+++ /dev/null
-/*
-
- silcmessage.c
-
- Author: Pekka Riikonen <priikone@silcnet.org>
-
- Copyright (C) 1997 - 2007 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.
-
-*/
-/* Implementation of the Message Payload used as channel messages and
- private messages. */
-/* $Id$ */
-
-#include "silc.h"
-#include "silcmessage.h"
-
-/*************************** Types and definitions **************************/
-
-/* Calculates padding length for message payload */
-#define SILC_MESSAGE_PAD(__payloadlen) (16 - ((__payloadlen) % 16))
-
-/* Header length plus maximum padding length */
-#define SILC_MESSAGE_HLEN 6 + 16
-
-/* Maximum message length */
-#define SILC_MESSAGE_MAX_LEN SILC_PACKET_MAX_LEN - SILC_MESSAGE_HLEN - 16
-
-/* Payload encoding context */
-typedef struct {
- SilcBuffer buffer;
- SilcBuffer sign;
- SilcStack stack;
- SilcMessagePayloadEncoded encoded;
- void *context;
- SilcMessageFlags flags;
- SilcPublicKey public_key;
- SilcPrivateKey private_key;
- SilcRng rng;
- SilcHash hash;
- SilcCipher cipher;
- SilcHmac hmac;
- unsigned char *iv;
- unsigned char *pk;
- SilcUInt16 pk_len;
- SilcUInt16 iv_len;
- SilcUInt16 payload_len;
- SilcID sid;
- SilcID rid;
-} SilcMessageEncode;
-
-
-/************************* Static utility functions *************************/
-
-static void
-silc_message_payload_encode_final(SilcBuffer buffer,
- SilcMessageFlags flags,
- SilcCipher cipher,
- SilcHmac hmac,
- unsigned char *iv,
- SilcUInt32 iv_len,
- SilcUInt32 payload_len,
- SilcID *sender_id,
- SilcID *receiver_id,
- SilcStack stack,
- SilcBuffer signature,
- SilcMessagePayloadEncoded encoded,
- void *context);
-
-/* Returns the data length that fits to the packet. If data length is too
- big it will be truncated to fit to the payload. */
-
-static inline
-SilcUInt32 silc_message_payload_datalen(SilcUInt32 data_len,
- SilcUInt32 header_len,
- SilcUInt32 flags,
- SilcPublicKey public_key,
- SilcPrivateKey private_key)
-{
- SilcUInt32 pklen = (flags & SILC_MESSAGE_FLAG_SIGNED && public_key ?
- silc_pkcs_public_key_get_len(public_key) : 0);
- SilcUInt32 prlen = (flags & SILC_MESSAGE_FLAG_SIGNED ?
- silc_pkcs_private_key_get_len(private_key) / 8 : 0);
- SilcUInt32 dlen = data_len + SILC_MESSAGE_HLEN + header_len + pklen + prlen;
-
- if (silc_unlikely(dlen > SILC_MESSAGE_MAX_LEN))
- data_len -= (dlen - SILC_MESSAGE_MAX_LEN);
-
- return data_len;
-}
-
-/* Free signed payload */
-
-static void silc_message_signed_payload_free(SilcMessageSignedPayload sig)
-{
- if (sig->sign_data) {
- memset(sig->sign_data, 0, sig->sign_len);
- silc_free(sig->sign_data);
- }
- silc_free(sig->pk_data);
-}
-
-/* Parses the SILC_MESSAGE_FLAG_SIGNED Payload */
-
-static SilcBool
-silc_message_signed_payload_parse(const unsigned char *data,
- SilcUInt32 data_len,
- SilcMessageSignedPayload sig)
-{
- SilcBufferStruct buffer;
- int ret;
-
- SILC_LOG_DEBUG(("Parsing SILC_MESSAGE_FLAG_SIGNED Payload"));
-
- SILC_LOG_HEXDUMP(("sig payload"), (unsigned char *)data, data_len);
-
- silc_buffer_set(&buffer, (unsigned char *)data, data_len);
-
- /* Parse the payload */
- ret = silc_buffer_unformat(&buffer,
- SILC_STR_UI_SHORT(&sig->pk_len),
- SILC_STR_UI_SHORT(&sig->pk_type),
- SILC_STR_END);
- if (ret == -1 || sig->pk_len > data_len - 4) {
- SILC_LOG_DEBUG(("Malformed public key in SILC_MESSAGE_FLAG_SIGNED "
- "Payload"));
- return FALSE;
- }
-
- silc_buffer_pull(&buffer, 4);
- ret = silc_buffer_unformat(&buffer,
- SILC_STR_UI_XNSTRING_ALLOC(&sig->pk_data,
- sig->pk_len),
- SILC_STR_UI16_NSTRING_ALLOC(&sig->sign_data,
- &sig->sign_len),
- SILC_STR_END);
- if (ret == -1 || sig->sign_len > silc_buffer_len(&buffer) -
- sig->pk_len - 2) {
- silc_message_signed_payload_free(sig);
- SILC_LOG_DEBUG(("Malformed SILC_MESSAGE_FLAG_SIGNED Payload"));
- return FALSE;
- }
- silc_buffer_push(&buffer, 4);
-
- /* Signature must be provided */
- if (sig->sign_len < 1) {
- SILC_LOG_DEBUG(("Malformed signature in SILC_MESSAGE_SIGNED_PAYLOAD "
- "Payload"));
- silc_message_signed_payload_free(sig);
- return FALSE;
- }
-
- return TRUE;
-}
-
-/* Encodes the data to be signed to SILC_MESSAGE_FLAG_SIGNED Payload */
-
-static SilcBuffer
-silc_message_signed_encode_data(SilcStack stack,
- const unsigned char *message_payload,
- SilcUInt32 message_payload_len,
- unsigned char *pk,
- SilcUInt32 pk_len, SilcUInt32 pk_type)
-{
- SilcBuffer sign;
-
- sign = silc_buffer_salloc_size(stack, message_payload_len + 4 + pk_len);
- if (!sign)
- return NULL;
-
- silc_buffer_sformat(stack, sign,
- SILC_STR_DATA(message_payload, message_payload_len),
- SILC_STR_UI_SHORT(pk_len),
- SILC_STR_UI_SHORT(pk_type),
- SILC_STR_END);
-
- if (pk && pk_len) {
- silc_buffer_pull(sign, message_payload_len + 4);
- silc_buffer_sformat(stack, sign,
- SILC_STR_UI_XNSTRING(pk, pk_len),
- SILC_STR_END);
- silc_buffer_push(sign, message_payload_len + 4);
- }
-
- return sign;
-}
-
-/* Signature callback */
-
-void silc_message_signed_payload_encode_cb(SilcBool success,
- const unsigned char *signature,
- SilcUInt32 signature_len,
- void *context)
-{
- SilcMessageEncode *e = context;
- SilcPKCSType pk_type;
- SilcStack stack = e->stack;
- SilcBuffer buffer, payload;
- SilcMessageFlags flags;
- SilcCipher cipher;
- SilcHmac hmac;
- unsigned char *iv;
- SilcUInt32 iv_len, payload_len;
- SilcID *sid, *rid;
- SilcMessagePayloadEncoded encoded;
- void *encoded_context;
-
- if (!success) {
- e->encoded(NULL, e->context);
- silc_buffer_sfree(stack, e->sign);
- silc_sfree(stack, e->pk);
- silc_sfree(stack, e);
- silc_stack_free(stack);
- return;
- }
-
- pk_type = silc_pkcs_get_type(e->private_key);
-
- /* Encode the SILC_MESSAGE_FLAG_SIGNED Payload */
- buffer = silc_buffer_salloc_size(stack, 4 + e->pk_len + 2 + signature_len);
- if (!buffer) {
- e->encoded(NULL, e->context);
- silc_buffer_sfree(stack, e->sign);
- silc_sfree(stack, e->pk);
- silc_sfree(stack, e);
- silc_stack_free(stack);
- return;
- }
-
- silc_buffer_sformat(stack, buffer,
- SILC_STR_UI_SHORT(e->pk_len),
- SILC_STR_UI_SHORT(pk_type),
- SILC_STR_END);
-
- if (e->pk_len && e->pk) {
- silc_buffer_pull(buffer, 4);
- silc_buffer_sformat(stack, buffer,
- SILC_STR_DATA(e->pk, e->pk_len),
- SILC_STR_END);
- silc_buffer_push(buffer, 4);
- }
-
- silc_buffer_pull(buffer, 4 + e->pk_len);
- silc_buffer_sformat(stack, buffer,
- SILC_STR_UI_SHORT(signature_len),
- SILC_STR_DATA(signature, signature_len),
- SILC_STR_END);
- silc_buffer_push(buffer, 4 + e->pk_len);
-
- SILC_LOG_HEXDUMP(("SIG payload"), buffer->data, silc_buffer_len(buffer));
-
- payload = e->buffer;
- flags = e->flags;
- cipher = e->cipher;
- hmac = e->hmac;
- iv = e->iv;
- iv_len = e->iv_len;
- payload_len = e->payload_len;
- sid = &e->sid;
- rid = &e->rid;
- encoded = e->encoded;
- encoded_context = e->context;
-
- silc_sfree(stack, e->pk);
- silc_buffer_sfree(stack, e->sign);
- silc_sfree(stack, e);
-
- /* Finalize message payload encoding */
- silc_message_payload_encode_final(payload, flags, cipher, hmac,
- iv, iv_len, payload_len,
- sid, rid, stack, buffer,
- encoded, encoded_context);
-}
-
-/* Encodes the SILC_MESSAGE_FLAG_SIGNED Payload and computes the digital
- signature. */
-
-static SilcAsyncOperation
-silc_message_signed_payload_encode(SilcBuffer payload,
- SilcMessageEncode *e)
-{
- SilcAsyncOperation op;
- SilcBuffer sign;
- unsigned char *pk = NULL;
- SilcUInt32 pk_len = 0;
- SilcUInt16 pk_type;
- SilcStack stack = e->stack;
- SilcRng rng = e->rng;
- SilcHash hash = e->hash;
- SilcPublicKey public_key = e->public_key;
- SilcPrivateKey private_key = e->private_key;
- unsigned char *message_payload;
- SilcUInt16 message_payload_len;
-
- message_payload = payload->head;
- message_payload_len = silc_buffer_headlen(payload);
-
- if (!message_payload || !message_payload_len || !private_key || !hash) {
- e->encoded(NULL, e->context);
- silc_sfree(stack, e);
- silc_stack_free(stack);
- return NULL;
- }
-
- if (public_key) {
- e->pk = pk = silc_pkcs_public_key_encode(stack, public_key, &pk_len);
- if (!pk) {
- e->encoded(NULL, e->context);
- silc_sfree(stack, e);
- silc_stack_free(stack);
- return NULL;
- }
- e->pk_len = pk_len;
- }
- pk_type = silc_pkcs_get_type(private_key);
-
- /* Encode the data to be signed */
- e->sign = sign = silc_message_signed_encode_data(stack, message_payload,
- message_payload_len,
- pk, pk_len, pk_type);
- if (!sign) {
- e->encoded(NULL, e->context);
- silc_sfree(stack, pk);
- silc_sfree(stack, e);
- silc_stack_free(stack);
- return NULL;
- }
-
- /* Compute signature */
- op = silc_pkcs_sign(private_key, sign->data, silc_buffer_len(sign),
- TRUE, hash, rng,
- silc_message_signed_payload_encode_cb, e);
-
- return op;
-}
-
-/***************************** Payload parsing ******************************/
-
-/* Decrypts the Message Payload. The `data' is the actual Message Payload. */
-
-SilcBool silc_message_payload_decrypt(unsigned char *data,
- size_t data_len,
- SilcBool private_message,
- SilcBool static_key,
- SilcCipher cipher,
- SilcHmac hmac,
- unsigned char *sender_id,
- SilcUInt32 sender_id_len,
- unsigned char *receiver_id,
- SilcUInt32 receiver_id_len,
- SilcBool check_mac)
-{
- SilcUInt32 mac_len, iv_len = 0, block_len;
- SilcUInt16 len, totlen;
- unsigned char mac[32], *ivp;
-
- mac_len = silc_hmac_len(hmac);
- block_len = silc_cipher_get_block_len(cipher);
-
- /* IV is present for all channel messages, and private messages when
- static key (pre-shared key) is used. */
- if (!private_message || (private_message && static_key))
- iv_len = block_len;
-
- if (silc_unlikely(data_len < (mac_len + iv_len + block_len)))
- return FALSE;
-
- if (silc_likely(check_mac)) {
- /* Check the MAC of the message */
- SILC_LOG_DEBUG(("Checking message MAC"));
- silc_hmac_init(hmac);
- silc_hmac_update(hmac, data, data_len - mac_len);
- silc_hmac_update(hmac, sender_id, sender_id_len);
- silc_hmac_update(hmac, receiver_id, receiver_id_len);
- silc_hmac_final(hmac, mac, &mac_len);
- if (silc_unlikely(memcmp(data + (data_len - mac_len), mac, mac_len))) {
- /* Check for old style (version 1.2) message MAC. Remove this check
- at some point. */
- silc_hmac_init(hmac);
- silc_hmac_update(hmac, data, data_len - mac_len);
- silc_hmac_final(hmac, mac, &mac_len);
- if (silc_unlikely(memcmp(data + (data_len - mac_len), mac, mac_len))) {
- SILC_LOG_DEBUG(("Message MAC does not match"));
- return FALSE;
- }
- }
- SILC_LOG_DEBUG(("MAC is Ok"));
- }
-
- /* Decrypt first only one block to get the header and then rest of
- the data. This is done because there might be unencrypted data at
- the end and we don't know the encrypted length yet. */
-
- /* Get pointer to the IV */
- ivp = (iv_len ? data + (data_len - iv_len - mac_len) :
- silc_cipher_get_iv(cipher));
-
- /* Decrypt block */
- if (silc_unlikely(!silc_cipher_decrypt(cipher, data, data, block_len,
- ivp))) {
- SILC_ASSERT(FALSE);
- return FALSE;
- }
-
- /* Get the payload length and decrypt rest */
- totlen = 2;
- SILC_GET16_MSB(len, data + totlen);
- totlen += 2 + len;
- if (silc_unlikely(totlen + iv_len + mac_len + 2 > data_len))
- return FALSE;
- totlen += 2;
- if (totlen >= block_len)
- if (silc_unlikely(!silc_cipher_decrypt(cipher, data + block_len,
- data + block_len,
- (totlen - block_len) +
- SILC_MESSAGE_PAD(totlen), ivp))) {
- SILC_ASSERT(FALSE);
- return FALSE;
- }
-
- return TRUE;
-}
-
-/* Parses Message Payload returning new payload structure. This also
- decrypts it and checks the MAC. */
-
-SilcMessagePayload
-silc_message_payload_parse(unsigned char *payload,
- SilcUInt32 payload_len,
- SilcBool private_message,
- SilcBool static_key,
- SilcCipher cipher,
- SilcHmac hmac,
- unsigned char *sender_id,
- SilcUInt32 sender_id_len,
- unsigned char *receiver_id,
- SilcUInt32 receiver_id_len,
- SilcStack stack,
- SilcBool no_allocation,
- SilcMessagePayload message)
-{
- SilcBufferStruct buffer;
- SilcMessagePayload newp = NULL;
- int ret;
- SilcUInt32 mac_len = 0, iv_len = 0;
-
- SILC_LOG_DEBUG(("Parsing Message Payload"));
-
- silc_buffer_set(&buffer, payload, payload_len);
-
- /* Decrypt the payload */
- if (silc_likely(cipher)) {
- ret = silc_message_payload_decrypt(buffer.data, silc_buffer_len(&buffer),
- private_message, static_key,
- cipher, hmac, sender_id,
- sender_id_len, receiver_id,
- receiver_id_len, TRUE);
- if (silc_unlikely(ret == FALSE))
- return NULL;
- }
-
- if (silc_likely(hmac))
- mac_len = silc_hmac_len(hmac);
-
- /* IV is present for all channel messages, and private messages when
- static key (pre-shared key) is used. */
- if (cipher && (!private_message || (private_message && static_key)))
- iv_len = silc_cipher_get_block_len(cipher);
-
- if (!message) {
- newp = message = silc_calloc(1, sizeof(*newp));
- if (silc_unlikely(!newp))
- return NULL;
- }
- memset(message, 0, sizeof(*message));
- message->allocated = (stack || no_allocation ? FALSE : TRUE);
-
- /* Parse the Message Payload. */
- if (!no_allocation)
- ret = silc_buffer_sunformat(stack, &buffer,
- SILC_STR_UI_SHORT(&message->flags),
- SILC_STR_UI16_NSTRING_ALLOC(&message->data,
- &message->data_len),
- SILC_STR_UI16_NSTRING_ALLOC(&message->pad,
- &message->pad_len),
- SILC_STR_END);
- else
- ret = silc_buffer_unformat(&buffer,
- SILC_STR_UI_SHORT(&message->flags),
- SILC_STR_UI16_NSTRING(&message->data,
- &message->data_len),
- SILC_STR_UI16_NSTRING(&message->pad,
- &message->pad_len),
- SILC_STR_END);
- if (silc_unlikely(ret == -1))
- goto err;
-
- if (silc_unlikely((message->data_len > silc_buffer_len(&buffer) -
- 6 - mac_len - iv_len) ||
- (message->pad_len + message->data_len >
- silc_buffer_len(&buffer) - 6 - mac_len - iv_len))) {
- SILC_LOG_ERROR(("Incorrect Message Payload in packet"));
- goto err;
- }
-
- /* Parse Signed Message Payload if provided */
- if (message->flags & SILC_MESSAGE_FLAG_SIGNED &&
- message->data_len + message->pad_len + 6 + mac_len +
- iv_len < silc_buffer_len(&buffer)) {
- if (!silc_message_signed_payload_parse(buffer.data + 6 +
- message->data_len +
- message->pad_len,
- silc_buffer_len(&buffer) -
- iv_len - mac_len - 6 -
- message->data_len -
- message->pad_len,
- &message->sig))
- goto err;
- }
-
- /* Parse MAC from the payload */
- if (mac_len)
- message->mac = buffer.data + (silc_buffer_len(&buffer) - mac_len);
-
- return newp;
-
- err:
- if (newp)
- silc_message_payload_free(newp);
- return NULL;
-}
-
-
-/***************************** Payload encoding *****************************/
-
-/* This function is used to encrypt the Messsage Payload which is
- the `data' and `data_len'. This is used internally by the Message
- Payload encoding routines but application may call this too if needed.
- The `true_len' is the data length which is used to create MAC out of. */
-
-SilcBool silc_message_payload_encrypt(unsigned char *data,
- SilcUInt32 data_len,
- SilcUInt32 true_len,
- unsigned char *iv,
- SilcID *sender_id,
- SilcID *receiver_id,
- SilcCipher cipher,
- SilcHmac hmac)
-{
- unsigned char sid[32], rid[32];
- SilcUInt32 sid_len = 0, rid_len = 0;
-
- /* Encrypt payload of the packet */
- if (silc_unlikely(!silc_cipher_encrypt(cipher, data, data, data_len, iv)))
- return FALSE;
-
- /* Encode IDs */
- silc_id_id2str(&sender_id->u.client_id, SILC_ID_CLIENT, sid, sizeof(sid),
- &sid_len);
- if (receiver_id->type == SILC_ID_CLIENT)
- silc_id_id2str(&receiver_id->u.client_id, SILC_ID_CLIENT, rid,
- sizeof(rid), &rid_len);
- else if (receiver_id->type == SILC_ID_CHANNEL)
- silc_id_id2str(&receiver_id->u.channel_id, SILC_ID_CHANNEL, rid,
- sizeof(rid), &rid_len);
-
- /* Compute the MAC of the encrypted message data */
- silc_hmac_init(hmac);
- silc_hmac_update(hmac, data, true_len);
- silc_hmac_update(hmac, sid, sid_len);
- silc_hmac_update(hmac, rid, rid_len);
- silc_hmac_final(hmac, data + true_len, NULL);
-
- return TRUE;
-}
-
-/* Encrypt message payload */
-
-static int silc_message_payload_encode_encrypt(SilcStack stack,
- SilcBuffer buffer,
- void *value, void *context)
-{
- SilcMessageEncode *e = context;
- SilcUInt32 mac_len;
-
- if (!e->cipher || !e->hmac)
- return 0;
-
- mac_len = silc_hmac_len(e->hmac);
- if (silc_unlikely(!silc_buffer_enlarge(buffer, mac_len)))
- return -1;
-
- if (silc_unlikely(!silc_message_payload_encrypt(buffer->head,
- e->payload_len,
- silc_buffer_headlen(buffer),
- e->iv, &e->sid, &e->rid,
- e->cipher, e->hmac)))
- return -1;
-
- return mac_len;
-}
-
-/* Finalize message payload encoding */
-
-static void
-silc_message_payload_encode_final(SilcBuffer buffer,
- SilcMessageFlags flags,
- SilcCipher cipher,
- SilcHmac hmac,
- unsigned char *iv,
- SilcUInt32 iv_len,
- SilcUInt32 payload_len,
- SilcID *sender_id,
- SilcID *receiver_id,
- SilcStack stack,
- SilcBuffer signature,
- SilcMessagePayloadEncoded encoded,
- void *context)
-{
- SilcMessageEncode e;
-
- e.flags = flags;
- e.cipher = cipher;
- e.hmac = hmac;
- e.sid = *sender_id;
- e.rid = *receiver_id;
- e.iv = iv;
- e.payload_len = payload_len;
-
- /* Encrypt */
- if (silc_buffer_format(buffer,
- SILC_STR_DATA(signature ?
- silc_buffer_data(signature) : NULL,
- signature ?
- silc_buffer_len(signature) : 0),
- SILC_STR_DATA(iv, iv_len),
- SILC_STR_FUNC(silc_message_payload_encode_encrypt,
- NULL, &e),
- SILC_STR_END) < 0) {
- silc_buffer_sfree(stack, buffer);
- encoded(NULL, context);
- return;
- }
-
- /* Deliver message payload */
- silc_buffer_start(buffer);
- encoded(buffer, context);
-
- silc_buffer_sfree(stack, buffer);
- silc_buffer_sfree(stack, signature);
- silc_stack_free(stack);
-}
-
-/* Encodes Message Payload into a buffer and returns it. */
-
-SilcAsyncOperation
-silc_message_payload_encode(SilcMessageFlags flags,
- const unsigned char *data,
- SilcUInt32 data_len,
- SilcBool generate_iv,
- SilcBool private_message,
- SilcCipher cipher,
- SilcHmac hmac,
- SilcRng rng,
- SilcPublicKey public_key,
- SilcPrivateKey private_key,
- SilcHash hash,
- SilcID *sender_id,
- SilcID *receiver_id,
- SilcStack stack,
- SilcMessagePayloadEncoded encoded,
- void *context)
-{
- SilcUInt32 pad_len = 0, mac_len = 0, iv_len = 0;
- unsigned char pad[16], iv[SILC_CIPHER_MAX_IV_SIZE];
- SilcBuffer buffer;
- int i;
-
- SILC_LOG_DEBUG(("Encoding Message Payload"));
-
- if (silc_unlikely(!data_len)) {
- encoded(NULL, context);
- return NULL;
- }
- if (silc_unlikely(!private_message && (!cipher || !hmac))) {
- encoded(NULL, context);
- return NULL;
- }
-
- stack = silc_stack_alloc(0, stack ? stack : silc_crypto_stack());
-
- buffer = silc_buffer_salloc(stack, 0);
- if (silc_unlikely(!buffer)) {
- encoded(NULL, context);
- silc_stack_free(stack);
- return NULL;
- }
-
- /* For channel messages IV is always generated */
- if (!private_message && !generate_iv)
- generate_iv = TRUE;
-
- /* Generate IV */
- if (cipher && generate_iv) {
- iv_len = silc_cipher_get_block_len(cipher);
- if (rng) {
- for (i = 0; i < iv_len; i++) iv[i] = silc_rng_get_byte_fast(rng);
- } else {
- for (i = 0; i < iv_len; i++) iv[i] = silc_rng_global_get_byte_fast();
- }
- }
-
- if (hmac)
- mac_len = silc_hmac_len(hmac);
- data_len = silc_message_payload_datalen(data_len, mac_len + iv_len, flags,
- public_key, private_key);
-
- /* Calculate length of padding. IV is not included into the calculation
- since it is not encrypted. */
- pad_len = SILC_MESSAGE_PAD(6 + data_len);
-
- /* Generate padding */
- if (cipher) {
- if (rng) {
- for (i = 0; i < pad_len; i++) pad[i] = silc_rng_get_byte_fast(rng);
- } else {
- for (i = 0; i < pad_len; i++) pad[i] = silc_rng_global_get_byte_fast();
- }
- }
-
- /* Encode the Message Payload */
- if (silc_buffer_format(buffer,
- SILC_STR_ADVANCE,
- SILC_STR_UI_SHORT(flags),
- SILC_STR_UI_SHORT(data_len),
- SILC_STR_DATA(data, data_len),
- SILC_STR_UI_SHORT(pad_len),
- SILC_STR_DATA(pad, pad_len),
- SILC_STR_END) < 0) {
- silc_buffer_sfree(stack, buffer);
- encoded(NULL, context);
- silc_stack_free(stack);
- return NULL;
- }
-
- if (flags & SILC_MESSAGE_FLAG_SIGNED) {
- SilcMessageEncode *e = silc_scalloc(stack, 1, sizeof(*e));
- if (!e) {
- silc_buffer_sfree(stack, buffer);
- encoded(NULL, context);
- silc_stack_free(stack);
- return NULL;
- }
-
- e->stack = stack;
- e->buffer = buffer;
- e->flags = flags;
- e->public_key = public_key;
- e->private_key = private_key;
- e->rng = rng;
- e->hash = hash;
- e->cipher = cipher;
- e->hmac = hmac;
- e->sid = *sender_id;
- e->rid = *receiver_id;
- e->iv = iv_len ? iv : NULL;
- e->iv_len = iv_len;
- e->payload_len = 6 + data_len + pad_len;
- e->encoded = encoded;
- e->context = context;
-
- /* Compute signature */
- return silc_message_signed_payload_encode(buffer, e);
- }
-
- /* Finalize */
- silc_message_payload_encode_final(buffer, flags, cipher, hmac,
- iv_len ? iv : NULL, iv_len,
- 6 + data_len + pad_len,
- sender_id, receiver_id, stack, NULL,
- encoded, context);
- return NULL;
-}
-
-/* Free's Message Payload */
-
-void silc_message_payload_free(SilcMessagePayload payload)
-{
- silc_message_signed_payload_free(&payload->sig);
- if (payload->data) {
- memset(payload->data, 0, payload->data_len);
- if (payload->allocated)
- silc_free(payload->data);
- }
- if (payload->allocated) {
- silc_free(payload->pad);
- silc_free(payload);
- }
-}
-
-/* Return flags */
-
-SilcMessageFlags silc_message_get_flags(SilcMessagePayload payload)
-{
- return payload->flags;
-}
-
-/* Return data */
-
-unsigned char *silc_message_get_data(SilcMessagePayload payload,
- SilcUInt32 *data_len)
-{
- if (data_len)
- *data_len = payload->data_len;
- return payload->data;
-}
-
-/* Return MAC. The caller knows the length of the MAC */
-
-unsigned char *silc_message_get_mac(SilcMessagePayload payload)
-{
- return payload->mac;
-}
-
-/* Verify the signature in SILC_MESSAGE_FLAG_SIGNED Payload */
-
-SilcAsyncOperation
-silc_message_signed_verify(SilcMessagePayload message,
- SilcPublicKey remote_public_key,
- SilcHash hash,
- SilcAuthResultCb result,
- void *context)
-{
- SilcAsyncOperation op;
- SilcBuffer sign, tmp;
- SilcStack stack = NULL;
- SilcMessageSignedPayload sig = &message->sig;
-
- if (!(message->flags & SILC_MESSAGE_FLAG_SIGNED) ||
- !sig->sign_len || !remote_public_key || !hash) {
- result(FALSE, context);
- return NULL;
- }
-
- if (silc_crypto_stack())
- stack = silc_stack_alloc(0, silc_crypto_stack());
-
- /* Generate the signature verification data, the Message Payload */
- tmp = silc_buffer_salloc_size(stack,
- 6 + message->data_len + message->pad_len);
- silc_buffer_sformat(stack, tmp,
- SILC_STR_UI_SHORT(message->flags),
- SILC_STR_UI_SHORT(message->data_len),
- SILC_STR_DATA(message->data, message->data_len),
- SILC_STR_UI_SHORT(message->pad_len),
- SILC_STR_DATA(message->pad, message->pad_len),
- SILC_STR_END);
- sign = silc_message_signed_encode_data(stack, tmp->data, silc_buffer_len(tmp),
- sig->pk_data, sig->pk_len,
- sig->pk_type);
- silc_buffer_clear(tmp);
- silc_buffer_sfree(stack, tmp);
-
- if (!sign) {
- result(FALSE, context);
- silc_stack_free(stack);
- return NULL;
- }
-
- /* Verify the authentication data */
- op = silc_pkcs_verify(remote_public_key, sig->sign_data, sig->sign_len,
- silc_buffer_data(sign), silc_buffer_len(sign),
- hash, result, context);
-
- silc_buffer_clear(sign);
- silc_buffer_sfree(stack, sign);
- silc_stack_free(stack);
-
- return op;
-}
-
-/* Return the public key from the payload */
-
-SilcPublicKey
-silc_message_signed_get_public_key(SilcMessagePayload payload,
- const unsigned char **pk_data,
- SilcUInt32 *pk_data_len)
-{
- SilcPublicKey pk;
- SilcMessageSignedPayload sig = &payload->sig;
-
- if (!sig->pk_data)
- return NULL;
-
- if (!silc_pkcs_public_key_alloc(sig->pk_type, sig->pk_data,
- sig->pk_len, &pk))
- return NULL;
-
- if (pk_data)
- *pk_data = sig->pk_data;
- if (pk_data_len)
- *pk_data_len = sig->pk_len;
-
- return pk;
-}
projects / crypto.git / blobdiff