Support sending empty OTP secrets for slot edit (+test)

Signed-off-by: Szczepan Zalega <szczepan@nitrokey.com>

2 files changed, 32 insertions, 1 deletions

diff --git a/misc.cc b/misc.cc
index 7a3c199..3f15520 100644
--- a/misc.cc
+++ b/misc.cc
@@ -13,7 +13,7 @@ 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){
+    if (s_size%2!=0 || s_size>big_string_size){
         throw InvalidHexString(0);
     }
     auto data = std::vector<uint8_t>();
diff --git a/unittest/test_pro.py b/unittest/test_pro.py
index 71abfba..b8109f2 100644
--- a/unittest/test_pro.py
+++ b/unittest/test_pro.py
@@ -630,3 +630,34 @@ def test_HOTP_secrets(C, secret):
     lib_res += (counter, lib_at(counter))
     assert dev_res == lib_res
 
+
+def test_edit_OTP_slot(C):
+    """
+    should change slots counter and name without changing its secret (using null secret for second update)
+    """
+    secret = RFC_SECRET
+    counter = 0
+    PIN_protection = False
+    use_8_digits = False
+    assert C.NK_first_authenticate(DefaultPasswords.ADMIN, DefaultPasswords.ADMIN_TEMP) == DeviceErrorCode.STATUS_OK
+    assert C.NK_write_config(255, 255, 255, PIN_protection, not PIN_protection,
+                             DefaultPasswords.ADMIN_TEMP) == DeviceErrorCode.STATUS_OK
+    slot_number = 0
+    assert C.NK_first_authenticate(DefaultPasswords.ADMIN, DefaultPasswords.ADMIN_TEMP) == DeviceErrorCode.STATUS_OK
+    first_name = 'edit slot'
+    assert C.NK_write_hotp_slot(slot_number, first_name, secret, counter, use_8_digits, False, False, "",
+                                DefaultPasswords.ADMIN_TEMP) == DeviceErrorCode.STATUS_OK
+    assert gs(C.NK_get_hotp_slot_name(slot_number)) == first_name
+
+
+    first_code = C.NK_get_hotp_code(slot_number)
+    changed_name = 'changedname'
+    empty_secret = ''
+    assert C.NK_first_authenticate(DefaultPasswords.ADMIN, DefaultPasswords.ADMIN_TEMP) == DeviceErrorCode.STATUS_OK
+    assert C.NK_write_hotp_slot(slot_number, changed_name, empty_secret, counter, use_8_digits, False, False, "",
+                                DefaultPasswords.ADMIN_TEMP) == DeviceErrorCode.STATUS_OK
+    second_code = C.NK_get_hotp_code(slot_number)
+    assert first_code == second_code
+    assert gs(C.NK_get_hotp_slot_name(slot_number)) == changed_name
+
+