d3187d77 |
1 | /* -*-c-*- |
2 | * |
4e66da02 |
3 | * $Id: md2.c,v 1.2 2004/04/02 01:03:49 mdw Exp $ |
d3187d77 |
4 | * |
5 | * The MD2 message digest function |
6 | * |
7 | * (c) 2001 Straylight/Edgeware |
8 | */ |
9 | |
10 | /*----- Licensing notice --------------------------------------------------* |
11 | * |
12 | * This file is part of Catacomb. |
13 | * |
14 | * Catacomb is free software; you can redistribute it and/or modify |
15 | * it under the terms of the GNU Library General Public License as |
16 | * published by the Free Software Foundation; either version 2 of the |
17 | * License, or (at your option) any later version. |
18 | * |
19 | * Catacomb is distributed in the hope that it will be useful, |
20 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
21 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
22 | * GNU Library General Public License for more details. |
23 | * |
24 | * You should have received a copy of the GNU Library General Public |
25 | * License along with Catacomb; if not, write to the Free |
26 | * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, |
27 | * MA 02111-1307, USA. |
28 | */ |
29 | |
30 | /*----- Revision history --------------------------------------------------* |
31 | * |
32 | * $Log: md2.c,v $ |
4e66da02 |
33 | * Revision 1.2 2004/04/02 01:03:49 mdw |
34 | * Miscellaneous constification. |
35 | * |
d3187d77 |
36 | * Revision 1.1 2001/02/21 20:03:22 mdw |
37 | * Added support for MD2 hash function. |
38 | * |
39 | */ |
40 | |
41 | /*----- Header files ------------------------------------------------------*/ |
42 | |
43 | #include <mLib/bits.h> |
44 | |
45 | #include "ghash.h" |
46 | #include "ghash-def.h" |
47 | #include "hash.h" |
48 | #include "md2.h" |
49 | #include "md2-tab.h" |
50 | |
51 | /*----- Tables ------------------------------------------------------------*/ |
52 | |
4e66da02 |
53 | static const octet s[256] = MD2_S; |
d3187d77 |
54 | |
55 | /*----- Main code ---------------------------------------------------------*/ |
56 | |
57 | /* --- @md2_compress@ --- * |
58 | * |
59 | * Arguments: @md2_ctx *ctx@ = pointer to context block |
60 | * @const void *sbuf@ = pointer to buffer of appropriate size |
61 | * |
62 | * Returns: --- |
63 | * |
64 | * Use: MD2 compression and checksum function. |
65 | */ |
66 | |
67 | void md2_compress(md2_ctx *ctx, const void *sbuf) |
68 | { |
69 | unsigned i; |
70 | unsigned t; |
71 | octet x[MD2_BUFSZ]; |
72 | octet y[MD2_BUFSZ]; |
73 | |
74 | /* --- Handy macro for doing something lots of times --- */ |
75 | |
76 | #define DO(what, where) do { \ |
77 | what(where, 0); what(where, 1); what(where, 2); what(where, 3); \ |
78 | what(where, 4); what(where, 5); what(where, 6); what(where, 7); \ |
79 | what(where, 8); what(where, 9); what(where, 10); what(where, 11); \ |
80 | what(where, 12); what(where, 13); what(where, 14); what(where, 15); \ |
81 | } while (0) |
82 | |
83 | /* --- Do the hashing first to avoid corrupting the checksum --- */ |
84 | |
85 | memcpy(x, sbuf, sizeof(x)); |
86 | #define X(z, i) y[i] = z[i] ^ ctx->h[i] |
87 | DO(X, x); |
88 | #undef X |
89 | |
90 | t = 0; |
91 | for (i = 0; i < 18; i++) { |
92 | #define X(z, i) t = z[i] ^= s[t]; |
93 | DO(X, ctx->h); |
94 | DO(X, x); |
95 | DO(X, y); |
96 | #undef X |
97 | t = U8(t + i); |
98 | } |
99 | |
100 | /* --- Now compute the checksum --- */ |
101 | |
102 | t = ctx->c[MD2_BUFSZ - 1]; |
103 | #define X(z, i) t = ctx->c[i] ^= s[z[i] ^ t] |
104 | DO(X, ((const octet *)sbuf)); |
105 | #undef X |
106 | |
107 | #undef DO |
108 | } |
109 | |
110 | /* --- @md2_init@ --- * |
111 | * |
112 | * Arguments: @md2_ctx *ctx@ = pointer to context block to initialize |
113 | * |
114 | * Returns: --- |
115 | * |
116 | * Use: Initializes a context block ready for hashing. |
117 | */ |
118 | |
119 | void md2_init(md2_ctx *ctx) |
120 | { |
121 | memset(ctx->c, 0, sizeof(ctx->c)); |
122 | memset(ctx->h, 0, sizeof(ctx->h)); |
123 | ctx->off = 0; |
124 | } |
125 | |
126 | /* --- @md2_set@ --- * |
127 | * |
128 | * Arguments: @md2_ctx *ctx@ = pointer to context block |
129 | * @const void *buf@ = pointer to state buffer |
130 | * @unsigned long count@ = current count of bytes processed |
131 | * |
132 | * Returns: --- |
133 | * |
134 | * Use: Initializes a context block from a given state. This is |
135 | * useful in cases where the initial hash state is meant to be |
136 | * secret, e.g., for NMAC and HMAC support. |
137 | */ |
138 | |
139 | void md2_set(md2_ctx *ctx, const void *buf, unsigned long count) |
140 | { |
141 | const octet *p = buf; |
142 | memcpy(ctx->h, p, MD2_BUFSZ); |
143 | memcpy(ctx->c, p + MD2_BUFSZ, MD2_BUFSZ); |
144 | ctx->off = 0; |
145 | } |
146 | |
147 | /* --- @md2_hash@ --- * |
148 | * |
149 | * Arguments: @md2_ctx *ctx@ = pointer to context block |
150 | * @const void *buf@ = buffer of data to hash |
151 | * @size_t sz@ = size of buffer to hash |
152 | * |
153 | * Returns: --- |
154 | * |
155 | * Use: Hashes a buffer of data. The buffer may be of any size and |
156 | * alignment. |
157 | */ |
158 | |
159 | void md2_hash(md2_ctx *ctx, const void *buf, size_t sz) |
160 | { |
161 | const octet *bbuf = (octet *)buf; |
162 | |
163 | /* --- Code automatically expanded from @HASH_BUFFER@ and tidied --- */ |
164 | |
165 | if (ctx->off + sz < MD2_BUFSZ) { |
166 | memcpy(ctx->buf + ctx->off, bbuf, sz); |
167 | ctx->off += sz; |
168 | } else { |
169 | if (ctx->off) { |
170 | size_t s = MD2_BUFSZ - ctx->off; |
171 | memcpy(ctx->buf + ctx->off, bbuf, s); |
172 | md2_compress(ctx, ctx->buf); |
173 | sz -= s; |
174 | bbuf += s; |
175 | } |
176 | while (sz >= MD2_BUFSZ) { |
177 | md2_compress(ctx, bbuf); |
178 | sz -= MD2_BUFSZ; bbuf += MD2_BUFSZ; |
179 | } |
180 | if (sz) |
181 | memcpy(ctx->buf, bbuf, sz); |
182 | ctx->off = sz; |
183 | } |
184 | } |
185 | |
186 | /* --- @md2_done@ --- * |
187 | * |
188 | * Arguments: @md2_ctx *ctx@ = pointer to context block |
189 | * @void *hash@ = pointer to output buffer |
190 | * |
191 | * Returns: --- |
192 | * |
193 | * Use: Returns the hash of the data read so far. |
194 | */ |
195 | |
196 | void md2_done(md2_ctx *ctx, void *hash) |
197 | { |
198 | unsigned pad = MD2_BUFSZ - ctx->off; |
199 | unsigned i; |
200 | for (i = ctx->off; i < MD2_BUFSZ; i++) |
201 | ctx->buf[i] = pad; |
202 | md2_compress(ctx, ctx->buf); |
203 | md2_compress(ctx, ctx->c); |
204 | memcpy(hash, ctx->h, MD2_BUFSZ); |
205 | } |
206 | |
207 | /* --- @md2_state@ --- * |
208 | * |
209 | * Arguments: @md2_ctx *ctx@ = pointer to context |
210 | * @void *state@ = pointer to buffer for current state |
211 | * |
212 | * Returns: Number of bytes written to the hash function so far. |
213 | * |
214 | * Use: Returns the current state of the hash function such that |
215 | * it can be passed to @md2_set@. |
216 | */ |
217 | |
218 | unsigned long md2_state(md2_ctx *ctx, void *state) |
219 | { |
220 | octet *p = state; |
221 | memcpy(p, ctx->h, MD2_BUFSZ); |
222 | memcpy(p + MD2_BUFSZ, ctx->c, MD2_BUFSZ); |
223 | return (0); |
224 | } |
225 | |
226 | /* --- Generic interface --- */ |
227 | |
228 | GHASH_DEF(MD2, md2) |
229 | |
230 | /* --- Test code --- */ |
231 | |
232 | HASH_TEST(MD2, md2) |
233 | |
234 | /*----- That's all, folks -------------------------------------------------*/ |