X-Git-Url: http://git.silcnet.org/gitweb/?a=blobdiff_plain;f=lib%2Fsilccrypt%2Fsilchmac.c;h=babadd05788bb6a4aac42eced701b0a0d147fb18;hb=a818c5b5411bbc4436d1c5f011236985c96bb787;hp=8554ddbddef92b5ca14233ec3664f9ea1eb8fd61;hpb=a24dcffe20a3f0059fb58619b57b488d2bfae5ad;p=silc.git

diff --git a/lib/silccrypt/silchmac.c b/lib/silccrypt/silchmac.c
index 8554ddbd..babadd05 100644
--- a/lib/silccrypt/silchmac.c
+++ b/lib/silccrypt/silchmac.c
@@ -1,120 +1,333 @@
 /*
 
-  silchmac.c
+  silchmac.c 
 
-  Author: Pekka Riikonen <priikone@poseidon.pspt.fi>
+  Author: Pekka Riikonen <priikone@silcnet.org>
 
-  Copyright (C) 1997 - 2000 Pekka Riikonen
+  Copyright (C) 1999 - 2001 Pekka Riikonen
 
   This program 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.
-  
+  the Free Software Foundation; version 2 of the License.
+
   This program 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.
 
 */
-/*
- * $Id$
- * $Log$
- * Revision 1.2  2000/07/05 06:08:43  priikone
- * 	Global cosmetic change.
- *
- * Revision 1.1.1.1  2000/06/27 11:36:55  priikone
- * 	Imported from internal CVS/Added Log headers.
- *
- *
- */
+/* $Id$ */
 
 #include "silcincludes.h"
 
-/* Allocates a new SilcHmac object. First argument is the hash function
-   object to tell the hmac which hash function should be used when creating
-   HMAC's. The new SilcHmac object is returned to new_hmac argument. */
+/* HMAC context */
+struct SilcHmacStruct {
+  SilcHmacObject *hmac;
+  SilcHash hash;
+  bool allocated_hash;		/* TRUE if the hash was allocated */
+
+  unsigned char *key;
+  SilcUInt32 key_len;
+
+  unsigned char inner_pad[64];
+  unsigned char outer_pad[64];
+  void *hash_context;
+};
+
+/* List of dynamically registered HMACs. */
+SilcDList silc_hmac_list = NULL;
+
+/* Default hmacs for silc_hmac_register_default(). */
+SilcHmacObject silc_default_hmacs[] =
+{
+  { "hmac-sha1-96", 12 },
+  { "hmac-md5-96", 12 },
+  { "hmac-sha1", 20 },
+  { "hmac-md5", 16 },
+
+  { NULL, 0 }
+};
+
+static void silc_hmac_init_internal(SilcHmac hmac, unsigned char *key,
+				    SilcUInt32 key_len)
+{
+  SilcHash hash = hmac->hash;
+  unsigned char hvalue[20];
+  int i;
+
+  memset(hmac->inner_pad, 0, sizeof(hmac->inner_pad));
+  memset(hmac->outer_pad, 0, sizeof(hmac->outer_pad));
+
+  /* If the key length is more than block size of the hash function, the
+     key is hashed. */
+  if (key_len > hash->hash->block_len) {
+    silc_hash_make(hash, key, key_len, hvalue);
+    key = hvalue;
+    key_len = hash->hash->hash_len;
+  }
+
+  /* Copy the key into the pads */
+  memcpy(hmac->inner_pad, key, key_len);
+  memcpy(hmac->outer_pad, key, key_len);
+
+  /* XOR the key with pads */
+  for (i = 0; i < hash->hash->block_len; i++) {
+    hmac->inner_pad[i] ^= 0x36;
+    hmac->outer_pad[i] ^= 0x5c;
+  }
+}
+
+/* Registers a new HMAC into the SILC. This function is used at the
+   initialization of the SILC. */
 
-int silc_hmac_alloc(SilcHash hash, SilcHmac *new_hmac)
+bool silc_hmac_register(SilcHmacObject *hmac)
 {
-  SILC_LOG_DEBUG(("Allocating new hmac object"));
+  SilcHmacObject *new;
 
+  SILC_LOG_DEBUG(("Registering new HMAC `%s'", hmac->name));
+
+  /* Check for existing */
+  if (silc_hmac_list) {
+    SilcHmacObject *entry;
+    silc_dlist_start(silc_hmac_list);
+    while ((entry = silc_dlist_get(silc_hmac_list)) != SILC_LIST_END) {
+      if (!strcmp(entry->name, hmac->name))
+	return FALSE;
+    }
+  }
+
+  new = silc_calloc(1, sizeof(*new));
+  new->name = strdup(hmac->name);
+  new->len = hmac->len;
+
+  /* Add to list */
+  if (silc_hmac_list == NULL)
+    silc_hmac_list = silc_dlist_init();
+  silc_dlist_add(silc_hmac_list, new);
+
+  return TRUE;
+}
+
+/* Unregister a HMAC from the SILC. */
+
+bool silc_hmac_unregister(SilcHmacObject *hmac)
+{
+  SilcHmacObject *entry;
+
+  SILC_LOG_DEBUG(("Unregistering HMAC"));
+
+  if (!silc_hmac_list)
+    return FALSE;
+
+  silc_dlist_start(silc_hmac_list);
+  while ((entry = silc_dlist_get(silc_hmac_list)) != SILC_LIST_END) {
+    if (hmac == SILC_ALL_HMACS || entry == hmac) {
+      silc_dlist_del(silc_hmac_list, entry);
+
+      if (silc_dlist_count(silc_hmac_list) == 0) {
+	silc_dlist_uninit(silc_hmac_list);
+	silc_hmac_list = NULL;
+      }
+
+      return TRUE;
+    }
+  }
+
+  return FALSE;
+}
+
+/* Function that registers all the default hmacs (all builtin ones). 
+   The application may use this to register the default hmacs if
+   specific hmacs in any specific order is not wanted. */
+
+bool silc_hmac_register_default(void)
+{
+  int i;
+
+  for (i = 0; silc_default_hmacs[i].name; i++)
+    silc_hmac_register(&(silc_default_hmacs[i]));
+
+  return TRUE;
+}
+
+/* Allocates a new SilcHmac object of name of `name'.  The `hash' may
+   be provided as argument.  If provided it is used as the hash function
+   of the HMAC.  If it is NULL then the hash function is allocated and
+   the name of the hash algorithm is derived from the `name'. */
+
+bool silc_hmac_alloc(char *name, SilcHash hash, SilcHmac *new_hmac)
+{
+  SilcHmacObject *entry;
+
+  SILC_LOG_DEBUG(("Allocating new HMAC"));
+
+  /* Allocate the new object */
   *new_hmac = silc_calloc(1, sizeof(**new_hmac));
+
+  if (!hash) {
+    char *tmp = strdup(name), *hname;
+
+    hname = tmp;
+    if (strchr(hname, '-'))
+      hname = strchr(hname, '-') + 1;
+    if (strchr(hname, '-'))
+      *strchr(hname, '-') = '\0';
+
+    if (!silc_hash_alloc(hname, &hash)) {
+      silc_free(tmp);
+      silc_free(*new_hmac);
+      *new_hmac = NULL;
+      return FALSE;
+    }
+
+    (*new_hmac)->allocated_hash = TRUE;
+    silc_free(tmp);
+  }
+
   (*new_hmac)->hash = hash;
-  (*new_hmac)->set_key = silc_hmac_set_key;
-  (*new_hmac)->make_hmac = silc_hmac_make;
-  (*new_hmac)->make_hmac_with_key = silc_hmac_make_with_key;
-  (*new_hmac)->make_hmac_truncated = silc_hmac_make_truncated;
 
-  return 1;
+  if (silc_hmac_list) {
+    silc_dlist_start(silc_hmac_list);
+    while ((entry = silc_dlist_get(silc_hmac_list)) != SILC_LIST_END) {
+      if (!strcmp(entry->name, name)) {
+	(*new_hmac)->hmac = entry; 
+	return TRUE;
+      }
+    }
+  }
+
+  silc_free(*new_hmac);
+  *new_hmac = NULL;
+  return FALSE;
 }
 
 /* Free's the SilcHmac object. */
 
 void silc_hmac_free(SilcHmac hmac)
 {
-  if (hmac)
+  if (hmac) {
+    if (hmac->allocated_hash)
+      silc_hash_free(hmac->hash);
+
+    if (hmac->key) {
+      memset(hmac->key, 0, hmac->key_len);
+      silc_free(hmac->key);
+    }
+
+    silc_free(hmac->hash_context);
     silc_free(hmac);
+  }
 }
 
-/* Creates the HMAC. The created keyed hash value is returned to 
-   return_hash argument. */
+/* Returns the length of the MAC that the HMAC will produce. */
 
-void silc_hmac_make_internal(SilcHmac hmac, unsigned char *data,
-			     unsigned int data_len, unsigned char *key,
-			     unsigned int key_len, unsigned char *return_hash)
+SilcUInt32 silc_hmac_len(SilcHmac hmac)
 {
-  SilcHash hash = hmac->hash;
-  unsigned char inner_pad[hash->hash->block_len + 1];
-  unsigned char outer_pad[hash->hash->block_len + 1];
-  unsigned char hvalue[hash->hash->hash_len];
-  void *hash_context;
-  int i;
+  return hmac->hmac->len;
+}
 
-  SILC_LOG_DEBUG(("Making HMAC for message"));
+/* Get hash context */
 
-  hash_context = silc_calloc(1, hash->hash->context_len());
+SilcHash silc_hmac_get_hash(SilcHmac hmac)
+{
+  return hmac->hash;
+}
 
-  memset(inner_pad, 0, sizeof(inner_pad));
-  memset(outer_pad, 0, sizeof(outer_pad));
+/* Return name of hmac */
 
-  /* If the key length is more than block size of the hash function, the
-     key is hashed. */
-  if (key_len > hash->hash->block_len) {
-    hash->make_hash(hash, key, key_len, hvalue);
-    key = hvalue;
-    key_len = hash->hash->hash_len;
+const char *silc_hmac_get_name(SilcHmac hmac)
+{
+  return hmac->hmac->name;
+}
+
+/* Returns TRUE if HMAC `name' is supported. */
+
+bool silc_hmac_is_supported(const char *name)
+{
+  SilcHmacObject *entry;
+
+  if (!name)
+    return FALSE;
+  
+  if (silc_hmac_list) {
+    silc_dlist_start(silc_hmac_list);
+    while ((entry = silc_dlist_get(silc_hmac_list)) != SILC_LIST_END) {
+      if (!strcmp(entry->name, name))
+	return TRUE;
+    }
   }
 
-  /* Copy the key into the pads */
-  memcpy(inner_pad, key, key_len);
-  memcpy(outer_pad, key, key_len);
+  return FALSE;
+}
 
-  /* XOR the key with pads */
-  for (i = 0; i < hash->hash->block_len; i++) {
-    inner_pad[i] ^= 0x36;
-    outer_pad[i] ^= 0x5c;
+/* Returns comma separated list of supported HMACs. */
+
+char *silc_hmac_get_supported()
+{
+  SilcHmacObject *entry;
+  char *list = NULL;
+  int len;
+
+  len = 0;
+  if (silc_hmac_list) {
+    silc_dlist_start(silc_hmac_list);
+    while ((entry = silc_dlist_get(silc_hmac_list)) != SILC_LIST_END) {
+      len += strlen(entry->name);
+      list = silc_realloc(list, len + 1);
+      
+      memcpy(list + (len - strlen(entry->name)), 
+	     entry->name, strlen(entry->name));
+      memcpy(list + len, ",", 1);
+      len++;
+    }
+    list[len - 1] = 0;
   }
 
-  /* Do the HMAC transform (too bad I can't do make_hash directly, sigh) */
-  hash->hash->init(hash_context);
-  hash->hash->update(hash_context, inner_pad, hash->hash->block_len);
-  hash->hash->update(hash_context, data, data_len);
-  hash->hash->final(hash_context, return_hash);
-  hash->hash->init(hash_context);
-  hash->hash->update(hash_context, outer_pad, hash->hash->block_len);
-  hash->hash->update(hash_context, return_hash, hash->hash->hash_len);
-  hash->hash->final(hash_context, return_hash);
+  return list;
+}
+
+/* Sets the HMAC key used in the HMAC creation */
+
+void silc_hmac_set_key(SilcHmac hmac, const unsigned char *key,
+		       SilcUInt32 key_len)
+{
+  if (hmac->key) {
+    memset(hmac->key, 0, hmac->key_len);
+    silc_free(hmac->key);
+  }
+  hmac->key = silc_calloc(key_len, sizeof(unsigned char));
+  hmac->key_len = key_len;
+  memcpy(hmac->key, key, key_len);
 }
 
 /* Create the HMAC. This is thee make_hmac function pointer.  This
    uses the internal key set with silc_hmac_set_key. */
 
 void silc_hmac_make(SilcHmac hmac, unsigned char *data,
-		    unsigned int data_len, unsigned char *return_hash)
+		    SilcUInt32 data_len, unsigned char *return_hash,
+		    SilcUInt32 *return_len)
+{
+  SILC_LOG_DEBUG(("Making HMAC for message"));
+
+  silc_hmac_init(hmac);
+  silc_hmac_update(hmac, data, data_len);
+  silc_hmac_final(hmac, return_hash, return_len);
+}
+
+/* Creates HMAC just as above except that this doesn't use the internal
+   key. The key is sent as argument to the function. */
+
+void silc_hmac_make_with_key(SilcHmac hmac, unsigned char *data,
+			     SilcUInt32 data_len, 
+			     unsigned char *key, SilcUInt32 key_len,
+			     unsigned char *return_hash,
+			     SilcUInt32 *return_len)
 {
-  silc_hmac_make_internal(hmac, data, data_len, hmac->key, 
-			  hmac->key_len, return_hash);
+  SILC_LOG_DEBUG(("Making HMAC for message"));
+
+  silc_hmac_init_with_key(hmac, key, key_len);
+  silc_hmac_update(hmac, data, data_len);
+  silc_hmac_final(hmac, return_hash, return_len);
 }
 
 /* Creates the HMAC just as above except that the hash value is truncated
@@ -123,34 +336,71 @@ void silc_hmac_make(SilcHmac hmac, unsigned char *data,
    routine allows these dangerous truncations. */
 
 void silc_hmac_make_truncated(SilcHmac hmac, unsigned char *data,
-			      unsigned int data_len,
-			      unsigned int truncated_len,
+			      SilcUInt32 data_len,
+			      SilcUInt32 truncated_len,
 			      unsigned char *return_hash)
 {
-  unsigned char hvalue[hmac->hash->hash->hash_len];
+  unsigned char hvalue[20];
+
+  SILC_LOG_DEBUG(("Making HMAC for message"));
 
-  silc_hmac_make_internal(hmac, data, data_len, 
-			  hmac->key, hmac->key_len, hvalue);
+  silc_hmac_init(hmac);
+  silc_hmac_update(hmac, data, data_len);
+  silc_hmac_final(hmac, return_hash, NULL);
   memcpy(return_hash, hvalue, truncated_len);
   memset(hvalue, 0, sizeof(hvalue));
 }
 
-/* Creates HMAC just as above except that this doesn't use the internal
-   key. The key is sent as argument to the function. */
+/* Init HMAC for silc_hmac_update and silc_hmac_final. */
 
-void silc_hmac_make_with_key(SilcHmac hmac, unsigned char *data,
-			     unsigned int data_len, 
-			     unsigned char *key, unsigned int key_len,
-			     unsigned char *return_hash)
+void silc_hmac_init(SilcHmac hmac)
 {
-  silc_hmac_make_internal(hmac, data, data_len, key, key_len, return_hash);
+  silc_hmac_init_with_key(hmac, hmac->key, hmac->key_len);
 }
 
-/* Sets the HMAC key used in the HMAC creation */
+/* Same as above but with specific key */
 
-void silc_hmac_set_key(SilcHmac hmac, const unsigned char *key,
-		       unsigned int key_len)
+void silc_hmac_init_with_key(SilcHmac hmac, const unsigned char *key,
+			     SilcUInt32 key_len)
 {
-  hmac->key = silc_calloc(key_len, sizeof(unsigned char));
-  memcpy(hmac->key, key, key_len);
+  SilcHash hash = hmac->hash;
+
+  silc_hmac_init_internal(hmac, hmac->key, hmac->key_len);
+
+  if (!hmac->hash_context)
+    hmac->hash_context = silc_calloc(1, hash->hash->context_len());
+
+  hash->hash->init(hmac->hash_context);
+  hash->hash->update(hmac->hash_context, hmac->inner_pad, 
+		     hash->hash->block_len);
+}
+
+/* Add data to be used in the MAC computation. */
+
+void silc_hmac_update(SilcHmac hmac, const unsigned char *data,
+		      SilcUInt32 data_len)
+{
+  SilcHash hash = hmac->hash;
+  hash->hash->update(hmac->hash_context, (unsigned char *)data, data_len);
+}
+
+/* Compute the final MAC. */
+
+void silc_hmac_final(SilcHmac hmac, unsigned char *return_hash,
+		     SilcUInt32 *return_len)
+{
+  SilcHash hash = hmac->hash;
+  unsigned char mac[20];
+
+  hash->hash->final(hmac->hash_context, mac);
+  hash->hash->init(hmac->hash_context);
+  hash->hash->update(hmac->hash_context, hmac->outer_pad, 
+		     hash->hash->block_len);
+  hash->hash->update(hmac->hash_context, mac, hash->hash->hash_len);
+  hash->hash->final(hmac->hash_context, mac);
+  memcpy(return_hash, mac, hmac->hmac->len);
+  memset(mac, 0, sizeof(mac));
+
+  if (return_len)
+    *return_len = hmac->hmac->len;
 }