Finish crypto wrapping. Also provide wrappers for OpenSSL.
Disable libgcrypt by default. Since it doesn't support the OFB cipher mode, we can't use it in a backwards compatible way.
This commit is contained in:
Guus Sliepen
parent
f42e57f663
commit
1b8f891836
28 changed files with 951 additions and 497 deletions
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@ -22,14 +22,10 @@
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#include "system.h"
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#include <openssl/sha.h>
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#include <openssl/rand.h>
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#include <openssl/err.h>
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#include <openssl/evp.h>
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#include "splay_tree.h"
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#include "conf.h"
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#include "connection.h"
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#include "crypto.h"
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#include "edge.h"
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#include "graph.h"
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#include "logger.h"
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@ -116,27 +112,22 @@ bool id_h(connection_t *c, char *request) {
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}
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bool send_metakey(connection_t *c) {
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char *buffer;
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unsigned int len;
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bool x;
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size_t len = rsa_size(&c->rsa);
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char key[len];
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char enckey[len];
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char hexkey[2 * len + 1];
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cp();
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len = get_rsa_size(&c->rsa_key);
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/* Allocate buffers for the meta key */
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buffer = alloca(2 * len + 1);
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if(!cipher_open_blowfish_ofb(&c->outcipher))
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return false;
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if(!c->outkey)
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c->outkey = xmalloc(len);
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if(!digest_open_sha1(&c->outdigest))
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return false;
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if(!c->outctx)
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c->outctx = xmalloc_and_zero(sizeof(*c->outctx));
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cp();
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/* Copy random data to the buffer */
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/* Create a random key */
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RAND_pseudo_bytes((unsigned char *)c->outkey, len);
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randomize(key, len);
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/* The message we send must be smaller than the modulus of the RSA key.
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By definition, for a key of k bits, the following formula holds:
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@ -148,13 +139,14 @@ bool send_metakey(connection_t *c) {
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This can be done by setting the most significant bit to zero.
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*/
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c->outkey[0] &= 0x7F;
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key[0] &= 0x7F;
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cipher_set_key_from_rsa(&c->outcipher, key, len, true);
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ifdebug(SCARY_THINGS) {
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bin2hex(c->outkey, buffer, len);
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buffer[len * 2] = '\0';
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logger(LOG_DEBUG, _("Generated random meta key (unencrypted): %s"),
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buffer);
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bin2hex(key, hexkey, len);
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hexkey[len * 2] = '\0';
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logger(LOG_DEBUG, _("Generated random meta key (unencrypted): %s"), hexkey);
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}
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/* Encrypt the random data
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@ -164,134 +156,78 @@ bool send_metakey(connection_t *c) {
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with a length equal to that of the modulus of the RSA key.
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*/
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if(!rsa_public_encrypt(len, (unsigned char *)c->outkey, (unsigned char *)buffer, &c->rsa_key)) {
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logger(LOG_ERR, _("Error during encryption of meta key for %s (%s)"),
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c->name, c->hostname);
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if(!rsa_public_encrypt(&c->rsa, key, len, enckey)) {
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logger(LOG_ERR, _("Error during encryption of meta key for %s (%s)"), c->name, c->hostname);
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return false;
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}
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/* Convert the encrypted random data to a hexadecimal formatted string */
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bin2hex(buffer, buffer, len);
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buffer[len * 2] = '\0';
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bin2hex(enckey, hexkey, len);
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hexkey[len * 2] = '\0';
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/* Send the meta key */
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x = send_request(c, "%d %d %d %d %d %s", METAKEY,
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c->outcipher ? c->outcipher->nid : 0,
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c->outdigest ? c->outdigest->type : 0, c->outmaclength,
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c->outcompression, buffer);
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/* Further outgoing requests are encrypted with the key we just generated */
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if(c->outcipher) {
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if(!EVP_EncryptInit(c->outctx, c->outcipher,
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(unsigned char *)c->outkey + len - c->outcipher->key_len,
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(unsigned char *)c->outkey + len - c->outcipher->key_len -
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c->outcipher->iv_len)) {
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logger(LOG_ERR, _("Error during initialisation of cipher for %s (%s): %s"),
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c->name, c->hostname, ERR_error_string(ERR_get_error(), NULL));
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return false;
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}
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c->status.encryptout = true;
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}
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return x;
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bool result = send_request(c, "%d %d %d %d %d %s", METAKEY,
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cipher_get_nid(&c->outcipher),
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digest_get_nid(&c->outdigest), c->outmaclength,
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c->outcompression, hexkey);
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c->status.encryptout = true;
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return result;
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}
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bool metakey_h(connection_t *c, char *request) {
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char buffer[MAX_STRING_SIZE];
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char hexkey[MAX_STRING_SIZE];
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int cipher, digest, maclength, compression;
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int len;
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size_t len = rsa_size(&myself->connection->rsa);
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char enckey[len];
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char key[len];
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cp();
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if(sscanf(request, "%*d %d %d %d %d " MAX_STRING, &cipher, &digest, &maclength, &compression, buffer) != 5) {
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logger(LOG_ERR, _("Got bad %s from %s (%s)"), "METAKEY", c->name,
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c->hostname);
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if(sscanf(request, "%*d %d %d %d %d " MAX_STRING, &cipher, &digest, &maclength, &compression, hexkey) != 5) {
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logger(LOG_ERR, _("Got bad %s from %s (%s)"), "METAKEY", c->name, c->hostname);
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return false;
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}
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len = get_rsa_size(&myself->connection->rsa_key);
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/* Check if the length of the meta key is all right */
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if(strlen(buffer) != len * 2) {
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if(strlen(hexkey) != len * 2) {
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logger(LOG_ERR, _("Possible intruder %s (%s): %s"), c->name, c->hostname, "wrong keylength");
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return false;
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}
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/* Allocate buffers for the meta key */
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if(!c->inkey)
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c->inkey = xmalloc(len);
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if(!c->inctx)
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c->inctx = xmalloc_and_zero(sizeof(*c->inctx));
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/* Convert the challenge from hexadecimal back to binary */
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hex2bin(buffer, buffer, len);
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hex2bin(hexkey, enckey, len);
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/* Decrypt the meta key */
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if(!rsa_private_decrypt(len, (unsigned char *)buffer, (unsigned char *)c->inkey, &myself->connection->rsa_key)) {
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if(!rsa_private_decrypt(&myself->connection->rsa, enckey, len, key)) {
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logger(LOG_ERR, _("Error during encryption of meta key for %s (%s)"), c->name, c->hostname);
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return false;
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}
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ifdebug(SCARY_THINGS) {
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bin2hex(c->inkey, buffer, len);
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buffer[len * 2] = '\0';
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logger(LOG_DEBUG, _("Received random meta key (unencrypted): %s"), buffer);
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bin2hex(key, hexkey, len);
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hexkey[len * 2] = '\0';
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logger(LOG_DEBUG, _("Received random meta key (unencrypted): %s"), hexkey);
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}
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/* All incoming requests will now be encrypted. */
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/* Check and lookup cipher and digest algorithms */
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if(cipher) {
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c->incipher = EVP_get_cipherbynid(cipher);
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if(!c->incipher) {
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logger(LOG_ERR, _("%s (%s) uses unknown cipher!"), c->name, c->hostname);
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return false;
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}
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if(!EVP_DecryptInit(c->inctx, c->incipher,
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(unsigned char *)c->inkey + len - c->incipher->key_len,
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(unsigned char *)c->inkey + len - c->incipher->key_len -
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c->incipher->iv_len)) {
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logger(LOG_ERR, _("Error during initialisation of cipher from %s (%s): %s"),
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c->name, c->hostname, ERR_error_string(ERR_get_error(), NULL));
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return false;
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}
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c->status.decryptin = true;
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} else {
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c->incipher = NULL;
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if(!cipher_open_by_nid(&c->incipher, cipher) || !cipher_set_key_from_rsa(&c->incipher, key, len, false)) {
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logger(LOG_ERR, _("Error during initialisation of cipher from %s (%s)"), c->name, c->hostname);
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return false;
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}
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c->inmaclength = maclength;
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if(digest) {
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c->indigest = EVP_get_digestbynid(digest);
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if(!c->indigest) {
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logger(LOG_ERR, _("Node %s (%s) uses unknown digest!"), c->name, c->hostname);
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return false;
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}
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if(c->inmaclength > c->indigest->md_size || c->inmaclength < 0) {
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logger(LOG_ERR, _("%s (%s) uses bogus MAC length!"), c->name, c->hostname);
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return false;
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}
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} else {
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c->indigest = NULL;
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if(!digest_open_by_nid(&c->indigest, digest)) {
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logger(LOG_ERR, _("Error during initialisation of digest from %s (%s)"), c->name, c->hostname);
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return false;
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}
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c->incompression = compression;
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c->status.decryptin = true;
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c->allow_request = CHALLENGE;
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@ -299,25 +235,17 @@ bool metakey_h(connection_t *c, char *request) {
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}
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bool send_challenge(connection_t *c) {
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char *buffer;
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int len;
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size_t len = rsa_size(&c->rsa);
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char buffer[len * 2 + 1];
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cp();
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/* CHECKME: what is most reasonable value for len? */
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len = get_rsa_size(&c->rsa_key);
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/* Allocate buffers for the challenge */
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buffer = alloca(2 * len + 1);
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if(!c->hischallenge)
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c->hischallenge = xmalloc(len);
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/* Copy random data to the buffer */
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RAND_pseudo_bytes((unsigned char *)c->hischallenge, len);
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randomize(c->hischallenge, len);
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/* Convert to hex */
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@ -331,72 +259,48 @@ bool send_challenge(connection_t *c) {
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bool challenge_h(connection_t *c, char *request) {
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char buffer[MAX_STRING_SIZE];
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int len;
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size_t len = rsa_size(&myself->connection->rsa);
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size_t digestlen = digest_length(&c->outdigest);
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char digest[digestlen];
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cp();
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if(sscanf(request, "%*d " MAX_STRING, buffer) != 1) {
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logger(LOG_ERR, _("Got bad %s from %s (%s)"), "CHALLENGE", c->name,
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c->hostname);
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logger(LOG_ERR, _("Got bad %s from %s (%s)"), "CHALLENGE", c->name, c->hostname);
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return false;
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}
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len = get_rsa_size(&myself->connection->rsa_key);
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/* Check if the length of the challenge is all right */
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if(strlen(buffer) != len * 2) {
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logger(LOG_ERR, _("Possible intruder %s (%s): %s"), c->name,
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c->hostname, "wrong challenge length");
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logger(LOG_ERR, _("Possible intruder %s (%s): %s"), c->name, c->hostname, "wrong challenge length");
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return false;
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}
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/* Allocate buffers for the challenge */
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if(!c->mychallenge)
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c->mychallenge = xmalloc(len);
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/* Convert the challenge from hexadecimal back to binary */
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hex2bin(buffer, c->mychallenge, len);
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hex2bin(buffer, buffer, len);
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c->allow_request = CHAL_REPLY;
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/* Rest is done by send_chal_reply() */
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return send_chal_reply(c);
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}
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bool send_chal_reply(connection_t *c) {
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char hash[EVP_MAX_MD_SIZE * 2 + 1];
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EVP_MD_CTX ctx;
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cp();
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/* Calculate the hash from the challenge we received */
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if(!EVP_DigestInit(&ctx, c->indigest)
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|| !EVP_DigestUpdate(&ctx, c->mychallenge, get_rsa_size(&myself->connection->rsa_key))
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|| !EVP_DigestFinal(&ctx, (unsigned char *)hash, NULL)) {
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logger(LOG_ERR, _("Error during calculation of response for %s (%s): %s"),
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c->name, c->hostname, ERR_error_string(ERR_get_error(), NULL));
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return false;
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}
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digest_create(&c->indigest, buffer, len, digest);
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/* Convert the hash to a hexadecimal formatted string */
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bin2hex(hash, hash, c->indigest->md_size);
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hash[c->indigest->md_size * 2] = '\0';
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bin2hex(digest, buffer, digestlen);
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buffer[digestlen * 2] = '\0';
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/* Send the reply */
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return send_request(c, "%d %s", CHAL_REPLY, hash);
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return send_request(c, "%d %s", CHAL_REPLY, buffer);
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}
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bool chal_reply_h(connection_t *c, char *request) {
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char hishash[MAX_STRING_SIZE];
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char myhash[EVP_MAX_MD_SIZE];
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EVP_MD_CTX ctx;
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cp();
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@ -408,38 +312,19 @@ bool chal_reply_h(connection_t *c, char *request) {
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/* Check if the length of the hash is all right */
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if(strlen(hishash) != c->outdigest->md_size * 2) {
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logger(LOG_ERR, _("Possible intruder %s (%s): %s"), c->name,
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c->hostname, _("wrong challenge reply length"));
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if(strlen(hishash) != digest_length(&c->outdigest) * 2) {
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logger(LOG_ERR, _("Possible intruder %s (%s): %s"), c->name, c->hostname, _("wrong challenge reply length"));
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return false;
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}
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/* Convert the hash to binary format */
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hex2bin(hishash, hishash, c->outdigest->md_size);
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hex2bin(hishash, hishash, digest_length(&c->outdigest));
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/* Calculate the hash from the challenge we sent */
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if(!EVP_DigestInit(&ctx, c->outdigest)
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|| !EVP_DigestUpdate(&ctx, c->hischallenge, get_rsa_size(&c->rsa_key))
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|| !EVP_DigestFinal(&ctx, (unsigned char *)myhash, NULL)) {
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logger(LOG_ERR, _("Error during calculation of response from %s (%s): %s"),
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c->name, c->hostname, ERR_error_string(ERR_get_error(), NULL));
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return false;
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}
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/* Verify the incoming hash with the calculated hash */
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if(memcmp(hishash, myhash, c->outdigest->md_size)) {
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logger(LOG_ERR, _("Possible intruder %s (%s): %s"), c->name,
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c->hostname, _("wrong challenge reply"));
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ifdebug(SCARY_THINGS) {
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bin2hex(myhash, hishash, SHA_DIGEST_LENGTH);
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hishash[SHA_DIGEST_LENGTH * 2] = '\0';
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logger(LOG_DEBUG, _("Expected challenge reply: %s"), hishash);
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}
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/* Verify the hash */
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if(!digest_verify(&c->outdigest, c->hischallenge, rsa_size(&c->rsa), hishash)) {
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logger(LOG_ERR, _("Possible intruder %s (%s): %s"), c->name, c->hostname, _("wrong challenge reply"));
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return false;
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}
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@ -447,6 +332,7 @@ bool chal_reply_h(connection_t *c, char *request) {
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Send an acknowledgement with the rest of the information needed.
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*/
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free(c->hischallenge);
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c->allow_request = ACK;
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return send_ack(c);
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