X-Git-Url: http://git.silcnet.org/gitweb/?p=crypto.git;a=blobdiff_plain;f=lib%2Fsilccrypt%2Fsilcmac.c;fp=lib%2Fsilccrypt%2Fsilcmac.c;h=6a2a8b4b4358355bab1c278d95107576846c397c;hp=0000000000000000000000000000000000000000;hb=8cbd4e2524c7e45c506bd00779d05f6608a81f66;hpb=57af98efbd82c4c89c81850f42b02585fed1a16a

diff --git a/lib/silccrypt/silcmac.c b/lib/silccrypt/silcmac.c
new file mode 100644
index 00000000..6a2a8b4b
--- /dev/null
+++ b/lib/silccrypt/silcmac.c
@@ -0,0 +1,484 @@
+/*
+
+  silcmac.c
+
+  Author: Pekka Riikonen <priikone@silcnet.org>
+
+  Copyright (C) 1999 - 2008 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; 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.
+
+*/
+
+#include "silccrypto.h"
+
+/* MAC context */
+struct SilcMacStruct {
+  SilcMacObject *mac;
+  SilcHash hash;
+  unsigned char inner_pad[64];
+  unsigned char outer_pad[64];
+  unsigned char *key;
+  unsigned int key_len        : 31;
+  unsigned int allocated_hash : 1;   /* TRUE if the hash was allocated */
+};
+
+#ifndef SILC_SYMBIAN
+/* List of dynamically registered MACs. */
+SilcDList silc_mac_list = NULL;
+#endif /* SILC_SYMBIAN */
+
+/* Default macs for silc_mac_register_default(). */
+const SilcMacObject silc_default_macs[] =
+{
+  { "hmac-sha256-96", 12 },
+  { "hmac-sha512-96", 12 },
+  { "hmac-sha1-96", 12 },
+  { "hmac-md5-96", 12 },
+  { "hmac-sha256", 32 },
+  { "hmac-sha512", 64 },
+  { "hmac-sha1", 20 },
+  { "hmac-md5", 16 },
+
+  { NULL, 0 }
+};
+
+static void silc_mac_init_internal(SilcMac mac, unsigned char *key,
+				    SilcUInt32 key_len)
+{
+  SilcHash hash = mac->hash;
+  SilcUInt32 block_len;
+  unsigned char hvalue[SILC_HASH_MAXLEN];
+  int i;
+
+  memset(mac->inner_pad, 0, sizeof(mac->inner_pad));
+  memset(mac->outer_pad, 0, sizeof(mac->outer_pad));
+
+  block_len = silc_hash_block_len(hash);
+
+  /* If the key length is more than block size of the hash function, the
+     key is hashed. */
+  if (key_len > block_len) {
+    silc_hash_make(hash, key, key_len, hvalue);
+    key = hvalue;
+    key_len = silc_hash_len(hash);
+  }
+
+  /* Copy the key into the pads */
+  memcpy(mac->inner_pad, key, key_len);
+  memcpy(mac->outer_pad, key, key_len);
+
+  /* XOR the key with pads */
+  for (i = 0; i < block_len; i++) {
+    mac->inner_pad[i] ^= 0x36;
+    mac->outer_pad[i] ^= 0x5c;
+  }
+}
+
+/* Registers a new MAC */
+
+SilcBool silc_mac_register(const SilcMacObject *mac)
+{
+#ifndef SILC_SYMBIAN
+  SilcMacObject *new;
+
+  SILC_LOG_DEBUG(("Registering new MAC `%s'", mac->name));
+
+  /* Check for existing */
+  if (silc_mac_list) {
+    SilcMacObject *entry;
+    silc_dlist_start(silc_mac_list);
+    while ((entry = silc_dlist_get(silc_mac_list)) != SILC_LIST_END) {
+      if (!strcmp(entry->name, mac->name))
+	return FALSE;
+    }
+  }
+
+  new = silc_calloc(1, sizeof(*new));
+  if (!new)
+    return FALSE;
+  new->name = strdup(mac->name);
+  new->len = mac->len;
+
+  /* Add to list */
+  if (silc_mac_list == NULL)
+    silc_mac_list = silc_dlist_init();
+  silc_dlist_add(silc_mac_list, new);
+
+#endif /* SILC_SYMBIAN */
+  return TRUE;
+}
+
+/* Unregister a MAC */
+
+SilcBool silc_mac_unregister(SilcMacObject *mac)
+{
+#ifndef SILC_SYMBIAN
+  SilcMacObject *entry;
+
+  SILC_LOG_DEBUG(("Unregistering MAC"));
+
+  if (!silc_mac_list)
+    return FALSE;
+
+  silc_dlist_start(silc_mac_list);
+  while ((entry = silc_dlist_get(silc_mac_list)) != SILC_LIST_END) {
+    if (mac == SILC_ALL_MACS || entry == mac) {
+      silc_dlist_del(silc_mac_list, entry);
+      silc_free(entry->name);
+      silc_free(entry);
+
+      if (silc_dlist_count(silc_mac_list) == 0) {
+	silc_dlist_uninit(silc_mac_list);
+	silc_mac_list = NULL;
+      }
+
+      return TRUE;
+    }
+  }
+
+#endif /* SILC_SYMBIAN */
+  return FALSE;
+}
+
+/* Register default MACs */
+
+SilcBool silc_mac_register_default(void)
+{
+  /* We use builtin MACs */
+  return TRUE;
+}
+
+/* Unregister all MACs */
+
+SilcBool silc_mac_unregister_all(void)
+{
+#ifndef SILC_SYMBIAN
+  SilcMacObject *entry;
+
+  if (!silc_mac_list)
+    return FALSE;
+
+  silc_dlist_start(silc_mac_list);
+  while ((entry = silc_dlist_get(silc_mac_list)) != SILC_LIST_END) {
+    silc_mac_unregister(entry);
+    if (!silc_mac_list)
+      break;
+  }
+#endif /* SILC_SYMBIAN */
+  return TRUE;
+}
+
+/* Allocates a new SilcMac object of name of `name'.  The `hash' may
+   be provided as argument.  If provided it is used as the hash function
+   of the MAC.  If it is NULL then the hash function is allocated and
+   the name of the hash algorithm is derived from the `name'. */
+
+SilcBool silc_mac_alloc(const char *name, SilcMac *new_mac)
+{
+  SilcMacObject *entry = NULL;
+  SilcHash hash = NULL;
+  int i;
+
+  SILC_LOG_DEBUG(("Allocating new MAC"));
+
+  /* Allocate the new object */
+  *new_mac = silc_calloc(1, sizeof(**new_mac));
+  if (!(*new_mac))
+    return FALSE;
+
+  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_mac);
+      *new_mac = NULL;
+      return FALSE;
+    }
+
+    (*new_mac)->allocated_hash = TRUE;
+    silc_free(tmp);
+  }
+
+  (*new_mac)->hash = hash;
+
+#ifndef SILC_SYMBIAN
+  /* Check registered list of MACs */
+  if (silc_mac_list) {
+    silc_dlist_start(silc_mac_list);
+    while ((entry = silc_dlist_get(silc_mac_list)) != SILC_LIST_END) {
+      if (!strcmp(entry->name, name)) {
+	(*new_mac)->mac = entry;
+	return TRUE;
+      }
+    }
+  }
+#endif /* SILC_SYMBIAN */
+
+  if (!entry) {
+    /* Check builtin list of MACs */
+    for (i = 0; silc_default_macs[i].name; i++) {
+      if (!strcmp(silc_default_macs[i].name, name)) {
+	(*new_mac)->mac = (SilcMacObject *)&(silc_default_macs[i]);
+	return TRUE;
+      }
+    }
+  }
+
+  silc_free(*new_mac);
+  *new_mac = NULL;
+  return FALSE;
+}
+
+/* Free's the SilcMac object. */
+
+void silc_mac_free(SilcMac mac)
+{
+  if (mac) {
+    if (mac->allocated_hash)
+      silc_hash_free(mac->hash);
+
+    if (mac->key) {
+      memset(mac->key, 0, mac->key_len);
+      silc_free(mac->key);
+    }
+
+    silc_free(mac);
+  }
+}
+
+/* Returns the length of the MAC that the MAC will produce. */
+
+SilcUInt32 silc_mac_len(SilcMac mac)
+{
+  return mac->mac->len;
+}
+
+/* Get hash context */
+
+SilcHash silc_mac_get_hash(SilcMac mac)
+{
+  return mac->hash;
+}
+
+/* Return name of mac */
+
+const char *silc_mac_get_name(SilcMac mac)
+{
+  return mac->mac->name;
+}
+
+/* Returns TRUE if MAC `name' is supported. */
+
+SilcBool silc_mac_is_supported(const char *name)
+{
+  SilcMacObject *entry;
+  int i;
+
+  if (!name)
+    return FALSE;
+
+#ifndef SILC_SYMBIAN
+  if (silc_mac_list) {
+    silc_dlist_start(silc_mac_list);
+    while ((entry = silc_dlist_get(silc_mac_list)) != SILC_LIST_END) {
+      if (!strcmp(entry->name, name))
+	return TRUE;
+    }
+  }
+#endif /* SILC_SYMBIAN */
+
+  for (i = 0; silc_default_macs[i].name; i++)
+    if (!strcmp(silc_default_macs[i].name, name))
+      return TRUE;
+
+  return FALSE;
+}
+
+/* Returns comma separated list of supported MACs. */
+
+char *silc_mac_get_supported()
+{
+  SilcMacObject *entry, *entry2;
+  char *list = NULL;
+  int len = 0, i;
+
+#ifndef SILC_SYMBIAN
+  if (silc_mac_list) {
+    silc_dlist_start(silc_mac_list);
+    while ((entry = silc_dlist_get(silc_mac_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++;
+    }
+  }
+#endif /* SILC_SYMBIAN */
+
+
+  for (i = 0; silc_default_macs[i].name; i++) {
+    entry = (SilcMacObject *)&(silc_default_macs[i]);
+
+    if (silc_mac_list) {
+      silc_dlist_start(silc_mac_list);
+      while ((entry2 = silc_dlist_get(silc_mac_list)) != SILC_LIST_END) {
+	if (!strcmp(entry2->name, entry->name))
+	  break;
+      }
+      if (entry2)
+	continue;
+    }
+
+    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;
+
+  return list;
+}
+
+/* Sets the MAC key used in the MAC creation */
+
+void silc_mac_set_key(SilcMac mac, const unsigned char *key,
+		       SilcUInt32 key_len)
+{
+  if (mac->key) {
+    memset(mac->key, 0, mac->key_len);
+    silc_free(mac->key);
+  }
+  mac->key = silc_malloc(key_len);
+  if (!mac->key)
+    return;
+  mac->key_len = key_len;
+  memcpy(mac->key, key, key_len);
+}
+
+/* Return MAC key */
+
+const unsigned char *silc_mac_get_key(SilcMac mac, SilcUInt32 *key_len)
+{
+  if (key_len)
+    *key_len = mac->key_len;
+  return (const unsigned char *)mac->key;
+}
+
+/* Create the MAC. This is thee make_mac function pointer.  This
+   uses the internal key set with silc_mac_set_key. */
+
+void silc_mac_make(SilcMac mac, unsigned char *data,
+		    SilcUInt32 data_len, unsigned char *return_hash,
+		    SilcUInt32 *return_len)
+{
+  SILC_LOG_DEBUG(("Making MAC for message"));
+
+  silc_mac_init(mac);
+  silc_mac_update(mac, data, data_len);
+  silc_mac_final(mac, return_hash, return_len);
+}
+
+/* Creates MAC just as above except that this doesn't use the internal
+   key. The key is sent as argument to the function. */
+
+void silc_mac_make_with_key(SilcMac mac, unsigned char *data,
+			     SilcUInt32 data_len,
+			     unsigned char *key, SilcUInt32 key_len,
+			     unsigned char *return_hash,
+			     SilcUInt32 *return_len)
+{
+  SILC_LOG_DEBUG(("Making MAC for message"));
+
+  silc_mac_init_with_key(mac, key, key_len);
+  silc_mac_update(mac, data, data_len);
+  silc_mac_final(mac, return_hash, return_len);
+}
+
+/* Creates the MAC just as above except that the hash value is truncated
+   to the truncated_len sent as argument. NOTE: One should not truncate to
+   less than half of the length of original hash value. However, this
+   routine allows these dangerous truncations. */
+
+void silc_mac_make_truncated(SilcMac mac, unsigned char *data,
+			      SilcUInt32 data_len,
+			      SilcUInt32 truncated_len,
+			      unsigned char *return_hash)
+{
+  unsigned char hvalue[SILC_HASH_MAXLEN];
+
+  SILC_LOG_DEBUG(("Making MAC for message"));
+
+  silc_mac_init(mac);
+  silc_mac_update(mac, data, data_len);
+  silc_mac_final(mac, return_hash, NULL);
+  memcpy(return_hash, hvalue, truncated_len);
+  memset(hvalue, 0, sizeof(hvalue));
+}
+
+/* Init MAC for silc_mac_update and silc_mac_final. */
+
+void silc_mac_init(SilcMac mac)
+{
+  silc_mac_init_with_key(mac, mac->key, mac->key_len);
+}
+
+/* Same as above but with specific key */
+
+void silc_mac_init_with_key(SilcMac mac, const unsigned char *key,
+			     SilcUInt32 key_len)
+{
+  SilcHash hash = mac->hash;
+  silc_mac_init_internal(mac, (unsigned char *)key, key_len);
+  silc_hash_init(hash);
+  silc_hash_update(hash, mac->inner_pad, silc_hash_block_len(hash));
+}
+
+/* Add data to be used in the MAC computation. */
+
+void silc_mac_update(SilcMac mac, const unsigned char *data,
+		      SilcUInt32 data_len)
+{
+  SilcHash hash = mac->hash;
+  silc_hash_update(hash, data, data_len);
+}
+
+/* Compute the final MAC. */
+
+void silc_mac_final(SilcMac mac, unsigned char *return_hash,
+		    SilcUInt32 *return_len)
+{
+  SilcHash hash = mac->hash;
+  unsigned char digest[SILC_HASH_MAXLEN];
+
+  silc_hash_final(hash, digest);
+  silc_hash_init(hash);
+  silc_hash_update(hash, mac->outer_pad, silc_hash_block_len(hash));
+  silc_hash_update(hash, digest, silc_hash_len(hash));
+  silc_hash_final(hash, digest);
+  memcpy(return_hash, digest, mac->mac->len);
+  memset(digest, 0, sizeof(digest));
+
+  if (return_len)
+    *return_len = mac->mac->len;
+}