1 /*
2 mdfour.c
3
4 An implementation of MD4 designed for use in the samba SMB
5 authentication protocol
6
7 Copyright (C) 1997-1998 Andrew Tridgell
8
9 This program is free software; you can redistribute it and/or
10 modify it under the terms of the GNU General Public License
11 as published by the Free Software Foundation; either version 2
12 of the License, or (at your option) any later version.
13
14 This program is distributed in the hope that it will be useful,
15 but WITHOUT ANY WARRANTY; without even the implied warranty of
16 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
17
18 See the GNU General Public License for more details.
19
20 You should have received a copy of the GNU General Public License
21 along with this program; if not, write to:
22
23 Free Software Foundation, Inc.
24 59 Temple Place - Suite 330
25 Boston, MA 02111-1307, USA
26
27 $Id: mdfour.c,v 1.1 2002/08/23 22:03:27 abster Exp $
28 */
29
30 #include "q_shared.h"
31 #include "qcommon.h"
32
33 struct mdfour {
34 uint32_t A, B, C, D;
35 uint32_t totalN;
36 };
37
38
39 /* NOTE: This code makes no attempt to be fast!
40
41 It assumes that a int is at least 32 bits long
42 */
43
44 static struct mdfour *m;
45
46 #define F(X,Y,Z) (((X)&(Y)) | ((~(X))&(Z)))
47 #define G(X,Y,Z) (((X)&(Y)) | ((X)&(Z)) | ((Y)&(Z)))
48 #define H(X,Y,Z) ((X)^(Y)^(Z))
49 #define lshift(x,s) (((x)<<(s)) | ((x)>>(32-(s))))
50
51 #define ROUND1(a,b,c,d,k,s) a = lshift(a + F(b,c,d) + X[k], s)
52 #define ROUND2(a,b,c,d,k,s) a = lshift(a + G(b,c,d) + X[k] + 0x5A827999,s)
53 #define ROUND3(a,b,c,d,k,s) a = lshift(a + H(b,c,d) + X[k] + 0x6ED9EBA1,s)
54
55 /* this applies md4 to 64 byte chunks */
mdfour64(uint32_t * M)56 static void mdfour64(uint32_t *M)
57 {
58 int j;
59 uint32_t AA, BB, CC, DD;
60 uint32_t X[16];
61 uint32_t A,B,C,D;
62
63 for (j=0;j<16;j++)
64 X[j] = M[j];
65
66 A = m->A; B = m->B; C = m->C; D = m->D;
67 AA = A; BB = B; CC = C; DD = D;
68
69 ROUND1(A,B,C,D, 0, 3); ROUND1(D,A,B,C, 1, 7);
70 ROUND1(C,D,A,B, 2, 11); ROUND1(B,C,D,A, 3, 19);
71 ROUND1(A,B,C,D, 4, 3); ROUND1(D,A,B,C, 5, 7);
72 ROUND1(C,D,A,B, 6, 11); ROUND1(B,C,D,A, 7, 19);
73 ROUND1(A,B,C,D, 8, 3); ROUND1(D,A,B,C, 9, 7);
74 ROUND1(C,D,A,B, 10, 11); ROUND1(B,C,D,A, 11, 19);
75 ROUND1(A,B,C,D, 12, 3); ROUND1(D,A,B,C, 13, 7);
76 ROUND1(C,D,A,B, 14, 11); ROUND1(B,C,D,A, 15, 19);
77
78 ROUND2(A,B,C,D, 0, 3); ROUND2(D,A,B,C, 4, 5);
79 ROUND2(C,D,A,B, 8, 9); ROUND2(B,C,D,A, 12, 13);
80 ROUND2(A,B,C,D, 1, 3); ROUND2(D,A,B,C, 5, 5);
81 ROUND2(C,D,A,B, 9, 9); ROUND2(B,C,D,A, 13, 13);
82 ROUND2(A,B,C,D, 2, 3); ROUND2(D,A,B,C, 6, 5);
83 ROUND2(C,D,A,B, 10, 9); ROUND2(B,C,D,A, 14, 13);
84 ROUND2(A,B,C,D, 3, 3); ROUND2(D,A,B,C, 7, 5);
85 ROUND2(C,D,A,B, 11, 9); ROUND2(B,C,D,A, 15, 13);
86
87 ROUND3(A,B,C,D, 0, 3); ROUND3(D,A,B,C, 8, 9);
88 ROUND3(C,D,A,B, 4, 11); ROUND3(B,C,D,A, 12, 15);
89 ROUND3(A,B,C,D, 2, 3); ROUND3(D,A,B,C, 10, 9);
90 ROUND3(C,D,A,B, 6, 11); ROUND3(B,C,D,A, 14, 15);
91 ROUND3(A,B,C,D, 1, 3); ROUND3(D,A,B,C, 9, 9);
92 ROUND3(C,D,A,B, 5, 11); ROUND3(B,C,D,A, 13, 15);
93 ROUND3(A,B,C,D, 3, 3); ROUND3(D,A,B,C, 11, 9);
94 ROUND3(C,D,A,B, 7, 11); ROUND3(B,C,D,A, 15, 15);
95
96 A += AA; B += BB; C += CC; D += DD;
97
98 for (j=0;j<16;j++)
99 X[j] = 0;
100
101 m->A = A; m->B = B; m->C = C; m->D = D;
102 }
103
copy64(uint32_t * M,byte * in)104 static void copy64(uint32_t *M, byte *in)
105 {
106 int i;
107
108 for (i=0;i<16;i++)
109 M[i] = (in[i*4+3]<<24) | (in[i*4+2]<<16) |
110 (in[i*4+1]<<8) | (in[i*4+0]<<0);
111 }
112
copy4(byte * out,uint32_t x)113 static void copy4(byte *out,uint32_t x)
114 {
115 out[0] = x&0xFF;
116 out[1] = (x>>8)&0xFF;
117 out[2] = (x>>16)&0xFF;
118 out[3] = (x>>24)&0xFF;
119 }
120
mdfour_begin(struct mdfour * md)121 void mdfour_begin(struct mdfour *md)
122 {
123 md->A = 0x67452301;
124 md->B = 0xefcdab89;
125 md->C = 0x98badcfe;
126 md->D = 0x10325476;
127 md->totalN = 0;
128 }
129
130
mdfour_tail(byte * in,int n)131 static void mdfour_tail(byte *in, int n)
132 {
133 byte buf[128];
134 uint32_t M[16];
135 uint32_t b;
136
137 m->totalN += n;
138
139 b = m->totalN * 8;
140
141 Com_Memset(buf, 0, 128);
142 if (n) Com_Memcpy(buf, in, n);
143 buf[n] = 0x80;
144
145 if (n <= 55) {
146 copy4(buf+56, b);
147 copy64(M, buf);
148 mdfour64(M);
149 } else {
150 copy4(buf+120, b);
151 copy64(M, buf);
152 mdfour64(M);
153 copy64(M, buf+64);
154 mdfour64(M);
155 }
156 }
157
mdfour_update(struct mdfour * md,byte * in,int n)158 static void mdfour_update(struct mdfour *md, byte *in, int n)
159 {
160 uint32_t M[16];
161
162 m = md;
163
164 if (n == 0) mdfour_tail(in, n);
165
166 while (n >= 64) {
167 copy64(M, in);
168 mdfour64(M);
169 in += 64;
170 n -= 64;
171 m->totalN += 64;
172 }
173
174 mdfour_tail(in, n);
175 }
176
177
mdfour_result(struct mdfour * md,byte * out)178 static void mdfour_result(struct mdfour *md, byte *out)
179 {
180 m = md;
181
182 copy4(out, m->A);
183 copy4(out+4, m->B);
184 copy4(out+8, m->C);
185 copy4(out+12, m->D);
186 }
187
mdfour(byte * out,byte * in,int n)188 static void mdfour(byte *out, byte *in, int n)
189 {
190 struct mdfour md;
191 mdfour_begin(&md);
192 mdfour_update(&md, in, n);
193 mdfour_result(&md, out);
194 }
195
196 //===================================================================
197
Com_BlockChecksum(const void * buffer,int length)198 unsigned Com_BlockChecksum (const void *buffer, int length)
199 {
200 int digest[4];
201 unsigned val;
202
203 mdfour( (byte *)digest, (byte *)buffer, length );
204
205 val = digest[0] ^ digest[1] ^ digest[2] ^ digest[3];
206
207 return val;
208 }
209