server: Allow arbitrary RSA key length
Andri Yngvason
parent
74e9db19fd
commit
d74878fd00
67
src/server.c
67
src/server.c
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@ -68,7 +68,7 @@
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#define DEFAULT_NAME "Neat VNC"
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#define SECURITY_TYPES_MAX 3
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#define RSA_AES_SERVER_KEY_LENGTH 256
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#define APPLE_DH_SERVER_KEY_LENGTH 256
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#define UDIV_UP(a, b) (((a) + (b) - 1) / (b))
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@ -409,11 +409,11 @@ static int apple_dh_send_public_key(struct nvnc_client* client)
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crypto_derive_public_key(client->apple_dh_secret);
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assert(pub);
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uint8_t mod[RSA_AES_SERVER_KEY_LENGTH] = {};
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uint8_t mod[APPLE_DH_SERVER_KEY_LENGTH] = {};
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int mod_len = crypto_key_p(pub, mod, sizeof(mod));
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assert(mod_len == sizeof(mod));
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uint8_t q[RSA_AES_SERVER_KEY_LENGTH] = {};
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uint8_t q[APPLE_DH_SERVER_KEY_LENGTH] = {};
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int q_len = crypto_key_q(pub, q, sizeof(q));
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assert(q_len == sizeof(q));
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@ -437,7 +437,7 @@ static int on_apple_dh_response(struct nvnc_client* client)
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struct rfb_apple_dh_client_msg* msg =
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(void*)(client->msg_buffer + client->buffer_index);
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uint8_t p[RSA_AES_SERVER_KEY_LENGTH];
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uint8_t p[APPLE_DH_SERVER_KEY_LENGTH];
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int key_len = crypto_key_p(client->apple_dh_secret, p, sizeof(p));
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assert(key_len == sizeof(p));
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@ -454,7 +454,7 @@ static int on_apple_dh_response(struct nvnc_client* client)
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crypto_derive_shared_secret(client->apple_dh_secret, remote_key);
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assert(shared_secret);
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uint8_t shared_buf[RSA_AES_SERVER_KEY_LENGTH];
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uint8_t shared_buf[APPLE_DH_SERVER_KEY_LENGTH];
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crypto_key_q(shared_secret, shared_buf, sizeof(shared_buf));
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crypto_key_del(shared_secret);
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@ -504,22 +504,22 @@ static int rsa_aes_send_public_key(struct nvnc_client* client)
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}
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assert(server->rsa_pub && server->rsa_priv);
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char buffer[sizeof(struct rfb_rsa_aes_pub_key_msg) +
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RSA_AES_SERVER_KEY_LENGTH * 2] = {};
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size_t key_len = crypto_rsa_pub_key_length(server->rsa_pub);
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size_t buf_len = sizeof(struct rfb_rsa_aes_pub_key_msg) + key_len * 2;
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char* buffer = calloc(1, buf_len);
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assert(buffer);
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struct rfb_rsa_aes_pub_key_msg* msg =
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(struct rfb_rsa_aes_pub_key_msg*)buffer;
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uint8_t* modulus = msg->modulus_and_exponent;
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uint8_t* exponent = msg->modulus_and_exponent +
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RSA_AES_SERVER_KEY_LENGTH;
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uint8_t* exponent = msg->modulus_and_exponent + key_len;
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msg->length = htonl(RSA_AES_SERVER_KEY_LENGTH * 8);
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crypto_rsa_pub_key_modulus(server->rsa_pub, modulus,
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RSA_AES_SERVER_KEY_LENGTH);
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crypto_rsa_pub_key_exponent(server->rsa_pub, exponent,
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RSA_AES_SERVER_KEY_LENGTH);
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msg->length = htonl(key_len * 8);
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crypto_rsa_pub_key_modulus(server->rsa_pub, modulus, key_len);
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crypto_rsa_pub_key_exponent(server->rsa_pub, exponent, key_len);
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stream_write(client->net_stream, buffer, sizeof(buffer), NULL, NULL);
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stream_send(client->net_stream, rcbuf_new(buffer, buf_len), NULL, NULL);
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return 0;
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}
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@ -533,8 +533,8 @@ static int rsa_aes_send_challenge(struct nvnc_client* client,
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(struct rfb_rsa_aes_challenge_msg*)buffer;
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ssize_t len = crypto_rsa_encrypt(pub, msg->challenge,
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RSA_AES_SERVER_KEY_LENGTH, client->rsa.challenge,
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client->rsa.challenge_len);
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crypto_rsa_pub_key_length(client->rsa.pub),
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client->rsa.challenge, client->rsa.challenge_len);
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msg->length = htons(len);
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nvnc_trace("Challenge length is %zd", len);
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@ -638,12 +638,14 @@ static int on_rsa_aes_challenge(struct nvnc_client* client)
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stream_upgrade_to_rsa_eas(client->net_stream, client->rsa.cipher_type,
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server_session_key, client_session_key);
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uint8_t server_modulus[RSA_AES_SERVER_KEY_LENGTH];
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uint8_t server_exponent[RSA_AES_SERVER_KEY_LENGTH];
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size_t server_key_len = crypto_rsa_pub_key_length(server->rsa_pub);
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uint8_t* server_modulus = malloc(server_key_len * 2);
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uint8_t* server_exponent = server_modulus + server_key_len;
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crypto_rsa_pub_key_modulus(server->rsa_pub, server_modulus,
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RSA_AES_SERVER_KEY_LENGTH);
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server_key_len);
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crypto_rsa_pub_key_exponent(server->rsa_pub, server_exponent,
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RSA_AES_SERVER_KEY_LENGTH);
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server_key_len);
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size_t client_key_len = crypto_rsa_pub_key_length(client->rsa.pub);
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uint8_t* client_modulus = malloc(client_key_len * 2);
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@ -654,21 +656,22 @@ static int on_rsa_aes_challenge(struct nvnc_client* client)
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crypto_rsa_pub_key_exponent(client->rsa.pub, client_exponent,
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client_key_len);
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uint32_t server_key_len_be = htonl(RSA_AES_SERVER_KEY_LENGTH * 8);
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uint32_t server_key_len_be = htonl(server_key_len * 8);
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uint32_t client_key_len_be = htonl(client_key_len * 8);
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uint8_t server_hash[32] = {};
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crypto_hash_many(server_hash, client_rsa_aes_hash_len(client),
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client->rsa.hash_type, (const struct crypto_data_entry[]) {
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{ (uint8_t*)&server_key_len_be, 4 },
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{ server_modulus, RSA_AES_SERVER_KEY_LENGTH },
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{ server_exponent, RSA_AES_SERVER_KEY_LENGTH },
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{ server_modulus, server_key_len },
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{ server_exponent, server_key_len },
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{ (uint8_t*)&client_key_len_be, 4 },
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{ client_modulus, client_key_len },
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{ client_exponent, client_key_len },
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{}
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});
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free(server_modulus);
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free(client_modulus);
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stream_write(client->net_stream, server_hash,
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@ -688,12 +691,13 @@ static int on_rsa_aes_client_hash(struct nvnc_client* client)
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struct nvnc* server = client->server;
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uint8_t server_modulus[RSA_AES_SERVER_KEY_LENGTH];
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uint8_t server_exponent[RSA_AES_SERVER_KEY_LENGTH];
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size_t server_key_len = crypto_rsa_pub_key_length(server->rsa_pub);
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uint8_t* server_modulus = malloc(server_key_len * 2);
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uint8_t* server_exponent = server_modulus + server_key_len;
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crypto_rsa_pub_key_modulus(server->rsa_pub, server_modulus,
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RSA_AES_SERVER_KEY_LENGTH);
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server_key_len);
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crypto_rsa_pub_key_exponent(server->rsa_pub, server_exponent,
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RSA_AES_SERVER_KEY_LENGTH);
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server_key_len);
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size_t client_key_len = crypto_rsa_pub_key_length(client->rsa.pub);
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uint8_t* client_modulus = malloc(client_key_len * 2);
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@ -704,7 +708,7 @@ static int on_rsa_aes_client_hash(struct nvnc_client* client)
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crypto_rsa_pub_key_exponent(client->rsa.pub, client_exponent,
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client_key_len);
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uint32_t server_key_len_be = htonl(RSA_AES_SERVER_KEY_LENGTH * 8);
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uint32_t server_key_len_be = htonl(server_key_len * 8);
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uint32_t client_key_len_be = htonl(client_key_len * 8);
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uint8_t client_hash[32] = {};
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@ -714,12 +718,13 @@ static int on_rsa_aes_client_hash(struct nvnc_client* client)
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{ client_modulus, client_key_len },
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{ client_exponent, client_key_len },
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{ (uint8_t*)&server_key_len_be, 4 },
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{ server_modulus, RSA_AES_SERVER_KEY_LENGTH },
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{ server_exponent, RSA_AES_SERVER_KEY_LENGTH },
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{ server_modulus, server_key_len },
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{ server_exponent, server_key_len },
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{}
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});
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free(client_modulus);
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free(server_modulus);
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if (memcmp(msg, client_hash, client_rsa_aes_hash_len(client)) != 0) {
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nvnc_log(NVNC_LOG_INFO, "Client hash mismatch");
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