/*
- silcchannel.c
+ silcchannel.c
- Author: Pekka Riikonen <priikone@poseidon.pspt.fi>
+ Author: Pekka Riikonen <priikone@silcnet.org>
- Copyright (C) 1997 - 2000 Pekka Riikonen
+ Copyright (C) 1997 - 2002 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
/******************************************************************************
- Channel Message Payload
+ Channel Payload
******************************************************************************/
/* Channel Message Payload structure. Contents of this structure is parsed
from SILC packets. */
struct SilcChannelPayloadStruct {
- unsigned short data_len;
- unsigned char *data;
- unsigned char *mac;
- unsigned char *iv;
+ unsigned char *channel_name;
+ unsigned char *channel_id;
+ SilcUInt32 mode;
+ SilcUInt16 name_len;
+ SilcUInt16 id_len;
};
-/* Parses channel payload returning new channel payload structure. This
- also decrypts it and checks the MAC. */
+/* Parses channel payload returning new channel payload structure. */
-SilcChannelPayload silc_channel_payload_parse(SilcBuffer buffer,
- SilcCipher cipher,
- SilcHmac hmac)
+SilcChannelPayload silc_channel_payload_parse(const unsigned char *payload,
+ SilcUInt32 payload_len)
{
- SilcChannelPayload new;
+ SilcBufferStruct buffer;
+ SilcChannelPayload newp;
int ret;
- unsigned int iv_len, mac_len;
- unsigned char *mac, mac2[32];
SILC_LOG_DEBUG(("Parsing channel payload"));
- /* Decrypt the channel message. 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 successfull
- and we have the channel message ready to be displayed. */
-
- /* Push the IV out of the packet (it will be in buffer->tail) */
- iv_len = silc_cipher_get_block_len(cipher);
- silc_buffer_push_tail(buffer, iv_len);
-
- /* Decrypt the channel message */
- silc_cipher_decrypt(cipher, buffer->data, buffer->data,
- buffer->len, buffer->tail);
-
- /* Take the MAC */
- mac_len = silc_hmac_len(hmac);
- silc_buffer_push_tail(buffer, mac_len);
- mac = buffer->tail;
-
- /* Check the MAC of the message */
- SILC_LOG_DEBUG(("Checking channel message MACs"));
- silc_hmac_make(hmac, buffer->data, buffer->len, mac2, &mac_len);
- if (memcmp(mac, mac2, mac_len)) {
- SILC_LOG_DEBUG(("Channel message MACs does not match"));
+ silc_buffer_set(&buffer, (unsigned char *)payload, payload_len);
+ newp = silc_calloc(1, sizeof(*newp));
+ if (!newp)
return NULL;
- }
- SILC_LOG_DEBUG(("MAC is Ok"));
- silc_buffer_pull_tail(buffer, iv_len + mac_len);
-
- new = silc_calloc(1, sizeof(*new));
/* Parse the Channel Payload. Ignore the padding. */
- ret = silc_buffer_unformat(buffer,
- 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),
+ ret = silc_buffer_unformat(&buffer,
+ SILC_STR_UI16_NSTRING_ALLOC(&newp->channel_name,
+ &newp->name_len),
+ SILC_STR_UI16_NSTRING_ALLOC(&newp->channel_id,
+ &newp->id_len),
+ SILC_STR_UI_INT(&newp->mode),
SILC_STR_END);
if (ret == -1)
goto err;
- if (new->data_len < 1 || new->data_len > buffer->len) {
+ if ((newp->name_len < 1 || newp->name_len > buffer.len - 8) ||
+ (newp->id_len < 1 || newp->id_len > buffer.len - 8) ||
+ (newp->id_len + newp->name_len > buffer.len - 8)) {
SILC_LOG_ERROR(("Incorrect channel payload in packet, packet dropped"));
goto err;
}
- return new;
+ return newp;
err:
- silc_channel_payload_free(new);
+ silc_channel_payload_free(newp);
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
- 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,
- SilcCipher cipher,
- SilcHmac hmac,
- SilcRng rng)
+/* Parses list of channel payloads returning list of payloads. */
+
+SilcDList silc_channel_payload_parse_list(const unsigned char *payload,
+ SilcUInt32 payload_len)
{
- int i;
- SilcBuffer buffer;
- unsigned int len, pad_len, mac_len;
- unsigned char pad[SILC_PACKET_MAX_PADLEN];
- unsigned char mac[32];
+ SilcBufferStruct buffer;
+ SilcDList list;
+ SilcChannelPayload newp;
+ SilcUInt32 len;
+ int ret;
- SILC_LOG_DEBUG(("Encoding channel payload"));
+ SILC_LOG_DEBUG(("Parsing channel payload list"));
+
+ silc_buffer_set(&buffer, (unsigned char *)payload, payload_len);
+ list = silc_dlist_init();
+
+ while (buffer.len) {
+ newp = silc_calloc(1, sizeof(*newp));
+ if (!newp)
+ goto err;
+ ret = silc_buffer_unformat(&buffer,
+ SILC_STR_UI16_NSTRING_ALLOC(&newp->channel_name,
+ &newp->name_len),
+ SILC_STR_UI16_NSTRING_ALLOC(&newp->channel_id,
+ &newp->id_len),
+ SILC_STR_UI_INT(&newp->mode),
+ SILC_STR_END);
+ if (ret == -1)
+ goto err;
+
+ if ((newp->name_len < 1 || newp->name_len > buffer.len) ||
+ (newp->id_len < 1 || newp->id_len > buffer.len)) {
+ SILC_LOG_ERROR(("Incorrect channel payload in packet, packet dropped"));
+ goto err;
+ }
- /* Calculate length of padding. IV is not included into the calculation
- since it is not encrypted. */
- mac_len = silc_hmac_len(hmac);
- len = 4 + data_len + mac_len;
- pad_len = SILC_PACKET_PADLEN((len + 2));
+ len = 2 + newp->name_len + 2 + newp->id_len + 4;
+ if (buffer.len < len)
+ break;
+ silc_buffer_pull(&buffer, len);
- /* Allocate channel payload buffer */
- len += pad_len + iv_len;
- buffer = silc_buffer_alloc(len);
+ silc_dlist_add(list, newp);
+ }
+
+ return list;
- /* Generate padding */
- for (i = 0; i < pad_len; i++) pad[i] = silc_rng_get_byte(rng);
+ err:
+ silc_channel_payload_list_free(list);
+ return NULL;
+}
- /* Encode the Channel Payload */
- silc_buffer_pull_tail(buffer, 4 + data_len + pad_len);
- silc_buffer_format(buffer,
- 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);
+/* Encode new channel payload and returns it as buffer. */
- /* Compute the MAC of the channel message data */
- silc_hmac_make(hmac, buffer->data, buffer->len, mac, &mac_len);
+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;
- /* Put rest of the data to the payload */
- silc_buffer_pull_tail(buffer, mac_len + iv_len);
- silc_buffer_pull(buffer, 4 + 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, 4 + data_len + pad_len);
+ SILC_LOG_DEBUG(("Encoding message payload"));
- /* 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);
+ buffer = silc_buffer_alloc_size(2 + channel_name_len + 2 +
+ channel_id_len + 4);
+ if (!buffer)
+ return NULL;
- memset(pad, 0, sizeof(pad));
- memset(mac, 0, sizeof(mac));
+ /* 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;
}
-/* Free's Channel Payload */
+/* Frees Channel Payload */
void silc_channel_payload_free(SilcChannelPayload payload)
{
- if (payload) {
- if (payload->data)
- silc_free(payload->data);
- silc_free(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 data */
+/* Return the channel ID */
-unsigned char *silc_channel_get_data(SilcChannelPayload payload,
- unsigned int *data_len)
+unsigned char *silc_channel_get_id(SilcChannelPayload payload,
+ SilcUInt32 *channel_id_len)
{
- if (data_len)
- *data_len = payload->data_len;
+ if (channel_id_len)
+ *channel_id_len = payload->id_len;
- return payload->data;
+ return payload->channel_id;
}
-/* Return MAC. The caller knows the length of the MAC */
+/* Return the channel ID as parsed ID. */
-unsigned char *silc_channel_get_mac(SilcChannelPayload payload)
+SilcChannelID *silc_channel_get_id_parse(SilcChannelPayload payload)
{
- return payload->mac;
+ return silc_id_str2id(payload->channel_id, payload->id_len,
+ SILC_ID_CHANNEL);
}
-/* Return IV. The caller knows the length of the IV */
+/* 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. */
-unsigned char *silc_channel_get_iv(SilcChannelPayload payload)
+SilcUInt32 silc_channel_get_mode(SilcChannelPayload payload)
{
- return payload->iv;
+ return payload->mode;
}
+
/******************************************************************************
Channel Key Payload
/* Channel Key Payload structrue. Channel keys are parsed from SILC
packets into this structure. */
struct SilcChannelKeyPayloadStruct {
- unsigned short id_len;
unsigned char *id;
- unsigned short cipher_len;
unsigned char *cipher;
- unsigned short key_len;
unsigned char *key;
+ SilcUInt16 id_len;
+ SilcUInt16 cipher_len;
+ SilcUInt16 key_len;
};
/* 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)
{
- SilcChannelKeyPayload new;
+ SilcBufferStruct buffer;
+ SilcChannelKeyPayload newp;
int ret;
SILC_LOG_DEBUG(("Parsing channel key payload"));
- new = silc_calloc(1, sizeof(*new));
+ silc_buffer_set(&buffer, (unsigned char *)payload, payload_len);
+ newp = silc_calloc(1, sizeof(*newp));
+ if (!newp)
+ return NULL;
/* Parse the Channel Key Payload */
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_buffer_unformat(&buffer,
+ SILC_STR_UI16_NSTRING_ALLOC(&newp->id, &newp->id_len),
+ SILC_STR_UI16_NSTRING_ALLOC(&newp->cipher,
+ &newp->cipher_len),
+ SILC_STR_UI16_NSTRING_ALLOC(&newp->key,
+ &newp->key_len),
SILC_STR_END);
if (ret == -1)
goto err;
- if (new->id_len < 1 || new->key_len < 1 || new->cipher_len < 1) {
+ if (newp->id_len < 1 || newp->key_len < 1 || newp->cipher_len < 1 ||
+ newp->id_len + newp->cipher_len + newp->key_len > buffer.len - 6) {
SILC_LOG_ERROR(("Incorrect channel key payload in packet"));
goto err;
}
- return new;
+ return newp;
err:
- if (new->id)
- silc_free(new->id);
- if (new->cipher)
- silc_free(new->cipher);
- if (new->key)
- silc_free(new->key);
- silc_free(new);
+ if (newp->id)
+ silc_free(newp->id);
+ if (newp->cipher)
+ silc_free(newp->cipher);
+ if (newp->key)
+ silc_free(newp->key);
+ silc_free(newp);
return NULL;
}
/* 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"));
/* Allocate channel payload buffer. Length is 2 + id + 2 + key +
2 + cipher */
len = 2 + id_len + 2 + key_len + 2 + cipher_len;
- buffer = silc_buffer_alloc(len);
-
- silc_buffer_pull_tail(buffer, SILC_BUFFER_END(buffer));
+ buffer = silc_buffer_alloc_size(len);
+ if (!buffer)
+ return NULL;
/* Encode the Channel Payload */
silc_buffer_format(buffer,
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;
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