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[apple/security.git] / Security / libsecurity_ssl / lib / tls_hmac.c
diff --git a/Security/libsecurity_ssl/lib/tls_hmac.c b/Security/libsecurity_ssl/lib/tls_hmac.c
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+/*
+ * Copyright (c) 2002,2005-2008,2010-2012,2014 Apple Inc. All Rights Reserved.
+ *
+ * @APPLE_LICENSE_HEADER_START@
+ * 
+ * This file contains Original Code and/or Modifications of Original Code
+ * as defined in and that are subject to the Apple Public Source License
+ * Version 2.0 (the 'License'). You may not use this file except in
+ * compliance with the License. Please obtain a copy of the License at
+ * http://www.opensource.apple.com/apsl/ and read it before using this
+ * file.
+ * 
+ * The 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.
+ * 
+ * @APPLE_LICENSE_HEADER_END@
+ */
+
+/*
+ * tls_hmac.c - HMAC routines used by TLS
+ */
+
+/* THIS FILE CONTAINS KERNEL CODE */
+
+#include "tls_hmac.h"
+#include "tls_digest.h"
+#include "sslMemory.h"
+#include "sslDebug.h"
+#include <string.h>
+#include <AssertMacros.h>
+
+
+/* Per-session state, opaque to callers; all fields set at alloc time */
+struct HMACContext {
+       const HashReference         *digest;
+       SSLBuffer                                   outerHashCtx;
+       SSLBuffer                                   innerHashCtx;
+       SSLBuffer                                   currentHashCtx;
+};
+
+// MARK: -
+// MARK: Common HMAC routines
+
+/* Create an HMAC session */
+static int HMAC_Alloc(
+       const struct HMACReference      *hmac,
+       const void                                      *keyPtr,
+       size_t                      keyLen,
+       HMACContextRef                          *hmacCtx)                       // RETURNED
+{
+       const HashReference     *digest;
+       HMACContextRef href;
+       size_t ix;
+       uint8_t *context;
+       const uint8_t *key;
+    size_t digest_block_size;
+
+       switch(hmac->alg) {
+               case HA_SHA384:
+                       digest = &SSLHashSHA384;
+            digest_block_size = 128;
+                       break;
+               case HA_SHA256:
+                       digest = &SSLHashSHA256;
+            digest_block_size = 64;
+                       break;
+               case HA_SHA1:
+                       digest = &SSLHashSHA1;
+            digest_block_size = 64;
+                       break;
+               case HA_MD5:
+                       digest = &SSLHashMD5;
+            digest_block_size = 64;
+                       break;
+               default:
+                       check(0);
+                       return -1;
+       }
+
+       context = (uint8_t *)sslMalloc(sizeof(struct HMACContext) +
+                                   3 * digest->contextSize);
+       if(context == NULL) {
+        check(0);
+               return -1;
+    }
+       href = (HMACContextRef)context;
+    href->digest = digest;
+       href->outerHashCtx.data = context + sizeof(*href);
+       href->outerHashCtx.length = digest->contextSize;
+       href->innerHashCtx.data = href->outerHashCtx.data + digest->contextSize;
+       href->innerHashCtx.length = digest->contextSize;
+       href->currentHashCtx.data = href->innerHashCtx.data + digest->contextSize;
+       href->currentHashCtx.length = digest->contextSize;
+
+       digest->init(&href->outerHashCtx);
+       digest->init(&href->innerHashCtx);
+
+    uint8_t tmpkey[digest->digestSize];
+       uint8_t pad[digest_block_size];
+       SSLBuffer kpad = { digest_block_size, pad };
+
+       /* If the key is longer than digest_block_size, reset it to key=digest(key) */
+       if (keyLen <= digest_block_size) {
+       key = (const uint8_t *)keyPtr;
+    } else {
+        SSLBuffer keyBuffer = { keyLen, (uint8_t *)keyPtr };
+        SSLBuffer outBuffer = { digest->digestSize, tmpkey };
+       digest->update(&href->innerHashCtx, &keyBuffer);
+       digest->final(&href->innerHashCtx, &outBuffer);
+        key = outBuffer.data;
+        keyLen = outBuffer.length;
+        /* Re-initialize the inner context. */
+        digest->init(&href->innerHashCtx);
+       }
+
+       /* Copy the key into k_opad while doing the XOR. */
+       for (ix = 0; ix < keyLen; ++ix)
+               pad[ix] = key[ix] ^ 0x5c;
+       memset(pad + keyLen, 0x5c, digest_block_size - keyLen);
+       digest->update(&href->outerHashCtx, &kpad);
+
+       /* Copy the key into k_ipad while doing the XOR. */
+       for (ix = 0; ix < keyLen; ++ix)
+               pad[ix] = key[ix] ^ 0x36;
+       memset(pad + keyLen, 0x36, digest_block_size - keyLen);
+       digest->update(&href->innerHashCtx, &kpad);
+
+       /* Clear out the key bits in pad. */
+       bzero(pad, keyLen);
+
+       /* Now clone the inner digest so we are ready to receive an update. */
+       /* @@@ If init is always called before update we could skip this step. */
+       digest->clone(&href->innerHashCtx, &href->currentHashCtx);
+
+       /* success */
+       *hmacCtx = href;
+       return 0;
+}
+
+/* free a session */
+static int HMAC_Free(
+       HMACContextRef  hmacCtx)
+{
+       if(hmacCtx != NULL) {
+               hmacCtx->digest->close(&hmacCtx->outerHashCtx);
+               hmacCtx->digest->close(&hmacCtx->innerHashCtx);
+               hmacCtx->digest->close(&hmacCtx->currentHashCtx);
+
+               /* Clear out any key material left in the digest contexts. */
+               bzero(hmacCtx->outerHashCtx.data, hmacCtx->outerHashCtx.length);
+               bzero(hmacCtx->innerHashCtx.data, hmacCtx->innerHashCtx.length);
+               bzero(hmacCtx->currentHashCtx.data, hmacCtx->currentHashCtx.length);
+
+               sslFree(hmacCtx);
+       }
+       return 0;
+}
+
+/* Reusable init */
+static int HMAC_Init(
+       HMACContextRef  hmacCtx)
+{
+       if(hmacCtx == NULL) {
+        check(0);
+               return -1;
+    }
+
+       check(hmacCtx->digest != NULL);
+
+       hmacCtx->digest->close(&hmacCtx->currentHashCtx);
+       hmacCtx->digest->clone(&hmacCtx->innerHashCtx, &hmacCtx->currentHashCtx);
+
+       return 0;
+}
+
+/* normal crypt ops */
+static int HMAC_Update(
+       HMACContextRef  hmacCtx,
+       const void              *data,
+       size_t          dataLen)
+{
+       SSLBuffer       cdata = { dataLen, (uint8_t *)data };
+       if(hmacCtx == NULL) {
+        check(0);
+               return -1;
+    }
+
+       check(hmacCtx->digest != NULL);
+
+       hmacCtx->digest->update(&hmacCtx->currentHashCtx, &cdata);
+
+       return 0;
+}
+       
+static int HMAC_Final(
+       HMACContextRef  hmacCtx,
+       void                    *hmac,                  // mallocd by caller
+       size_t          *hmacLen)               // IN/OUT
+{
+       uint8_t                 bytes[TLS_HMAC_MAX_SIZE];
+       SSLBuffer       digest = { TLS_HMAC_MAX_SIZE, bytes };
+       SSLBuffer       cdata;
+
+       if(hmacCtx == NULL) {
+        check(0);
+               return -1;
+       }
+       if((hmac == NULL) || (hmacLen == NULL)) {
+        check(0);
+               return -1;
+       }
+       check(hmacCtx->digest != NULL);
+       check(*hmacLen >= hmacCtx->digest->digestSize);
+
+       cdata.length = *hmacLen;
+       cdata.data = (uint8_t *)hmac;
+
+       hmacCtx->digest->final(&hmacCtx->currentHashCtx, &digest);
+       hmacCtx->digest->clone(&hmacCtx->outerHashCtx, &hmacCtx->currentHashCtx);
+       hmacCtx->digest->update(&hmacCtx->currentHashCtx, &digest);
+       bzero(bytes, hmacCtx->digest->digestSize);
+       hmacCtx->digest->final(&hmacCtx->currentHashCtx, &cdata);
+       *hmacLen = hmacCtx->digest->digestSize;
+
+       return 0;
+}
+
+/* one-shot */
+static int HMAC_Hmac (
+       HMACContextRef  hmacCtx,
+       const void              *data,
+       size_t          dataLen,
+       void                    *hmac,                  // mallocd by caller
+       size_t          *hmacLen)               // IN/OUT
+{
+       int serr;
+       
+       if(hmacCtx == NULL) {
+        check(0);
+               return -1;
+       }
+       serr = HMAC_Init(hmacCtx);
+       if(serr) {
+               return serr;
+       }
+       serr = HMAC_Update(hmacCtx, data, dataLen);
+       if(serr) {
+               return serr;
+       }
+       return HMAC_Final(hmacCtx, hmac, hmacLen);
+}
+
+
+// MARK: -
+// MARK: Null HMAC
+
+static int HMAC_AllocNull(
+       const struct HMACReference      *hmac,
+       const void                                      *keyPtr,
+       size_t                      keyLen,
+       HMACContextRef                          *hmacCtx)                       // RETURNED
+{
+       *hmacCtx = NULL;
+       return 0;
+}
+
+static int HMAC_FreeNull(
+       HMACContextRef  hmacCtx)
+{
+       return 0;
+}
+
+static int HMAC_InitNull(
+       HMACContextRef  hmacCtx)
+       {
+       return 0;
+}
+
+static int HMAC_UpdateNull(
+       HMACContextRef  hmacCtx,
+       const void              *data,
+       size_t          dataLen)
+{
+       return 0;
+}
+
+static int HMAC_FinalNull(
+       HMACContextRef  hmacCtx,
+       void                    *hmac,                  // mallocd by caller
+       size_t          *hmacLen)               // IN/OUT
+{
+       return 0;
+}
+
+static int HMAC_HmacNull (
+       HMACContextRef  hmacCtx,
+       const void              *data,
+       size_t          dataLen,
+       void                    *hmac,                  // mallocd by caller
+       size_t          *hmacLen)
+{
+       return 0;
+}
+
+const HMACReference TlsHmacNull = {
+    0,
+    HA_Null,
+       HMAC_AllocNull,
+       HMAC_FreeNull,
+       HMAC_InitNull,
+       HMAC_UpdateNull,
+       HMAC_FinalNull,
+       HMAC_HmacNull
+};
+
+const HMACReference TlsHmacMD5 = {
+    16,
+    HA_MD5,
+       HMAC_Alloc,
+       HMAC_Free,
+       HMAC_Init,
+       HMAC_Update,
+       HMAC_Final,
+       HMAC_Hmac
+};
+
+const HMACReference TlsHmacSHA1 = {
+    20,
+    HA_SHA1,
+       HMAC_Alloc,
+       HMAC_Free,
+       HMAC_Init,
+       HMAC_Update,
+       HMAC_Final,
+       HMAC_Hmac
+};
+
+const HMACReference TlsHmacSHA256 = {
+    32,
+    HA_SHA256,
+       HMAC_Alloc,
+       HMAC_Free,
+       HMAC_Init,
+       HMAC_Update,
+       HMAC_Final,
+       HMAC_Hmac
+};
+
+const HMACReference TlsHmacSHA384 = {
+    48,
+    HA_SHA384,
+       HMAC_Alloc,
+       HMAC_Free,
+       HMAC_Init,
+       HMAC_Update,
+       HMAC_Final,
+       HMAC_Hmac
+};