext_second_cb_fn fn2, void *arg)
+	{
+	return custom_ext_set(&ctx->cert->srv_ext, ext_type, fn1, fn2, arg);
+	}
+#endif