X-Git-Url: https://www.bearssl.org/gitweb//home/git/?p=BearSSL;a=blobdiff_plain;f=src%2Fssl%2Fssl_keyexport.c;fp=src%2Fssl%2Fssl_keyexport.c;h=58e6dc3cde46300def072cb49af0f2847289481e;hp=0000000000000000000000000000000000000000;hb=ea95d8264c6aefe742a9c3f4f9d834b188566a29;hpb=2b738493bd16d57fdb12d38d03631981370259be

diff --git a/src/ssl/ssl_keyexport.c b/src/ssl/ssl_keyexport.c
new file mode 100644
index 0000000..58e6dc3
--- /dev/null
+++ b/src/ssl/ssl_keyexport.c
@@ -0,0 +1,83 @@
+/*
+ * Copyright (c) 2017 Thomas Pornin <pornin@bolet.org>
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining 
+ * a copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sublicense, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be 
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, 
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND 
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
+ * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+ * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+#include "inner.h"
+
+/*
+ * Supported cipher suites that use SHA-384 for the PRF when selected
+ * for TLS 1.2. All other cipher suites are deemed to use SHA-256.
+ */
+static const uint16_t suites_sha384[] = {
+	BR_TLS_RSA_WITH_AES_256_GCM_SHA384,
+	BR_TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA384,
+	BR_TLS_ECDH_ECDSA_WITH_AES_256_CBC_SHA384,
+	BR_TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384,
+	BR_TLS_ECDH_RSA_WITH_AES_256_CBC_SHA384,
+	BR_TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384,
+	BR_TLS_ECDH_ECDSA_WITH_AES_256_GCM_SHA384,
+	BR_TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384,
+	BR_TLS_ECDH_RSA_WITH_AES_256_GCM_SHA384
+};
+
+/* see bearssl_ssl.h */
+int
+br_ssl_key_export(br_ssl_engine_context *cc,
+	void *dst, size_t len, const char *label,
+	const void *context, size_t context_len)
+{
+	br_tls_prf_seed_chunk chunks[4];
+	br_tls_prf_impl iprf;
+	size_t num_chunks, u;
+	unsigned char tmp[2];
+	int prf_id;
+
+	if (cc->application_data != 1) {
+		return 0;
+	}
+	chunks[0].data = cc->client_random;
+	chunks[0].len = sizeof cc->client_random;
+	chunks[1].data = cc->server_random;
+	chunks[1].len = sizeof cc->server_random;
+	if (context != NULL) {
+		br_enc16be(tmp, (unsigned)context_len);
+		chunks[2].data = tmp;
+		chunks[2].len = 2;
+		chunks[3].data = context;
+		chunks[3].len = context_len;
+		num_chunks = 4;
+	} else {
+		num_chunks = 2;
+	}
+	prf_id = BR_SSLPRF_SHA256;
+	for (u = 0; u < (sizeof suites_sha384) / sizeof(uint16_t); u ++) {
+		if (suites_sha384[u] == cc->session.cipher_suite) {
+			prf_id = BR_SSLPRF_SHA384;
+		}
+	}
+	iprf = br_ssl_engine_get_PRF(cc, prf_id);
+	iprf(dst, len,
+		cc->session.master_secret, sizeof cc->session.master_secret,
+		label, num_chunks, chunks);
+	return 1;
+}