Author: Pekka Riikonen <priikone@poseidon.pspt.fi>
- Copyright (C) 1997 - 2000 Pekka Riikonen
+ Copyright (C) 1997 - 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
GNU General Public License for more details.
*/
-/* Channel Payload and Channel Key Payload implementations. */
+/* Channel Payload, Channel Message Payload and Channel Key Payload
+ implementations. */
/* $Id$ */
#include "silcincludes.h"
******************************************************************************/
-/* Channel Payload structure. Contents of this structure is parsed
+/* Channel Message Payload structure. Contents of this structure is parsed
from SILC packets. */
struct SilcChannelPayloadStruct {
- unsigned short data_len;
- unsigned char *data;
- unsigned short iv_len;
- unsigned char *iv;
+ SilcUInt16 name_len;
+ unsigned char *channel_name;
+ SilcUInt16 id_len;
+ unsigned char *channel_id;
+ SilcUInt32 mode;
};
-/* Parses channel payload returning new channel payload structure */
+/* Parses channel payload returning new channel payload structure. */
-SilcChannelPayload silc_channel_payload_parse(SilcBuffer buffer)
+SilcChannelPayload silc_channel_payload_parse(const unsigned char *payload,
+ SilcUInt32 payload_len)
{
+ SilcBufferStruct buffer;
SilcChannelPayload new;
+ int ret;
SILC_LOG_DEBUG(("Parsing channel payload"));
+ silc_buffer_set(&buffer, (unsigned char *)payload, payload_len);
new = silc_calloc(1, sizeof(*new));
- /* Parse the Channel Payload. Ignore padding and IV, we don't need
- them. */
- silc_buffer_unformat(buffer,
- SILC_STR_UI16_NSTRING_ALLOC(&new->data, &new->data_len),
- SILC_STR_UI16_NSTRING_ALLOC(NULL, NULL),
- SILC_STR_END);
+ /* Parse the Channel Payload. Ignore the padding. */
+ ret = silc_buffer_unformat(&buffer,
+ SILC_STR_UI16_NSTRING_ALLOC(&new->channel_name,
+ &new->name_len),
+ SILC_STR_UI16_NSTRING_ALLOC(&new->channel_id,
+ &new->id_len),
+ SILC_STR_UI_INT(&new->mode),
+ SILC_STR_END);
+ if (ret == -1)
+ goto err;
- if (new->data_len < 1 || new->data_len > buffer->len) {
+ if ((new->name_len < 1 || new->name_len > buffer.len) ||
+ (new->id_len < 1 || new->id_len > buffer.len)) {
SILC_LOG_ERROR(("Incorrect channel payload in packet, packet dropped"));
goto err;
}
return new;
err:
- if (new->data)
- silc_free(new->data);
- if (new->iv)
- silc_free(new->iv);
- silc_free(new);
+ silc_channel_payload_free(new);
return NULL;
}
-/* Encodes channel payload into a buffer and returns it. This is used
- to add channel payload into a packet. As the channel payload is
+/* Parses list of channel payloads returning list of payloads. */
+
+SilcDList silc_channel_payload_parse_list(const unsigned char *payload,
+ SilcUInt32 payload_len)
+{
+ SilcBufferStruct buffer;
+ SilcDList list;
+ SilcChannelPayload new;
+ int len, ret;
+
+ SILC_LOG_DEBUG(("Parsing channel payload list"));
+
+ silc_buffer_set(&buffer, (unsigned char *)payload, payload_len);
+ list = silc_dlist_init();
+
+ while (buffer.len) {
+ new = silc_calloc(1, sizeof(*new));
+ ret = silc_buffer_unformat(&buffer,
+ SILC_STR_UI16_NSTRING_ALLOC(&new->channel_name,
+ &new->name_len),
+ SILC_STR_UI16_NSTRING_ALLOC(&new->channel_id,
+ &new->id_len),
+ SILC_STR_UI_INT(&new->mode),
+ SILC_STR_END);
+ if (ret == -1)
+ goto err;
+
+ if ((new->name_len < 1 || new->name_len > buffer.len) ||
+ (new->id_len < 1 || new->id_len > buffer.len)) {
+ SILC_LOG_ERROR(("Incorrect channel payload in packet, packet dropped"));
+ goto err;
+ }
+
+ len = 2 + new->name_len + 2 + new->id_len + 4;
+ if (buffer.len < len)
+ break;
+ silc_buffer_pull(&buffer, len);
+
+ silc_dlist_add(list, new);
+ }
+
+ return list;
+
+ err:
+ silc_channel_payload_list_free(list);
+ return NULL;
+}
+
+/* Encode new channel payload and returns it as buffer. */
+
+SilcBuffer silc_channel_payload_encode(const unsigned char *channel_name,
+ SilcUInt16 channel_name_len,
+ const unsigned char *channel_id,
+ SilcUInt32 channel_id_len,
+ SilcUInt32 mode)
+{
+ SilcBuffer buffer;
+
+ SILC_LOG_DEBUG(("Encoding message payload"));
+
+ buffer = silc_buffer_alloc(2 + channel_name_len + 2 + channel_id_len + 4);
+ silc_buffer_pull_tail(buffer, SILC_BUFFER_END(buffer));
+
+ /* Encode the Channel Payload */
+ silc_buffer_format(buffer,
+ SILC_STR_UI_SHORT(channel_name_len),
+ SILC_STR_UI_XNSTRING(channel_name, channel_name_len),
+ SILC_STR_UI_SHORT(channel_id_len),
+ SILC_STR_UI_XNSTRING(channel_id, channel_id_len),
+ SILC_STR_UI_INT(mode),
+ SILC_STR_END);
+
+ return buffer;
+}
+
+/* Frees Channel Payload */
+
+void silc_channel_payload_free(SilcChannelPayload payload)
+{
+ silc_free(payload->channel_name);
+ silc_free(payload->channel_id);
+ silc_free(payload);
+}
+
+/* Free's list of Channel Payloads */
+
+void silc_channel_payload_list_free(SilcDList list)
+{
+ SilcChannelPayload entry;
+
+ silc_dlist_start(list);
+ while ((entry = silc_dlist_get(list)) != SILC_LIST_END) {
+ silc_free(entry->channel_name);
+ silc_free(entry->channel_id);
+ silc_dlist_del(list, entry);
+ silc_free(entry);
+ }
+
+ silc_dlist_uninit(list);
+}
+
+/* Return the channel name */
+
+unsigned char *silc_channel_get_name(SilcChannelPayload payload,
+ SilcUInt32 *channel_name_len)
+{
+ if (channel_name_len)
+ *channel_name_len = payload->name_len;
+
+ return payload->channel_name;
+}
+
+/* Return the channel ID */
+
+unsigned char *silc_channel_get_id(SilcChannelPayload payload,
+ SilcUInt32 *channel_id_len)
+{
+ if (channel_id_len)
+ *channel_id_len = payload->id_len;
+
+ return payload->channel_id;
+}
+
+/* Return the channel ID as parsed ID. */
+
+SilcChannelID *silc_channel_get_id_parse(SilcChannelPayload payload)
+{
+ return silc_id_str2id(payload->channel_id, payload->id_len,
+ SILC_ID_CHANNEL);
+}
+
+/* Return the mode. The mode is arbitrary. It can be the mode of the
+ channel or perhaps the mode of the client on the channel. The protocol
+ dictates what the usage of the mode is in different circumstances. */
+
+SilcUInt32 silc_channel_get_mode(SilcChannelPayload payload)
+{
+ return payload->mode;
+}
+
+/******************************************************************************
+
+ Channel Message Payload
+
+******************************************************************************/
+
+#define SILC_CHANNEL_MESSAGE_PAD(__payloadlen) (16 - (__payloadlen) % 16)
+
+/* Channel Message Payload structure. Contents of this structure is parsed
+ from SILC packets. */
+struct SilcChannelMessagePayloadStruct {
+ SilcMessageFlags flags;
+ SilcUInt16 data_len;
+ unsigned char *data;
+ unsigned char *mac;
+ unsigned char *iv;
+};
+
+/* Decrypts the channel message payload. First push the IV out of the
+ packet. The IV is used in the decryption process. Then decrypt the
+ message. After decyprtion, take the MAC from the decrypted packet,
+ compute MAC and compare the MACs. If they match, the decryption was
+ successful and we have the channel message ready to be displayed. */
+
+bool silc_channel_message_payload_decrypt(unsigned char *data,
+ size_t data_len,
+ SilcCipher cipher,
+ SilcHmac hmac)
+{
+ SilcUInt32 iv_len, mac_len;
+ unsigned char *end, *mac, mac2[32];
+ unsigned char *dst, iv[SILC_CIPHER_MAX_IV_SIZE];
+
+ /* Push the IV out of the packet, and copy the IV since we do not want
+ to modify the original data buffer. */
+ end = data + data_len;
+ iv_len = silc_cipher_get_block_len(cipher);
+ memcpy(iv, end - iv_len, iv_len);
+
+ /* Allocate destination decryption buffer since we do not want to modify
+ the original data buffer, since we might want to call this function
+ many times for same payload. */
+ if (hmac)
+ dst = silc_calloc(data_len - iv_len, sizeof(*dst));
+ else
+ dst = data;
+
+ /* Decrypt the channel message */
+ silc_cipher_decrypt(cipher, data, dst, data_len - iv_len, iv);
+
+ if (hmac) {
+ /* Take the MAC */
+ end = dst + (data_len - iv_len);
+ mac_len = silc_hmac_len(hmac);
+ mac = (end - mac_len);
+
+ /* Check the MAC of the message */
+ SILC_LOG_DEBUG(("Checking channel message MACs"));
+ silc_hmac_make(hmac, dst, (data_len - iv_len - mac_len), mac2, &mac_len);
+ if (memcmp(mac, mac2, mac_len)) {
+ SILC_LOG_DEBUG(("Channel message MACs does not match"));
+ silc_free(dst);
+ return FALSE;
+ }
+ SILC_LOG_DEBUG(("MAC is Ok"));
+
+ /* Now copy the decrypted data into the buffer since it is verified
+ it decrypted correctly. */
+ memcpy(data, dst, data_len - iv_len);
+ memset(dst, 0, data_len - iv_len);
+ silc_free(dst);
+ }
+
+ return TRUE;
+}
+
+/* Parses channel message payload returning new channel payload structure.
+ This also decrypts it and checks the MAC. */
+
+SilcChannelMessagePayload
+silc_channel_message_payload_parse(unsigned char *payload,
+ SilcUInt32 payload_len,
+ SilcCipher cipher,
+ SilcHmac hmac)
+{
+ SilcBufferStruct buffer;
+ SilcChannelMessagePayload new;
+ int ret;
+ SilcUInt32 iv_len, mac_len;
+
+ SILC_LOG_DEBUG(("Parsing channel message payload"));
+
+ silc_buffer_set(&buffer, payload, payload_len);
+
+ /* Decrypt the payload */
+ ret = silc_channel_message_payload_decrypt(buffer.data, buffer.len,
+ cipher, hmac);
+ if (ret == FALSE)
+ return NULL;
+
+ iv_len = silc_cipher_get_block_len(cipher);
+ mac_len = silc_hmac_len(hmac);
+
+ new = silc_calloc(1, sizeof(*new));
+
+ /* Parse the Channel Message Payload. Ignore the padding. */
+ ret = silc_buffer_unformat(&buffer,
+ SILC_STR_UI_SHORT(&new->flags),
+ SILC_STR_UI16_NSTRING_ALLOC(&new->data,
+ &new->data_len),
+ SILC_STR_UI16_NSTRING(NULL, NULL),
+ SILC_STR_UI_XNSTRING(&new->mac, mac_len),
+ SILC_STR_UI_XNSTRING(&new->iv, iv_len),
+ SILC_STR_END);
+ if (ret == -1)
+ goto err;
+
+ if (new->data_len > buffer.len) {
+ SILC_LOG_ERROR(("Incorrect channel message payload in packet, "
+ "packet dropped"));
+ goto err;
+ }
+
+ return new;
+
+ err:
+ silc_channel_message_payload_free(new);
+ return NULL;
+}
+
+/* Encodes channel message payload into a buffer and returns it. This is used
+ to add channel message payload into a packet. As the channel payload is
encrypted separately from other parts of the packet padding must
be applied to the payload. */
-SilcBuffer silc_channel_payload_encode(unsigned short data_len,
- unsigned char *data,
- unsigned short iv_len,
- unsigned char *iv,
- SilcRng rng)
+SilcBuffer silc_channel_message_payload_encode(SilcUInt16 flags,
+ SilcUInt16 data_len,
+ const unsigned char *data,
+ SilcUInt16 iv_len,
+ unsigned char *iv,
+ SilcCipher cipher,
+ SilcHmac hmac)
{
int i;
SilcBuffer buffer;
- unsigned int len, pad_len;
- unsigned char pad[SILC_PACKET_MAX_PADLEN];
+ SilcUInt32 len, pad_len, mac_len;
+ unsigned char pad[16];
+ unsigned char mac[32];
- SILC_LOG_DEBUG(("Encoding channel payload"));
+ SILC_LOG_DEBUG(("Encoding channel message payload"));
/* Calculate length of padding. IV is not included into the calculation
since it is not encrypted. */
- len = 2 + data_len + 2;
- pad_len = SILC_PACKET_PADLEN((len + 2));
+ mac_len = silc_hmac_len(hmac);
+ len = 6 + data_len + mac_len;
+ pad_len = SILC_CHANNEL_MESSAGE_PAD(len);
/* Allocate channel payload buffer */
- len += pad_len;
- buffer = silc_buffer_alloc(len + iv_len);
+ len += pad_len + iv_len;
+ buffer = silc_buffer_alloc(len);
/* Generate padding */
- for (i = 0; i < pad_len; i++)
- pad[i] = silc_rng_get_byte(rng);
+ for (i = 0; i < pad_len; i++) pad[i] = silc_rng_global_get_byte();
- silc_buffer_pull_tail(buffer, SILC_BUFFER_END(buffer));
-
- /* Encode the Channel Payload */
+ /* Encode the Channel Message Payload */
+ silc_buffer_pull_tail(buffer, 6 + data_len + pad_len);
silc_buffer_format(buffer,
+ SILC_STR_UI_SHORT(flags),
SILC_STR_UI_SHORT(data_len),
SILC_STR_UI_XNSTRING(data, data_len),
SILC_STR_UI_SHORT(pad_len),
SILC_STR_UI_XNSTRING(pad, pad_len),
+ SILC_STR_END);
+
+ /* Compute the MAC of the channel message data */
+ silc_hmac_make(hmac, buffer->data, buffer->len, mac, &mac_len);
+
+ /* Put rest of the data to the payload */
+ silc_buffer_pull_tail(buffer, mac_len + iv_len);
+ silc_buffer_pull(buffer, 6 + data_len + pad_len);
+ silc_buffer_format(buffer,
+ SILC_STR_UI_XNSTRING(mac, mac_len),
SILC_STR_UI_XNSTRING(iv, iv_len),
SILC_STR_END);
+ silc_buffer_push(buffer, 6 + data_len + pad_len);
+
+ /* Encrypt payload of the packet. This is encrypted with the channel key. */
+ silc_cipher_encrypt(cipher, buffer->data, buffer->data,
+ buffer->len - iv_len, iv);
+
+ memset(pad, 0, sizeof(pad));
+ memset(mac, 0, sizeof(mac));
- memset(pad, 0, pad_len);
return buffer;
}
-/* Free's Channel Payload */
+/* Free's Channel Message Payload */
-void silc_channel_payload_free(SilcChannelPayload payload)
+void silc_channel_message_payload_free(SilcChannelMessagePayload payload)
{
- if (payload) {
- if (payload->data)
- silc_free(payload->data);
- if (payload->iv)
- silc_free(payload->iv);
- silc_free(payload);
+ if (payload->data) {
+ memset(payload->data, 0, payload->data_len);
+ silc_free(payload->data);
}
+ silc_free(payload);
+}
+
+/* Return flags */
+
+SilcMessageFlags
+silc_channel_message_get_flags(SilcChannelMessagePayload payload)
+{
+ return payload->flags;
}
/* Return data */
-unsigned char *silc_channel_get_data(SilcChannelPayload payload,
- unsigned int *data_len)
+unsigned char *silc_channel_message_get_data(SilcChannelMessagePayload payload,
+ SilcUInt32 *data_len)
{
if (data_len)
*data_len = payload->data_len;
return payload->data;
}
-/* Return initial vector */
+/* Return MAC. The caller knows the length of the MAC */
-unsigned char *silc_channel_get_iv(SilcChannelPayload payload,
- unsigned int *iv_len)
+unsigned char *silc_channel_message_get_mac(SilcChannelMessagePayload payload)
{
- if (iv_len)
- *iv_len = payload->iv_len;
+ return payload->mac;
+}
+/* Return IV. The caller knows the length of the IV */
+
+unsigned char *silc_channel_message_get_iv(SilcChannelMessagePayload payload)
+{
return payload->iv;
}
/* Channel Key Payload structrue. Channel keys are parsed from SILC
packets into this structure. */
struct SilcChannelKeyPayloadStruct {
- unsigned short id_len;
+ SilcUInt16 id_len;
unsigned char *id;
- unsigned short cipher_len;
+ SilcUInt16 cipher_len;
unsigned char *cipher;
- unsigned short key_len;
+ SilcUInt16 key_len;
unsigned char *key;
};
/* Parses channel key payload returning new channel key payload structure */
-SilcChannelKeyPayload silc_channel_key_payload_parse(SilcBuffer buffer)
+SilcChannelKeyPayload
+silc_channel_key_payload_parse(const unsigned char *payload,
+ SilcUInt32 payload_len)
{
+ SilcBufferStruct buffer;
SilcChannelKeyPayload new;
+ int ret;
SILC_LOG_DEBUG(("Parsing channel key payload"));
+ silc_buffer_set(&buffer, (unsigned char *)payload, payload_len);
new = silc_calloc(1, sizeof(*new));
/* Parse the Channel Key Payload */
- silc_buffer_unformat(buffer,
- SILC_STR_UI16_NSTRING_ALLOC(&new->id, &new->id_len),
- SILC_STR_UI16_NSTRING_ALLOC(&new->cipher,
- &new->cipher_len),
- SILC_STR_UI16_NSTRING_ALLOC(&new->key, &new->key_len),
- SILC_STR_END);
+ ret =
+ silc_buffer_unformat(&buffer,
+ SILC_STR_UI16_NSTRING_ALLOC(&new->id, &new->id_len),
+ SILC_STR_UI16_NSTRING_ALLOC(&new->cipher,
+ &new->cipher_len),
+ SILC_STR_UI16_NSTRING_ALLOC(&new->key, &new->key_len),
+ SILC_STR_END);
+ if (ret == -1)
+ goto err;
if (new->id_len < 1 || new->key_len < 1 || new->cipher_len < 1) {
SILC_LOG_ERROR(("Incorrect channel key payload in packet"));
/* Encodes channel key payload into a buffer and returns it. This is used
to add channel key payload into a packet. */
-SilcBuffer silc_channel_key_payload_encode(unsigned short id_len,
- unsigned char *id,
- unsigned short cipher_len,
- unsigned char *cipher,
- unsigned short key_len,
- unsigned char *key)
+SilcBuffer silc_channel_key_payload_encode(SilcUInt16 id_len,
+ const unsigned char *id,
+ SilcUInt16 cipher_len,
+ const unsigned char *cipher,
+ SilcUInt16 key_len,
+ const unsigned char *key)
{
SilcBuffer buffer;
- unsigned int len;
+ SilcUInt32 len;
SILC_LOG_DEBUG(("Encoding channel key payload"));
- /* Sanity checks */
- if (!id_len || !key_len || !id || !key || !cipher_len || !cipher)
- return NULL;
-
/* Allocate channel payload buffer. Length is 2 + id + 2 + key +
2 + cipher */
len = 2 + id_len + 2 + key_len + 2 + cipher_len;
return buffer;
}
-/* Free's Channel Key Payload */
+/* Frees Channel Key Payload */
void silc_channel_key_payload_free(SilcChannelKeyPayload payload)
{
if (payload) {
- if (payload->id)
- silc_free(payload->id);
- if (payload->cipher)
- silc_free(payload->cipher);
+ silc_free(payload->id);
+ silc_free(payload->cipher);
if (payload->key) {
memset(payload->key, 0, payload->key_len);
silc_free(payload->key);
/* Return ID */
unsigned char *silc_channel_key_get_id(SilcChannelKeyPayload payload,
- unsigned int *id_len)
+ SilcUInt32 *id_len)
{
if (id_len)
*id_len = payload->id_len;
/* Return cipher name */
unsigned char *silc_channel_key_get_cipher(SilcChannelKeyPayload payload,
- unsigned int *cipher_len)
+ SilcUInt32 *cipher_len)
{
if (cipher_len)
*cipher_len = payload->cipher_len;
/* Return key */
unsigned char *silc_channel_key_get_key(SilcChannelKeyPayload payload,
- unsigned int *key_len)
+ SilcUInt32 *key_len)
{
if (key_len)
*key_len = payload->key_len;
projects / silc.git / blobdiff