Allow loading the 0x05keyY from aeskeydb.bin

... also searchin /Decrypt9 folder

source/nand/nand.c

@@ -39,6 +39,72 @@ static u8 TwlNandCtr[16];
 
 static u32 emunand_base_sector = 0x000000;
 
+bool LoadKeyFromFile(const char* folder, u8* keydata, u32 keyslot, char type, char* id)
+{
+    char path[256]; // should be enough
+    u8 key_magic[16];
+    u8 buffer[32];
+    u8* key = buffer + 16;
+    bool found = false;
+    
+    // check the obvious
+    if (keyslot >= 0x40)
+        return false; // invalid keyslot
+    if ((type != 'X') && (type != 'Y') && (type != 'N'))
+        return false; // invalid keytype 
+    
+    // search 'aeskeydb.bin' file - setup
+    snprintf(path, 256, "%s/aeskeydb.bin", folder);
+    memset(key_magic, 0x00, 16);
+    key_magic[0] = keyslot;
+    key_magic[1] = type;
+    if (id) strncpy((char*) key_magic + 2, id, 10);
+    
+    // try to find key in 'aeskeydb.bin' file
+    for (u32 p = 0; FileGetData(path, buffer, 32, p); p += 32) {
+        if (memcmp(buffer, key_magic, 12) == 0) {
+            found = true;
+            break;
+        }
+    }
+    if (found && buffer[15]) { // encrypted key -> decrypt first
+        u8 ctr[16] __attribute__((aligned(32)));
+        u8 keyY[16] __attribute__((aligned(32)));
+        memset(ctr, 0x00, 16);
+        memset(keyY, 0x00, 16);
+        memcpy(ctr, key_magic, 12);
+        setup_aeskeyY(0x2C, keyY);
+        use_aeskey(0x2C);
+        set_ctr(ctr);
+        aes_decrypt((void*) key, (void*) key, 1, AES_CNT_CTRNAND_MODE);
+    }
+    
+    // try legacy slot0x??Key?.bin file
+    if (!found) {
+        snprintf(path, 256, "%s/slot0x%02XKey%.10s", folder, (unsigned int) keyslot,
+            (id) ? id : (type == 'X') ? "X" : (type == 'Y') ? "Y" : "");
+        if (FileGetData(path, key, 16, 0))
+            found = true;
+    }
+    
+    // out of options here
+    if (!found) return false;
+    
+    // now, setup the key
+    if (type == 'X') { // keyX
+        setup_aeskeyX(keyslot, key);
+    } else if (type == 'Y') { // keyY
+        setup_aeskeyY(keyslot, key);
+    } else { // normalKey
+        setup_aeskey(keyslot, key);
+    }
+    use_aeskey(keyslot);
+    
+    // return the key if memory provided
+    if (keydata) memcpy(keydata, key, 16);
+    
+    return true;
+}
 
 bool InitNandCrypto(void)
 {
@@ -81,10 +147,8 @@ bool InitNandCrypto(void)
     use_aeskey(0x03);
     
     // part #3: CTRNAND N3DS KEY
-    if (FileGetData("0:/slot0x05KeyY.bin", slot0x05KeyY, 16, 0)) {
-        setup_aeskeyY(0x05, slot0x05KeyY);
-        use_aeskey(0x05);
-    }
+    if (!LoadKeyFromFile("0:", slot0x05KeyY, 0x05, 'Y', NULL))
+        LoadKeyFromFile("0:/Decrypt9", slot0x05KeyY, 0x05, 'Y', NULL);
     
     
     return true;

source/nand/nand.h

@@ -10,6 +10,7 @@
 #define NAND_TYPE_N3DS  (1<<4)
 #define NAND_TYPE_NO3DS (1<<5)
 
+bool LoadKeyFromFile(const char* folder, u8* keydata, u32 keyslot, char type, char* id);
 bool InitNandCrypto(void);
 bool CheckSlot0x05Crypto(void);