From: Nikos Mavrogiannopoulos <nmav@redhat.com>
Date: Mon, 20 Jul 2015 08:03:37 +0000 (+0200)
Subject: gnutls_prf_rfc5705: added
X-Git-Tag: gnutls_3_4_4~50
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=e4cddac1b97352587e8eefaf5c9e1f8dfcf2ad53;p=thirdparty%2Fgnutls.git

gnutls_prf_rfc5705: added

That includes support for RFC5705 when the context field is used.
Initial patch by Rick van Rein.
---

diff --git a/lib/gnutls_state.c b/lib/gnutls_state.c
index ef2a587f9e..f8880b28fd 100644
--- a/lib/gnutls_state.c
+++ b/lib/gnutls_state.c
@@ -1062,6 +1062,65 @@ gnutls_prf_raw(gnutls_session_t session,
 	return ret;
 }
 
+/**
+ * gnutls_prf_rfc5705:
+ * @session: is a #gnutls_session_t type.
+ * @label_size: length of the @label variable.
+ * @label: label used in PRF computation, typically a short string.
+ * @context_size: length of the @extra variable.
+ * @context: optional extra data to seed the PRF with.
+ * @outsize: size of pre-allocated output buffer to hold the output.
+ * @out: pre-allocated buffer to hold the generated data.
+ *
+ * Applies the TLS Pseudo-Random-Function (PRF) on the master secret
+ * and the provided data, seeded with the client and server random fields,
+ * as specified in RFC5705.
+ *
+ * The @label variable usually contains a string denoting the purpose
+ * for the generated data.  The @server_random_first indicates whether
+ * the client random field or the server random field should be first
+ * in the seed.  Non-zero indicates that the server random field is first,
+ * 0 that the client random field is first.
+ *
+ * The @context variable can be used to add more data to the seed, after
+ * the random variables.  It can be used to make sure the
+ * generated output is strongly connected to some additional data
+ * (e.g., a string used in user authentication). 
+ *
+ * The output is placed in @out, which must be pre-allocated.
+ *
+ * Returns: %GNUTLS_E_SUCCESS on success, or an error code.
+ **/
+int
+gnutls_prf_rfc5705(gnutls_session_t session,
+		   size_t label_size, const char *label,
+		   size_t context_size, const char *context,
+		   size_t outsize, char *out)
+{
+	char *pctx;
+	int ret;
+
+	if (context_size > 65535)  {
+		gnutls_assert();
+		return GNUTLS_E_INVALID_REQUEST;
+	}
+
+	pctx = gnutls_malloc(context_size+2);
+	if (!pctx) {
+		gnutls_assert();
+		return GNUTLS_E_MEMORY_ERROR;
+	}
+
+	_gnutls_write_uint16(context_size, (void*)pctx);
+	if (context && context_size) {
+		memcpy(pctx+2, context, context_size);
+	}
+	ret = gnutls_prf(session, label_size, label, 0,
+			 context_size+2, pctx, outsize, out);
+	gnutls_free(pctx);
+	return ret;
+}
+
 /**
  * gnutls_prf:
  * @session: is a #gnutls_session_t type.
@@ -1074,8 +1133,8 @@ gnutls_prf_raw(gnutls_session_t session,
  * @out: pre-allocated buffer to hold the generated data.
  *
  * Applies the TLS Pseudo-Random-Function (PRF) on the master secret
- * and the provided data, seeded with the client and server random fields,
- * as specified in RFC5705.
+ * and the provided data, seeded with the client and server random fields.
+ * For the key expansion specified in RFC5705 see gnutls_prf_rfc5705().
  *
  * The @label variable usually contains a string denoting the purpose
  * for the generated data.  The @server_random_first indicates whether
@@ -1097,7 +1156,8 @@ gnutls_prf(gnutls_session_t session,
 	   size_t label_size,
 	   const char *label,
 	   int server_random_first,
-	   size_t extra_size, const char *extra, size_t outsize, char *out)
+	   size_t extra_size, const char *extra,
+	   size_t outsize, char *out)
 {
 	int ret;
 	uint8_t *seed;
@@ -1118,7 +1178,9 @@ gnutls_prf(gnutls_session_t session,
 	       client_random : session->security_parameters.server_random,
 	       GNUTLS_RANDOM_SIZE);
 
-	memcpy(seed + 2 * GNUTLS_RANDOM_SIZE, extra, extra_size);
+	if (extra && extra_size) {
+		memcpy(seed + 2 * GNUTLS_RANDOM_SIZE, extra, extra_size);
+	}
 
 	ret =
 	    _gnutls_PRF(session,
diff --git a/lib/includes/gnutls/gnutls.h.in b/lib/includes/gnutls/gnutls.h.in
index a1c688c4b5..0b9c69d90a 100644
--- a/lib/includes/gnutls/gnutls.h.in
+++ b/lib/includes/gnutls/gnutls.h.in
@@ -1030,6 +1030,10 @@ int gnutls_prf(gnutls_session_t session,
 	       int server_random_first,
 	       size_t extra_size, const char *extra,
 	       size_t outsize, char *out);
+int gnutls_prf_rfc5705(gnutls_session_t session,
+	       size_t label_size, const char *label,
+	       size_t context_size, const char *context,
+	       size_t outsize, char *out);
 
 int gnutls_prf_raw(gnutls_session_t session,
 		   size_t label_size, const char *label,
diff --git a/lib/libgnutls.map b/lib/libgnutls.map
index d1772054b3..5547cbde47 100644
--- a/lib/libgnutls.map
+++ b/lib/libgnutls.map
@@ -1049,6 +1049,7 @@ GNUTLS_3_4
 	gnutls_oid_to_pk;
 	gnutls_oid_to_sign;
 	gnutls_oid_to_ecc_curve;
+	gnutls_prf_rfc5705;
  local:
 	*;
 };