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Clarify "data" and "message"

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Night Kaly 2024-09-18 08:38:44 +01:00
parent 18bda0a245
commit 9c1479bb73
Signed by: night0721
GPG key ID: 957D67B8DB7A119B
1 changed files with 37 additions and 193 deletions
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230
lib/packet.c
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@ -2,7 +2,7 @@
#include "key.h" #include "key.h"
#include "util.h" #include "util.h"
void print_packet(packet *pkt) void print_packet(packet_t *pkt)
{ {
printf("Status: %d\n", pkt->status); printf("Status: %d\n", pkt->status);
printf("Type: %d\n", pkt->type); printf("Type: %d\n", pkt->type);
@ -22,16 +22,16 @@ void print_packet(packet *pkt)
} }
/* /*
* Requires manually free message data * Requires manually free packet data
* pkt: packet to fill data in (must be created via create_packet) * pkt: packet to fill data in (must be created via create_packet)
* fd: file descriptor to read data from * fd: file descriptor to read data from
* required_type: Required packet type to receive, set 0 to not check * required_type: Required packet type to receive, set 0 to not check
*/ */
int recv_packet(packet *pkt, int fd, uint8_t required_type) int recv_packet(packet_t *pkt, int fd, uint8_t required_type)
{ {
int status = ZSM_STA_SUCCESS; int status = ZSM_STA_SUCCESS;
/* Read the message components */ /* Read the packet components */
if (recv(fd, &pkt->status, sizeof(pkt->status), 0) < 0 || if (recv(fd, &pkt->status, sizeof(pkt->status), 0) < 0 ||
recv(fd, &pkt->type, sizeof(pkt->type), 0) < 0 || recv(fd, &pkt->type, sizeof(pkt->type), 0) < 0 ||
recv(fd, &pkt->length, sizeof(pkt->length), 0) < 0) { recv(fd, &pkt->length, sizeof(pkt->length), 0) < 0) {
@ -45,7 +45,7 @@ int recv_packet(packet *pkt, int fd, uint8_t required_type)
if (pkt->type > 0xFF || pkt->type < 0x0) { if (pkt->type > 0xFF || pkt->type < 0x0) {
status = ZSM_STA_INVALID_TYPE; status = ZSM_STA_INVALID_TYPE;
error(0, "Invalid message type"); error(0, "Invalid packet type");
goto failure; goto failure;
} }
#if DEBUG == 1 #if DEBUG == 1
@ -55,13 +55,13 @@ int recv_packet(packet *pkt, int fd, uint8_t required_type)
/* Not the same type as wanted to receive */ /* Not the same type as wanted to receive */
if (pkt->type != required_type) { if (pkt->type != required_type) {
status = ZSM_STA_INVALID_TYPE; status = ZSM_STA_INVALID_TYPE;
error(0, "Invalid message type"); error(0, "Invalid packet type");
goto failure; goto failure;
} }
if (pkt->length > MAX_MESSAGE_LENGTH) { if (pkt->length > MAX_DATA_LENGTH) {
status = ZSM_STA_TOO_LONG; status = ZSM_STA_TOO_LONG;
error(0, "Message too long: %d", pkt->length); error(0, "Data too long: %d", pkt->length);
goto failure; goto failure;
} }
#if DEBUG == 1 #if DEBUG == 1
@ -77,16 +77,20 @@ int recv_packet(packet *pkt, int fd, uint8_t required_type)
goto failure; goto failure;
} }
/* Read message data from the socket */ /* Read data from the socket */
if ((bytes_read = recv(fd, pkt->data, pkt->length, 0)) < 0) { if ((bytes_read = recv(fd, pkt->data, pkt->length, 0)) < 0) {
status = ZSM_STA_READING_SOCKET; status = ZSM_STA_READING_SOCKET;
error(0, "Error reading from socket"); error(0, "Error reading from socket");
free(pkt->data); free(pkt->data);
goto failure; goto failure;
} }
if (bytes_read == 0) {
error(0, "Closed connection");
return ZSM_STA_READING_SOCKET;
}
if (bytes_read != pkt->length) { if (bytes_read != pkt->length) {
status = ZSM_STA_INVALID_LENGTH; status = ZSM_STA_INVALID_LENGTH;
error(0, "Invalid message length: bytes_read=%ld != pkt->length=%d", bytes_read, pkt->length); error(0, "Invalid data length: bytes_read=%ld != pkt->length=%d", bytes_read, pkt->length);
free(pkt->data); free(pkt->data);
goto failure; goto failure;
} }
@ -135,7 +139,7 @@ int recv_packet(packet *pkt, int fd, uint8_t required_type)
return status; return status;
failure:; failure:;
packet *error_pkt = create_packet(status, ZSM_TYP_ERROR, 0, NULL, packet_t *error_pkt = create_packet(status, ZSM_TYP_ERROR, 0, NULL,
create_signature(NULL, 0, NULL)); create_signature(NULL, 0, NULL));
if (send_packet(error_pkt, fd) != ZSM_STA_SUCCESS) { if (send_packet(error_pkt, fd) != ZSM_STA_SUCCESS) {
@ -150,9 +154,9 @@ failure:;
* Creates a packet for receive or send * Creates a packet for receive or send
* Requires heap allocated data * Requires heap allocated data
*/ */
packet *create_packet(uint8_t status, uint8_t type, uint32_t length, uint8_t *data, uint8_t *signature) packet_t *create_packet(uint8_t status, uint8_t type, uint32_t length, uint8_t *data, uint8_t *signature)
{ {
packet *pkt = memalloc(sizeof(packet)); packet_t *pkt = memalloc(sizeof(packet_t));
pkt->status = status; pkt->status = status;
pkt->type = type; pkt->type = type;
pkt->length = length; pkt->length = length;
@ -166,7 +170,7 @@ packet *create_packet(uint8_t status, uint8_t type, uint32_t length, uint8_t *da
* Requires heap allocated data * Requires heap allocated data
* Close file descriptor and free data on failure * Close file descriptor and free data on failure
*/ */
int send_packet(packet *pkt, int fd) int send_packet(packet_t *pkt, int fd)
{ {
int status = ZSM_STA_SUCCESS; int status = ZSM_STA_SUCCESS;
uint32_t length = pkt->length; uint32_t length = pkt->length;
@ -200,214 +204,54 @@ failure:
/* /*
* Free allocated memory in packet * Free allocated memory in packet
*/ */
void free_packet(packet *pkt) void free_packet(packet_t *pkt)
{ {
if (pkt->type != ZSM_TYP_AUTH) { if (pkt->type != ZSM_TYP_AUTH && pkt->type != ZSM_TYP_ERROR) {
if (pkt->signature != NULL) { if (pkt->signature != NULL) {
free(pkt->signature); free(pkt->signature);
} }
} }
free(pkt->data); if (pkt->data != NULL) {
free(pkt->data);
}
free(pkt); free(pkt);
} }
/*
* not going to stay
*/
char *getuserinput()
{
printf("Enter message to send: ");
fflush(stdout);
char *line = memalloc(1024);
line[0] = '\0';
size_t length = strlen(line);
while (length <= 1) {
fgets(line, 1024, stdin);
length = strlen(line);
}
length -= 1;
line[length] = '\0';
return line;
}
/*
* not going to stay
*/
char *getrecipient()
{
printf("Enter recipient: ");
fflush(stdout);
char *line = memalloc(32);
line[0] = '\0';
size_t length = strlen(line);
while (length <= 1) {
fgets(line, 1024, stdin);
length = strlen(line);
}
length -= 1;
line[length] = '\0';
return line;
}
int encrypt_packet(int sockfd, key_pair *kp)
{
int status = ZSM_STA_SUCCESS;
char *line = getuserinput();
uint8_t *recipient = getrecipient();
uint32_t data_len;
uint8_t *raw_data = memalloc(8192);
size_t length = strlen(recipient);
size_t length_line = strlen(line);
if (length < MAX_NAME) {
/* Pad with null characters up to max length */
memset(recipient + length, 0, MAX_NAME - length);
}
memcpy(raw_data, line, length_line);
size_t raw_data_size = MAX_NAME * 2 + strlen(line);
uint8_t *data = encrypt_data(kp->pk.username, recipient, raw_data, raw_data_size, &data_len);
uint8_t *signature = create_signature(data, data_len, &kp->sk);
packet *pkt = create_packet(1, ZSM_TYP_MESSAGE, data_len, data, signature);
if ((status = send_packet(pkt, sockfd)) != ZSM_STA_SUCCESS) {
close(sockfd);
return status;
}
free(recipient);
free(line);
free_packet(pkt);
return status;
}
/* /*
* Wrapper for recv_packet to verify packet * Wrapper for recv_packet to verify packet
* Reads packet from fd, stores in pkt * Reads packet from fd, stores in pkt
* TODO: pkt is unncessary * TODO: pkt is unncessary
*/ */
packet *verify_packet(packet *pkt, int fd) int verify_packet(packet_t *pkt, int fd)
{ {
if (recv_packet(pkt, fd, ZSM_TYP_MESSAGE) != ZSM_STA_SUCCESS) { if (recv_packet(pkt, fd, ZSM_TYP_MESSAGE) != ZSM_STA_SUCCESS) {
close(fd); close(fd);
return NULL; return ZSM_STA_ERROR_INTEGRITY;
} }
uint8_t from[MAX_NAME], to[MAX_NAME]; uint8_t from[MAX_NAME], to[MAX_NAME];
memcpy(from, pkt->data, MAX_NAME); memcpy(from, pkt->data, MAX_NAME);
/* TODO: replace with db operations */ /* TODO: replace with db operations */
key_pair *kp_from = get_key_pair(from); key_pair *kp_from = get_key_pair(from);
if (verify_integrity(pkt, &kp_from->pk) != ZSM_STA_SUCCESS) { /* Verify data confidentiality by signature */
free(pkt->data); /* Verify data integrity by hash */
free(pkt->signature); uint8_t hash[HASH_SIZE];
packet *error_pkt = create_packet(ZSM_STA_ERROR_INTEGRITY, ZSM_TYP_ERROR, 0, NULL, crypto_generichash(hash, HASH_SIZE, pkt->data, pkt->length, NULL, 0);
if (crypto_sign_verify_detached(pkt->signature, hash, HASH_SIZE, kp_from->pk.bin) != 0) {
/* Not match */
error(0, "Cannot verify data integrity");
packet_t *error_pkt = create_packet(ZSM_STA_ERROR_INTEGRITY, ZSM_TYP_ERROR, 0, NULL,
create_signature(NULL, 0, NULL)); create_signature(NULL, 0, NULL));
send_packet(error_pkt, fd); send_packet(error_pkt, fd);
free_packet(error_pkt); free_packet(error_pkt);
return NULL; return ZSM_STA_ERROR_INTEGRITY;
} }
return pkt; return ZSM_STA_SUCCESS;
} }
/*
* Encrypt raw with raw_length using to
* length is set to sum length of random bytes and scrambled data
*/
uint8_t *encrypt_data(uint8_t *from, uint8_t *to, uint8_t *raw, uint32_t raw_length, uint32_t *length)
{
key_pair *kp_from = get_key_pair(from);
key_pair *kp_to = get_key_pair(to);
uint8_t shared_key[SHARED_SIZE];
if (crypto_kx_client_session_keys(shared_key, NULL,
kp_from->pk.bin, kp_from->sk.bin, kp_to->pk.bin) != 0) {
/* Suspicious server public key, bail out */
error(0, "Error performing key exchange");
}
uint8_t nonce[NONCE_SIZE];
uint32_t encrypted_len = raw_length + ADDITIONAL_SIZE;
uint8_t encrypted[encrypted_len];
/* Generate random nonce(number used once) */
randombytes_buf(nonce, sizeof(nonce));
crypto_aead_xchacha20poly1305_ietf_encrypt(encrypted, NULL, raw,
raw_length, NULL, 0, NULL, nonce, shared_key);
size_t data_len = MAX_NAME * 2 + NONCE_SIZE + encrypted_len;
*length = data_len;
uint8_t *data = memalloc(data_len * sizeof(uint8_t));
memcpy(data, kp_from->sk.username, MAX_NAME);
memcpy(data + MAX_NAME, kp_to->sk.username, MAX_NAME);
memcpy(data + MAX_NAME * 2, nonce, NONCE_SIZE);
memcpy(data + MAX_NAME * 2 + NONCE_SIZE, encrypted, encrypted_len);
return data;
}
/*
* Should be used by clients
*/
uint8_t *decrypt_data(packet *pkt)
{
size_t encrypted_len = pkt->length - NONCE_SIZE - MAX_NAME * 2;
size_t data_len = encrypted_len - ADDITIONAL_SIZE;
uint8_t nonce[NONCE_SIZE], from[MAX_NAME], to[MAX_NAME], encrypted[encrypted_len];
uint8_t *decrypted = memalloc((data_len + 1) * sizeof(uint8_t));
memcpy(from, pkt->data, MAX_NAME);
memcpy(to, pkt->data + MAX_NAME, MAX_NAME);
memcpy(nonce, pkt->data + MAX_NAME * 2, NONCE_SIZE);
memcpy(encrypted, pkt->data + MAX_NAME * 2 + NONCE_SIZE, encrypted_len);
key_pair *kp_from = get_key_pair(from);
key_pair *kp_to = get_key_pair(to);
uint8_t shared_key[SHARED_SIZE];
if (crypto_kx_client_session_keys(shared_key, NULL,
kp_from->pk.bin, kp_from->sk.bin, kp_to->pk.bin) != 0) {
/* Suspicious server public key, bail out */
error(0, "Error performing key exchange");
}
/* We don't need it anymore */
free(pkt->data);
if (crypto_aead_xchacha20poly1305_ietf_decrypt(decrypted, NULL,
NULL, encrypted,
encrypted_len,
NULL, 0,
nonce, shared_key) != 0) {
free(decrypted);
error(0, "Cannot decrypt message");
return NULL;
} else {
/* Terminate decrypted message so we don't print random bytes */
decrypted[data_len] = '\0';
printf("<%s> to <%s>: %s\n", from, to, decrypted);
return decrypted;
}
}
/*
* Verify message integrity + confidentiality
* Verify using public key against hashed message
*/
int verify_integrity(packet *pkt, public_key *pk)
{
uint8_t hash[HASH_SIZE];
/* Hash data to check if matches user provided correct signature */
crypto_generichash(hash, HASH_SIZE,
pkt->data, pkt->length,
NULL, 0);
if (crypto_sign_verify_detached(pkt->signature, hash, HASH_SIZE, pk->bin) != 0) {
/* Not match */
error(0, "Cannot verify message integrity");
return ZSM_STA_ERROR_INTEGRITY;
}
return ZSM_STA_SUCCESS;
}
/* /*
* Create signature for packet * Create signature for packet