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
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
|
/*
KeePass Password Safe - The Open-Source Password Manager
Copyright (C) 2003-2012 Dominik Reichl <dominik.reichl@t-online.de>
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
using System;
using System.Collections.Generic;
using System.Text;
using System.Diagnostics;
using KeePassLib.Security;
using KeePassLib.Utility;
namespace KeePassLib.Cryptography.PasswordGenerator
{
internal static class PatternBasedGenerator
{
internal static PwgError Generate(out ProtectedString psOut,
PwProfile pwProfile, CryptoRandomStream crsRandomSource)
{
psOut = ProtectedString.Empty;
LinkedList<char> vGenerated = new LinkedList<char>();
PwCharSet pcsCurrent = new PwCharSet();
PwCharSet pcsCustom = new PwCharSet();
PwCharSet pcsUsed = new PwCharSet();
bool bInCharSetDef = false;
string strPattern = ExpandPattern(pwProfile.Pattern);
if(strPattern.Length == 0) return PwgError.Success;
CharStream csStream = new CharStream(strPattern);
char ch = csStream.ReadChar();
while(ch != char.MinValue)
{
pcsCurrent.Clear();
bool bGenerateChar = false;
if(ch == '\\')
{
ch = csStream.ReadChar();
if(ch == char.MinValue) // Backslash at the end
{
vGenerated.AddLast('\\');
break;
}
if(bInCharSetDef) pcsCustom.Add(ch);
else
{
vGenerated.AddLast(ch);
pcsUsed.Add(ch);
}
}
else if(ch == '[')
{
pcsCustom.Clear();
bInCharSetDef = true;
}
else if(ch == ']')
{
pcsCurrent.Add(pcsCustom.ToString());
bInCharSetDef = false;
bGenerateChar = true;
}
else if(bInCharSetDef)
{
if(pcsCustom.AddCharSet(ch) == false)
pcsCustom.Add(ch);
}
else if(pcsCurrent.AddCharSet(ch) == false)
{
vGenerated.AddLast(ch);
pcsUsed.Add(ch);
}
else bGenerateChar = true;
if(bGenerateChar)
{
PwGenerator.PrepareCharSet(pcsCurrent, pwProfile);
if(pwProfile.NoRepeatingCharacters)
pcsCurrent.Remove(pcsUsed.ToString());
char chGen = PwGenerator.GenerateCharacter(pwProfile,
pcsCurrent, crsRandomSource);
if(chGen == char.MinValue) return PwgError.TooFewCharacters;
vGenerated.AddLast(chGen);
pcsUsed.Add(chGen);
}
ch = csStream.ReadChar();
}
if(vGenerated.Count == 0) return PwgError.Success;
char[] vArray = new char[vGenerated.Count];
vGenerated.CopyTo(vArray, 0);
if(pwProfile.PatternPermutePassword)
PwGenerator.ShufflePassword(vArray, crsRandomSource);
byte[] pbUtf8 = StrUtil.Utf8.GetBytes(vArray);
psOut = new ProtectedString(true, pbUtf8);
MemUtil.ZeroByteArray(pbUtf8);
Array.Clear(vArray, 0, vArray.Length);
vGenerated.Clear();
return PwgError.Success;
}
private static string ExpandPattern(string strPattern)
{
Debug.Assert(strPattern != null); if(strPattern == null) return string.Empty;
string str = strPattern;
while(true)
{
int nOpen = FindFirstUnescapedChar(str, '{');
int nClose = FindFirstUnescapedChar(str, '}');
if((nOpen >= 0) && (nOpen < nClose))
{
string strCount = str.Substring(nOpen + 1, nClose - nOpen - 1);
str = str.Remove(nOpen, nClose - nOpen + 1);
uint uRepeat;
if(StrUtil.TryParseUInt(strCount, out uRepeat) && (nOpen >= 1))
{
if(uRepeat == 0)
str = str.Remove(nOpen - 1, 1);
else
str = str.Insert(nOpen, new string(str[nOpen - 1], (int)uRepeat - 1));
}
}
else break;
}
return str;
}
private static int FindFirstUnescapedChar(string str, char ch)
{
for(int i = 0; i < str.Length; ++i)
{
char chCur = str[i];
if(chCur == '\\') ++i; // Next is escaped, skip it
else if(chCur == ch) return i;
}
return -1;
}
}
}
|
