rsa keys base64 encoding/decoding

dependencies/tlibc

@@ -1 +1 @@
-Subproject commit 7e7bd195a9715abceb4131b21232aed7d990b75d
+Subproject commit 14ffede476b786d9e31006f4bac52289ff656158

src/client/ClientCredential.c

@@ -13,6 +13,7 @@ void ClientCredential_free(ClientCredential* cred){
 }
 
 #define __passhash_lvl_iter 1e5
+#define __rsa_key_size 2048
 
 Result(ClientCredential*) ClientCredential_create(str username, str password){
     Deferral(32);
@@ -56,7 +57,8 @@ Result(ClientCredential*) ClientCredential_create(str username, str password){
     // generate client rsa keys from password hash
     br_hmac_drbg_context passhash_based_rng = { .vtable = &br_hmac_drbg_vtable };
     br_hmac_drbg_init(&passhash_based_rng, &br_sha256_vtable, passhash_lvl1.data, password_hash_size);
-    try_void(RSA_generateKeyPair(4096, &cred->sk, &cred->pk, &passhash_based_rng.vtable));
+    // TODO: does client really need it's own RSA private key? At least i should generate it once using seedFromTime and save in a file encrypted by user_data_aes_enc
+    try_void(RSA_generateKeyPair(__rsa_key_size, &cred->sk, &cred->pk, &passhash_based_rng.vtable));
     Defer(
         if(!success){
             RSA_destroyPrivateKey(&cred->sk);
@@ -66,8 +68,8 @@ Result(ClientCredential*) ClientCredential_create(str username, str password){
 
     DecryptorRSA_construct(&cred->rsa_dec, &cred->sk);
     EncryptorRSA_construct(&cred->rsa_enc, &cred->pk);
-    DecryptorAES_construct(&cred->aes_dec, cred->aes_key);
+    DecryptorAES_construct(&cred->user_data_aes_dec, cred->aes_key);
-    EncryptorAES_construct(&cred->aes_enc, cred->aes_key);
+    EncryptorAES_construct(&cred->user_data_aes_enc, cred->aes_key);
 
     success = true;
     Return RESULT_VALUE(p, cred);

src/client/ServerConnection.c

@@ -5,17 +5,43 @@ void ServerConnection_close(ServerConnection* conn){
         return;
     socket_close(conn->system_socket);
     socket_close(conn->content_socket);
+    RSA_destroyPublicKey(&conn->server_pk);
     free(conn);
 }
 
-Result(ServerConnection*) ServerConnection_open(ClientCredential* client_credential, EndpointIPv4 server_end, str server_key){
+/// @brief 
-    Deferral(64);
+/// @param server_link_cstr address:port:public_key
+/// @return 
+Result(void) ServerLink_parse(cstr server_link_cstr, EndpointIPv4* server_end_out, br_rsa_public_key* server_key_out){
+    Deferral(16);
+    str server_link_str = str_from_cstr(server_link_cstr);
+    i32 sep_pos = 0;
     
-    str end_str = EndpointIPv4_toStr(server_end);
+    // parse address and port
-    Defer(free(end_str.data));
+    sep_pos = str_seekChar(server_link_str, ':', sep_pos);
-    if(EndpointIPv4_is_invalid(server_end)){
+    if(sep_pos == -1){
-        Return RESULT_ERROR_FMT("endpoint is invalid: %s", end_str.data);
+        Return RESULT_ERROR_FMT("server link is invalid: %s", server_link_cstr);
     }
+    *server_end_out = EndpointIPv4_INVALID;
+    try_void(EndpointIPv4_parse(server_link_cstr, server_end_out));    
+    if(EndpointIPv4_is_invalid(*server_end_out)){
+        Return RESULT_ERROR_FMT("server address or port is invalid: %s", server_link_cstr);
+    }
+
+    // parse public key
+    sep_pos = str_seekChar(server_link_str, ':', sep_pos);
+    if(sep_pos == -1){
+        Return RESULT_ERROR_FMT("server link is invalid: %s", server_link_cstr);
+    }
+    str server_key_str = server_link_str;
+    server_key_str.data += sep_pos + 1;
+    try_void(RSA_parsePublicKey_base64(server_key_str, server_key_out));
+    
+    Return RESULT_VOID;
+}
+
+Result(ServerConnection*) ServerConnection_open(ClientCredential* client_credential, cstr server_link_cstr){
+    Deferral(64);
 
     ServerConnection* conn = (ServerConnection*)malloc(sizeof(ServerConnection));
     memset(conn, 0, sizeof(ServerConnection));
@@ -25,12 +51,10 @@ Result(ServerConnection*) ServerConnection_open(ClientCredential* client_credent
             ServerConnection_close(conn);
     );
     
-    printf("connecting to server %s\n", end_str.data);
+    printf("connecting to server %s\n", server_link_cstr);
     try(conn->system_socket, i, socket_open_TCP());
-    try_void(socket_connect(conn->system_socket, server_end));
+    try_void(socket_connect(conn->system_socket, conn->server_end));
 
-    // ask user name and password
-    // calculate key pair from password hash
     // send client public key to server
     // request server info
     // show server info

src/client/client.c

@@ -26,10 +26,16 @@ static Result(void) commandExec(str command, bool* stop);
 
 static Result(void) askUserNameAndPassword(ClientCredential** cred){
     Deferral(8);
+
+    printf("username: ");
     char username[1024];
+    fgets(username, sizeof(username), stdin);
+
+    printf("password: ");
     char password[1024];
-    scanf("username: %s", username);
+    // TODO: hide password
-    scanf("password: %s", password);
+    fgets(password, sizeof(password), stdin);
+
     try(*cred, p, ClientCredential_create(str_from_cstr(username), str_from_cstr(password)));
     Return RESULT_VOID;
 }
@@ -96,13 +102,10 @@ static Result(void) commandExec(str command, bool* stop){
     else if (is_alias("j") || is_alias("join")){
         puts("Enter server address (ip:port): ");
         fgets(answer_buf, answer_buf_size, stdin);
-        EndpointIPv4 new_server_end;
+        str new_server_link = str_from_cstr(answer_buf);
-        try_void(EndpointIPv4_parse(answer_buf, &new_server_end));
+        str_trim(&new_server_link, true);
-        puts("Enter server key (): ");
+        try(ServerConnection* conn, p, ServerConnection_open(client_credential, new_server_link.data));
-        fgets(answer_buf, answer_buf_size, stdin);
+        // TODO: store server connection somewhere
-        str new_server_key = str_from_cstr(answer_buf);
-        try(ServerConnection* conn, p, ServerConnection_open(client_credential, new_server_end, new_server_key));
-        // TODO: close server connection somewhere
     }
     else if(is_alias("c") || is_alias("connect")){
         // TODO: read saved servers from database

src/client/client.h

@@ -12,8 +12,8 @@ typedef struct ClientCredential {
     br_rsa_public_key pk;
     EncryptorRSA rsa_enc;
     DecryptorRSA rsa_dec;
-    EncryptorAES aes_enc;
+    EncryptorAES user_data_aes_enc;
-    DecryptorAES aes_dec;
+    DecryptorAES user_data_aes_dec;
 } ClientCredential;
 
 Result(ClientCredential*) ClientCredential_create(str username, str password);
@@ -23,10 +23,11 @@ typedef struct ServerConnection {
     EndpointIPv4 server_end;
     Socket system_socket;
     Socket content_socket;
+    br_rsa_public_key server_pk;
     EncryptorRSA rsa_enc;
     EncryptorAES session_aes_enc;
     DecryptorAES session_aes_dec;
 } ServerConnection;
 
-Result(ServerConnection*) ServerConnection_open(ClientCredential* client_credential, EndpointIPv4 server_end, str server_key);
+Result(ServerConnection*) ServerConnection_open(ClientCredential* client_credential, cstr server_link_cstr);
 void ServerConnection_close(ServerConnection* conn);

src/cryptography/RSA.c

@@ -2,6 +2,7 @@
 #include <assert.h>
 #include "bearssl_x509.h"
 #include "bearssl_pem.h"
+#include "tlibc/base64.h"
 
 // https://crypto.stackexchange.com/questions/3110/impacts-of-not-using-rsa-exponent-of-65537
 #define DEFAULT_PUBLIC_EXPONENT 65537
@@ -71,110 +72,88 @@ Result(void) RSA_computePublicKey(const br_rsa_private_key* sk, br_rsa_public_ke
     Return RESULT_VOID;
 }
 
-Result(void) RSA_serializePrivateKey_RawDER(
+str RSA_serializePrivateKey_base64(const br_rsa_private_key* sk){
-    const br_rsa_private_key* sk,
+    u32 key_buffer_size = BR_RSA_KBUF_PRIV_SIZE(sk->n_bitlen);
-    NULLABLE(const br_rsa_public_key*) pk,
+    u32 key_base64_size = base64_encodedSize(key_buffer_size);
-    Array(u8)* out_der)
+    char* serialized_buf = malloc(32 + key_base64_size);
-{
+    sprintf(serialized_buf, "RSA-Private-%u:", sk->n_bitlen);
-    Deferral(32);
+    u32 offset = strlen(serialized_buf);
-	br_rsa_compute_pubexp compute_pubexp = br_rsa_i31_compute_pubexp;
+    offset += base64_encode(sk->p, key_buffer_size, serialized_buf + offset);
-	br_rsa_compute_privexp compute_privexp = br_rsa_i31_compute_privexp;
+    serialized_buf[offset] = '\0';
+    return str_construct(serialized_buf, offset, true);
+}
 
-    br_rsa_public_key pk_computed;
+str RSA_serializePublicKey_base64(const br_rsa_public_key* pk){
-    if(pk == NULL){
+    u32 n_bitlen = pk->nlen * 8;
-        pk = &pk_computed;
+    u32 key_buffer_size = BR_RSA_KBUF_PUB_SIZE(n_bitlen);
-        try_void(RSA_computePublicKey(sk, &pk_computed));
+    u32 key_base64_size = base64_encodedSize(key_buffer_size);
-        Defer(free(pk->n));
+    char* serialized_buf = malloc(32 + key_base64_size);
+    sprintf(serialized_buf, "RSA-Public-%u:", n_bitlen);
+    u32 offset = strlen(serialized_buf);
+    offset += base64_encode(pk->n, key_buffer_size, serialized_buf + offset);
+    serialized_buf[offset] = '\0';
+    return str_construct(serialized_buf, offset, true);
+}
+
+Result(void) RSA_parsePublicKey_base64(const str src, br_rsa_public_key* pk){
+    Deferral(8);
+    u32 n_bitlen = 0;
+    if(sscanf(src.data, "RSA-Public-%u:", &n_bitlen) != 1){
+        Return RESULT_ERROR("can't parse key size", false);
     }
-	
+    u32 key_buffer_size = BR_RSA_KBUF_PUB_SIZE(n_bitlen);
-	u32 pubexp_little_endian = compute_pubexp(sk);
+    pk->n = malloc(key_buffer_size);
-	if (pubexp_little_endian == 0) {
+    pk->elen = 4;
-		Return RESULT_ERROR("compute_pubexp", false);
+    pk->nlen = key_buffer_size - 4;
-	}
+    pk->e = pk->n + pk->nlen;
-	size_t privexp_size = compute_privexp(NULL, sk, pubexp_little_endian);
+    u32 offset = str_seekChar(src, ':', 14) + 1;
-	if (privexp_size == 0) {
+    if(offset == 0){
-		Return RESULT_ERROR("compute_privexp", false);
+        Return RESULT_ERROR("missing ':' before key data", false);
-	}
-	void* privexp = malloc(privexp_size);
-    Defer(free(privexp));
-	if (compute_privexp(privexp, sk, pubexp_little_endian) != privexp_size) {
-		Return RESULT_ERROR("compute_privexp", false);
-	}
-    
-
-    size_t der_size = br_encode_rsa_raw_der(NULL, sk, pk, privexp, privexp_size);
-    if (der_size == 0) {
-		Return RESULT_ERROR("br_encode_rsa_raw_der", false);
     }
-    void* der = malloc(der_size);
+    str key_base64_str = src;
-    bool success = false;
+    key_base64_str.data += offset;
-    Defer(
+    key_base64_str.size -= offset;
-        if(!success)
+    u32 decoded_size = base64_decodedSize(key_base64_str.data, key_base64_str.size);
-            free(der)
+    if(decoded_size != key_buffer_size){
-    );
+        Return RESULT_ERROR_FMT("decoded key size is %u, must be %u", decoded_size, key_buffer_size);
-    if (br_encode_rsa_raw_der(der, sk, pk, privexp, privexp_size) != der_size) {
+    }
-		Return RESULT_ERROR("br_encode_rsa_raw_der", false);
+    decoded_size = base64_decode(key_base64_str.data, key_base64_str.size, pk->n);
+    if(decoded_size != key_buffer_size){
+        Return RESULT_ERROR("key decoding failed", false);
     }
-
-    success = true;
-    out_der->data = der;
-    out_der->size = der_size;
     Return RESULT_VOID;
 }
 
-void PEM_encode(Array(u8) src, Array(u8)* dst, cstr label){
+Result(void) RSA_parsePrivateKey_base64(const str src, br_rsa_private_key* sk){
-    u64 encoded_size = br_pem_encode(NULL, src.data, src.size, label, 0);
+    Deferral(8);
-    // br_pem_encode doesn't count '\0' but writes it
+    u32 n_bitlen = 0;
-    *dst = Array_alloc_size(encoded_size + 1);
+    if(sscanf(src.data, "RSA-Private-%u:", &n_bitlen) != 1){
-    br_pem_encode(dst->data, src.data, src.size, label, 0);
+        Return RESULT_ERROR("can't parse key size", false);
-}
-
-
-Result(void) RSA_parsePrivateKey_DER(Array(u8) _src, br_rsa_private_key* sk){
-    Deferral(16);
-    // private key data will be written in this buffer on success
-    Array(u8) buf = Array_copy(_src);
-    bool success = false;
-    Defer(free(buf.data));
-
-    br_skey_decoder_context decoder;
-    br_skey_decoder_init(&decoder);
-    br_skey_decoder_push(&decoder, buf.data, buf.size);
-    i32 errcode = br_skey_decoder_last_error(&decoder);
-	if (errcode != 0) {
-        Return RESULT_ERROR_FMT("br_skey_decoder error %i", errcode);
-	}
-    i32 parsed_type = br_skey_decoder_key_type(&decoder);
-    if(parsed_type != BR_KEYTYPE_RSA){
-        Return RESULT_ERROR_FMT("parsed key has unsupported type %i", parsed_type);
     }
-    const br_rsa_private_key* decoded_key = br_skey_decoder_get_rsa(&decoder);
+    sk->n_bitlen = n_bitlen;
-    if(decoded_key == NULL){
+    u32 key_buffer_size = BR_RSA_KBUF_PRIV_SIZE(n_bitlen);
-        Return RESULT_ERROR("decoder failed without errors", false);
+    u32 field_len = key_buffer_size / 5;
+    sk->plen = sk->qlen = sk->dplen = sk->dqlen = sk->iqlen = field_len;
+    sk->p = malloc(key_buffer_size);
+    sk->q = sk->p + field_len;
+    sk->dp = sk->q + field_len;
+    sk->dq = sk->dp + field_len;
+    sk->iq = sk->dq + field_len;
+    u32 offset = str_seekChar(src, ':', 14) + 1;
+    if(offset == 0){
+        Return RESULT_ERROR("missing ':' before key data", false);
     }
-
+    str key_base64_str = src;
-    success = true;
+    key_base64_str.data += offset;
-    memcpy(sk, decoded_key, sizeof(*decoded_key));
+    key_base64_str.size -= offset;
-    
+    u32 decoded_size = base64_decodedSize(key_base64_str.data, key_base64_str.size);
-    // sk fields still point to stack array decoder.key_data
+    if(decoded_size != key_buffer_size){
-    // This code copies the data and adjusts sk fields to point to the copied chunk
+        Return RESULT_ERROR_FMT("decoded key size is %u, must be %u", decoded_size, key_buffer_size);
-    Array(u8) key_data_copy = Array_alloc_size(BR_RSA_KBUF_PRIV_SIZE(decoded_key->n_bitlen));
+    }
-    Defer(
+    decoded_size = base64_decode(key_base64_str.data, key_base64_str.size, sk->p);
-        if(!success)
+    if(decoded_size != key_buffer_size){
-            free(key_data_copy.data);
+        Return RESULT_ERROR("key decoding failed", false);
-    );
-    memcpy(key_data_copy.data, decoder.key_data, key_data_copy.size);
-    u64 memory_distance =  (u64)key_data_copy.data - (u64)(void*)decoder.key_data;
-    u8** sk_pointer_fields[] = {
-        &sk->p, &sk->q, &sk->dp, &sk->dq, &sk->iq
-    };
-    for(u32 i = 0; i < ARRAY_LEN(sk_pointer_fields); i++){
-        u8** field_place = sk_pointer_fields[i];
-        u64 field_value = (u64)*field_place;
-        field_value += memory_distance;
-        *field_place = (void*)field_value;
     }
-
     Return RESULT_VOID;
 }
 

src/cryptography/cryptography.h

@@ -107,24 +107,24 @@ static inline void RSA_destroyPublicKey(br_rsa_public_key* sk){
 /// @param pk out public key. WARNING: .n is allocated on heap
 Result(void) RSA_computePublicKey(const br_rsa_private_key* sk, br_rsa_public_key* pk);
 
-/// @brief Serialize key in raw DER binary format
+/// @brief Encode key data in human-readable format
-/// @param sk the private key
+/// @param src some data
-/// @param pk set to NULL to calculate automatically
+/// @return heap-allocated string
-/// @param out_der out array. WARNING: .data is allocated on heap
+str RSA_serializePrivateKey_base64(const br_rsa_private_key* sk);
-Result(void) RSA_serializePrivateKey_RawDER(
+
-    const br_rsa_private_key* sk,
+/// @param src serialized private key format "RSA-Private-%SIZE%:%DATA_BASE64%"
-    NULLABLE(const br_rsa_public_key*) pk,
+/// @param sk out private key. WARNING: .p is allocated on heap
-    Array(u8)* out_der);
+Result(void) RSA_parsePrivateKey_base64(const str src, br_rsa_private_key* sk);
 
 /// @brief Encode key data in human-readable format
 /// @param src some data
-/// @param dst out array. WARNING: .data is allocated on heap
+/// @return heap-allocated string
-/// @param label some string to write at the top of PEM file
+str RSA_serializePublicKey_base64(const br_rsa_public_key* sk);
-void PEM_encode(Array(u8) src, Array(u8)* dst, cstr label);
+
+/// @param src serialized public key format "RSA-Public-%SIZE%:%DATA_BASE64%"
+/// @param sk out public key. WARNING: .p is allocated on heap
+Result(void) RSA_parsePublicKey_base64(const str src, br_rsa_public_key* sk);
 
-/// @param src serialized private key in DER format
-/// @param sk out private key. WARNING: .p is allocated on heap
-Result(void) RSA_parsePrivateKey_DER(Array(u8) src, br_rsa_private_key* sk);
 
 typedef struct EncryptorRSA {
     const br_rsa_public_key* pk;

src/network/endpoint.h

@@ -29,7 +29,7 @@ typedef struct EndpointIPv4 {
 } EndpointIPv4;
 
 #define EndpointIPv4_INVALID EndpointIPv4_create(AddressIPv4_INVALID, port_INVALID)
-#define EndpointIPv4_is_invalid(ENDP) (AddressIPv4_is_invalid(ENDP.address) || port_is_invalid(ENDP.port))
+#define EndpointIPv4_is_invalid(ENDP) (AddressIPv4_is_invalid((ENDP).address) || port_is_invalid((ENDP).port))
 
 #define EndpointIPv4_create(ADDR, PORT) ((EndpointIPv4){ADDR, PORT})
 Result(void) EndpointIPv4_parse(cstr s, EndpointIPv4* end);