From 7eb9882877b6567ceeb1c0e591fa569892896143 Mon Sep 17 00:00:00 2001 From: Andri Yngvason Date: Tue, 5 Sep 2023 08:41:25 +0000 Subject: [PATCH] server: Define rsa-aes server key length constant --- src/server.c | 69 ++++++++++++++++++++++++++-------------------------- 1 file changed, 35 insertions(+), 34 deletions(-) diff --git a/src/server.c b/src/server.c index ade03ff..dd74fe2 100644 --- a/src/server.c +++ b/src/server.c @@ -68,6 +68,7 @@ #define DEFAULT_NAME "Neat VNC" #define SECURITY_TYPES_MAX 3 +#define RSA_AES_SERVER_KEY_LENGTH 256 #define UDIV_UP(a, b) (((a) + (b) - 1) / (b)) @@ -402,11 +403,11 @@ static int apple_dh_send_public_key(struct nvnc_client* client) crypto_derive_public_key(client->apple_dh_secret); assert(pub); - uint8_t mod[256] = {}; + uint8_t mod[RSA_AES_SERVER_KEY_LENGTH] = {}; int mod_len = crypto_key_p(pub, mod, sizeof(mod)); assert(mod_len == sizeof(mod)); - uint8_t q[256] = {}; + uint8_t q[RSA_AES_SERVER_KEY_LENGTH] = {}; int q_len = crypto_key_q(pub, q, sizeof(q)); assert(q_len == sizeof(q)); @@ -430,7 +431,7 @@ static int on_apple_dh_response(struct nvnc_client* client) struct rfb_apple_dh_client_msg* msg = (void*)(client->msg_buffer + client->buffer_index); - uint8_t p[256]; + uint8_t p[RSA_AES_SERVER_KEY_LENGTH]; int key_len = crypto_key_p(client->apple_dh_secret, p, sizeof(p)); assert(key_len == sizeof(p)); @@ -447,7 +448,7 @@ static int on_apple_dh_response(struct nvnc_client* client) crypto_derive_shared_secret(client->apple_dh_secret, remote_key); assert(shared_secret); - uint8_t shared_buf[256]; + uint8_t shared_buf[RSA_AES_SERVER_KEY_LENGTH]; crypto_key_q(shared_secret, shared_buf, sizeof(shared_buf)); crypto_key_del(shared_secret); @@ -497,19 +498,20 @@ static int rsa_aes_send_public_key(struct nvnc_client* client) } assert(server->rsa_pub && server->rsa_priv); - char buffer[sizeof(struct rfb_rsa_aes_pub_key_msg) + 512] = {}; + char buffer[sizeof(struct rfb_rsa_aes_pub_key_msg) + + RSA_AES_SERVER_KEY_LENGTH * 2] = {}; struct rfb_rsa_aes_pub_key_msg* msg = (struct rfb_rsa_aes_pub_key_msg*)buffer; uint8_t* modulus = msg->modulus_and_exponent; - uint8_t* exponent = msg->modulus_and_exponent + 256; + uint8_t* exponent = msg->modulus_and_exponent + + RSA_AES_SERVER_KEY_LENGTH; - msg->length = htonl(2048); - crypto_rsa_pub_key_modulus(server->rsa_pub, modulus, 256); - crypto_rsa_pub_key_exponent(server->rsa_pub, exponent, 256); - - crypto_dump_base16("Sending public key modulus", modulus, 256); - crypto_dump_base16("Sending public key exponent", exponent, 256); + msg->length = htonl(RSA_AES_SERVER_KEY_LENGTH * 8); + crypto_rsa_pub_key_modulus(server->rsa_pub, modulus, + RSA_AES_SERVER_KEY_LENGTH); + crypto_rsa_pub_key_exponent(server->rsa_pub, exponent, + RSA_AES_SERVER_KEY_LENGTH); stream_write(client->net_stream, buffer, sizeof(buffer), NULL, NULL); return 0; @@ -524,8 +526,9 @@ static int rsa_aes_send_challenge(struct nvnc_client* client, struct rfb_rsa_aes_challenge_msg *msg = (struct rfb_rsa_aes_challenge_msg*)buffer; - ssize_t len = crypto_rsa_encrypt(pub, msg->challenge, 256, - client->rsa.challenge, sizeof(client->rsa.challenge)); + ssize_t len = crypto_rsa_encrypt(pub, msg->challenge, + RSA_AES_SERVER_KEY_LENGTH, client->rsa.challenge, + sizeof(client->rsa.challenge)); msg->length = htons(len); nvnc_trace("Challenge length is %zd", len); @@ -561,10 +564,6 @@ static int on_rsa_aes_public_key(struct nvnc_client* client) crypto_rsa_pub_key_import(modulus, exponent, byte_length); assert(client->rsa.pub); - uint8_t foo[256]; - crypto_rsa_pub_key_exponent(client->rsa.pub, foo, 256); - crypto_dump_base16("Got public key exponent check", foo, 256); - client->state = VNC_CLIENT_STATE_WAITING_FOR_RSA_AES_CHALLENGE; rsa_aes_send_challenge(client, client->rsa.pub); @@ -630,10 +629,12 @@ static int on_rsa_aes_challenge(struct nvnc_client* client) stream_upgrade_to_rsa_eas(client->net_stream, server_session_key, client_session_key); - uint8_t server_modulus[256]; - uint8_t server_exponent[256]; - crypto_rsa_pub_key_modulus(server->rsa_pub, server_modulus, 256); - crypto_rsa_pub_key_exponent(server->rsa_pub, server_exponent, 256); + uint8_t server_modulus[RSA_AES_SERVER_KEY_LENGTH]; + uint8_t server_exponent[RSA_AES_SERVER_KEY_LENGTH]; + crypto_rsa_pub_key_modulus(server->rsa_pub, server_modulus, + RSA_AES_SERVER_KEY_LENGTH); + crypto_rsa_pub_key_exponent(server->rsa_pub, server_exponent, + RSA_AES_SERVER_KEY_LENGTH); size_t client_key_len = crypto_rsa_pub_key_length(client->rsa.pub); uint8_t* client_modulus = malloc(client_key_len * 2); @@ -644,15 +645,15 @@ static int on_rsa_aes_challenge(struct nvnc_client* client) crypto_rsa_pub_key_exponent(client->rsa.pub, client_exponent, client_key_len); - uint32_t server_key_len_be = htonl(256 * 8); + uint32_t server_key_len_be = htonl(RSA_AES_SERVER_KEY_LENGTH * 8); uint32_t client_key_len_be = htonl(client_key_len * 8); uint8_t server_hash[20] = {}; crypto_hash_many(server_hash, sizeof(server_hash), CRYPTO_HASH_SHA1, (const struct crypto_data_entry[]) { { (uint8_t*)&server_key_len_be, 4 }, - { server_modulus, 256 }, - { server_exponent, 256 }, + { server_modulus, RSA_AES_SERVER_KEY_LENGTH }, + { server_exponent, RSA_AES_SERVER_KEY_LENGTH }, { (uint8_t*)&client_key_len_be, 4 }, { client_modulus, client_key_len }, { client_exponent, client_key_len }, @@ -661,8 +662,6 @@ static int on_rsa_aes_challenge(struct nvnc_client* client) free(client_modulus); - crypto_dump_base16("Server hash", server_hash, 20); - stream_write(client->net_stream, server_hash, 20, NULL, NULL); client->state = VNC_CLIENT_STATE_WAITING_FOR_RSA_AES_CLIENT_HASH; @@ -679,10 +678,12 @@ static int on_rsa_aes_client_hash(struct nvnc_client* client) struct nvnc* server = client->server; - uint8_t server_modulus[256]; - uint8_t server_exponent[256]; - crypto_rsa_pub_key_modulus(server->rsa_pub, server_modulus, 256); - crypto_rsa_pub_key_exponent(server->rsa_pub, server_exponent, 256); + uint8_t server_modulus[RSA_AES_SERVER_KEY_LENGTH]; + uint8_t server_exponent[RSA_AES_SERVER_KEY_LENGTH]; + crypto_rsa_pub_key_modulus(server->rsa_pub, server_modulus, + RSA_AES_SERVER_KEY_LENGTH); + crypto_rsa_pub_key_exponent(server->rsa_pub, server_exponent, + RSA_AES_SERVER_KEY_LENGTH); size_t client_key_len = crypto_rsa_pub_key_length(client->rsa.pub); uint8_t* client_modulus = malloc(client_key_len * 2); @@ -693,7 +694,7 @@ static int on_rsa_aes_client_hash(struct nvnc_client* client) crypto_rsa_pub_key_exponent(client->rsa.pub, client_exponent, client_key_len); - uint32_t server_key_len_be = htonl(256 * 8); + uint32_t server_key_len_be = htonl(RSA_AES_SERVER_KEY_LENGTH * 8); uint32_t client_key_len_be = htonl(client_key_len * 8); uint8_t client_hash[20] = {}; @@ -703,8 +704,8 @@ static int on_rsa_aes_client_hash(struct nvnc_client* client) { client_modulus, client_key_len }, { client_exponent, client_key_len }, { (uint8_t*)&server_key_len_be, 4 }, - { server_modulus, 256 }, - { server_exponent, 256 }, + { server_modulus, RSA_AES_SERVER_KEY_LENGTH }, + { server_exponent, RSA_AES_SERVER_KEY_LENGTH }, {} });