/
BktrCryptoStream.cs
110 lines (94 loc) · 3.82 KB
/
BktrCryptoStream.cs
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using LibHac.Streams;
namespace LibHac
{
public class BktrCryptoStream : Aes128CtrStream
{
public SubsectionBlock SubsectionBlock { get; }
private List<SubsectionEntry> SubsectionEntries { get; } = new List<SubsectionEntry>();
private List<long> SubsectionOffsets { get; }
private SubsectionEntry CurrentEntry { get; set; }
public BktrCryptoStream(Stream baseStream, byte[] key, long offset, long length, long counterOffset, byte[] ctrHi, BktrSuperblock bktr)
: base(baseStream, key, offset, length, counterOffset, ctrHi)
{
BktrHeader header = bktr.SubsectionHeader;
byte[] subsectionBytes;
using (var streamDec = new RandomAccessSectorStream(new Aes128CtrStream(baseStream, key, offset, length, counterOffset, ctrHi)))
{
streamDec.Position = header.Offset;
subsectionBytes = new byte[header.Size];
streamDec.Read(subsectionBytes, 0, subsectionBytes.Length);
}
using (var reader = new BinaryReader(new MemoryStream(subsectionBytes)))
{
SubsectionBlock = new SubsectionBlock(reader);
}
foreach (SubsectionBucket bucket in SubsectionBlock.Buckets)
{
SubsectionEntries.AddRange(bucket.Entries);
}
// Add a subsection for the BKTR headers to make things easier
var headerSubsection = new SubsectionEntry
{
Offset = bktr.RelocationHeader.Offset,
Counter = (uint)(ctrHi[4] << 24 | ctrHi[5] << 16 | ctrHi[6] << 8 | ctrHi[7]),
OffsetEnd = long.MaxValue
};
SubsectionEntries.Add(headerSubsection);
for (int i = 0; i < SubsectionEntries.Count - 1; i++)
{
SubsectionEntries[i].Next = SubsectionEntries[i + 1];
SubsectionEntries[i].OffsetEnd = SubsectionEntries[i + 1].Offset;
}
SubsectionOffsets = SubsectionEntries.Select(x => x.Offset).ToList();
CurrentEntry = GetSubsectionEntry(0);
UpdateCounterSubsection(CurrentEntry.Counter);
baseStream.Position = offset;
}
public override long Position
{
get => base.Position;
set
{
base.Position = value;
CurrentEntry = GetSubsectionEntry(value);
UpdateCounterSubsection(CurrentEntry.Counter);
}
}
public override int Read(byte[] buffer, int offset, int count)
{
int totalBytesRead = 0;
int outPos = offset;
while (count > 0)
{
int bytesToRead = (int)Math.Min(CurrentEntry.OffsetEnd - Position, count);
int bytesRead = base.Read(buffer, outPos, bytesToRead);
outPos += bytesRead;
totalBytesRead += bytesRead;
count -= bytesRead;
if (Position >= CurrentEntry.OffsetEnd)
{
CurrentEntry = CurrentEntry.Next;
UpdateCounterSubsection(CurrentEntry.Counter);
}
}
return totalBytesRead;
}
private SubsectionEntry GetSubsectionEntry(long offset)
{
int index = SubsectionOffsets.BinarySearch(offset);
if (index < 0) index = ~index - 1;
return SubsectionEntries[index];
}
private void UpdateCounterSubsection(uint value)
{
Counter[7] = (byte)value;
Counter[6] = (byte)(value >> 8);
Counter[5] = (byte)(value >> 16);
Counter[4] = (byte)(value >> 24);
}
}
}