Merge pull request #36 from Nitrokey/issue_31-secret_as_hex

#31 pass secret to OTP as hex (breaking change - previously any string was accepted)

7 files changed, 124 insertions, 12 deletions

diff --git a/NitrokeyManager.cc b/NitrokeyManager.cc
index 5b648b5..d827292 100644
--- a/NitrokeyManager.cc
+++ b/NitrokeyManager.cc
@@ -2,6 +2,7 @@
 #include <iostream>
 #include "include/NitrokeyManager.h"
 #include "include/LibraryException.h"
+#include <algorithm>
 
 namespace nitrokey{
 
@@ -157,6 +158,15 @@ namespace nitrokey{
         return erase_slot(slot_number, temporary_password);
     }
 
+    template <typename T, typename U>
+    void vector_copy(T& dest, std::vector<U> &vec){
+        const size_t d_size = sizeof(dest);
+        if(d_size < vec.size()){
+            throw TargetBufferSmallerThanSource(vec.size(), d_size);
+        }
+        std::fill(dest, dest+d_size, 0);
+        std::copy(vec.begin(), vec.end(), dest);
+    }
 
     bool NitrokeyManager::write_HOTP_slot(uint8_t slot_number, const char *slot_name, const char *secret, uint8_t hotp_counter,
                                               bool use_8_digits, bool use_enter, bool use_tokenID, const char *token_ID,
@@ -166,7 +176,8 @@ namespace nitrokey{
         slot_number = get_internal_slot_number_for_hotp(slot_number);
         auto payload = get_payload<WriteToHOTPSlot>();
         payload.slot_number = slot_number;
-        strcpyT(payload.slot_secret, secret);
+        auto secret_bin = misc::hex_string_to_byte(secret);
+        vector_copy(payload.slot_secret, secret_bin);
         strcpyT(payload.slot_name, slot_name);
         strcpyT(payload.slot_token_id, token_ID);
         payload.slot_counter = hotp_counter;
@@ -188,7 +199,8 @@ namespace nitrokey{
 
         slot_number = get_internal_slot_number_for_totp(slot_number);
         payload.slot_number = slot_number;
-        strcpyT(payload.slot_secret, secret);
+        auto secret_bin = misc::hex_string_to_byte(secret);
+        vector_copy(payload.slot_secret, secret_bin);
         strcpyT(payload.slot_name, slot_name);
         strcpyT(payload.slot_token_id, token_ID);
         payload.slot_interval = time_window; //FIXME naming
diff --git a/include/LibraryException.h b/include/LibraryException.h
index 5036320..72891fb 100644
--- a/include/LibraryException.h
+++ b/include/LibraryException.h
@@ -12,6 +12,47 @@ public:
 
 
 
+class TargetBufferSmallerThanSource: public LibraryException {
+public:
+    virtual uint8_t exception_id() override {
+        return 203;
+    }
+
+public:
+    size_t source_size;
+    size_t target_size;
+
+    TargetBufferSmallerThanSource(
+            size_t source_size, size_t target_size
+            ) : source_size(source_size),  target_size(target_size) {}
+
+    virtual const char *what() const throw() override {
+        std::string s = " ";
+        auto ts = [](int x){ return std::to_string(x); };
+        std::string msg = std::string("Target buffer size is smaller than source: [source size, buffer size]")
+            +s+ ts(source_size) +s+ ts(target_size);
+        return msg.c_str();
+    }
+
+};
+
+class InvalidHexString : public LibraryException {
+public:
+    virtual uint8_t exception_id() override {
+        return 202;
+    }
+
+public:
+    uint8_t invalid_char;
+
+    InvalidHexString (uint8_t invalid_char) : invalid_char( invalid_char) {}
+
+    virtual const char *what() const throw() override {
+        return "Invalid character in hex string";
+    }
+
+};
+
 class InvalidSlotException : public LibraryException {
 public:
     virtual uint8_t exception_id() override {
diff --git a/include/misc.h b/include/misc.h
index cccd830..5fcd16d 100644
--- a/include/misc.h
+++ b/include/misc.h
@@ -2,6 +2,7 @@
 #define MISC_H
 #include <stdio.h>
 #include <string>
+#include <vector>
 
 namespace nitrokey {
 namespace misc {
@@ -16,7 +17,8 @@ typename T::CommandPayload get_payload(){
 
 
     std::string hexdump(const char *p, size_t size, bool print_header=true);
-uint32_t stm_crc32(const uint8_t *data, size_t size);
+    uint32_t stm_crc32(const uint8_t *data, size_t size);
+    std::vector<uint8_t> hex_string_to_byte(const char* hexString);
 }
 }
 
diff --git a/misc.cc b/misc.cc
index d004d0f..9b339cd 100644
--- a/misc.cc
+++ b/misc.cc
@@ -2,10 +2,38 @@
 #include <string>
 #include "misc.h"
 #include "inttypes.h"
+#include <cstdlib>
+#include <cstring>
+#include "LibraryException.h"
 
 namespace nitrokey {
 namespace misc {
 
+std::vector<uint8_t> hex_string_to_byte(const char* hexString){
+    const size_t big_string_size = 256; //arbitrary 'big' number
+    const size_t s_size = strlen(hexString);
+    const size_t d_size = s_size/2;
+    if (s_size%2!=0 || s_size==0 || s_size>big_string_size){
+        throw InvalidHexString(0);
+    }
+    auto data = std::vector<uint8_t>(d_size, 0);
+
+    char buf[2];
+    for(int i=0; i<s_size; i++){
+
+        char c = hexString[i];
+        bool char_from_range = (('0' <= c && c <='9') || ('A' <= c && c <= 'F') || ('a' <= c && c<= 'f'));
+        if (!char_from_range){
+            throw InvalidHexString(c);
+        }
+        buf[i%2] = c;
+        if (i%2==1){
+            data[i/2] = strtoul(buf, NULL, 16) & 0xFF;
+        }
+    }
+    return data;
+};
+
 std::string hexdump(const char *p, size_t size, bool print_header) {
   std::stringstream out;
   char formatbuf[128];
diff --git a/unittest/test.cc b/unittest/test.cc
index 6267512..6744b45 100644
--- a/unittest/test.cc
+++ b/unittest/test.cc
@@ -18,7 +18,7 @@ std::string getSlotName(Stick10 &stick, int slotNo) {
   auto slot_req = get_payload<ReadSlot>();
   slot_req.slot_number = slotNo;
   auto slot = ReadSlot::CommandTransaction::run(stick, slot_req);
-  std::string sName(reinterpret_cast<char *>(slot.slot_name));
+  std::string sName(reinterpret_cast<char *>(slot.data().slot_name));
   return sName;
 }
 
@@ -47,18 +47,18 @@ TEST_CASE("Slot names are correct", "[slotNames]") {
 
   {
     auto resp = GetPasswordRetryCount::CommandTransaction::run(stick);
-    REQUIRE(resp.password_retry_count == 3);
+    REQUIRE(resp.data().password_retry_count == 3);
   }
   {
     auto resp = GetUserPasswordRetryCount::CommandTransaction::run(stick);
-    REQUIRE(resp.password_retry_count == 3);
+    REQUIRE(resp.data().password_retry_count == 3);
   }
 
   {
     auto slot = get_payload<GetPasswordSafeSlotName>();
     slot.slot_number = 0;
     auto resp2 = GetPasswordSafeSlotName::CommandTransaction::run(stick, slot);
-    std::string sName(reinterpret_cast<char *>(resp2.slot_name));
+    std::string sName(reinterpret_cast<char *>(resp2.data().slot_name));
     REQUIRE(sName == std::string("web1"));
   }
 
@@ -67,7 +67,7 @@ TEST_CASE("Slot names are correct", "[slotNames]") {
     slot.slot_number = 0;
     auto resp2 =
         GetPasswordSafeSlotPassword::CommandTransaction::run(stick, slot);
-    std::string sName(reinterpret_cast<char *>(resp2.slot_password));
+    std::string sName(reinterpret_cast<char *>(resp2.data().slot_password));
     REQUIRE(sName == std::string("pass1"));
   }
 
@@ -75,7 +75,7 @@ TEST_CASE("Slot names are correct", "[slotNames]") {
     auto slot = get_payload<GetPasswordSafeSlotLogin>();
     slot.slot_number = 0;
     auto resp2 = GetPasswordSafeSlotLogin::CommandTransaction::run(stick, slot);
-    std::string sName(reinterpret_cast<char *>(resp2.slot_login));
+    std::string sName(reinterpret_cast<char *>(resp2.data().slot_login));
     REQUIRE(sName == std::string("login1"));
   }
 
diff --git a/unittest/test_HOTP.cc b/unittest/test_HOTP.cc
index f25bad4..d31df55 100644
--- a/unittest/test_HOTP.cc
+++ b/unittest/test_HOTP.cc
@@ -84,7 +84,7 @@ TEST_CASE("Test HOTP codes according to RFC", "[HOTP]") {
         auto gh = get_payload<GetHOTP>();
         gh.slot_number =  0x10;
         auto resp = GetHOTP::CommandTransaction::run(stick, gh);
-        REQUIRE( resp.code == code);
+        REQUIRE( resp.data().code == code);
     }
     //checking slot programmed before with nitro-app
     /*
diff --git a/unittest/test_bindings.py b/unittest/test_bindings.py
index eeda247..9c266aa 100644
--- a/unittest/test_bindings.py
+++ b/unittest/test_bindings.py
@@ -5,8 +5,16 @@ from enum import Enum
 ffi = cffi.FFI()
 gs = ffi.string
 
-RFC_SECRET = '12345678901234567890'
 
+def to_hex(s):
+    return "".join("{:02x}".format(ord(c)) for c in s)
+
+
+RFC_SECRET_HR = '12345678901234567890'
+RFC_SECRET = to_hex(RFC_SECRET_HR)  # '12345678901234567890'
+
+
+# print( repr((RFC_SECRET, RFC_SECRET_, len(RFC_SECRET))) )
 
 class DefaultPasswords(Enum):
     ADMIN = '12345678'
@@ -26,6 +34,8 @@ class DeviceErrorCode(Enum):
 class LibraryErrors(Enum):
     TOO_LONG_STRING = 200
     INVALID_SLOT = 201
+    INVALID_HEX_STRING = 202
+    TARGET_BUFFER_SIZE_SMALLER_THAN_SOURCE = 203
 
 
 @pytest.fixture(scope="module")
@@ -214,7 +224,7 @@ def test_invalid_slot(C):
     invalid_slot = 255
     assert C.NK_erase_totp_slot(invalid_slot, 'some password') == LibraryErrors.INVALID_SLOT
     assert C.NK_write_hotp_slot(invalid_slot, 'long_test', RFC_SECRET, 0, False, False, False, "",
-                            'aaa') == LibraryErrors.INVALID_SLOT
+                                'aaa') == LibraryErrors.INVALID_SLOT
     assert C.NK_get_hotp_code_PIN(invalid_slot, 'some password') == 0
     assert C.NK_get_last_command_status() == LibraryErrors.INVALID_SLOT
     assert C.NK_erase_password_safe_slot(invalid_slot) == LibraryErrors.INVALID_SLOT
@@ -503,3 +513,22 @@ def test_get_serial_number(C):
     sn = gs(sn)
     assert len(sn) > 0
     print(('Serial number of the device: ', sn))
+
+
+@pytest.mark.parametrize("invalid_hex_string",
+                         ['text', '00  ', '0xff', 'zzzzzzzzzzzz', 'fff', '', 'f' * 257, 'f' * 258])
+def test_invalid_secret_hex_string_for_OTP_write(C, invalid_hex_string):
+    """
+    Tests for invalid secret hex string during writing to OTP slot. Invalid strings are not hexadecimal number,
+    empty or longer than 255 characters.
+    """
+    assert C.NK_write_hotp_slot(1, 'slot_name', invalid_hex_string, 0, True, False, False, '',
+                                DefaultPasswords.ADMIN_TEMP) == LibraryErrors.INVALID_HEX_STRING
+    assert C.NK_write_totp_slot(1, 'python_test', invalid_hex_string, 30, True, False, False, "",
+                                DefaultPasswords.ADMIN_TEMP) == LibraryErrors.INVALID_HEX_STRING
+
+
+def test_warning_binary_bigger_than_secret_buffer(C):
+    invalid_hex_string = to_hex('1234567890') * 3
+    assert C.NK_write_hotp_slot(1, 'slot_name', invalid_hex_string, 0, True, False, False, '',
+                                DefaultPasswords.ADMIN_TEMP) == LibraryErrors.TARGET_BUFFER_SIZE_SMALLER_THAN_SOURCE