/*
- silcpacket.c
+ silcpacket.c
- Author: Pekka Riikonen <priikone@poseidon.pspt.fi>
+ Author: Pekka Riikonen <priikone@silcnet.org>
- 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
- 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
******************************************************************************/
-/* Writes data from encrypted buffer to the socket connection. If the
- data cannot be written at once, it will be written later with a timeout.
- The data is written from the data section of the buffer, not from head
- or tail section. This automatically pulls the data section towards end
- after writing the data. */
-
-int silc_packet_write(int sock, SilcBuffer src)
-{
- int ret = 0;
-
- SILC_LOG_DEBUG(("Writing data to socket %d", sock));
-
- if (src->len > 0) {
- ret = write(sock, src->data, src->len);
- if (ret < 0) {
- if (errno == EAGAIN) {
- SILC_LOG_DEBUG(("Could not write immediately, will do it later"));
- return -2;
- }
- SILC_LOG_ERROR(("Cannot write to socket: %s", strerror(errno)));
- return -1;
- }
-
- silc_buffer_pull(src, ret);
- }
-
- SILC_LOG_DEBUG(("Wrote data %d bytes", ret));
-
- return ret;
-}
-
/* Actually sends the packet. This flushes the connections outgoing data
buffer. If data is sent directly to the network this returns the bytes
written, if error occured this returns -1 and if the data could not
later time. If `force_send' is TRUE this attempts to write the data
directly to the network, if FALSE, this returns -2. */
-int silc_packet_send(SilcSocketConnection sock, int force_send)
+int silc_packet_send(SilcSocketConnection sock, bool force_send)
{
+ SILC_LOG_DEBUG(("Sending packet to %s:%d [%s]", sock->hostname,
+ sock->port,
+ (sock->type == SILC_SOCKET_TYPE_UNKNOWN ? "Unknown" :
+ sock->type == SILC_SOCKET_TYPE_CLIENT ? "Client" :
+ sock->type == SILC_SOCKET_TYPE_SERVER ? "Server" :
+ "Router")));
+
/* Send now if forced to do so */
if (force_send == TRUE) {
int ret;
SILC_LOG_DEBUG(("Forcing packet send, packet sent immediately"));
/* Write to network */
- ret = silc_packet_write(sock->sock, sock->outbuf);
+ ret = silc_socket_write(sock);
if (ret == -1) {
- SILC_LOG_ERROR(("Error sending packet, dropped"));
+ SILC_LOG_ERROR(("Error sending packet, dropped: %s",
+ strerror(errno)));
}
if (ret != -2)
return ret;
other process of HMAC computing and encryption is needed this function
cannot be used. */
-void silc_packet_encrypt(SilcCipher cipher, SilcHmac hmac,
- SilcBuffer buffer, unsigned int len)
+void silc_packet_encrypt(SilcCipher cipher, SilcHmac hmac, SilcUInt32 sequence,
+ SilcBuffer buffer, SilcUInt32 len)
{
unsigned char mac[32];
-
- if (cipher) {
- SILC_LOG_DEBUG(("Encrypting packet, cipher %s, len %d (%d)",
- cipher->cipher->name, len, len - 2));
- }
+ SilcUInt32 mac_len;
/* Compute HMAC. This assumes that HMAC is created from the entire
data area thus this uses the length found in buffer, not the length
sent as argument. */
if (hmac) {
- silc_hmac_make(hmac, buffer->data, buffer->len, mac);
- silc_buffer_put_tail(buffer, mac, hmac->hash->hash->hash_len);
+ unsigned char psn[4];
+
+ silc_hmac_init(hmac);
+ SILC_PUT32_MSB(sequence, psn);
+ silc_hmac_update(hmac, psn, 4);
+ silc_hmac_update(hmac, buffer->data, buffer->len);
+ silc_hmac_final(hmac, mac, &mac_len);
+ silc_buffer_put_tail(buffer, mac, mac_len);
memset(mac, 0, sizeof(mac));
}
- /* Encrypt the data area of the packet. 2 bytes of the packet
- are not encrypted. */
- if (cipher)
- cipher->cipher->encrypt(cipher->context, buffer->data + 2,
- buffer->data + 2, len - 2, cipher->iv);
+ /* Encrypt the data area of the packet. */
+ if (cipher) {
+ SILC_LOG_DEBUG(("Encrypting packet, cipher %s, len %d",
+ cipher->cipher->name, len));
+ silc_cipher_encrypt(cipher, buffer->data, buffer->data, len, cipher->iv);
+ }
/* Pull the HMAC into the visible data area in the buffer */
if (hmac)
- silc_buffer_pull_tail(buffer, hmac->hash->hash->hash_len);
+ silc_buffer_pull_tail(buffer, mac_len);
}
/* Assembles a new packet to be ready for send out. The buffer sent as
^ ^
Start of assembled packet
- Packet construct is as follows (* = won't be encrypted):
+ Packet construct is as follows:
- x bytes SILC Header
- 2 bytes Payload length (*)
+ n bytes SILC Header
+ 2 bytes Payload length
1 byte Flags
1 byte Packet type
+ 1 byte Padding length
+ 1 byte RESERVED
+ 1 bytes Source ID Length
+ 1 bytes Destination ID Length
1 byte Source ID Type
- 2 bytes Source ID Length
- x bytes Source ID
+ n bytes Source ID
1 byte Destination ID Type
- 2 bytes Destination ID Length
- x bytes Destination ID
+ n bytes Destination ID
1 - 16 bytes Padding
- x bytes Data payload
+ n bytes Data payload
All fields in the packet will be authenticated by MAC. The MAC is
- not computed here, it must be computed differently before encrypting
+ not computed here, it must be computed separately before encrypting
the packet.
*/
-void silc_packet_assemble(SilcPacketContext *ctx)
+void silc_packet_assemble(SilcPacketContext *ctx, SilcCipher cipher)
{
unsigned char tmppad[SILC_PACKET_MAX_PADLEN];
+ int block_len = cipher ? silc_cipher_get_block_len(cipher) : 0;
int i;
SILC_LOG_DEBUG(("Assembling outgoing packet"));
ctx->src_id_len + ctx->dst_id_len;
/* Calculate the length of the padding. The padding is calculated from
- the data that will be encrypted. As protocol states 3 first bytes
- of the packet are not encrypted they are not included in the
- padding calculation. */
- if (!ctx->padlen)
- ctx->padlen = SILC_PACKET_PADLEN(ctx->truelen);
+ the data that will be encrypted. */
+ if (!ctx->padlen) {
+ if (ctx->long_pad)
+ ctx->padlen = SILC_PACKET_PADLEN_MAX(ctx->truelen);
+ else
+ ctx->padlen = SILC_PACKET_PADLEN(ctx->truelen, block_len);
+ }
/* Put the start of the data section to the right place. */
silc_buffer_push(ctx->buffer, SILC_PACKET_HEADER_LEN +
/* Get random padding */
#if 1
- for (i = 0; i < ctx->padlen; i++) tmppad[i] = silc_rng_get_byte(ctx->rng);
+ for (i = 0; i < ctx->padlen; i++) tmppad[i] =
+ silc_rng_global_get_byte_fast();
#else
/* XXX: For testing - to be removed */
memset(tmppad, 65, sizeof(tmppad));
SILC_STR_UI_SHORT(ctx->truelen),
SILC_STR_UI_CHAR(ctx->flags),
SILC_STR_UI_CHAR(ctx->type),
- SILC_STR_UI_SHORT(ctx->src_id_len),
- SILC_STR_UI_SHORT(ctx->dst_id_len),
+ SILC_STR_UI_CHAR(ctx->padlen),
+ SILC_STR_UI_CHAR(0),
+ SILC_STR_UI_CHAR(ctx->src_id_len),
+ SILC_STR_UI_CHAR(ctx->dst_id_len),
SILC_STR_UI_CHAR(ctx->src_id_type),
SILC_STR_UI_XNSTRING(ctx->src_id, ctx->src_id_len),
SILC_STR_UI_CHAR(ctx->dst_id_type),
outgoing buffer in SilcSocketConnection object. */
void silc_packet_send_prepare(SilcSocketConnection sock,
- unsigned int header_len,
- unsigned int padlen,
- unsigned int data_len)
+ SilcUInt32 header_len,
+ SilcUInt32 padlen,
+ SilcUInt32 data_len)
{
int totlen, oldlen;
/* Allocate new buffer. This is done only once per connection. */
SILC_LOG_DEBUG(("Allocating outgoing data buffer"));
- sock->outbuf = silc_buffer_alloc(SILC_PACKET_DEFAULT_SIZE);
+ if (totlen > SILC_PACKET_DEFAULT_SIZE)
+ sock->outbuf = silc_buffer_alloc(totlen);
+ else
+ sock->outbuf = silc_buffer_alloc(SILC_PACKET_DEFAULT_SIZE);
silc_buffer_pull_tail(sock->outbuf, totlen);
silc_buffer_pull(sock->outbuf, header_len + padlen);
} else {
/* There is some pending data in the buffer. */
/* Allocate more space if needed */
- if ((sock->outbuf->end - sock->outbuf->tail) < data_len) {
+ if ((sock->outbuf->end - sock->outbuf->tail) <
+ (totlen + 20)) {
SILC_LOG_DEBUG(("Reallocating outgoing data buffer"));
sock->outbuf = silc_buffer_realloc(sock->outbuf,
- sock->outbuf->truelen + totlen);
+ sock->outbuf->truelen +
+ (totlen * 2));
}
oldlen = sock->outbuf->len;
} else {
/* Buffer is free for use */
silc_buffer_clear(sock->outbuf);
+
+ /* Allocate more space if needed */
+ if ((sock->outbuf->end - sock->outbuf->tail) < (totlen + 20)) {
+ SILC_LOG_DEBUG(("Reallocating outgoing data buffer"));
+ sock->outbuf = silc_buffer_realloc(sock->outbuf,
+ sock->outbuf->truelen +
+ (totlen * 2));
+ }
+
silc_buffer_pull_tail(sock->outbuf, totlen);
silc_buffer_pull(sock->outbuf, header_len + padlen);
}
******************************************************************************/
-/* Reads data from the socket connection into the incoming data buffer.
- However, this does not parse the packet, it only reads some amount from
- the network. If there are more data available that can be read at a time
- the rest of the data will be read later with a timeout and only after
- that the packet is ready to be parsed.
+static int silc_packet_decrypt(SilcCipher cipher, SilcHmac hmac,
+ SilcUInt32 sequence, SilcBuffer buffer,
+ bool normal);
- The destination buffer sent as argument must be initialized before
- calling this function, and, the data section and the start of the tail
- section must be same. Ie. we add the read data to the tail section of
- the buffer hence the data section is the start of the buffer.
-
- This returns amount of bytes read or -1 on error or -2 on case where
- all of the data could not be read at once. */
+/* Receives packet from network and reads the data into connection's
+ incoming data buffer. If the data was read directly this returns the
+ read bytes, if error occured this returns -1, if the data could not
+ be read directly at this time this returns -2 in which case the data
+ should be read again at some later time, or If EOF occured this returns
+ 0. */
-int silc_packet_read(int sock, SilcBuffer dest)
+int silc_packet_receive(SilcSocketConnection sock)
{
- int len = 0;
- unsigned char buf[SILC_PACKET_READ_SIZE];
-
- SILC_LOG_DEBUG(("Reading data from socket %d", sock));
-
- /* Read the data from the socket. */
- len = read(sock, buf, sizeof(buf));
- if (len < 0) {
- if (errno == EAGAIN || errno == EINTR) {
- SILC_LOG_DEBUG(("Could not read immediately, will do it later"));
- return -2;
- }
- SILC_LOG_ERROR(("Cannot read from socket: %d", strerror(errno)));
- return -1;
- }
-
- if (!len)
- return 0;
-
- /* Insert the data to the buffer. If the data doesn't fit to the
- buffer space is allocated for the buffer. */
- /* XXX: This may actually be bad thing as if there is pending data in
- the buffer they will be lost! */
- if (dest) {
-
- /* If the data doesn't fit we just have to allocate a whole new
- data area */
- if (dest->truelen <= len) {
-
- /* Free the old buffer */
- memset(dest->head, 'F', dest->truelen);
- silc_free(dest->head);
-
- /* Allocate new data area */
- len += SILC_PACKET_DEFAULT_SIZE;
- dest->data = silc_calloc(len, sizeof(char));
- dest->truelen = len;
- dest->len = 0;
- dest->head = dest->data;
- dest->data = dest->data;
- dest->tail = dest->data;
- dest->end = dest->data + dest->truelen;
- len -= SILC_PACKET_DEFAULT_SIZE;
- }
+ int ret;
- silc_buffer_put_tail(dest, buf, len);
- silc_buffer_pull_tail(dest, len);
- }
+ SILC_LOG_DEBUG(("Receiving packet from %s:%d [%s]", sock->hostname,
+ sock->port,
+ (sock->type == SILC_SOCKET_TYPE_UNKNOWN ? "Unknown" :
+ sock->type == SILC_SOCKET_TYPE_CLIENT ? "Client" :
+ sock->type == SILC_SOCKET_TYPE_SERVER ? "Server" :
+ "Router")));
- SILC_LOG_DEBUG(("Read %d bytes", len));
+ /* Read some data from connection */
+ ret = silc_socket_read(sock);
- return len;
+ return ret;
}
-/* Processes the received data. This checks the received data and
- calls parser callback that handles the actual packet decryption
- and parsing. If more than one packet was received this calls the
- parser multiple times. The parser callback will get context
- SilcPacketParserContext that includes the packet and the `context'
- sent to this function. */
-
-void silc_packet_receive_process(SilcSocketConnection sock,
+/* Processes and decrypts the incmoing data, and calls parser callback
+ for each received packet that will handle the actual packet parsing.
+ If more than one packet was received this calls the parser multiple
+ times. The parser callback will get context SilcPacketParserContext
+ that includes the packet and the `parser_context' sent to this
+ function.
+
+ The `local_is_router' indicates whether the caller is router server
+ in which case the receiving process of a certain packet types may
+ be special. Normal server and client must set it to FALSE. The
+ SilcPacketParserContext will indicate also whether the received
+ packet was normal or special packet. */
+
+bool silc_packet_receive_process(SilcSocketConnection sock,
+ bool local_is_router,
SilcCipher cipher, SilcHmac hmac,
+ SilcUInt32 sequence,
SilcPacketParserCallback parser,
- void *context)
+ void *parser_context)
{
SilcPacketParserContext *parse_ctx;
- int packetlen, paddedlen, count, mac_len = 0;
+ int packetlen, paddedlen, mac_len = 0;
+ bool cont = TRUE;
- /* We need at least 2 bytes of data to be able to start processing
- the packet. */
- if (sock->inbuf->len < 2)
- return;
+ /* Do not process for disconnected connection */
+ if (SILC_IS_DISCONNECTED(sock))
+ return TRUE;
+
+ if (sock->inbuf->len < SILC_PACKET_MIN_HEADER_LEN)
+ return TRUE;
if (hmac)
- mac_len = hmac->hash->hash->hash_len;
+ mac_len = silc_hmac_len(hmac);
/* Parse the packets from the data */
- count = 0;
- while (sock->inbuf->len > 0) {
+ while (sock->inbuf->len > 0 && cont) {
+
+ if (sock->inbuf->len < SILC_PACKET_MIN_HEADER_LEN) {
+ SILC_LOG_DEBUG(("Partial packet in queue, waiting for the rest"));
+ return TRUE;
+ }
+
+ /* Decrypt first 16 bytes of the packet */
+ if (!SILC_IS_INBUF_PENDING(sock) && cipher)
+ silc_cipher_decrypt(cipher, sock->inbuf->data, sock->inbuf->data,
+ SILC_PACKET_MIN_HEADER_LEN, cipher->iv);
+
+ /* Get packet lenght and full packet length with padding */
SILC_PACKET_LENGTH(sock->inbuf, packetlen, paddedlen);
- paddedlen += 2;
- count++;
+ /* Sanity checks */
if (packetlen < SILC_PACKET_MIN_LEN) {
SILC_LOG_DEBUG(("Received invalid packet, dropped"));
- return;
+ silc_buffer_clear(sock->inbuf);
+ return FALSE;
}
if (sock->inbuf->len < paddedlen + mac_len) {
- SILC_LOG_DEBUG(("Received partial packet, waiting for the rest"));
- return;
+ SILC_LOG_DEBUG(("Received partial packet, waiting for the rest"
+ "(%d < %d)", sock->inbuf->len, paddedlen + mac_len));
+ SILC_SET_INBUF_PENDING(sock);
+ return TRUE;
}
+ SILC_UNSET_INBUF_PENDING(sock);
parse_ctx = silc_calloc(1, sizeof(*parse_ctx));
parse_ctx->packet = silc_packet_context_alloc();
parse_ctx->packet->buffer = silc_buffer_alloc(paddedlen + mac_len);
+ parse_ctx->packet->type = sock->inbuf->data[3];
+ parse_ctx->packet->padlen = sock->inbuf->data[4];
+ parse_ctx->packet->sequence = sequence++;
parse_ctx->sock = sock;
- parse_ctx->cipher = cipher;
- parse_ctx->hmac = hmac;
- parse_ctx->context = context;
+ parse_ctx->context = parser_context;
silc_buffer_pull_tail(parse_ctx->packet->buffer,
SILC_BUFFER_END(parse_ctx->packet->buffer));
silc_buffer_put(parse_ctx->packet->buffer, sock->inbuf->data,
- paddedlen + mac_len);
-
- SILC_LOG_HEXDUMP(("Incoming packet, len %d",
- parse_ctx->packet->buffer->len),
- parse_ctx->packet->buffer->data,
- parse_ctx->packet->buffer->len);
+ paddedlen + mac_len);
+
+ SILC_LOG_HEXDUMP(("Incoming packet (%d) (%dB decrypted), len %d",
+ sequence - 1, SILC_PACKET_MIN_HEADER_LEN,
+ paddedlen + mac_len),
+ sock->inbuf->data, paddedlen + mac_len);
+
+ /* Check whether this is normal or special packet */
+ if (local_is_router) {
+ if (sock->inbuf->data[3] == SILC_PACKET_PRIVATE_MESSAGE &&
+ (sock->inbuf->data[2] & SILC_PACKET_FLAG_PRIVMSG_KEY))
+ parse_ctx->normal = FALSE;
+ else if (sock->inbuf->data[3] != SILC_PACKET_CHANNEL_MESSAGE ||
+ (sock->inbuf->data[3] == SILC_PACKET_CHANNEL_MESSAGE &&
+ sock->type == SILC_SOCKET_TYPE_ROUTER))
+ parse_ctx->normal = TRUE;
+ } else {
+ if (sock->inbuf->data[3] == SILC_PACKET_PRIVATE_MESSAGE &&
+ (sock->inbuf->data[2] & SILC_PACKET_FLAG_PRIVMSG_KEY))
+ parse_ctx->normal = FALSE;
+ else if (sock->inbuf->data[3] != SILC_PACKET_CHANNEL_MESSAGE)
+ parse_ctx->normal = TRUE;
+ }
- /* Call the parser */
- if (parser)
- (*parser)(parse_ctx);
+ /* Decrypt rest of the packet */
+ if (cipher)
+ if (silc_packet_decrypt(cipher, hmac, parse_ctx->packet->sequence,
+ parse_ctx->packet->buffer,
+ parse_ctx->normal) == -1) {
+ SILC_LOG_WARNING(("Packet decryption failed %s:%d [%s]",
+ sock->hostname, sock->port,
+ (sock->type == SILC_SOCKET_TYPE_UNKNOWN ? "Unknown" :
+ sock->type == SILC_SOCKET_TYPE_CLIENT ? "Client" :
+ sock->type == SILC_SOCKET_TYPE_SERVER ? "Server" :
+ "Router")));
+ }
/* Pull the packet from inbuf thus we'll get the next one
in the inbuf. */
- silc_buffer_pull(sock->inbuf, paddedlen);
- if (hmac)
- silc_buffer_pull(sock->inbuf, mac_len);
- }
+ silc_buffer_pull(sock->inbuf, paddedlen + mac_len);
- silc_buffer_clear(sock->inbuf);
-}
-
-/* Receives packet from network and reads the data into connection's
- incoming data buffer. If the data was read directly this returns the
- read bytes, if error occured this returns -1, if the data could not
- be read directly at this time this returns -2 in which case the data
- should be read again at some later time, or If EOF occured this returns
- 0. */
-
-int silc_packet_receive(SilcSocketConnection sock)
-{
- int ret;
-
- /* Allocate the incoming data buffer if not done already. */
- if (!sock->inbuf)
- sock->inbuf = silc_buffer_alloc(SILC_PACKET_DEFAULT_SIZE);
-
- /* Read some data from connection */
- ret = silc_packet_read(sock->sock, sock->inbuf);
-
- /* Error */
- if (ret == -1) {
- SILC_LOG_ERROR(("Error reading packet, dropped"));
+ /* Call the parser */
+ cont = (*parser)(parse_ctx, parser_context);
}
- return ret;
+ if (cont == FALSE && sock->inbuf->len > 0)
+ return TRUE;
+
+ SILC_LOG_DEBUG(("Clearing inbound buffer"));
+ silc_buffer_clear(sock->inbuf);
+ return TRUE;
}
/* Checks MAC in the packet. Returns TRUE if MAC is Ok. This is called
after packet has been totally decrypted and parsed. */
-static int silc_packet_check_mac(SilcHmac hmac, SilcBuffer buffer)
+static int silc_packet_check_mac(SilcHmac hmac, SilcBuffer buffer,
+ SilcUInt32 sequence)
{
/* Check MAC */
if (hmac) {
- unsigned char mac[32];
+ unsigned char mac[32], psn[4];
+ SilcUInt32 mac_len;
SILC_LOG_DEBUG(("Verifying MAC"));
/* Compute HMAC of packet */
+
memset(mac, 0, sizeof(mac));
- silc_hmac_make(hmac, buffer->data, buffer->len, mac);
+ silc_hmac_init(hmac);
+ SILC_PUT32_MSB(sequence, psn);
+ silc_hmac_update(hmac, psn, 4);
+ silc_hmac_update(hmac, buffer->data, buffer->len);
+ silc_hmac_final(hmac, mac, &mac_len);
/* Compare the HMAC's (buffer->tail has the packet's HMAC) */
- if (memcmp(mac, buffer->tail, hmac->hash->hash->hash_len)) {
- SILC_LOG_DEBUG(("MAC failed"));
+ if (memcmp(buffer->tail, mac, mac_len)) {
+ SILC_LOG_ERROR(("MAC failed"));
return FALSE;
}
/* Pull MAC from packet before decryption */
if (hmac) {
- if ((buffer->len - hmac->hash->hash->hash_len) > SILC_PACKET_MIN_LEN) {
- silc_buffer_push_tail(buffer, hmac->hash->hash->hash_len);
+ if ((buffer->len - silc_hmac_len(hmac)) > SILC_PACKET_MIN_LEN) {
+ silc_buffer_push_tail(buffer, silc_hmac_len(hmac));
} else {
SILC_LOG_DEBUG(("Bad MAC length in packet, packet dropped"));
return FALSE;
SILC_LOG_DEBUG(("Decrypting rest of the packet"));
/* Decrypt rest of the packet */
- silc_buffer_pull(buffer, SILC_PACKET_MIN_HEADER_LEN - 2);
- cipher->cipher->decrypt(cipher->context, buffer->data + 2,
- buffer->data + 2, buffer->len - 2,
- cipher->iv);
- silc_buffer_push(buffer, SILC_PACKET_MIN_HEADER_LEN - 2);
+ silc_buffer_pull(buffer, SILC_PACKET_MIN_HEADER_LEN);
+ silc_cipher_decrypt(cipher, buffer->data, buffer->data, buffer->len,
+ cipher->iv);
+ silc_buffer_push(buffer, SILC_PACKET_MIN_HEADER_LEN);
SILC_LOG_HEXDUMP(("Fully decrypted packet, len %d", buffer->len),
buffer->data, buffer->len);
{
/* Decrypt rest of the header plus padding */
if (cipher) {
- unsigned short truelen, len1, len2, padlen;
+ SilcUInt16 len;
/* Pull MAC from packet before decryption */
if (hmac) {
- if ((buffer->len - hmac->hash->hash->hash_len) > SILC_PACKET_MIN_LEN) {
- silc_buffer_push_tail(buffer, hmac->hash->hash->hash_len);
+ if ((buffer->len - silc_hmac_len(hmac)) > SILC_PACKET_MIN_LEN) {
+ silc_buffer_push_tail(buffer, silc_hmac_len(hmac));
} else {
SILC_LOG_DEBUG(("Bad MAC length in packet, packet dropped"));
return FALSE;
SILC_LOG_DEBUG(("Decrypting rest of the header"));
- SILC_GET16_MSB(len1, &buffer->data[4]);
- SILC_GET16_MSB(len2, &buffer->data[6]);
-
- truelen = SILC_PACKET_HEADER_LEN + len1 + len2;
- padlen = SILC_PACKET_PADLEN(truelen);
- len1 = (truelen + padlen) - (SILC_PACKET_MIN_HEADER_LEN - 2);
+ /* padding length + src id len + dst id len + header length - 16
+ bytes already decrypted, gives the rest of the encrypted packet */
+ len = (((SilcUInt8)buffer->data[4] + (SilcUInt8)buffer->data[6] +
+ (SilcUInt8)buffer->data[7] + SILC_PACKET_HEADER_LEN) -
+ SILC_PACKET_MIN_HEADER_LEN);
- silc_buffer_pull(buffer, SILC_PACKET_MIN_HEADER_LEN - 2);
- cipher->cipher->decrypt(cipher->context, buffer->data + 2,
- buffer->data + 2, len1 - 2,
- cipher->iv);
- silc_buffer_push(buffer, SILC_PACKET_MIN_HEADER_LEN - 2);
+ silc_buffer_pull(buffer, SILC_PACKET_MIN_HEADER_LEN);
+ if (len > buffer->len) {
+ SILC_LOG_DEBUG(("Garbage in header of packet, bad packet length, "
+ "packet dropped"));
+ return FALSE;
+ }
+ silc_cipher_decrypt(cipher, buffer->data, buffer->data, len, cipher->iv);
+ silc_buffer_push(buffer, SILC_PACKET_MIN_HEADER_LEN);
+ SILC_LOG_HEXDUMP(("packet, len %d", buffer->len),
+ buffer->data, buffer->len);
}
return TRUE;
the HMAC of the packet. If any other special or customized decryption
processing is required this function cannot be used. This returns
-1 on error, 0 when packet is normal packet and 1 when the packet
- is special and requires special processing. */
-
-int silc_packet_decrypt(SilcCipher cipher, SilcHmac hmac,
- SilcBuffer buffer, SilcPacketContext *packet)
-{
-#if 0
- SILC_LOG_DEBUG(("Decrypting packet, cipher %s, len %d (%d)",
- cipher->cipher->name, len, len - 2));
-#endif
+ is special and requires special processing.
- /* Decrypt start of the packet header */
- if (cipher)
- cipher->cipher->decrypt(cipher->context, buffer->data + 2,
- buffer->data + 2, SILC_PACKET_MIN_HEADER_LEN - 2,
- cipher->iv);
+ The `check_packet' is a callback funtion that this function will
+ call. The callback relates to the checking whether the packet is
+ normal packet or special packet and how it should be processed. If
+ the callback return TRUE the packet is normal and FALSE if the packet
+ is special and requires special procesing. */
+static int silc_packet_decrypt(SilcCipher cipher, SilcHmac hmac,
+ SilcUInt32 sequence, SilcBuffer buffer,
+ bool normal)
+{
/* If the packet type is not any special type lets decrypt rest
of the packet here. */
- if ((buffer->data[3] == SILC_PACKET_PRIVATE_MESSAGE &&
- !(buffer->data[2] & SILC_PACKET_FLAG_PRIVMSG_KEY)) ||
- buffer->data[3] != SILC_PACKET_CHANNEL_MESSAGE) {
-
+ if (normal == TRUE) {
/* Normal packet, decrypt rest of the packet */
if (!silc_packet_decrypt_rest(cipher, hmac, buffer))
return -1;
/* Check MAC */
- if (!silc_packet_check_mac(hmac, buffer))
- return FALSE;
+ if (!silc_packet_check_mac(hmac, buffer, sequence))
+ return -1;
return 0;
} else {
/* Packet requires special handling, decrypt rest of the header.
This only decrypts. */
- silc_packet_decrypt_rest_special(cipher, hmac, buffer);
+ if (!silc_packet_decrypt_rest_special(cipher, hmac, buffer))
+ return -1;
/* Check MAC */
- if (!silc_packet_check_mac(hmac, buffer))
- return FALSE;
+ if (!silc_packet_check_mac(hmac, buffer, sequence))
+ return -1;
return 1;
}
function returns the type of the packet. The data section of the
buffer is parsed, not head or tail sections. */
-SilcPacketType silc_packet_parse(SilcPacketContext *ctx)
+SilcPacketType silc_packet_parse(SilcPacketContext *ctx, SilcCipher cipher)
{
SilcBuffer buffer = ctx->buffer;
- int len;
+ SilcUInt8 tmp;
+ int len, ret;
SILC_LOG_DEBUG(("Parsing incoming packet"));
SILC_STR_UI_SHORT(&ctx->truelen),
SILC_STR_UI_CHAR(&ctx->flags),
SILC_STR_UI_CHAR(&ctx->type),
- SILC_STR_UI_SHORT(&ctx->src_id_len),
- SILC_STR_UI_SHORT(&ctx->dst_id_len),
+ SILC_STR_UI_CHAR(&ctx->padlen),
+ SILC_STR_UI_CHAR(&tmp),
+ SILC_STR_UI_CHAR(&ctx->src_id_len),
+ SILC_STR_UI_CHAR(&ctx->dst_id_len),
SILC_STR_UI_CHAR(&ctx->src_id_type),
SILC_STR_END);
+ if (len == -1 || tmp != 0)
+ return SILC_PACKET_NONE;
if (ctx->src_id_len > SILC_PACKET_MAX_ID_LEN ||
ctx->dst_id_len > SILC_PACKET_MAX_ID_LEN) {
- SILC_LOG_ERROR(("Bad ID lengths in packet"));
+ SILC_LOG_ERROR(("Bad ID lengths in packet (%d and %d)",
+ ctx->src_id_len, ctx->dst_id_len));
return SILC_PACKET_NONE;
}
- /* Calculate length of padding in packet */
- ctx->padlen = SILC_PACKET_PADLEN(ctx->truelen);
-
silc_buffer_pull(buffer, len);
- silc_buffer_unformat(buffer,
- SILC_STR_UI_XNSTRING_ALLOC(&ctx->src_id,
- ctx->src_id_len),
- SILC_STR_UI_CHAR(&ctx->dst_id_type),
- SILC_STR_UI_XNSTRING_ALLOC(&ctx->dst_id,
- ctx->dst_id_len),
- SILC_STR_UI_XNSTRING(NULL, ctx->padlen),
- SILC_STR_END);
+ ret = silc_buffer_unformat(buffer,
+ SILC_STR_UI_XNSTRING_ALLOC(&ctx->src_id,
+ ctx->src_id_len),
+ SILC_STR_UI_CHAR(&ctx->dst_id_type),
+ SILC_STR_UI_XNSTRING_ALLOC(&ctx->dst_id,
+ ctx->dst_id_len),
+ SILC_STR_UI_XNSTRING(NULL, ctx->padlen),
+ SILC_STR_END);
+ if (ret == -1)
+ return SILC_PACKET_NONE;
+
silc_buffer_push(buffer, len);
SILC_LOG_HEXDUMP(("parsed packet, len %d", ctx->buffer->len),
the header in a way that it does not take the data area into account
and parses the header and padding area only. */
-SilcPacketType silc_packet_parse_special(SilcPacketContext *ctx)
+SilcPacketType silc_packet_parse_special(SilcPacketContext *ctx,
+ SilcCipher cipher)
{
SilcBuffer buffer = ctx->buffer;
- int len, tmplen;
+ SilcUInt8 tmp;
+ int len, ret;
SILC_LOG_DEBUG(("Parsing incoming packet"));
SILC_STR_UI_SHORT(&ctx->truelen),
SILC_STR_UI_CHAR(&ctx->flags),
SILC_STR_UI_CHAR(&ctx->type),
- SILC_STR_UI_SHORT(&ctx->src_id_len),
- SILC_STR_UI_SHORT(&ctx->dst_id_len),
+ SILC_STR_UI_CHAR(&ctx->padlen),
+ SILC_STR_UI_CHAR(&tmp),
+ SILC_STR_UI_CHAR(&ctx->src_id_len),
+ SILC_STR_UI_CHAR(&ctx->dst_id_len),
SILC_STR_UI_CHAR(&ctx->src_id_type),
SILC_STR_END);
+ if (len == -1 || tmp != 0) {
+ SILC_LOG_ERROR(("Malformed packet header, packet dropped"));
+ return SILC_PACKET_NONE;
+ }
if (ctx->src_id_len > SILC_PACKET_MAX_ID_LEN ||
ctx->dst_id_len > SILC_PACKET_MAX_ID_LEN) {
- SILC_LOG_ERROR(("Bad ID lengths in packet"));
+ SILC_LOG_ERROR(("Bad ID lengths in packet (%d and %d)",
+ ctx->src_id_len, ctx->dst_id_len));
return SILC_PACKET_NONE;
}
- /* Calculate length of padding in packet. As this is special packet
- the data area is not used in the padding calculation as it won't
- be decrypted by the caller. */
- tmplen = SILC_PACKET_HEADER_LEN + ctx->src_id_len + ctx->dst_id_len;
- ctx->padlen = SILC_PACKET_PADLEN(tmplen);
-
silc_buffer_pull(buffer, len);
- silc_buffer_unformat(buffer,
- SILC_STR_UI_XNSTRING_ALLOC(&ctx->src_id,
- ctx->src_id_len),
- SILC_STR_UI_CHAR(&ctx->dst_id_type),
- SILC_STR_UI_XNSTRING_ALLOC(&ctx->dst_id,
- ctx->dst_id_len),
- SILC_STR_UI_XNSTRING(NULL, ctx->padlen),
- SILC_STR_END);
+ ret = silc_buffer_unformat(buffer,
+ SILC_STR_UI_XNSTRING_ALLOC(&ctx->src_id,
+ ctx->src_id_len),
+ SILC_STR_UI_CHAR(&ctx->dst_id_type),
+ SILC_STR_UI_XNSTRING_ALLOC(&ctx->dst_id,
+ ctx->dst_id_len),
+ SILC_STR_UI_XNSTRING(NULL, ctx->padlen),
+ SILC_STR_END);
+ if (ret == -1) {
+ SILC_LOG_ERROR(("Malformed packet header, packet dropped"));
+ return SILC_PACKET_NONE;
+ }
+
silc_buffer_push(buffer, len);
SILC_LOG_HEXDUMP(("parsed packet, len %d", ctx->buffer->len),
/* Allocate packet context */
-SilcPacketContext *silc_packet_context_alloc()
+SilcPacketContext *silc_packet_context_alloc(void)
{
SilcPacketContext *ctx = silc_calloc(1, sizeof(*ctx));
ctx->users++;
SilcPacketContext *silc_packet_context_dup(SilcPacketContext *ctx)
{
ctx->users++;
+ SILC_LOG_DEBUG(("Packet context %p refcnt %d->%d", ctx, ctx->users - 1,
+ ctx->users));
return ctx;
}
void silc_packet_context_free(SilcPacketContext *ctx)
{
ctx->users--;
+ SILC_LOG_DEBUG(("Packet context %p refcnt %d->%d", ctx, ctx->users + 1,
+ ctx->users));
if (ctx->users < 1)
{
if (ctx->buffer)
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