Clarify "data" and "message"
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parent
18bda0a245
commit
9c1479bb73
GPG key ID:
957D67B8DB7A119B
1 changed files with 37 additions and 193 deletions
226
lib/packet.c
226
lib/packet.c
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@ -2,7 +2,7 @@
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#include "key.h"
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#include "util.h"
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void print_packet(packet *pkt)
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void print_packet(packet_t *pkt)
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{
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printf("Status: %d\n", pkt->status);
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printf("Type: %d\n", pkt->type);
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@ -22,16 +22,16 @@ void print_packet(packet *pkt)
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}
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/*
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* Requires manually free message data
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* Requires manually free packet data
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* pkt: packet to fill data in (must be created via create_packet)
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* fd: file descriptor to read data from
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* required_type: Required packet type to receive, set 0 to not check
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*/
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int recv_packet(packet *pkt, int fd, uint8_t required_type)
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int recv_packet(packet_t *pkt, int fd, uint8_t required_type)
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{
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int status = ZSM_STA_SUCCESS;
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/* Read the message components */
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/* Read the packet components */
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if (recv(fd, &pkt->status, sizeof(pkt->status), 0) < 0 ||
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recv(fd, &pkt->type, sizeof(pkt->type), 0) < 0 ||
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recv(fd, &pkt->length, sizeof(pkt->length), 0) < 0) {
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@ -45,7 +45,7 @@ int recv_packet(packet *pkt, int fd, uint8_t required_type)
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if (pkt->type > 0xFF || pkt->type < 0x0) {
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status = ZSM_STA_INVALID_TYPE;
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error(0, "Invalid message type");
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error(0, "Invalid packet type");
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goto failure;
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}
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#if DEBUG == 1
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@ -55,13 +55,13 @@ int recv_packet(packet *pkt, int fd, uint8_t required_type)
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/* Not the same type as wanted to receive */
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if (pkt->type != required_type) {
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status = ZSM_STA_INVALID_TYPE;
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error(0, "Invalid message type");
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error(0, "Invalid packet type");
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goto failure;
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}
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if (pkt->length > MAX_MESSAGE_LENGTH) {
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if (pkt->length > MAX_DATA_LENGTH) {
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status = ZSM_STA_TOO_LONG;
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error(0, "Message too long: %d", pkt->length);
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error(0, "Data too long: %d", pkt->length);
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goto failure;
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}
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#if DEBUG == 1
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@ -77,16 +77,20 @@ int recv_packet(packet *pkt, int fd, uint8_t required_type)
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goto failure;
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}
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/* Read message data from the socket */
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/* Read data from the socket */
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if ((bytes_read = recv(fd, pkt->data, pkt->length, 0)) < 0) {
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status = ZSM_STA_READING_SOCKET;
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error(0, "Error reading from socket");
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free(pkt->data);
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goto failure;
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}
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if (bytes_read == 0) {
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error(0, "Closed connection");
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return ZSM_STA_READING_SOCKET;
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}
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if (bytes_read != pkt->length) {
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status = ZSM_STA_INVALID_LENGTH;
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error(0, "Invalid message length: bytes_read=%ld != pkt->length=%d", bytes_read, pkt->length);
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error(0, "Invalid data length: bytes_read=%ld != pkt->length=%d", bytes_read, pkt->length);
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free(pkt->data);
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goto failure;
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}
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@ -135,7 +139,7 @@ int recv_packet(packet *pkt, int fd, uint8_t required_type)
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return status;
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failure:;
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packet *error_pkt = create_packet(status, ZSM_TYP_ERROR, 0, NULL,
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packet_t *error_pkt = create_packet(status, ZSM_TYP_ERROR, 0, NULL,
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create_signature(NULL, 0, NULL));
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if (send_packet(error_pkt, fd) != ZSM_STA_SUCCESS) {
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@ -150,9 +154,9 @@ failure:;
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* Creates a packet for receive or send
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* Requires heap allocated data
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*/
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packet *create_packet(uint8_t status, uint8_t type, uint32_t length, uint8_t *data, uint8_t *signature)
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packet_t *create_packet(uint8_t status, uint8_t type, uint32_t length, uint8_t *data, uint8_t *signature)
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{
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packet *pkt = memalloc(sizeof(packet));
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packet_t *pkt = memalloc(sizeof(packet_t));
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pkt->status = status;
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pkt->type = type;
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pkt->length = length;
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@ -166,7 +170,7 @@ packet *create_packet(uint8_t status, uint8_t type, uint32_t length, uint8_t *da
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* Requires heap allocated data
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* Close file descriptor and free data on failure
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*/
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int send_packet(packet *pkt, int fd)
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int send_packet(packet_t *pkt, int fd)
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{
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int status = ZSM_STA_SUCCESS;
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uint32_t length = pkt->length;
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@ -200,215 +204,55 @@ failure:
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/*
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* Free allocated memory in packet
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*/
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void free_packet(packet *pkt)
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void free_packet(packet_t *pkt)
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{
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if (pkt->type != ZSM_TYP_AUTH) {
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if (pkt->type != ZSM_TYP_AUTH && pkt->type != ZSM_TYP_ERROR) {
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if (pkt->signature != NULL) {
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free(pkt->signature);
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}
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}
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if (pkt->data != NULL) {
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free(pkt->data);
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}
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free(pkt);
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}
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/*
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* not going to stay
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*/
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char *getuserinput()
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{
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printf("Enter message to send: ");
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fflush(stdout);
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char *line = memalloc(1024);
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line[0] = '\0';
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size_t length = strlen(line);
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while (length <= 1) {
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fgets(line, 1024, stdin);
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length = strlen(line);
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}
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length -= 1;
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line[length] = '\0';
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return line;
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}
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/*
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* not going to stay
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*/
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char *getrecipient()
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{
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printf("Enter recipient: ");
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fflush(stdout);
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char *line = memalloc(32);
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line[0] = '\0';
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size_t length = strlen(line);
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while (length <= 1) {
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fgets(line, 1024, stdin);
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length = strlen(line);
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}
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length -= 1;
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line[length] = '\0';
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return line;
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}
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int encrypt_packet(int sockfd, key_pair *kp)
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{
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int status = ZSM_STA_SUCCESS;
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char *line = getuserinput();
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uint8_t *recipient = getrecipient();
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uint32_t data_len;
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uint8_t *raw_data = memalloc(8192);
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size_t length = strlen(recipient);
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size_t length_line = strlen(line);
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if (length < MAX_NAME) {
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/* Pad with null characters up to max length */
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memset(recipient + length, 0, MAX_NAME - length);
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}
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memcpy(raw_data, line, length_line);
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size_t raw_data_size = MAX_NAME * 2 + strlen(line);
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uint8_t *data = encrypt_data(kp->pk.username, recipient, raw_data, raw_data_size, &data_len);
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uint8_t *signature = create_signature(data, data_len, &kp->sk);
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packet *pkt = create_packet(1, ZSM_TYP_MESSAGE, data_len, data, signature);
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if ((status = send_packet(pkt, sockfd)) != ZSM_STA_SUCCESS) {
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close(sockfd);
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return status;
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}
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free(recipient);
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free(line);
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free_packet(pkt);
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return status;
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}
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/*
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* Wrapper for recv_packet to verify packet
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* Reads packet from fd, stores in pkt
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* TODO: pkt is unncessary
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*/
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packet *verify_packet(packet *pkt, int fd)
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int verify_packet(packet_t *pkt, int fd)
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{
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if (recv_packet(pkt, fd, ZSM_TYP_MESSAGE) != ZSM_STA_SUCCESS) {
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close(fd);
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return NULL;
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return ZSM_STA_ERROR_INTEGRITY;
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}
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uint8_t from[MAX_NAME], to[MAX_NAME];
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memcpy(from, pkt->data, MAX_NAME);
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/* TODO: replace with db operations */
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key_pair *kp_from = get_key_pair(from);
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if (verify_integrity(pkt, &kp_from->pk) != ZSM_STA_SUCCESS) {
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free(pkt->data);
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free(pkt->signature);
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packet *error_pkt = create_packet(ZSM_STA_ERROR_INTEGRITY, ZSM_TYP_ERROR, 0, NULL,
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/* Verify data confidentiality by signature */
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/* Verify data integrity by hash */
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uint8_t hash[HASH_SIZE];
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crypto_generichash(hash, HASH_SIZE, pkt->data, pkt->length, NULL, 0);
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if (crypto_sign_verify_detached(pkt->signature, hash, HASH_SIZE, kp_from->pk.bin) != 0) {
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/* Not match */
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error(0, "Cannot verify data integrity");
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packet_t *error_pkt = create_packet(ZSM_STA_ERROR_INTEGRITY, ZSM_TYP_ERROR, 0, NULL,
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create_signature(NULL, 0, NULL));
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send_packet(error_pkt, fd);
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free_packet(error_pkt);
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return NULL;
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}
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return pkt;
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}
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/*
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* Encrypt raw with raw_length using to
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* length is set to sum length of random bytes and scrambled data
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*/
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uint8_t *encrypt_data(uint8_t *from, uint8_t *to, uint8_t *raw, uint32_t raw_length, uint32_t *length)
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{
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key_pair *kp_from = get_key_pair(from);
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key_pair *kp_to = get_key_pair(to);
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uint8_t shared_key[SHARED_SIZE];
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if (crypto_kx_client_session_keys(shared_key, NULL,
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kp_from->pk.bin, kp_from->sk.bin, kp_to->pk.bin) != 0) {
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/* Suspicious server public key, bail out */
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error(0, "Error performing key exchange");
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}
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uint8_t nonce[NONCE_SIZE];
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uint32_t encrypted_len = raw_length + ADDITIONAL_SIZE;
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uint8_t encrypted[encrypted_len];
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/* Generate random nonce(number used once) */
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randombytes_buf(nonce, sizeof(nonce));
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crypto_aead_xchacha20poly1305_ietf_encrypt(encrypted, NULL, raw,
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raw_length, NULL, 0, NULL, nonce, shared_key);
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size_t data_len = MAX_NAME * 2 + NONCE_SIZE + encrypted_len;
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*length = data_len;
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uint8_t *data = memalloc(data_len * sizeof(uint8_t));
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memcpy(data, kp_from->sk.username, MAX_NAME);
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memcpy(data + MAX_NAME, kp_to->sk.username, MAX_NAME);
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memcpy(data + MAX_NAME * 2, nonce, NONCE_SIZE);
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memcpy(data + MAX_NAME * 2 + NONCE_SIZE, encrypted, encrypted_len);
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return data;
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}
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/*
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* Should be used by clients
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*/
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uint8_t *decrypt_data(packet *pkt)
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{
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size_t encrypted_len = pkt->length - NONCE_SIZE - MAX_NAME * 2;
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size_t data_len = encrypted_len - ADDITIONAL_SIZE;
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uint8_t nonce[NONCE_SIZE], from[MAX_NAME], to[MAX_NAME], encrypted[encrypted_len];
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uint8_t *decrypted = memalloc((data_len + 1) * sizeof(uint8_t));
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memcpy(from, pkt->data, MAX_NAME);
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memcpy(to, pkt->data + MAX_NAME, MAX_NAME);
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memcpy(nonce, pkt->data + MAX_NAME * 2, NONCE_SIZE);
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memcpy(encrypted, pkt->data + MAX_NAME * 2 + NONCE_SIZE, encrypted_len);
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key_pair *kp_from = get_key_pair(from);
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key_pair *kp_to = get_key_pair(to);
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uint8_t shared_key[SHARED_SIZE];
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if (crypto_kx_client_session_keys(shared_key, NULL,
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kp_from->pk.bin, kp_from->sk.bin, kp_to->pk.bin) != 0) {
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/* Suspicious server public key, bail out */
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error(0, "Error performing key exchange");
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}
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/* We don't need it anymore */
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free(pkt->data);
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if (crypto_aead_xchacha20poly1305_ietf_decrypt(decrypted, NULL,
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NULL, encrypted,
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encrypted_len,
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NULL, 0,
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nonce, shared_key) != 0) {
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free(decrypted);
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error(0, "Cannot decrypt message");
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return NULL;
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} else {
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/* Terminate decrypted message so we don't print random bytes */
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decrypted[data_len] = '\0';
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printf("<%s> to <%s>: %s\n", from, to, decrypted);
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return decrypted;
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}
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}
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/*
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* Verify message integrity + confidentiality
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* Verify using public key against hashed message
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*/
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int verify_integrity(packet *pkt, public_key *pk)
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{
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uint8_t hash[HASH_SIZE];
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/* Hash data to check if matches user provided correct signature */
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crypto_generichash(hash, HASH_SIZE,
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pkt->data, pkt->length,
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NULL, 0);
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if (crypto_sign_verify_detached(pkt->signature, hash, HASH_SIZE, pk->bin) != 0) {
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/* Not match */
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error(0, "Cannot verify message integrity");
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return ZSM_STA_ERROR_INTEGRITY;
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}
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return ZSM_STA_SUCCESS;
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}
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/*
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* Create signature for packet
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* When data, secret is null, length is 0, empty siganture is created
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