X-Git-Url: https://git.saurik.com/apple/security.git/blobdiff_plain/c25717e3bfe9397829b8aac32a966f746fc3c4f5..2965425374ca4413339436c2f706f7b5508402e2:/AppleCSP/DiffieHellman/DH_exchange.cpp

diff --git a/AppleCSP/DiffieHellman/DH_exchange.cpp b/AppleCSP/DiffieHellman/DH_exchange.cpp
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+++ b/AppleCSP/DiffieHellman/DH_exchange.cpp
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+/*
+ * Copyright (c) 2000-2002 Apple Computer, Inc. All Rights Reserved.
+ * 
+ * The contents of this file constitute Original Code as defined in and are
+ * subject to the Apple Public Source License Version 1.2 (the 'License').
+ * You may not use this file except in compliance with the License. Please obtain
+ * a copy of the License at http://www.apple.com/publicsource and read it before
+ * using this file.
+ * 
+ * This Original Code and all software distributed under the License are
+ * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESS
+ * OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, INCLUDING WITHOUT
+ * LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
+ * PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT. Please see the License for the
+ * specific language governing rights and limitations under the License.
+ */
+
+
+/*
+ * DH_exchange.cp - Diffie-Hellman key exchange
+ */
+ 
+#include "DH_exchange.h"
+#include <Security/cssmerr.h>
+#include <Security/utilities.h>
+#include "DH_utils.h"
+#include <strings.h>
+#include <open_ssl/opensslUtils/opensslUtils.h>
+
+void DeriveKey_DH (
+	const Context &context,
+	const CssmData &Param,			// other's public key
+	CSSM_DATA *keyData,				// mallocd by caller
+									// we fill in keyData->Length bytes
+	AppleCSPSession &session)
+{
+	bool mallocdKey;
+	size_t privSize;
+	
+	/* private DH key from context */
+	DH *privKey = contextToDhKey(context, session, CSSM_KEYUSE_DERIVE, 
+		mallocdKey);
+	privSize = DH_size(privKey);
+	if(privSize < keyData->Length) {
+		/* we've been asked for more bits than this key can generate */
+		CssmError::throwMe(CSSMERR_CSP_UNSUPPORTED_KEY_SIZE);
+	}
+	BIGNUM *pubKey = BN_bin2bn(Param.Data, Param.Length, NULL);
+	if(pubKey == NULL) {
+		CssmError::throwMe(CSSMERR_CSP_MEMORY_ERROR);
+	}
+	unsigned char *buf = (unsigned char *)session.malloc(privSize);
+	int rtn = DH_compute_key(buf, pubKey, privKey);
+	if(rtn >= 0) {
+		/*
+		 * FIXME : I have not found a specification describing *which*
+		 * bytes of the value we just computed we are supposed to
+		 * use as the actual key bytes. We use the M.S. bytes.
+		 */
+		memmove(keyData->Data, buf, keyData->Length);
+	}
+	if(mallocdKey) {
+		DH_free(privKey);
+	}
+	BN_free(pubKey);
+	session.free(buf);
+	if(rtn < 0) {
+		throwRsaDsa("DH_compute_key");
+	}
+}
+