nfp: Allow files without password data

src/core/hle/service/nfp/nfp.cpp

@@ -479,25 +479,35 @@ void Module::Interface::CreateUserInterface(Kernel::HLERequestContext& ctx) {
 }
 
 bool Module::Interface::LoadAmiibo(const std::vector<u8>& buffer) {
-    if (buffer.size() < sizeof(NTAG215File)) {
-        LOG_ERROR(Service_NFP, "Wrong file size");
+    if (device_state != DeviceState::SearchingForTag) {
+        LOG_ERROR(Service_NFP, "Game is not looking for amiibos, current state {}", device_state);
         return false;
     }
 
-    if (device_state != DeviceState::SearchingForTag) {
-        LOG_ERROR(Service_NFP, "Game is not looking for amiibos, current state {}", device_state);
+    constexpr auto tag_size = sizeof(NTAG215File);
+    constexpr auto tag_size_without_password = sizeof(NTAG215File) - sizeof(NTAG215Password);
+
+    std::vector<u8> amiibo_buffer = buffer;
+
+    if (amiibo_buffer.size() < tag_size_without_password) {
+        LOG_ERROR(Service_NFP, "Wrong file size {}", buffer.size());
         return false;
     }
 
+    // Ensure it has the correct size
+    if (amiibo_buffer.size() != tag_size) {
+        amiibo_buffer.resize(tag_size, 0);
+    }
+
     LOG_INFO(Service_NFP, "Amiibo detected");
-    std::memcpy(&tag_data, buffer.data(), sizeof(tag_data));
+    std::memcpy(&tag_data, buffer.data(), tag_size);
 
     if (!IsAmiiboValid()) {
         return false;
     }
 
     // This value can't be dumped from a tag. Generate it
-    tag_data.PWD = GetTagPassword(tag_data.uuid);
+    tag_data.password.PWD = GetTagPassword(tag_data.uuid);
 
     device_state = DeviceState::TagFound;
     activate_event->GetWritableEvent().Signal();

src/core/hle/service/nfp/nfp.h

@@ -153,6 +153,13 @@ public:
         };
         static_assert(sizeof(EncryptedAmiiboFile) == 0x1F8, "AmiiboFile is an invalid size");
 
+        struct NTAG215Password {
+            u32 PWD;  // Password to allow write access
+            u16 PACK; // Password acknowledge reply
+            u16 RFUI; // Reserved for future use
+        };
+        static_assert(sizeof(NTAG215Password) == 0x8, "NTAG215Password is an invalid size");
+
         struct NTAG215File {
             TagUuid uuid;                    // Unique serial number
             u16 lock_bytes;                  // Set defined pages as read only
@@ -161,9 +168,7 @@ public:
             u32 dynamic_lock;                // Dynamic lock
             u32 CFG0;                        // Defines memory protected by password
             u32 CFG1;                        // Defines number of verification attempts
-            u32 PWD;                         // Password to allow write access
-            u16 PACK;                        // Password acknowledge reply
-            u16 RFUI;                        // Reserved for future use
+            NTAG215Password password;        // Password data
         };
         static_assert(sizeof(NTAG215File) == 0x21C, "NTAG215File is an invalid size");