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fixed connection bugs

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This commit is contained in:
Timerix 2025-11-02 15:26:30 +05:00
parent 8179609d47
commit 94fcbe5daf
9 changed files with 61 additions and 29 deletions
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13
src/client/ServerConnection.c
View File

@ -60,8 +60,8 @@ Result(ServerConnection*) ServerConnection_open(ClientCredentials* client_creden
br_hmac_drbg_generate(&key_rng, conn->session_key.data, conn->session_key.size);
// connect to server address
Socket _s;
try(_s, i, socket_open_TCP());
try(Socket _s, i, socket_open_TCP());
// TODO: set socket timeout to 5 seconds
try_void(socket_connect(_s, conn->server_end));
EncryptedSocketTCP_construct(&conn->sock, _s, conn->session_key);
@ -73,11 +73,12 @@ Result(ServerConnection*) ServerConnection_open(ClientCredentials* client_creden
// construct ClientHandshake in dec_buf
try_void(ClientHandshake_tryConstruct((ClientHandshake*)dec_buf.data, conn->session_key));
dec_size = sizeof(ClientHandshake);
// encrypt by server public key
try(enc_size, u,
RSAEncryptor_encrypt(
&conn->rsa_enc,
Array_sliceBefore(dec_buf, sizeof(ClientHandshake)),
Array_sliceBefore(dec_buf, dec_size),
enc_buf
)
);
@ -107,7 +108,7 @@ Result(ServerConnection*) ServerConnection_open(ClientCredentials* client_creden
);
// receive error message of length packet_header->content_size
enc_size = AESStreamEncryptor_calcDstSize(packet_header->content_size);
enc_size = packet_header->content_size;
if(enc_size > enc_buf.size)
enc_size = enc_buf.size;
try_void(
@ -124,12 +125,12 @@ Result(ServerConnection*) ServerConnection_open(ClientCredentials* client_creden
Return RESULT_ERROR((char*)err_buf.data, true);
}
case PacketType_ServerHandshake: {
enc_size = AESStreamEncryptor_calcDstSize(sizeof(ServerHandshake) - sizeof(PacketHeader));
enc_size = sizeof(ServerHandshake) - sizeof(PacketHeader);
try_void(
EncryptedSocketTCP_recv(
&conn->sock,
Array_sliceBefore(enc_buf, enc_size),
Array_sliceAfter(dec_buf, sizeof(PacketHeader)),
dec_buf,
SocketRecvFlag_WaitAll
)
);

27
src/client/client.c
View File

@ -23,16 +23,32 @@ static Result(void) commandExec(str command, bool* stop);
static Result(void) askUserNameAndPassword(ClientCredentials** cred){
Deferral(8);
char username_buf[1024];
str usrername = str_null;
while(true) {
printf("username: ");
char username[1024];
fgets(username, sizeof(username), stdin);
fgets(username_buf, sizeof(username_buf), stdin);
usrername = str_from_cstr(username_buf);
if(usrername.size < 4){
printf("ERROR: username length must be at least 4\n");
}
else break;
}
char password_buf[1024];
str password = str_null;
while(true) {
printf("password: ");
char password[1024];
// TODO: hide password
fgets(password, sizeof(password), stdin);
fgets(password_buf, sizeof(password_buf), stdin);
password = str_from_cstr(password_buf);
if(password.size < 8){
printf("ERROR: password length must be at least 8\n");
}
else break;
}
try(*cred, p, ClientCredentials_create(str_from_cstr(username), str_from_cstr(password)));
try(*cred, p, ClientCredentials_create(usrername, password));
Return RESULT_VOID;
}
@ -106,6 +122,7 @@ static Result(void) commandExec(str command, bool* stop){
printf("connecting to server...\n");
try(_server_connection, p, ServerConnection_open(_client_credentials, new_server_link.data));
printf("connection established\n");
// TODO: request server info
// show server info

1
src/cryptography/AES.c
View File

@ -176,7 +176,6 @@ void AESStreamDecryptor_construct(AESStreamDecryptor* ptr, Array(u8) key, const
Result(u32) AESStreamDecryptor_decrypt(AESStreamDecryptor* ptr, Array(u8) src, Array(u8) dst){
Deferral(4);
try_assert(src.size >= AESStreamEncryptor_calcDstSize(0));
u32 decrypted_size = __AESStreamDecryptor_calcDstSize(src.size);
try_assert(dst.size >= decrypted_size);

3
src/cryptography/AES.h
View File

@ -88,6 +88,7 @@ typedef struct AESStreamEncryptor {
/// @param dec_class &br_aes_XXX_ctr_vtable
void AESStreamEncryptor_construct(AESStreamEncryptor* ptr, Array(u8) key, const br_block_ctr_class* ctr_class);
/// use this only at the beginning of the stream
#define AESStreamEncryptor_calcDstSize(src_size) (src_size + __AES_BLOCK_IV_SIZE)
/// @brief If ptr->block_counter == 0, writes random IV to `dst`. After that writes encrypted data to dst.
@ -114,7 +115,7 @@ typedef struct AESStreamDecryptor {
void AESStreamDecryptor_construct(AESStreamDecryptor* ptr, Array(u8) key, const br_block_ctr_class* ctr_class);
/// @brief Reads IV from `src`, then decrypts data and writes it to dst
/// @param src array of size at least AESStreamEncryptor_calcDstSize(0).
/// @param src array of any size
/// @param dst array of size >= src.size
/// @return size of decrypted data
Result(u32) AESStreamDecryptor_decrypt(AESStreamDecryptor* ptr, Array(u8) src, Array(u8) dst);

27
src/cryptography/RSA.c
View File

@ -180,14 +180,15 @@ void RSAEncryptor_construct(RSAEncryptor* ptr, const br_rsa_public_key* pk){
}
Result(u32) RSAEncryptor_encrypt(RSAEncryptor* ptr, Array(u8) src, Array(u8) dst){
const u32 max_src_size = RSAEncryptor_calcMaxSrcSize(ptr->pk->nlen * 8, 256);
u32 key_size_bytes = ptr->pk->nlen;
const u32 max_src_size = RSAEncryptor_calcMaxSrcSize(key_size_bytes * 8, 256);
if(src.size > max_src_size){
return RESULT_ERROR_FMT("src.size (%u) must be <= %u (use RSAEncryptor_calcMaxSrcSize)",
src.size, max_src_size);
}
if(dst.size < ptr->pk->nlen){
if(dst.size < key_size_bytes){
return RESULT_ERROR_FMT("dst.size (%u) must be >= %u (key length in bytes)",
dst.size, (u32)ptr->pk->nlen);
dst.size, key_size_bytes);
}
size_t sz = br_rsa_i31_oaep_encrypt(
&ptr->rng.vtable, &br_sha256_vtable,
@ -207,18 +208,26 @@ void RSADecryptor_construct(RSADecryptor* ptr, const br_rsa_private_key* sk){
ptr->sk = sk;
}
Result(u32) RSADecryptor_decrypt(RSADecryptor* ptr, Array(u8) buf){
if(buf.size != ptr->sk->n_bitlen/8){
return RESULT_ERROR_FMT("buf.size (%u) must be == %u (key length in bytes)",
buf.size, ptr->sk->n_bitlen/8);
Result(u32) RSADecryptor_decrypt(RSADecryptor* ptr, Array(u8) src, Array(u8) dst){
u32 key_size_bits = ptr->sk->n_bitlen;
if(src.size != key_size_bits/8){
return RESULT_ERROR_FMT("src.size (%u) must be == %u (key length in bytes)",
src.size, key_size_bits/8);
}
size_t sz = buf.size;
const u32 max_src_size = RSAEncryptor_calcMaxSrcSize(key_size_bits, 256);
if(dst.size < max_src_size){
return RESULT_ERROR_FMT("dst.size (%u) must be >= %u (use RSAEncryptor_calcMaxSrcSize)",
dst.size, max_src_size);
}
memcpy(dst.data, src.data, src.size);
size_t sz = src.size;
size_t r = br_rsa_i31_oaep_decrypt(
&br_sha256_vtable,
NULL, 0,
ptr->sk,
buf.data, &sz);
dst.data, &sz);
if(r == 0){
return RESULT_ERROR("RSA encryption failed", false);

5
src/cryptography/RSA.h
View File

@ -101,6 +101,7 @@ typedef struct RSADecryptor {
/// RSA OAEP encryption with SHA256 hashing algorithm
void RSADecryptor_construct(RSADecryptor* ptr, const br_rsa_private_key* sk);
/// @param buf buffer with size == key size in bytes
/// @param src buffer with size == key size in bytes
/// @param dst buffer with size >= `RSAEncryptor_calcMaxSrcSize(key_size_bits, 256)`
/// @return size of decrypted data
Result(u32) RSADecryptor_decrypt(RSADecryptor* ptr, Array(u8) buf);
Result(u32) RSADecryptor_decrypt(RSADecryptor* ptr, Array(u8) src, Array(u8) dst);

1
src/network/encrypted_sockets.c
View File

@ -24,6 +24,7 @@ Result(i32) EncryptedSocketTCP_recv(EncryptedSocketTCP* ptr,
{
Deferral(4);
try(i32 received_size, i, socket_recv(ptr->sock, encrypted_buf, flags));
//TODO: return error if WaitAll flag was set and socket closed before filling the buffer
//TODO: return something when received_size == 0 (socket has been closed)
encrypted_buf.size = received_size;
try(i32 decrypted_size, u, AESStreamDecryptor_decrypt(&ptr->dec, encrypted_buf, decrypted_buf));

2
src/network/tcp-chat-protocol/v1.c
View File

@ -9,6 +9,6 @@ Result(void) ClientHandshake_tryConstruct(ClientHandshake* ptr, Array(u8) sessio
}
void ServerHandshake_construct(ServerHandshake* ptr, u64 session_id){
PacketHeader_construct(&ptr->header, PROTOCOL_VERSION, PacketType_ClientHandshake, sizeof(session_id));
PacketHeader_construct(&ptr->header, PROTOCOL_VERSION, PacketType_ServerHandshake, sizeof(session_id));
ptr->session_id = session_id;
}

5
src/server/ClientConnection.c
View File

@ -32,6 +32,8 @@ Result(ClientConnection*) ClientConnection_accept(ServerCredentials* server_cred
Defer(free(dec_buf.data));
u32 enc_size = 0, dec_size = 0;
// TODO: set socket timeout to 5 seconds
// receive message encrypted by server public key
try(enc_size, u,
socket_recv(
@ -47,7 +49,8 @@ Result(ClientConnection*) ClientConnection_accept(ServerCredentials* server_cred
try(dec_size, u,
RSADecryptor_decrypt(
&rsa_dec,
Array_sliceBefore(enc_buf, enc_size)
Array_sliceBefore(enc_buf, enc_size),
dec_buf
)
);