Fix for trophy decryption (#2005)

* fix for trophy decryption

* more sanity checks

* switch back to strings for simplicity

* get rid of unnecessary span

src/common/config.cpp

@@ -67,7 +67,7 @@ static int cursorHideTimeout = 5; // 5 seconds (default)
 static bool separateupdatefolder = false;
 static bool compatibilityData = false;
 static bool checkCompatibilityOnStartup = false;
-static std::string trophyKey = "";
+static std::string trophyKey;
 
 // Gui
 std::vector<std::filesystem::path> settings_install_dirs = {};

src/core/crypto/crypto.cpp

@@ -2,7 +2,7 @@
 // SPDX-License-Identifier: GPL-2.0-or-later
 
 #include <array>
-#include <common/config.h>
+
 #include "crypto.h"
 
 CryptoPP::RSA::PrivateKey Crypto::key_pkg_derived_key3_keyset_init() {
@@ -138,29 +138,19 @@ void Crypto::aesCbcCfb128DecryptEntry(std::span<const CryptoPP::byte, 32> ivkey,
     }
 }
 
-static void hexToBytes(const char* hex, unsigned char* dst) {
+void Crypto::decryptEFSM(std::span<CryptoPP::byte, 16> trophyKey,
-    for (size_t i = 0; hex[i] != 0; i++) {
+                         std::span<CryptoPP::byte, 16> NPcommID,
-        const unsigned char value = (hex[i] < 0x3A) ? (hex[i] - 0x30) : (hex[i] - 0x37);
-        dst[i / 2] |= ((i % 2) == 0) ? (value << 4) : (value);
-    }
-}
-
-void Crypto::decryptEFSM(std::span<CryptoPP::byte, 16> NPcommID,
                          std::span<CryptoPP::byte, 16> efsmIv, std::span<CryptoPP::byte> ciphertext,
                          std::span<CryptoPP::byte> decrypted) {
 
-    std::vector<CryptoPP::byte> TrophyIV = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0};
     // step 1: Encrypt NPcommID
     CryptoPP::CBC_Mode<CryptoPP::AES>::Encryption encrypt;
 
-    const char* TrophyKeyget = Config::getTrophyKey().c_str();
+    std::vector<CryptoPP::byte> trophyIv(16, 0);
-    std::vector<CryptoPP::byte> TrophyKey;
-    hexToBytes(TrophyKeyget, TrophyKey.data());
-
     std::vector<CryptoPP::byte> trpKey(16);
 
+    encrypt.SetKeyWithIV(trophyKey.data(), trophyKey.size(), trophyIv.data());
     encrypt.ProcessData(trpKey.data(), NPcommID.data(), 16);
-    encrypt.SetKeyWithIV(TrophyKey.data(), TrophyKey.size(), TrophyIV.data());
 
     // step 2: decrypt efsm.
     CryptoPP::CBC_Mode<CryptoPP::AES>::Decryption decrypt;

src/core/crypto/crypto.h

@@ -32,7 +32,8 @@ public:
     void aesCbcCfb128DecryptEntry(std::span<const CryptoPP::byte, 32> ivkey,
                                   std::span<CryptoPP::byte> ciphertext,
                                   std::span<CryptoPP::byte> decrypted);
-    void decryptEFSM(std::span<CryptoPP::byte, 16>, std::span<CryptoPP::byte, 16> efsmIv,
+    void decryptEFSM(std::span<CryptoPP::byte, 16> trophyKey,
+                     std::span<CryptoPP::byte, 16> NPcommID, std::span<CryptoPP::byte, 16> efsmIv,
                      std::span<CryptoPP::byte> ciphertext, std::span<CryptoPP::byte> decrypted);
     void PfsGenCryptoKey(std::span<const CryptoPP::byte, 32> ekpfs,
                          std::span<const CryptoPP::byte, 16> seed,

src/core/file_format/trp.cpp

@@ -1,6 +1,7 @@
 // SPDX-FileCopyrightText: Copyright 2024 shadPS4 Emulator Project
 // SPDX-License-Identifier: GPL-2.0-or-later
 
+#include "common/config.h"
 #include "common/logging/log.h"
 #include "common/path_util.h"
 #include "trp.h"
@@ -33,12 +34,29 @@ static void removePadding(std::vector<u8>& vec) {
     }
 }
 
+static void hexToBytes(const char* hex, unsigned char* dst) {
+    for (size_t i = 0; hex[i] != 0; i++) {
+        const unsigned char value = (hex[i] < 0x3A) ? (hex[i] - 0x30) : (hex[i] - 0x37);
+        dst[i / 2] |= ((i % 2) == 0) ? (value << 4) : (value);
+    }
+}
+
 bool TRP::Extract(const std::filesystem::path& trophyPath, const std::string titleId) {
     std::filesystem::path gameSysDir = trophyPath / "sce_sys/trophy/";
     if (!std::filesystem::exists(gameSysDir)) {
         LOG_CRITICAL(Common_Filesystem, "Game sce_sys directory doesn't exist");
         return false;
     }
+
+    const auto user_key_str = Config::getTrophyKey();
+    if (user_key_str.size() != 32) {
+        LOG_CRITICAL(Common_Filesystem, "Trophy decryption key is not specified");
+        return false;
+    }
+
+    std::array<CryptoPP::byte, 16> user_key{};
+    hexToBytes(user_key_str.c_str(), user_key.data());
+
     for (int index = 0; const auto& it : std::filesystem::directory_iterator(gameSysDir)) {
         if (it.is_regular_file()) {
             GetNPcommID(trophyPath, index);
@@ -97,7 +115,7 @@ bool TRP::Extract(const std::filesystem::path& trophyPath, const std::string tit
                         return false;
                     }
                     file.Read(ESFM);
-                    crypto.decryptEFSM(np_comm_id, esfmIv, ESFM, XML); // decrypt
+                    crypto.decryptEFSM(user_key, np_comm_id, esfmIv, ESFM, XML); // decrypt
                     removePadding(XML);
                     std::string xml_name = entry.entry_name;
                     size_t pos = xml_name.find("ESFM");