033b4cef |
1 | #include <stdarg.h> /* FIXME */ |
2 | #include <windows.h> /* FIXME */ |
3 | #include "putty.h" /* FIXME */ |
4 | |
374330e2 |
5 | /* |
e5574168 |
6 | * SHA1 hash algorithm. Used in SSH2 as a MAC, and the transform is |
7 | * also used as a `stirring' function for the PuTTY random number |
8 | * pool. Implemented directly from the specification by Simon |
9 | * Tatham. |
374330e2 |
10 | */ |
11 | |
12 | #include "ssh.h" |
13 | |
e5574168 |
14 | typedef unsigned int uint32; |
15 | |
16 | /* ---------------------------------------------------------------------- |
17 | * Core SHA algorithm: processes 16-word blocks into a message digest. |
18 | */ |
19 | |
20 | #define rol(x,y) ( ((x) << (y)) | (((uint32)x) >> (32-y)) ) |
21 | |
22 | void SHA_Core_Init(uint32 h[5]) { |
23 | h[0] = 0x67452301; |
24 | h[1] = 0xefcdab89; |
25 | h[2] = 0x98badcfe; |
26 | h[3] = 0x10325476; |
27 | h[4] = 0xc3d2e1f0; |
28 | } |
e9483e66 |
29 | |
30 | void SHATransform(word32 *digest, word32 *block) { |
31 | word32 w[80]; |
32 | word32 a,b,c,d,e; |
33 | int t; |
34 | |
35 | for (t = 0; t < 16; t++) |
36 | w[t] = block[t]; |
37 | |
38 | for (t = 16; t < 80; t++) { |
39 | word32 tmp = w[t-3] ^ w[t-8] ^ w[t-14] ^ w[t-16]; |
40 | w[t] = rol(tmp, 1); |
41 | } |
42 | |
43 | a = digest[0]; |
44 | b = digest[1]; |
45 | c = digest[2]; |
46 | d = digest[3]; |
47 | e = digest[4]; |
48 | |
49 | for (t = 0; t < 20; t++) { |
50 | word32 tmp = rol(a, 5) + ( (b&c) | (d&~b) ) + e + w[t] + 0x5a827999; |
51 | e = d; d = c; c = rol(b, 30); b = a; a = tmp; |
52 | } |
53 | for (t = 20; t < 40; t++) { |
54 | word32 tmp = rol(a, 5) + (b^c^d) + e + w[t] + 0x6ed9eba1; |
55 | e = d; d = c; c = rol(b, 30); b = a; a = tmp; |
56 | } |
57 | for (t = 40; t < 60; t++) { |
58 | word32 tmp = rol(a, 5) + ( (b&c) | (b&d) | (c&d) ) + e + w[t] + 0x8f1bbcdc; |
59 | e = d; d = c; c = rol(b, 30); b = a; a = tmp; |
60 | } |
61 | for (t = 60; t < 80; t++) { |
62 | word32 tmp = rol(a, 5) + (b^c^d) + e + w[t] + 0xca62c1d6; |
63 | e = d; d = c; c = rol(b, 30); b = a; a = tmp; |
64 | } |
65 | |
66 | digest[0] += a; |
67 | digest[1] += b; |
68 | digest[2] += c; |
69 | digest[3] += d; |
70 | digest[4] += e; |
374330e2 |
71 | } |
e5574168 |
72 | |
73 | /* ---------------------------------------------------------------------- |
74 | * Outer SHA algorithm: take an arbitrary length byte string, |
75 | * convert it into 16-word blocks with the prescribed padding at |
76 | * the end, and pass those blocks to the core SHA algorithm. |
77 | */ |
78 | |
79 | void SHA_Init(SHA_State *s) { |
80 | SHA_Core_Init(s->h); |
81 | s->blkused = 0; |
82 | s->lenhi = s->lenlo = 0; |
83 | } |
84 | |
85 | void SHA_Bytes(SHA_State *s, void *p, int len) { |
86 | unsigned char *q = (unsigned char *)p; |
87 | uint32 wordblock[16]; |
88 | uint32 lenw = len; |
89 | int i; |
90 | |
91 | /* |
92 | * Update the length field. |
93 | */ |
94 | s->lenlo += lenw; |
95 | s->lenhi += (s->lenlo < lenw); |
96 | |
97 | if (s->blkused && s->blkused+len < 64) { |
98 | /* |
99 | * Trivial case: just add to the block. |
100 | */ |
101 | memcpy(s->block + s->blkused, q, len); |
102 | s->blkused += len; |
103 | } else { |
104 | /* |
105 | * We must complete and process at least one block. |
106 | */ |
107 | while (s->blkused + len >= 64) { |
108 | memcpy(s->block + s->blkused, q, 64 - s->blkused); |
109 | q += 64 - s->blkused; |
110 | len -= 64 - s->blkused; |
111 | /* Now process the block. Gather bytes big-endian into words */ |
112 | for (i = 0; i < 16; i++) { |
113 | wordblock[i] = |
114 | ( ((uint32)s->block[i*4+0]) << 24 ) | |
115 | ( ((uint32)s->block[i*4+1]) << 16 ) | |
116 | ( ((uint32)s->block[i*4+2]) << 8 ) | |
117 | ( ((uint32)s->block[i*4+3]) << 0 ); |
118 | } |
119 | SHATransform(s->h, wordblock); |
120 | s->blkused = 0; |
121 | } |
122 | memcpy(s->block, q, len); |
123 | s->blkused = len; |
124 | } |
125 | } |
126 | |
127 | void SHA_Final(SHA_State *s, unsigned char *output) { |
128 | int i; |
129 | int pad; |
130 | unsigned char c[64]; |
131 | uint32 lenhi, lenlo; |
132 | |
133 | if (s->blkused >= 56) |
134 | pad = 56 + 64 - s->blkused; |
135 | else |
136 | pad = 56 - s->blkused; |
137 | |
138 | lenhi = (s->lenhi << 3) | (s->lenlo >> (32-3)); |
139 | lenlo = (s->lenlo << 3); |
140 | |
141 | memset(c, 0, pad); |
142 | c[0] = 0x80; |
143 | SHA_Bytes(s, &c, pad); |
144 | |
145 | c[0] = (lenhi >> 24) & 0xFF; |
146 | c[1] = (lenhi >> 16) & 0xFF; |
147 | c[2] = (lenhi >> 8) & 0xFF; |
148 | c[3] = (lenhi >> 0) & 0xFF; |
149 | c[4] = (lenlo >> 24) & 0xFF; |
150 | c[5] = (lenlo >> 16) & 0xFF; |
151 | c[6] = (lenlo >> 8) & 0xFF; |
152 | c[7] = (lenlo >> 0) & 0xFF; |
153 | |
154 | SHA_Bytes(s, &c, 8); |
155 | |
156 | for (i = 0; i < 5; i++) { |
157 | output[i*4 ] = (s->h[i] >> 24) & 0xFF; |
158 | output[i*4+1] = (s->h[i] >> 16) & 0xFF; |
159 | output[i*4+2] = (s->h[i] >> 8) & 0xFF; |
160 | output[i*4+3] = (s->h[i] ) & 0xFF; |
161 | } |
162 | } |
163 | |
164 | void SHA_Simple(void *p, int len, unsigned char *output) { |
165 | SHA_State s; |
166 | |
167 | SHA_Init(&s); |
168 | SHA_Bytes(&s, p, len); |
169 | SHA_Final(&s, output); |
170 | } |
171 | |
172 | /* ---------------------------------------------------------------------- |
173 | * The above is the SHA-1 algorithm itself. Now we implement the |
174 | * HMAC wrapper on it. |
175 | */ |
176 | |
d39f364a |
177 | static SHA_State sha1_cs_mac_s1, sha1_cs_mac_s2; |
178 | static SHA_State sha1_sc_mac_s1, sha1_sc_mac_s2; |
e5574168 |
179 | |
d39f364a |
180 | static void sha1_key(SHA_State *s1, SHA_State *s2, |
181 | unsigned char *key, int len) { |
e5574168 |
182 | unsigned char foo[64]; |
183 | int i; |
033b4cef |
184 | {int j; |
185 | debug(("Key supplied is:\r\n")); |
186 | for (j=0; j<len; j++) debug((" %02X", key[j])); |
187 | debug(("\r\n")); |
188 | } |
e5574168 |
189 | |
190 | memset(foo, 0x36, 64); |
191 | for (i = 0; i < len && i < 64; i++) |
192 | foo[i] ^= key[i]; |
d39f364a |
193 | SHA_Init(s1); |
194 | SHA_Bytes(s1, foo, 64); |
e5574168 |
195 | |
196 | memset(foo, 0x5C, 64); |
197 | for (i = 0; i < len && i < 64; i++) |
198 | foo[i] ^= key[i]; |
d39f364a |
199 | SHA_Init(s2); |
200 | SHA_Bytes(s2, foo, 64); |
e5574168 |
201 | |
202 | memset(foo, 0, 64); /* burn the evidence */ |
203 | } |
204 | |
d39f364a |
205 | static void sha1_cskey(unsigned char *key) { |
206 | sha1_key(&sha1_cs_mac_s1, &sha1_cs_mac_s2, key, 20); |
207 | } |
208 | |
209 | static void sha1_sckey(unsigned char *key) { |
210 | sha1_key(&sha1_sc_mac_s1, &sha1_sc_mac_s2, key, 20); |
211 | } |
212 | |
213 | static void sha1_do_hmac(SHA_State *s1, SHA_State *s2, |
214 | unsigned char *blk, int len, unsigned long seq, |
e5574168 |
215 | unsigned char *hmac) { |
216 | SHA_State s; |
217 | unsigned char intermediate[20]; |
218 | |
219 | intermediate[0] = (unsigned char)((seq >> 24) & 0xFF); |
220 | intermediate[1] = (unsigned char)((seq >> 16) & 0xFF); |
221 | intermediate[2] = (unsigned char)((seq >> 8) & 0xFF); |
222 | intermediate[3] = (unsigned char)((seq ) & 0xFF); |
223 | |
d39f364a |
224 | s = *s1; /* structure copy */ |
e5574168 |
225 | SHA_Bytes(&s, intermediate, 4); |
226 | SHA_Bytes(&s, blk, len); |
227 | SHA_Final(&s, intermediate); |
d39f364a |
228 | s = *s2; /* structure copy */ |
e5574168 |
229 | SHA_Bytes(&s, intermediate, 20); |
230 | SHA_Final(&s, hmac); |
231 | } |
232 | |
233 | static void sha1_generate(unsigned char *blk, int len, unsigned long seq) { |
033b4cef |
234 | {int i; |
235 | debug(("Gen HMAC on block len=%d seq=%d:\r\n", len, seq)); |
236 | for (i=0; i<len; i++) debug((" %02X", blk[i])); |
237 | debug(("\r\n")); |
238 | } |
d39f364a |
239 | sha1_do_hmac(&sha1_cs_mac_s1, &sha1_cs_mac_s2, blk, len, seq, blk+len); |
033b4cef |
240 | {int i; |
241 | debug(("We compute HMAC as:\r\n")); |
242 | for (i=0; i<20; i++) debug((" %02X", blk[len+i])); |
243 | debug(("\r\n")); |
244 | } |
e5574168 |
245 | } |
246 | |
247 | static int sha1_verify(unsigned char *blk, int len, unsigned long seq) { |
248 | unsigned char correct[20]; |
033b4cef |
249 | {int i; |
250 | debug(("HMAC on block len=%d seq=%d:\r\n", len, seq)); |
251 | for (i=0; i<len; i++) debug((" %02X", blk[i])); |
252 | debug(("\r\n")); |
253 | } |
d39f364a |
254 | sha1_do_hmac(&sha1_sc_mac_s1, &sha1_sc_mac_s2, blk, len, seq, correct); |
033b4cef |
255 | {int i; |
256 | debug(("We compute HMAC as:\r\n")); |
257 | for (i=0; i<20; i++) debug((" %02X", correct[i])); |
258 | debug(("\r\n")); |
259 | } |
e5574168 |
260 | return !memcmp(correct, blk+len, 20); |
261 | } |
262 | |
263 | struct ssh_mac ssh_sha1 = { |
d39f364a |
264 | sha1_cskey, sha1_sckey, |
e5574168 |
265 | sha1_generate, |
266 | sha1_verify, |
267 | "hmac-sha1", |
268 | 20 |
269 | }; |