From 77f47866dfb4fbf330292957031b1914b2ac3a3e Mon Sep 17 00:00:00 2001
From: Pierre Bourdon <delroth@gmail.com>
Date: Fri, 4 May 2012 12:49:10 +0200
Subject: Add Wii DVD integrity checking to Dolphin

This allows users to easily check whether their Wii dump is corrupted or not
using the Dolphin properties window. Right click on a game, Properties,
Filesystem tab, then right click on the game partition and select "Check
partition integrity".

This may have some false negatives due to the unused clusters heuristic (see
the comment in VolumeWiiCrypted.cpp). False positives are unlikely.
---
 Source/Core/DiscIO/Src/VolumeWiiCrypted.cpp | 65 +++++++++++++++++++++++++++++
 1 file changed, 65 insertions(+)

(limited to 'Source/Core/DiscIO/Src/VolumeWiiCrypted.cpp')

diff --git a/Source/Core/DiscIO/Src/VolumeWiiCrypted.cpp b/Source/Core/DiscIO/Src/VolumeWiiCrypted.cpp
index 9e7865d9c6..ca010b5ae4 100644
--- a/Source/Core/DiscIO/Src/VolumeWiiCrypted.cpp
+++ b/Source/Core/DiscIO/Src/VolumeWiiCrypted.cpp
@@ -17,6 +17,7 @@
 
 #include "VolumeWiiCrypted.h"
 #include "StringUtil.h"
+#include "Crypto/sha1.h"
 
 namespace DiscIO
 {
@@ -232,4 +233,68 @@ u64 CVolumeWiiCrypted::GetSize() const
 	}
 }
 
+bool CVolumeWiiCrypted::CheckIntegrity() const
+{
+	// Get partition data size
+	u32 partSizeDiv4;
+	RAWRead(m_VolumeOffset + 0x2BC, 4, (u8*)&partSizeDiv4);
+	u64 partDataSize = (u64)Common::swap32(partSizeDiv4) * 4;
+
+	u32 nClusters = (u32)(partDataSize / 0x8000);
+	for (u32 clusterID = 0; clusterID < nClusters; ++clusterID)
+	{
+		u64 clusterOff = m_VolumeOffset + dataOffset + (u64)clusterID * 0x8000;
+
+		// Read and decrypt the cluster metadata
+		u8 clusterMDCrypted[0x400];
+		u8 clusterMD[0x400];
+		u8 IV[16] = { 0 };
+		if (!m_pReader->Read(clusterOff, 0x400, clusterMDCrypted))
+		{
+			NOTICE_LOG(DISCIO, "Integrity Check: fail at cluster %d: could not read metadata", clusterID);
+			return false;
+		}
+		AES_cbc_encrypt(clusterMDCrypted, clusterMD, 0x400, &m_AES_KEY, IV, AES_DECRYPT);
+
+		// Some clusters have invalid data and metadata because they aren't
+		// meant to be read by the game (for example, holes between files). To
+		// try to avoid reporting errors because of these clusters, we check
+		// the 0x00 paddings in the metadata.
+		//
+		// This may cause some false negatives though: some bad clusters may be
+		// skipped because they are *too* bad and are not even recognized as
+		// valid clusters. To be improved.
+		bool meaningless = false;
+		for (u32 idx = 0x26C; idx < 0x280; ++idx)
+			if (clusterMD[idx] != 0)
+				meaningless = true;
+
+		if (meaningless)
+			continue;
+
+		u8 clusterData[0x7C00];
+		if (!Read((u64)clusterID * 0x7C00, 0x7C00, clusterData))
+		{
+			NOTICE_LOG(DISCIO, "Integrity Check: fail at cluster %d: could not read data", clusterID);
+			return false;
+		}
+
+		for (u32 hashID = 0; hashID < 31; ++hashID)
+		{
+			u8 hash[20];
+
+			sha1(clusterData + hashID * 0x400, 0x400, hash);
+
+			// Note that we do not use strncmp here
+			if (memcmp(hash, clusterMD + hashID * 20, 20))
+			{
+				NOTICE_LOG(DISCIO, "Integrity Check: fail at cluster %d: hash %d is invalid", clusterID, hashID);
+				return false;
+			}
+		}
+	}
+
+	return true;
+}
+
 } // namespace
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