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/*
* Copyright (c) 2023-2024 Ian Marco Moffett and the Osmora Team.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of Hyra nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
#include <ostp/net/stpsession.h>
#include <ostp/crypto/aes.h>
#include <arpa/inet.h>
#include <string.h>
#include <stdlib.h>
#include <stdio.h>
static int
decrypt_frame(const struct msg_frame *frame, const unsigned char *key, size_t len,
void *res)
{
struct aes_message am;
unsigned char *tmp;
int error;
/* Construct an AES message with the message frame */
am.ciphertext = (unsigned char *)frame->payload;
am.ciphertext_len = frame->len;
memcpy(am.tag, frame->tag, AES_GCM_TAG_SIZE);
memcpy(am.iv, frame->iv, AES_IV_SIZE);
memcpy(am.ciphertext, frame->payload, frame->len);
/* Decrypt and deserialize the frame payload */
if ((error = aes256_decrypt(&am, key, &tmp)) < 0) {
return error;
}
memcpy(res, tmp, len);
free(tmp);
return 0;
}
int
send_frame(int client_fd, void *data, size_t len, const unsigned char *session_key)
{
struct aes_message am;
struct msg_frame msg_frame;
int error;
error = aes256_encrypt((void *)data, len, session_key, &am);
if (error < 0) {
printf("send_frame: Failed to encrypt data\n");
return error;
}
memcpy(msg_frame.iv, am.iv, AES_IV_SIZE);
memcpy(msg_frame.tag, am.tag, AES_GCM_TAG_SIZE);
memcpy(msg_frame.payload, am.ciphertext, am.ciphertext_len);
msg_frame.len = am.ciphertext_len;
/* Send in the message frame */
error = send(client_fd, &msg_frame, sizeof(msg_frame), 0);
if (error < 0) {
printf("send_frame: Failed sending frame to server\n");
aes256_free_msg(&am);
return error;
}
return 0;
}
int
recv_frame(int client_fd, size_t len, const unsigned char *session_key, void *res)
{
struct msg_frame frame;
int error, ret;
/* Get the message frame over the network */
ret = recv(client_fd, &frame, sizeof(struct msg_frame), MSG_WAITALL);
if (ret < 0) {
printf("Failed to get frame payload from peer\n");
return error;
}
if (ret == 0) {
printf("Connection closed by peer\n");
return 0;
}
/* Decrypt the payload */
if ((error = decrypt_frame(&frame, session_key, len, res)) < 0) {
printf("Failed to decrypt frame payload, rejecting...\n");
return error;
}
return (ret < len) ? ret : len;
}
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