--- /dev/null
+/*
+
+ 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;
+}
projects / crypto.git / blobdiff