- if(!read_rsa_public_key(c)) {
- return false;
- }
-
- c->allow_request = METAKEY;
-
- return send_metakey(c);
-}
-
-bool send_metakey(connection_t *c)
-{
- char buffer[MAX_STRING_SIZE];
- int len;
- bool x;
-
- cp();
-
- len = RSA_size(c->rsa_key);
-
- /* Allocate buffers for the meta key */
-
- if(!c->outkey)
- c->outkey = xmalloc(len);
-
- if(!c->outctx)
- c->outctx = xmalloc_and_zero(sizeof(*c->outctx));
- cp();
- /* Copy random data to the buffer */
-
- RAND_pseudo_bytes(c->outkey, len);
-
- /* The message we send must be smaller than the modulus of the RSA key.
- By definition, for a key of k bits, the following formula holds:
-
- 2^(k-1) <= modulus < 2^(k)
-
- Where ^ means "to the power of", not "xor".
- This means that to be sure, we must choose our message < 2^(k-1).
- This can be done by setting the most significant bit to zero.
- */
-
- c->outkey[0] &= 0x7F;
-
- ifdebug(SCARY_THINGS) {
- bin2hex(c->outkey, buffer, len);
- buffer[len * 2] = '\0';
- logger(LOG_DEBUG, _("Generated random meta key (unencrypted): %s"),
- buffer);
- }
-
- /* Encrypt the random data
-
- We do not use one of the PKCS padding schemes here.
- This is allowed, because we encrypt a totally random string
- with a length equal to that of the modulus of the RSA key.
- */
-
- if(RSA_public_encrypt(len, c->outkey, buffer, c->rsa_key, RSA_NO_PADDING) != len) {
- logger(LOG_ERR, _("Error during encryption of meta key for %s (%s)"),
- c->name, c->hostname);
- return false;
- }
-
- /* Convert the encrypted random data to a hexadecimal formatted string */
-
- bin2hex(buffer, buffer, len);
- buffer[len * 2] = '\0';
-
- /* Send the meta key */
-
- x = send_request(c, "%d %d %d %d %d %s", METAKEY,
- c->outcipher ? c->outcipher->nid : 0,
- c->outdigest ? c->outdigest->type : 0, c->outmaclength,
- c->outcompression, buffer);
-
- /* Further outgoing requests are encrypted with the key we just generated */
-
- if(c->outcipher) {
- if(!EVP_EncryptInit(c->outctx, c->outcipher,
- c->outkey + len - c->outcipher->key_len,
- c->outkey + len - c->outcipher->key_len -
- c->outcipher->iv_len)) {
- logger(LOG_ERR, _("Error during initialisation of cipher for %s (%s): %s"),
- c->name, c->hostname, ERR_error_string(ERR_get_error(), NULL));
- return false;
- }
-
- c->status.encryptout = true;
- }
-
- return x;
-}
-
-bool metakey_h(connection_t *c)
-{
- char buffer[MAX_STRING_SIZE];
- int cipher, digest, maclength, compression;
- int len;
-
- cp();
-
- if(sscanf(c->buffer, "%*d %d %d %d %d " MAX_STRING, &cipher, &digest, &maclength, &compression, buffer) != 5) {
- logger(LOG_ERR, _("Got bad %s from %s (%s)"), "METAKEY", c->name,
- c->hostname);
- return false;
- }
-
- len = RSA_size(myself->connection->rsa_key);
-
- /* Check if the length of the meta key is all right */
-
- if(strlen(buffer) != len * 2) {
- logger(LOG_ERR, _("Possible intruder %s (%s): %s"), c->name, c->hostname, "wrong keylength");
- return false;
- }
-
- /* Allocate buffers for the meta key */
-
- if(!c->inkey)
- c->inkey = xmalloc(len);
-
- if(!c->inctx)
- c->inctx = xmalloc_and_zero(sizeof(*c->inctx));
-
- /* Convert the challenge from hexadecimal back to binary */
-
- hex2bin(buffer, buffer, len);
-
- /* Decrypt the meta key */
-
- if(RSA_private_decrypt(len, buffer, c->inkey, myself->connection->rsa_key, RSA_NO_PADDING) != len) { /* See challenge() */
- logger(LOG_ERR, _("Error during encryption of meta key for %s (%s)"),
- c->name, c->hostname);
- return false;
- }
-
- ifdebug(SCARY_THINGS) {
- bin2hex(c->inkey, buffer, len);
- buffer[len * 2] = '\0';
- logger(LOG_DEBUG, _("Received random meta key (unencrypted): %s"), buffer);
- }
-
- /* All incoming requests will now be encrypted. */
-
- /* Check and lookup cipher and digest algorithms */
-
- if(cipher) {
- c->incipher = EVP_get_cipherbynid(cipher);
-
- if(!c->incipher) {
- logger(LOG_ERR, _("%s (%s) uses unknown cipher!"), c->name, c->hostname);
- return false;
- }
-
- if(!EVP_DecryptInit(c->inctx, c->incipher,
- c->inkey + len - c->incipher->key_len,
- c->inkey + len - c->incipher->key_len -
- c->incipher->iv_len)) {
- logger(LOG_ERR, _("Error during initialisation of cipher from %s (%s): %s"),
- c->name, c->hostname, ERR_error_string(ERR_get_error(), NULL));
- return false;
- }
-
- c->status.decryptin = true;
- } else {
- c->incipher = NULL;
- }
-
- c->inmaclength = maclength;
-
- if(digest) {
- c->indigest = EVP_get_digestbynid(digest);
-
- if(!c->indigest) {
- logger(LOG_ERR, _("Node %s (%s) uses unknown digest!"), c->name, c->hostname);
- return false;
- }
-
- if(c->inmaclength > c->indigest->md_size || c->inmaclength < 0) {
- logger(LOG_ERR, _("%s (%s) uses bogus MAC length!"), c->name, c->hostname);
- return false;
- }
- } else {
- c->indigest = NULL;
- }
-
- c->incompression = compression;
-
- c->allow_request = CHALLENGE;
-
- return send_challenge(c);
-}
-
-bool send_challenge(connection_t *c)
-{
- char buffer[MAX_STRING_SIZE];
- int len;
-
- cp();
-
- /* CHECKME: what is most reasonable value for len? */
-
- len = RSA_size(c->rsa_key);
-
- /* Allocate buffers for the challenge */
-
- if(!c->hischallenge)
- c->hischallenge = xmalloc(len);
-
- /* Copy random data to the buffer */
-
- RAND_pseudo_bytes(c->hischallenge, len);
-
- /* Convert to hex */
-
- bin2hex(c->hischallenge, buffer, len);
- buffer[len * 2] = '\0';
-
- /* Send the challenge */
-
- return send_request(c, "%d %s", CHALLENGE, buffer);
-}
-
-bool challenge_h(connection_t *c)
-{
- char buffer[MAX_STRING_SIZE];
- int len;
-
- cp();
-
- if(sscanf(c->buffer, "%*d " MAX_STRING, buffer) != 1) {
- logger(LOG_ERR, _("Got bad %s from %s (%s)"), "CHALLENGE", c->name,
- c->hostname);
- return false;
- }
-
- len = RSA_size(myself->connection->rsa_key);
-
- /* Check if the length of the challenge is all right */
-
- if(strlen(buffer) != len * 2) {
- logger(LOG_ERR, _("Possible intruder %s (%s): %s"), c->name,
- c->hostname, "wrong challenge length");
- return false;
- }
-
- /* Allocate buffers for the challenge */
-
- if(!c->mychallenge)
- c->mychallenge = xmalloc(len);
-
- /* Convert the challenge from hexadecimal back to binary */
-
- hex2bin(buffer, c->mychallenge, len);
-
- c->allow_request = CHAL_REPLY;
-
- /* Rest is done by send_chal_reply() */
-
- return send_chal_reply(c);
-}
-
-bool send_chal_reply(connection_t *c)
-{
- char hash[EVP_MAX_MD_SIZE * 2 + 1];
- EVP_MD_CTX ctx;
-
- cp();
-
- /* Calculate the hash from the challenge we received */
-
- if(!EVP_DigestInit(&ctx, c->indigest)
- || !EVP_DigestUpdate(&ctx, c->mychallenge, RSA_size(myself->connection->rsa_key))
- || !EVP_DigestFinal(&ctx, hash, NULL)) {
- logger(LOG_ERR, _("Error during calculation of response for %s (%s): %s"),
- c->name, c->hostname, ERR_error_string(ERR_get_error(), NULL));
- return false;
- }
-
- /* Convert the hash to a hexadecimal formatted string */
-
- bin2hex(hash, hash, c->indigest->md_size);
- hash[c->indigest->md_size * 2] = '\0';
-
- /* Send the reply */
-
- return send_request(c, "%d %s", CHAL_REPLY, hash);
-}
-
-bool chal_reply_h(connection_t *c)
-{
- char hishash[MAX_STRING_SIZE];
- char myhash[EVP_MAX_MD_SIZE];
- EVP_MD_CTX ctx;
-
- cp();
-
- if(sscanf(c->buffer, "%*d " MAX_STRING, hishash) != 1) {
- logger(LOG_ERR, _("Got bad %s from %s (%s)"), "CHAL_REPLY", c->name,
- c->hostname);
- return false;
- }
-
- /* Check if the length of the hash is all right */
-
- if(strlen(hishash) != c->outdigest->md_size * 2) {
- logger(LOG_ERR, _("Possible intruder %s (%s): %s"), c->name,
- c->hostname, _("wrong challenge reply length"));
- return false;
- }
-
- /* Convert the hash to binary format */
-
- hex2bin(hishash, hishash, c->outdigest->md_size);
-
- /* Calculate the hash from the challenge we sent */
-
- if(!EVP_DigestInit(&ctx, c->outdigest)
- || !EVP_DigestUpdate(&ctx, c->hischallenge, RSA_size(c->rsa_key))
- || !EVP_DigestFinal(&ctx, myhash, NULL)) {
- logger(LOG_ERR, _("Error during calculation of response from %s (%s): %s"),
- c->name, c->hostname, ERR_error_string(ERR_get_error(), NULL));
- return false;
- }
-
- /* Verify the incoming hash with the calculated hash */
-
- if(memcmp(hishash, myhash, c->outdigest->md_size)) {
- logger(LOG_ERR, _("Possible intruder %s (%s): %s"), c->name,
- c->hostname, _("wrong challenge reply"));
-
- ifdebug(SCARY_THINGS) {
- bin2hex(myhash, hishash, SHA_DIGEST_LENGTH);
- hishash[SHA_DIGEST_LENGTH * 2] = '\0';
- logger(LOG_DEBUG, _("Expected challenge reply: %s"), hishash);
- }
-
- return false;
- }
-
- /* Identity has now been positively verified.
- Send an acknowledgement with the rest of the information needed.
- */
-
- c->allow_request = ACK;
-
- return send_ack(c);
-}
-
-bool send_ack(connection_t *c)
-{
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