Diff: tls.c

Revision:

0:5045d2638c29

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/tls.c	Sat Feb 05 01:09:17 2011 +0000
@@ -0,0 +1,451 @@
+/* tls.c
+ *
+ * Copyright (C) 2006-2009 Sawtooth Consulting Ltd.
+ *
+ * This file is part of CyaSSL.
+ *
+ * CyaSSL is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * CyaSSL is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
+ */
+
+
+#include "ssl.h"
+#include "cyassl_int.h"
+#include "cyassl_error.h"
+#include "ctc_hmac.h"
+
+
+
+#ifndef NO_TLS
+
+
+#ifndef min
+
+    static INLINE word32 min(word32 a, word32 b)
+    {
+        return a > b ? b : a;
+    }
+
+#endif /* min */
+
+
+/* calculate XOR for TLSv1 PRF */
+static INLINE void get_xor(byte *digest, word32 digLen, byte* md5, byte* sha)
+{
+    word32 i;
+
+    for (i = 0; i < digLen; i++) 
+        digest[i] = md5[i] ^ sha[i];
+}
+
+
+
+/* compute p_hash for MD5, SHA-1, or SHA-256 for TLSv1 PRF */
+void p_hash(byte* result, word32 resLen, const byte* secret, word32 secLen,
+            const byte* seed, word32 seedLen, int hash)
+{
+    word32   len = hash == md5_mac ? MD5_DIGEST_SIZE : hash == sha_mac ?
+                                           SHA_DIGEST_SIZE : SHA256_DIGEST_SIZE;
+    word32   times = resLen / len;
+    word32   lastLen = resLen % len;
+    word32   lastTime;
+    word32   i;
+    word32   idx = 0;
+    byte     previous[SHA256_DIGEST_SIZE];  /* max size */
+    byte     current[SHA256_DIGEST_SIZE];   /* max size */
+
+    Hmac hmac;
+
+    if (lastLen) times += 1;
+    lastTime = times - 1;
+
+    HmacSetKey(&hmac, hash == md5_mac ? MD5 : hash == sha_mac ? SHA : SHA256,
+               secret, secLen);
+    HmacUpdate(&hmac, seed, seedLen);       /* A0 = seed */
+    HmacFinal(&hmac, previous);             /* A1 */
+
+    for (i = 0; i < times; i++) {
+        HmacUpdate(&hmac, previous, len);
+        HmacUpdate(&hmac, seed, seedLen);
+        HmacFinal(&hmac, current);
+
+        if ( (i == lastTime) && lastLen)
+            XMEMCPY(&result[idx], current, lastLen);
+        else {
+            XMEMCPY(&result[idx], current, len);
+            idx += len;
+            HmacUpdate(&hmac, previous, len);
+            HmacFinal(&hmac, previous);
+        }
+    }
+}
+
+
+
+/* compute TLSv1 PRF (pseudo random function using HMAC) */
+static void PRF(byte* digest, word32 digLen, const byte* secret, word32 secLen,
+            const byte* label, word32 labLen, const byte* seed, word32 seedLen,
+            int useSha256)
+{
+    word32 half = (secLen + 1) / 2;
+
+    byte md5_half[MAX_PRF_HALF];        /* half is real size */
+    byte sha_half[MAX_PRF_HALF];        /* half is real size */
+    byte labelSeed[MAX_PRF_LABSEED];    /* labLen + seedLen is real size */
+    byte md5_result[MAX_PRF_DIG];       /* digLen is real size */
+    byte sha_result[MAX_PRF_DIG];       /* digLen is real size */
+
+    if (half > MAX_PRF_HALF)
+        return;
+    if (labLen + seedLen > MAX_PRF_LABSEED)
+        return;
+    if (digLen > MAX_PRF_DIG)
+        return;
+    
+    XMEMCPY(md5_half, secret, half);
+    XMEMCPY(sha_half, secret + half - secLen % 2, half);
+
+    XMEMCPY(labelSeed, label, labLen);
+    XMEMCPY(labelSeed + labLen, seed, seedLen);
+
+    if (useSha256) {
+        p_hash(digest, digLen, secret, secLen, labelSeed, labLen + seedLen,
+               sha256_mac);
+        return;
+    }
+
+    p_hash(md5_result, digLen, md5_half, half, labelSeed, labLen + seedLen,
+           md5_mac);
+    p_hash(sha_result, digLen, sha_half, half, labelSeed, labLen + seedLen,
+           sha_mac);
+    get_xor(digest, digLen, md5_result, sha_result);
+}
+
+
+void BuildTlsFinished(SSL* ssl, Hashes* hashes, const byte* sender)
+{
+    const byte* side;
+    byte handshake_hash[FINISHED_SZ];
+
+    Md5Final(&ssl->hashMd5, handshake_hash);
+    ShaFinal(&ssl->hashSha, &handshake_hash[MD5_DIGEST_SIZE]);
+   
+    if ( XSTRNCMP((const char*)sender, (const char*)client, SIZEOF_SENDER) == 0)
+        side = tls_client;
+    else
+        side = tls_server;
+
+    PRF(hashes->md5, TLS_FINISHED_SZ, ssl->arrays.masterSecret, SECRET_LEN,
+        side, FINISHED_LABEL_SZ, handshake_hash, FINISHED_SZ,
+        IsAtLeastTLSv1_2(ssl));
+}
+
+
+ProtocolVersion MakeTLSv1(void)
+{
+    ProtocolVersion pv;
+    pv.major = SSLv3_MAJOR;
+    pv.minor = TLSv1_MINOR;
+
+    return pv;
+}
+
+
+ProtocolVersion MakeTLSv1_1(void)
+{
+    ProtocolVersion pv;
+    pv.major = SSLv3_MAJOR;
+    pv.minor = TLSv1_1_MINOR;
+
+    return pv;
+}
+
+
+ProtocolVersion MakeTLSv1_2(void)
+{
+    ProtocolVersion pv;
+    pv.major = SSLv3_MAJOR;
+    pv.minor = TLSv1_2_MINOR;
+
+    return pv;
+}
+
+
+static const byte master_label[MASTER_LABEL_SZ + 1] = "master secret";
+static const byte key_label   [KEY_LABEL_SZ + 1]    = "key expansion";
+
+
+int DeriveTlsKeys(SSL* ssl)
+{
+    int length = 2 * ssl->specs.hash_size + 
+                 2 * ssl->specs.key_size  +
+                 2 * ssl->specs.iv_size;
+    byte         seed[SEED_LEN];
+    byte         key_data[MAX_PRF_DIG];
+
+    XMEMCPY(seed, ssl->arrays.serverRandom, RAN_LEN);
+    XMEMCPY(&seed[RAN_LEN], ssl->arrays.clientRandom, RAN_LEN);
+
+    PRF(key_data, length, ssl->arrays.masterSecret, SECRET_LEN, key_label,
+        KEY_LABEL_SZ, seed, SEED_LEN, IsAtLeastTLSv1_2(ssl));
+
+    return StoreKeys(ssl, key_data);
+}
+
+
+int MakeTlsMasterSecret(SSL* ssl)
+{
+    byte seed[SEED_LEN];
+    
+    XMEMCPY(seed, ssl->arrays.clientRandom, RAN_LEN);
+    XMEMCPY(&seed[RAN_LEN], ssl->arrays.serverRandom, RAN_LEN);
+
+    PRF(ssl->arrays.masterSecret, SECRET_LEN,
+        ssl->arrays.preMasterSecret, ssl->arrays.preMasterSz,
+        master_label, MASTER_LABEL_SZ, 
+        seed, SEED_LEN, IsAtLeastTLSv1_2(ssl));
+
+#ifdef SHOW_SECRETS
+    {
+        int i;
+        printf("master secret: ");
+        for (i = 0; i < SECRET_LEN; i++)
+            printf("%02x", ssl->arrays.masterSecret[i]);
+        printf("\n");
+    }
+#endif
+
+    return DeriveTlsKeys(ssl);
+}
+
+
+/*** next for static INLINE s copied from cyassl_int.c ***/
+
+/* convert 16 bit integer to opaque */
+static void INLINE c16toa(word16 u16, byte* c)
+{
+    c[0] = (u16 >> 8) & 0xff;
+    c[1] =  u16 & 0xff;
+}
+
+
+/* convert 32 bit integer to opaque */
+static INLINE void c32toa(word32 u32, byte* c)
+{
+    c[0] = (u32 >> 24) & 0xff;
+    c[1] = (u32 >> 16) & 0xff;
+    c[2] = (u32 >>  8) & 0xff;
+    c[3] =  u32 & 0xff;
+}
+
+
+static INLINE word32 GetSEQIncrement(SSL* ssl, int verify)
+{
+#ifdef CYASSL_DTLS
+    if (ssl->options.dtls) {
+        if (verify)
+            return ssl->keys.dtls_peer_sequence_number; /* explicit from peer */
+        else
+            return ssl->keys.dtls_sequence_number - 1; /* already incremented */
+    }
+#endif
+    if (verify)
+        return ssl->keys.peer_sequence_number++; 
+    else
+        return ssl->keys.sequence_number++; 
+}
+
+
+#ifdef CYASSL_DTLS
+
+static INLINE word32 GetEpoch(SSL* ssl, int verify)
+{
+    if (verify)
+        return ssl->keys.dtls_peer_epoch; 
+    else
+        return ssl->keys.dtls_epoch; 
+}
+
+#endif /* CYASSL_DTLS */
+
+
+static INLINE const byte* GetMacSecret(SSL* ssl, int verify)
+{
+    if ( (ssl->options.side == CLIENT_END && !verify) ||
+         (ssl->options.side == SERVER_END &&  verify) )
+        return ssl->keys.client_write_MAC_secret;
+    else
+        return ssl->keys.server_write_MAC_secret;
+}
+
+/*** end copy ***/
+
+
+/* TLS type HAMC */
+void TLS_hmac(SSL* ssl, byte* digest, const byte* buffer, word32 sz,
+              int content, int verify)
+{
+    Hmac hmac;
+    byte seq[SEQ_SZ] = { 0x00, 0x00, 0x00, 0x00 };
+    byte length[LENGTH_SZ];
+    byte inner[ENUM_LEN + VERSION_SZ + LENGTH_SZ]; /* type + version +len */
+    int  type;
+
+    c16toa((word16)sz, length);
+#ifdef CYASSL_DTLS
+    if (ssl->options.dtls)
+        c16toa(GetEpoch(ssl, verify), seq);
+#endif
+    c32toa(GetSEQIncrement(ssl, verify), &seq[sizeof(word32)]);
+    
+    if (ssl->specs.mac_algorithm == md5_mac)
+        type = MD5;
+    else
+        type = SHA;
+    HmacSetKey(&hmac, type, GetMacSecret(ssl, verify), ssl->specs.hash_size);
+    
+    HmacUpdate(&hmac, seq, SEQ_SZ);                               /* seq_num */
+    inner[0] = content;                                           /* type */
+    inner[ENUM_LEN] = ssl->version.major;
+    inner[ENUM_LEN + ENUM_LEN] = ssl->version.minor;              /* version */
+    XMEMCPY(&inner[ENUM_LEN + VERSION_SZ], length, LENGTH_SZ);     /* length */
+    HmacUpdate(&hmac, inner, sizeof(inner));
+    HmacUpdate(&hmac, buffer, sz);                                /* content */
+    HmacFinal(&hmac, digest);
+}
+
+
+#ifndef NO_CYASSL_CLIENT
+
+    SSL_METHOD* TLSv1_client_method(void)
+    {
+        SSL_METHOD* method = (SSL_METHOD*) XMALLOC(sizeof(SSL_METHOD), 0,
+                                                   DYNAMIC_TYPE_METHOD);
+        if (method)
+            InitSSL_Method(method, MakeTLSv1());
+        return method;
+    }
+
+
+    SSL_METHOD* TLSv1_1_client_method(void)
+    {
+        SSL_METHOD* method = (SSL_METHOD*) XMALLOC(sizeof(SSL_METHOD), 0,
+                                                   DYNAMIC_TYPE_METHOD);
+        if (method)
+            InitSSL_Method(method, MakeTLSv1_1());
+        return method;
+    }
+
+
+    SSL_METHOD* TLSv1_2_client_method(void)
+    {
+        SSL_METHOD* method = (SSL_METHOD*) XMALLOC(sizeof(SSL_METHOD), 0,
+                                                   DYNAMIC_TYPE_METHOD);
+        if (method)
+            InitSSL_Method(method, MakeTLSv1_2());
+        return method;
+    }
+
+
+    /* TODO: add downgrade */
+    SSL_METHOD* SSLv23_client_method(void)
+    {
+        SSL_METHOD* method = (SSL_METHOD*) XMALLOC(sizeof(SSL_METHOD), 0,
+                                                   DYNAMIC_TYPE_METHOD);
+        if (method)
+            InitSSL_Method(method, MakeTLSv1());
+        return method;
+    }
+
+
+#endif /* NO_CYASSL_CLIENT */
+
+
+
+#ifndef NO_CYASSL_SERVER
+
+    SSL_METHOD* TLSv1_server_method(void)
+    {
+        SSL_METHOD* method = (SSL_METHOD*) XMALLOC(sizeof(SSL_METHOD), 0, 
+                                                   DYNAMIC_TYPE_METHOD);
+        if (method) {
+            InitSSL_Method(method, MakeTLSv1());
+            method->side = SERVER_END;
+        }
+        return method;
+    }
+
+
+    SSL_METHOD* TLSv1_1_server_method(void)
+    {
+        SSL_METHOD* method = (SSL_METHOD*) XMALLOC(sizeof(SSL_METHOD), 0,
+                                                   DYNAMIC_TYPE_METHOD);
+        if (method) {
+            InitSSL_Method(method, MakeTLSv1_1());
+            method->side = SERVER_END;
+        }
+        return method;
+    }
+
+
+    SSL_METHOD* TLSv1_2_server_method(void)
+    {
+        SSL_METHOD* method = (SSL_METHOD*) XMALLOC(sizeof(SSL_METHOD), 0,
+                                                   DYNAMIC_TYPE_METHOD);
+        if (method) {
+            InitSSL_Method(method, MakeTLSv1_2());
+            method->side = SERVER_END;
+        }
+        return method;
+    }
+
+
+    SSL_METHOD *SSLv23_server_method(void)
+    {
+        SSL_METHOD* method = (SSL_METHOD*) XMALLOC(sizeof(SSL_METHOD), 0,
+                                                   DYNAMIC_TYPE_METHOD);
+        if (method) {
+            InitSSL_Method(method, MakeTLSv1());
+            method->side      = SERVER_END;
+            method->downgrade = 1;
+        }
+        return method;
+    }
+
+
+
+#endif /* NO_CYASSL_SERVER */
+
+#else /* NO_TLS */
+
+/* catch CyaSSL programming errors */
+void BuildTlsFinished(SSL* ssl, Hashes* hashes, const byte* sender)
+{
+   
+}
+
+
+int DeriveTlsKeys(SSL* ssl)
+{
+    return -1;
+}
+
+
+int MakeTlsMasterSecret(SSL* ssl)
+{ 
+    return -1;
+}
+
+#endif /* NO_TLS */
+