The Tor Browser: security/nss/lib/ssl/derive.c@b8a032363ba2 (annotated)

security/nss/lib/ssl/derive.c@b8a032363ba2 (annotated)

security/nss/lib/ssl/derive.c

Thu, 22 Jan 2015 13:21:57 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Thu, 22 Jan 2015 13:21:57 +0100
branch: TOR_BUG_9701
changeset 15: b8a032363ba2
permissions: -rw-r--r--

Incorporate requested changes from Mozilla in review:
https://bugzilla.mozilla.org/show_bug.cgi?id=1123480#c6

 /*
  * Key Derivation that doesn't use PKCS11
  *
  * This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 #include "ssl.h" 	/* prereq to sslimpl.h */
 #include "certt.h"	/* prereq to sslimpl.h */
 #include "keythi.h"	/* prereq to sslimpl.h */
 #include "sslimpl.h"
 #ifndef NO_PKCS11_BYPASS
 #include "blapi.h"
 #endif
 #include "keyhi.h"
 #include "pk11func.h"
 #include "secasn1.h"
 #include "cert.h"
 #include "secmodt.h"
 #include "sslproto.h"
 #include "sslerr.h"
 #ifndef NO_PKCS11_BYPASS
 /* make this a macro! */
 #ifdef NOT_A_MACRO
 static void
 buildSSLKey(unsigned char * keyBlock, unsigned int keyLen, SECItem * result,
             const char * label)
 {
     result->type = siBuffer;
     result->data = keyBlock;
     result->len  = keyLen;
     PRINT_BUF(100, (NULL, label, keyBlock, keyLen));
 }
 #else
 #define buildSSLKey(keyBlock, keyLen, result, label) \
 { \
     (result)->type = siBuffer; \
     (result)->data = keyBlock; \
     (result)->len  = keyLen; \
     PRINT_BUF(100, (NULL, label, keyBlock, keyLen)); \
 }
 #endif
 /*
  * SSL Key generation given pre master secret
  */
 #ifndef NUM_MIXERS
 #define NUM_MIXERS 9
 #endif
 static const char * const mixers[NUM_MIXERS] = {
     "A",
     "BB",
     "CCC",
     "DDDD",
     "EEEEE",
     "FFFFFF",
     "GGGGGGG",
     "HHHHHHHH",
     "IIIIIIIII"
 };
 SECStatus
 ssl3_KeyAndMacDeriveBypass(
     ssl3CipherSpec *      pwSpec,
     const unsigned char * cr,
     const unsigned char * sr,
     PRBool                isTLS,
     PRBool                isExport)
 {
     const ssl3BulkCipherDef *cipher_def = pwSpec->cipher_def;
     unsigned char * key_block    = pwSpec->key_block;
     unsigned char * key_block2   = NULL;
     unsigned int    block_bytes  = 0;
     unsigned int    block_needed = 0;
     unsigned int    i;
     unsigned int    keySize;            /* actual    size of cipher keys */
     unsigned int    effKeySize;		/* effective size of cipher keys */
     unsigned int    macSize;		/* size of MAC secret */
     unsigned int    IVSize;		/* size of IV */
     PRBool          explicitIV = PR_FALSE;
     SECStatus       rv    = SECFailure;
     SECStatus       status = SECSuccess;
     PRBool          isFIPS = PR_FALSE;
     PRBool          isTLS12 = pwSpec->version >= SSL_LIBRARY_VERSION_TLS_1_2;
     SECItem         srcr;
     SECItem         crsr;
     unsigned char     srcrdata[SSL3_RANDOM_LENGTH * 2];
     unsigned char     crsrdata[SSL3_RANDOM_LENGTH * 2];
     PRUint64          md5buf[22];
     PRUint64          shabuf[40];
 #define md5Ctx ((MD5Context *)md5buf)
 #define shaCtx ((SHA1Context *)shabuf)
     static const SECItem zed  = { siBuffer, NULL, 0 };
     if (pwSpec->msItem.data == NULL ||
         pwSpec->msItem.len  != SSL3_MASTER_SECRET_LENGTH) {
 	PORT_SetError(SEC_ERROR_INVALID_ARGS);
 	return rv;
     }
     PRINT_BUF(100, (NULL, "Master Secret", pwSpec->msItem.data,
                                            pwSpec->msItem.len));
     /* figure out how much is needed */
     macSize    = pwSpec->mac_size;
     keySize    = cipher_def->key_size;
     effKeySize = cipher_def->secret_key_size;
     IVSize     = cipher_def->iv_size;
     if (keySize == 0) {
 	effKeySize = IVSize = 0; /* only MACing */
     }
     if (cipher_def->type == type_block &&
 	pwSpec->version >= SSL_LIBRARY_VERSION_TLS_1_1) {
 	/* Block ciphers in >= TLS 1.1 use a per-record, explicit IV. */
 	explicitIV = PR_TRUE;
     }
     block_needed =
 * (macSize + effKeySize + ((!isExport && !explicitIV) * IVSize));
     /*
      * clear out our returned keys so we can recover on failure
      */
     pwSpec->client.write_key_item     = zed;
     pwSpec->client.write_mac_key_item = zed;
     pwSpec->server.write_key_item     = zed;
     pwSpec->server.write_mac_key_item = zed;
     /* initialize the server random, client random block */
     srcr.type   = siBuffer;
     srcr.data   = srcrdata;
     srcr.len    = sizeof srcrdata;
     PORT_Memcpy(srcrdata, sr, SSL3_RANDOM_LENGTH);
     PORT_Memcpy(srcrdata + SSL3_RANDOM_LENGTH, cr, SSL3_RANDOM_LENGTH);
     /* initialize the client random, server random block */
     crsr.type   = siBuffer;
     crsr.data   = crsrdata;
     crsr.len    = sizeof crsrdata;
     PORT_Memcpy(crsrdata, cr, SSL3_RANDOM_LENGTH);
     PORT_Memcpy(crsrdata + SSL3_RANDOM_LENGTH, sr, SSL3_RANDOM_LENGTH);
     PRINT_BUF(100, (NULL, "Key & MAC CRSR", crsr.data, crsr.len));
     /*
      * generate the key material:
      */
     if (isTLS) {
 	SECItem       keyblk;
 	keyblk.type = siBuffer;
 	keyblk.data = key_block;
 	keyblk.len  = block_needed;
 	if (isTLS12) {
 	    status = TLS_P_hash(HASH_AlgSHA256, &pwSpec->msItem,
 				"key expansion", &srcr, &keyblk, isFIPS);
 	} else {
 	    status = TLS_PRF(&pwSpec->msItem, "key expansion", &srcr, &keyblk,
 			     isFIPS);
 	}
 	if (status != SECSuccess) {
 	    goto key_and_mac_derive_fail;
 	}
 	block_bytes = keyblk.len;
     } else {
 	/* key_block =
 	 *     MD5(master_secret + SHA('A' + master_secret +
 	 *                      ServerHello.random + ClientHello.random)) +
 	 *     MD5(master_secret + SHA('BB' + master_secret +
 	 *                      ServerHello.random + ClientHello.random)) +
 	 *     MD5(master_secret + SHA('CCC' + master_secret +
 	 *                      ServerHello.random + ClientHello.random)) +
 	 *     [...];
 	 */
 	unsigned int made = 0;
 	for (i = 0; made < block_needed && i < NUM_MIXERS; ++i) {
 	    unsigned int    outLen;
 	    unsigned char   sha_out[SHA1_LENGTH];
 	    SHA1_Begin(shaCtx);
 	    SHA1_Update(shaCtx, (unsigned char*)(mixers[i]), i+1);
 	    SHA1_Update(shaCtx, pwSpec->msItem.data, pwSpec->msItem.len);
 	    SHA1_Update(shaCtx, srcr.data, srcr.len);
 	    SHA1_End(shaCtx, sha_out, &outLen, SHA1_LENGTH);
 	    PORT_Assert(outLen == SHA1_LENGTH);
 	    MD5_Begin(md5Ctx);
 	    MD5_Update(md5Ctx, pwSpec->msItem.data, pwSpec->msItem.len);
 	    MD5_Update(md5Ctx, sha_out, outLen);
 	    MD5_End(md5Ctx, key_block + made, &outLen, MD5_LENGTH);
 	    PORT_Assert(outLen == MD5_LENGTH);
 	    made += MD5_LENGTH;
 	}
 	block_bytes = made;
     }
     PORT_Assert(block_bytes >= block_needed);
     PORT_Assert(block_bytes <= sizeof pwSpec->key_block);
     PRINT_BUF(100, (NULL, "key block", key_block, block_bytes));
     /*
      * Put the key material where it goes.
      */
     key_block2 = key_block + block_bytes;
     i = 0;			/* now shows how much consumed */
     /*
      * The key_block is partitioned as follows:
      * client_write_MAC_secret[CipherSpec.hash_size]
      */
     buildSSLKey(&key_block[i],macSize, &pwSpec->client.write_mac_key_item, \
                 "Client Write MAC Secret");
     i += macSize;
     /*
      * server_write_MAC_secret[CipherSpec.hash_size]
      */
     buildSSLKey(&key_block[i],macSize, &pwSpec->server.write_mac_key_item, \
                 "Server Write MAC Secret");
     i += macSize;
     if (!keySize) {
 	/* only MACing */
 	buildSSLKey(NULL, 0, &pwSpec->client.write_key_item, \
 	            "Client Write Key (MAC only)");
 	buildSSLKey(NULL, 0, &pwSpec->server.write_key_item, \
 	            "Server Write Key (MAC only)");
 	buildSSLKey(NULL, 0, &pwSpec->client.write_iv_item, \
 	            "Client Write IV (MAC only)");
 	buildSSLKey(NULL, 0, &pwSpec->server.write_iv_item, \
 	            "Server Write IV (MAC only)");
     } else if (!isExport) {
 	/*
 	** Generate Domestic write keys and IVs.
 	** client_write_key[CipherSpec.key_material]
 	*/
 	buildSSLKey(&key_block[i], keySize, &pwSpec->client.write_key_item, \
 	            "Domestic Client Write Key");
 	i += keySize;
 	/*
 	** server_write_key[CipherSpec.key_material]
 	*/
 	buildSSLKey(&key_block[i], keySize, &pwSpec->server.write_key_item, \
 	            "Domestic Server Write Key");
 	i += keySize;
 	if (IVSize > 0) {
 	    if (explicitIV) {
 		static unsigned char zero_block[32];
 		PORT_Assert(IVSize <= sizeof zero_block);
 		buildSSLKey(&zero_block[0], IVSize, \
 			    &pwSpec->client.write_iv_item, \
 			    "Domestic Client Write IV");
 		buildSSLKey(&zero_block[0], IVSize, \
 			    &pwSpec->server.write_iv_item, \
 			    "Domestic Server Write IV");
 	    } else {
 		/*
 		** client_write_IV[CipherSpec.IV_size]
 		*/
 		buildSSLKey(&key_block[i], IVSize, \
 			    &pwSpec->client.write_iv_item, \
 			    "Domestic Client Write IV");
 		i += IVSize;
 		/*
 		** server_write_IV[CipherSpec.IV_size]
 		*/
 		buildSSLKey(&key_block[i], IVSize, \
 			    &pwSpec->server.write_iv_item, \
 			    "Domestic Server Write IV");
 		i += IVSize;
 	    }
 	}
 	PORT_Assert(i <= block_bytes);
     } else if (!isTLS) {
 	/*
 	** Generate SSL3 Export write keys and IVs.
 	*/
 	unsigned int    outLen;
 	/*
 	** client_write_key[CipherSpec.key_material]
 	** final_client_write_key = MD5(client_write_key +
 	**                   ClientHello.random + ServerHello.random);
 	*/
 	MD5_Begin(md5Ctx);
 	MD5_Update(md5Ctx, &key_block[i], effKeySize);
 	MD5_Update(md5Ctx, crsr.data, crsr.len);
 	MD5_End(md5Ctx, key_block2, &outLen, MD5_LENGTH);
 	i += effKeySize;
 	buildSSLKey(key_block2, keySize, &pwSpec->client.write_key_item, \
 	            "SSL3 Export Client Write Key");
 	key_block2 += keySize;
 	/*
 	** server_write_key[CipherSpec.key_material]
 	** final_server_write_key = MD5(server_write_key +
 	**                    ServerHello.random + ClientHello.random);
 	*/
 	MD5_Begin(md5Ctx);
 	MD5_Update(md5Ctx, &key_block[i], effKeySize);
 	MD5_Update(md5Ctx, srcr.data, srcr.len);
 	MD5_End(md5Ctx, key_block2, &outLen, MD5_LENGTH);
 	i += effKeySize;
 	buildSSLKey(key_block2, keySize, &pwSpec->server.write_key_item, \
 	            "SSL3 Export Server Write Key");
 	key_block2 += keySize;
 	PORT_Assert(i <= block_bytes);
 	if (IVSize) {
 	    /*
 	    ** client_write_IV =
 	    **	MD5(ClientHello.random + ServerHello.random);
 	    */
 	    MD5_Begin(md5Ctx);
 	    MD5_Update(md5Ctx, crsr.data, crsr.len);
 	    MD5_End(md5Ctx, key_block2, &outLen, MD5_LENGTH);
 	    buildSSLKey(key_block2, IVSize, &pwSpec->client.write_iv_item, \
 	                "SSL3 Export Client Write IV");
 	    key_block2 += IVSize;
 	    /*
 	    ** server_write_IV =
 	    **	MD5(ServerHello.random + ClientHello.random);
 	    */
 	    MD5_Begin(md5Ctx);
 	    MD5_Update(md5Ctx, srcr.data, srcr.len);
 	    MD5_End(md5Ctx, key_block2, &outLen, MD5_LENGTH);
 	    buildSSLKey(key_block2, IVSize, &pwSpec->server.write_iv_item, \
 	                "SSL3 Export Server Write IV");
 	    key_block2 += IVSize;
 	}
 	PORT_Assert(key_block2 - key_block <= sizeof pwSpec->key_block);
     } else {
 	/*
 	** Generate TLS Export write keys and IVs.
 	*/
 	SECItem       secret ;
 	SECItem       keyblk ;
 	secret.type = siBuffer;
 	keyblk.type = siBuffer;
 	/*
 	** client_write_key[CipherSpec.key_material]
 	** final_client_write_key = PRF(client_write_key,
 	**                              "client write key",
 	**                              client_random + server_random);
 	*/
 	secret.data = &key_block[i];
 	secret.len  = effKeySize;
 	i          += effKeySize;
 	keyblk.data = key_block2;
 	keyblk.len  = keySize;
 	status = TLS_PRF(&secret, "client write key", &crsr, &keyblk, isFIPS);
 	if (status != SECSuccess) {
 	    goto key_and_mac_derive_fail;
 	}
 	buildSSLKey(key_block2, keySize, &pwSpec->client.write_key_item, \
 	            "TLS Export Client Write Key");
 	key_block2 += keySize;
 	/*
 	** server_write_key[CipherSpec.key_material]
 	** final_server_write_key = PRF(server_write_key,
 	**                              "server write key",
 	**                              client_random + server_random);
 	*/
 	secret.data = &key_block[i];
 	secret.len  = effKeySize;
 	i          += effKeySize;
 	keyblk.data = key_block2;
 	keyblk.len  = keySize;
 	status = TLS_PRF(&secret, "server write key", &crsr, &keyblk, isFIPS);
 	if (status != SECSuccess) {
 	    goto key_and_mac_derive_fail;
 	}
 	buildSSLKey(key_block2, keySize, &pwSpec->server.write_key_item, \
 	            "TLS Export Server Write Key");
 	key_block2 += keySize;
 	/*
 	** iv_block = PRF("", "IV block", client_random + server_random);
 	** client_write_IV[SecurityParameters.IV_size]
 	** server_write_IV[SecurityParameters.IV_size]
 	*/
 	if (IVSize) {
 	    secret.data = NULL;
 	    secret.len  = 0;
 	    keyblk.data = key_block2;
 	    keyblk.len  = 2 * IVSize;
 	    status = TLS_PRF(&secret, "IV block", &crsr, &keyblk, isFIPS);
 	    if (status != SECSuccess) {
 		goto key_and_mac_derive_fail;
 	    }
 	    buildSSLKey(key_block2,          IVSize, \
 	                &pwSpec->client.write_iv_item, \
 			"TLS Export Client Write IV");
 	    buildSSLKey(key_block2 + IVSize, IVSize, \
 	                &pwSpec->server.write_iv_item, \
 			"TLS Export Server Write IV");
 	    key_block2 += 2 * IVSize;
 	}
 	PORT_Assert(key_block2 - key_block <= sizeof pwSpec->key_block);
     }
     rv = SECSuccess;
 key_and_mac_derive_fail:
     MD5_DestroyContext(md5Ctx, PR_FALSE);
     SHA1_DestroyContext(shaCtx, PR_FALSE);
     if (rv != SECSuccess) {
 	PORT_SetError(SSL_ERROR_SESSION_KEY_GEN_FAILURE);
     }
     return rv;
 }
 /* derive the Master Secret from the PMS */
 /* Presently, this is only done wtih RSA PMS, and only on the server side,
  * so isRSA is always true.
  */
 SECStatus
 ssl3_MasterKeyDeriveBypass(
     ssl3CipherSpec *      pwSpec,
     const unsigned char * cr,
     const unsigned char * sr,
     const SECItem *       pms,
     PRBool                isTLS,
     PRBool                isRSA)
 {
     unsigned char * key_block    = pwSpec->key_block;
     SECStatus       rv    = SECSuccess;
     PRBool          isFIPS = PR_FALSE;
     PRBool          isTLS12 = pwSpec->version >= SSL_LIBRARY_VERSION_TLS_1_2;
     SECItem         crsr;
     unsigned char     crsrdata[SSL3_RANDOM_LENGTH * 2];
     PRUint64          md5buf[22];
     PRUint64          shabuf[40];
 #define md5Ctx ((MD5Context *)md5buf)
 #define shaCtx ((SHA1Context *)shabuf)
     /* first do the consistancy checks */
     if (isRSA) {
 	PORT_Assert(pms->len == SSL3_RSA_PMS_LENGTH);
 	if (pms->len != SSL3_RSA_PMS_LENGTH) {
 	    PORT_SetError(SEC_ERROR_INVALID_ARGS);
 	    return SECFailure;
 	}
 	/* caller must test PMS version for rollback */
     }
     /* initialize the client random, server random block */
     crsr.type   = siBuffer;
     crsr.data   = crsrdata;
     crsr.len    = sizeof crsrdata;
     PORT_Memcpy(crsrdata, cr, SSL3_RANDOM_LENGTH);
     PORT_Memcpy(crsrdata + SSL3_RANDOM_LENGTH, sr, SSL3_RANDOM_LENGTH);
     PRINT_BUF(100, (NULL, "Master Secret CRSR", crsr.data, crsr.len));
     /* finally do the key gen */
     if (isTLS) {
 	SECItem master = { siBuffer, NULL, 0 };
 	master.data = key_block;
 	master.len = SSL3_MASTER_SECRET_LENGTH;
 	if (isTLS12) {
 	    rv = TLS_P_hash(HASH_AlgSHA256, pms, "master secret", &crsr,
 			    &master, isFIPS);
 	} else {
 	    rv = TLS_PRF(pms, "master secret", &crsr, &master, isFIPS);
 	}
 	if (rv != SECSuccess) {
 	    PORT_SetError(SSL_ERROR_SESSION_KEY_GEN_FAILURE);
 	}
     } else {
 	int i;
 	unsigned int made = 0;
 	for (i = 0; i < 3; i++) {
 	    unsigned int    outLen;
 	    unsigned char   sha_out[SHA1_LENGTH];
 	    SHA1_Begin(shaCtx);
 	    SHA1_Update(shaCtx, (unsigned char*) mixers[i], i+1);
 	    SHA1_Update(shaCtx, pms->data, pms->len);
 	    SHA1_Update(shaCtx, crsr.data, crsr.len);
 	    SHA1_End(shaCtx, sha_out, &outLen, SHA1_LENGTH);
 	    PORT_Assert(outLen == SHA1_LENGTH);
 	    MD5_Begin(md5Ctx);
 	    MD5_Update(md5Ctx, pms->data, pms->len);
 	    MD5_Update(md5Ctx, sha_out, outLen);
 	    MD5_End(md5Ctx, key_block + made, &outLen, MD5_LENGTH);
 	    PORT_Assert(outLen == MD5_LENGTH);
 	    made += outLen;
 	}
     }
     /* store the results */
     PORT_Memcpy(pwSpec->raw_master_secret, key_block,
 		SSL3_MASTER_SECRET_LENGTH);
     pwSpec->msItem.data = pwSpec->raw_master_secret;
     pwSpec->msItem.len  = SSL3_MASTER_SECRET_LENGTH;
     PRINT_BUF(100, (NULL, "Master Secret", pwSpec->msItem.data,
                                            pwSpec->msItem.len));
     return rv;
 }
 static SECStatus
 ssl_canExtractMS(PK11SymKey *pms, PRBool isTLS, PRBool isDH, PRBool *pcbp)
 {   SECStatus	      rv;
     PK11SymKey *    ms = NULL;
     SECItem         params = {siBuffer, NULL, 0};
     CK_SSL3_MASTER_KEY_DERIVE_PARAMS master_params;
     unsigned char   rand[SSL3_RANDOM_LENGTH];
     CK_VERSION      pms_version;
     CK_MECHANISM_TYPE master_derive;
     CK_MECHANISM_TYPE key_derive;
     CK_FLAGS          keyFlags;
     if (pms == NULL)
 	return(SECFailure);
     PORT_Memset(rand, 0, SSL3_RANDOM_LENGTH);
     if (isTLS) {
 	if(isDH) master_derive = CKM_TLS_MASTER_KEY_DERIVE_DH;
 	else master_derive = CKM_TLS_MASTER_KEY_DERIVE;
 	key_derive    = CKM_TLS_KEY_AND_MAC_DERIVE;
 	keyFlags      = CKF_SIGN | CKF_VERIFY;
     } else {
 	if (isDH) master_derive = CKM_SSL3_MASTER_KEY_DERIVE_DH;
 	else master_derive = CKM_SSL3_MASTER_KEY_DERIVE;
 	key_derive    = CKM_SSL3_KEY_AND_MAC_DERIVE;
 	keyFlags      = 0;
     }
     master_params.pVersion                     = &pms_version;
     master_params.RandomInfo.pClientRandom     = rand;
     master_params.RandomInfo.ulClientRandomLen = SSL3_RANDOM_LENGTH;
     master_params.RandomInfo.pServerRandom     = rand;
     master_params.RandomInfo.ulServerRandomLen = SSL3_RANDOM_LENGTH;
     params.data = (unsigned char *) &master_params;
     params.len  = sizeof master_params;
     ms = PK11_DeriveWithFlags(pms, master_derive, &params, key_derive,
 			      CKA_DERIVE, 0, keyFlags);
     if (ms == NULL)
 	return(SECFailure);
     rv = PK11_ExtractKeyValue(ms);
     *pcbp = (rv == SECSuccess);
     PK11_FreeSymKey(ms);
     return(rv);
 }
 #endif  /* !NO_PKCS11_BYPASS */
 /* Check the key exchange algorithm for each cipher in the list to see if
  * a master secret key can be extracted. If the KEA will use keys from the
  * specified cert make sure the extract operation is attempted from the slot
  * where the private key resides.
  * If MS can be extracted for all ciphers, (*pcanbypass) is set to TRUE and
  * SECSuccess is returned. In all other cases but one (*pcanbypass) is
  * set to FALSE and SECFailure is returned.
  * In that last case Derive() has been called successfully but the MS is null,
  * CanBypass sets (*pcanbypass) to FALSE and returns SECSuccess indicating the
  * arguments were all valid but the slot cannot be bypassed.
  */
 /* XXX Add SSL_CBP_TLS1_1 and test it in protocolmask when setting isTLS. */
 SECStatus
 SSL_CanBypass(CERTCertificate *cert, SECKEYPrivateKey *srvPrivkey,
 	      PRUint32 protocolmask, PRUint16 *ciphersuites, int nsuites,
               PRBool *pcanbypass, void *pwArg)
 {
 #ifdef NO_PKCS11_BYPASS
     if (!pcanbypass) {
         PORT_SetError(SEC_ERROR_INVALID_ARGS);
         return SECFailure;
     }
     *pcanbypass = PR_FALSE;
     return SECSuccess;
 #else
     SECStatus	      rv;
     int		      i;
     PRUint16	      suite;
     PK11SymKey *      pms = NULL;
     SECKEYPublicKey * srvPubkey = NULL;
     KeyType	      privKeytype;
     PK11SlotInfo *    slot = NULL;
     SECItem           param;
     CK_VERSION 	      version;
     CK_MECHANISM_TYPE mechanism_array[2];
     SECItem           enc_pms = {siBuffer, NULL, 0};
     PRBool	      isTLS = PR_FALSE;
     SSLCipherSuiteInfo csdef;
     PRBool	      testrsa = PR_FALSE;
     PRBool	      testrsa_export = PR_FALSE;
     PRBool	      testecdh = PR_FALSE;
     PRBool	      testecdhe = PR_FALSE;
 #ifndef NSS_DISABLE_ECC
     SECKEYECParams ecParams = { siBuffer, NULL, 0 };
 #endif
     if (!cert || !srvPrivkey || !ciphersuites || !pcanbypass) {
 	PORT_SetError(SEC_ERROR_INVALID_ARGS);
         return SECFailure;
     }
     srvPubkey = CERT_ExtractPublicKey(cert);
     if (!srvPubkey)
         return SECFailure;
     *pcanbypass = PR_TRUE;
     rv = SECFailure;
     /* determine which KEAs to test */
     /* 0 (TLS_NULL_WITH_NULL_NULL) is used as a list terminator because
      * SSL3 and TLS specs forbid negotiating that cipher suite number.
      */
     for (i=0; i < nsuites && (suite = *ciphersuites++) != 0; i++) {
 	/* skip SSL2 cipher suites and ones NSS doesn't support */
 	if (SSL_GetCipherSuiteInfo(suite, &csdef, sizeof(csdef)) != SECSuccess
 	    || SSL_IS_SSL2_CIPHER(suite) )
 	    continue;
 	switch (csdef.keaType) {
 	case ssl_kea_rsa:
 	    switch (csdef.cipherSuite) {
 	    case TLS_RSA_EXPORT1024_WITH_RC4_56_SHA:
 	    case TLS_RSA_EXPORT1024_WITH_DES_CBC_SHA:
 	    case TLS_RSA_EXPORT_WITH_RC4_40_MD5:
 	    case TLS_RSA_EXPORT_WITH_RC2_CBC_40_MD5:
 		testrsa_export = PR_TRUE;
 	    }
 	    if (!testrsa_export)
 		testrsa = PR_TRUE;
 	    break;
 	case ssl_kea_ecdh:
 	    if (strcmp(csdef.keaTypeName, "ECDHE") == 0) /* ephemeral? */
 		testecdhe = PR_TRUE;
 	    else
 		testecdh = PR_TRUE;
 	    break;
 	case ssl_kea_dh:
 	    /* this is actually DHE */
 	default:
 	    continue;
 	}
     }
     /* For each protocol try to derive and extract an MS.
      * Failure of function any function except MS extract means
      * continue with the next cipher test. Stop testing when the list is
      * exhausted or when the first MS extract--not derive--fails.
      */
     privKeytype = SECKEY_GetPrivateKeyType(srvPrivkey);
     protocolmask &= SSL_CBP_SSL3|SSL_CBP_TLS1_0;
     while (protocolmask) {
 	if (protocolmask & SSL_CBP_SSL3) {
 	    isTLS = PR_FALSE;
 	    protocolmask ^= SSL_CBP_SSL3;
 	} else {
 	    isTLS = PR_TRUE;
 	    protocolmask ^= SSL_CBP_TLS1_0;
 	}
 	if (privKeytype == rsaKey && testrsa_export) {
 	    if (PK11_GetPrivateModulusLen(srvPrivkey) > EXPORT_RSA_KEY_LENGTH) {
 		*pcanbypass = PR_FALSE;
 		rv = SECSuccess;
 		break;
 	    } else
 		testrsa = PR_TRUE;
 	}
 	for (; privKeytype == rsaKey && testrsa; ) {
 	    /* TLS_RSA */
 	    unsigned char     rsaPmsBuf[SSL3_RSA_PMS_LENGTH];
 	    unsigned int      outLen = 0;
 	    CK_MECHANISM_TYPE target;
 	    SECStatus	      irv;
 	    mechanism_array[0] = CKM_SSL3_PRE_MASTER_KEY_GEN;
 	    mechanism_array[1] = CKM_RSA_PKCS;
 	    slot = PK11_GetBestSlotMultiple(mechanism_array, 2, pwArg);
 	    if (slot == NULL) {
 		PORT_SetError(SSL_ERROR_TOKEN_SLOT_NOT_FOUND);
 		break;
 	    }
 	    /* Generate the pre-master secret ...  (client side) */
 	    version.major = 3 /*MSB(clientHelloVersion)*/;
 	    version.minor = 0 /*LSB(clientHelloVersion)*/;
 	    param.data = (unsigned char *)&version;
 	    param.len  = sizeof version;
 	    pms = PK11_KeyGen(slot, CKM_SSL3_PRE_MASTER_KEY_GEN, &param, 0, pwArg);
 	    PK11_FreeSlot(slot);
 	    if (!pms)
 		break;
 	    /* now wrap it */
 	    enc_pms.len  = SECKEY_PublicKeyStrength(srvPubkey);
 	    enc_pms.data = (unsigned char*)PORT_Alloc(enc_pms.len);
 	    if (enc_pms.data == NULL) {
 	        PORT_SetError(PR_OUT_OF_MEMORY_ERROR);
 	        break;
 	    }
 	    irv = PK11_PubWrapSymKey(CKM_RSA_PKCS, srvPubkey, pms, &enc_pms);
 	    if (irv != SECSuccess)
 		break;
 	    PK11_FreeSymKey(pms);
 	    pms = NULL;
 	    /* now do the server side--check the triple bypass first */
 	    rv = PK11_PrivDecryptPKCS1(srvPrivkey, rsaPmsBuf, &outLen,
 				       sizeof rsaPmsBuf,
 				       (unsigned char *)enc_pms.data,
 				       enc_pms.len);
 	    /* if decrypt worked we're done with the RSA test */
 	    if (rv == SECSuccess) {
 		*pcanbypass = PR_TRUE;
 		break;
 	    }
 	    /* check for fallback to double bypass */
 	    target = isTLS ? CKM_TLS_MASTER_KEY_DERIVE
 			: CKM_SSL3_MASTER_KEY_DERIVE;
 	    pms = PK11_PubUnwrapSymKey(srvPrivkey, &enc_pms,
 				       target, CKA_DERIVE, 0);
 	    rv = ssl_canExtractMS(pms, isTLS, PR_FALSE, pcanbypass);
 	    if (rv == SECSuccess && *pcanbypass == PR_FALSE)
 		goto done;
 	    break;
 	}
 	/* Check for NULL to avoid double free.
 	 * SECItem_FreeItem sets data NULL in secitem.c#265
 	 */
 	if (enc_pms.data != NULL) {
 	    SECITEM_FreeItem(&enc_pms, PR_FALSE);
         }
 #ifndef NSS_DISABLE_ECC
 	for (; (privKeytype == ecKey && ( testecdh || testecdhe)) ||
 	       (privKeytype == rsaKey && testecdhe); ) {
 	    CK_MECHANISM_TYPE target;
 	    SECKEYPublicKey  *keapub = NULL;
 	    SECKEYPrivateKey *keapriv;
 	    SECKEYPublicKey  *cpub = NULL; /* client's ephemeral ECDH keys */
 	    SECKEYPrivateKey *cpriv = NULL;
 	    SECKEYECParams   *pecParams = NULL;
 	    if (privKeytype == ecKey && testecdhe) {
 		/* TLS_ECDHE_ECDSA */
 		pecParams = &srvPubkey->u.ec.DEREncodedParams;
 	    } else if (privKeytype == rsaKey && testecdhe) {
 		/* TLS_ECDHE_RSA */
 		ECName       ec_curve;
 		int		 serverKeyStrengthInBits;
 		int		 signatureKeyStrength;
 		int		 requiredECCbits;
 		/* find a curve of equivalent strength to the RSA key's */
 		requiredECCbits = PK11_GetPrivateModulusLen(srvPrivkey);
 		if (requiredECCbits < 0)
 		    break;
 		requiredECCbits *= BPB;
 		serverKeyStrengthInBits = srvPubkey->u.rsa.modulus.len;
 		if (srvPubkey->u.rsa.modulus.data[0] == 0) {
 		    serverKeyStrengthInBits--;
 		}
 		/* convert to strength in bits */
 		serverKeyStrengthInBits *= BPB;
 		signatureKeyStrength =
 		    SSL_RSASTRENGTH_TO_ECSTRENGTH(serverKeyStrengthInBits);
 		if ( requiredECCbits > signatureKeyStrength )
 		     requiredECCbits = signatureKeyStrength;
 		ec_curve =
 		    ssl3_GetCurveWithECKeyStrength(
 					ssl3_GetSupportedECCurveMask(NULL),
 				  	requiredECCbits);
 		rv = ssl3_ECName2Params(NULL, ec_curve, &ecParams);
 		if (rv == SECFailure) {
 		    break;
 		}
 		pecParams = &ecParams;
 	    }
 	    if (testecdhe) {
 		/* generate server's ephemeral keys */
 		keapriv = SECKEY_CreateECPrivateKey(pecParams, &keapub, NULL);
 		if (!keapriv || !keapub) {
 		    if (keapriv)
 			SECKEY_DestroyPrivateKey(keapriv);
 		    if (keapub)
 			SECKEY_DestroyPublicKey(keapub);
 		    PORT_SetError(SEC_ERROR_KEYGEN_FAIL);
 		    rv = SECFailure;
 		    break;
 		}
 	    } else {
 		/* TLS_ECDH_ECDSA */
 		keapub = srvPubkey;
 		keapriv = srvPrivkey;
 		pecParams = &srvPubkey->u.ec.DEREncodedParams;
 	    }
 	    /* perform client side ops */
 	    /* generate a pair of ephemeral keys using server's parms */
 	    cpriv = SECKEY_CreateECPrivateKey(pecParams, &cpub, NULL);
 	    if (!cpriv || !cpub) {
 		if (testecdhe) {
 		    SECKEY_DestroyPrivateKey(keapriv);
 		    SECKEY_DestroyPublicKey(keapub);
 		}
 		PORT_SetError(SEC_ERROR_KEYGEN_FAIL);
 		rv = SECFailure;
 		break;
 	    }
 	    /* now do the server side */
 	    /* determine the PMS using client's public value */
 	    target = isTLS ? CKM_TLS_MASTER_KEY_DERIVE_DH
 			   : CKM_SSL3_MASTER_KEY_DERIVE_DH;
 	    pms = PK11_PubDeriveWithKDF(keapriv, cpub, PR_FALSE, NULL, NULL,
 				    CKM_ECDH1_DERIVE,
 				    target,
 				    CKA_DERIVE, 0, CKD_NULL, NULL, NULL);
 	    rv = ssl_canExtractMS(pms, isTLS, PR_TRUE, pcanbypass);
 	    SECKEY_DestroyPrivateKey(cpriv);
 	    SECKEY_DestroyPublicKey(cpub);
 	    if (testecdhe) {
 		SECKEY_DestroyPrivateKey(keapriv);
 		SECKEY_DestroyPublicKey(keapub);
 	    }
 	    if (rv == SECSuccess && *pcanbypass == PR_FALSE)
 		goto done;
 	    break;
 	}
 	/* Check for NULL to avoid double free. */
 	if (ecParams.data != NULL) {
 	    PORT_Free(ecParams.data);
 	    ecParams.data = NULL;
 	}
 #endif /* NSS_DISABLE_ECC */
 	if (pms)
 	    PK11_FreeSymKey(pms);
     }
     /* *pcanbypass has been set */
     rv = SECSuccess;
   done:
     if (pms)
 	PK11_FreeSymKey(pms);
     /* Check for NULL to avoid double free.
      * SECItem_FreeItem sets data NULL in secitem.c#265
      */
     if (enc_pms.data != NULL) {
     	SECITEM_FreeItem(&enc_pms, PR_FALSE);
     }
 #ifndef NSS_DISABLE_ECC
     if (ecParams.data != NULL) {
         PORT_Free(ecParams.data);
         ecParams.data = NULL;
     }
 #endif /* NSS_DISABLE_ECC */
     if (srvPubkey) {
     	SECKEY_DestroyPublicKey(srvPubkey);
 	srvPubkey = NULL;
     }
     return rv;
 #endif /* NO_PKCS11_BYPASS */
 }

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security/nss/lib/ssl/derive.c@b8a032363ba2 (annotated)

security/nss/lib/ssl/derive.c