7cca0d81 |
1 | #include <stdio.h> |
2 | #include <stdlib.h> |
65a22376 |
3 | #include <assert.h> |
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4 | |
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5 | #include "ssh.h" |
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6 | #include "misc.h" |
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7 | |
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8 | #define GET_32BIT(cp) \ |
9 | (((unsigned long)(unsigned char)(cp)[0] << 24) | \ |
10 | ((unsigned long)(unsigned char)(cp)[1] << 16) | \ |
11 | ((unsigned long)(unsigned char)(cp)[2] << 8) | \ |
12 | ((unsigned long)(unsigned char)(cp)[3])) |
13 | |
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14 | #define PUT_32BIT(cp, value) { \ |
15 | (cp)[0] = (unsigned char)((value) >> 24); \ |
16 | (cp)[1] = (unsigned char)((value) >> 16); \ |
17 | (cp)[2] = (unsigned char)((value) >> 8); \ |
18 | (cp)[3] = (unsigned char)(value); } |
19 | |
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20 | static void sha_mpint(SHA_State * s, Bignum b) |
21 | { |
22 | unsigned char *p; |
23 | unsigned char lenbuf[4]; |
24 | int len; |
25 | len = (bignum_bitcount(b) + 8) / 8; |
26 | PUT_32BIT(lenbuf, len); |
27 | SHA_Bytes(s, lenbuf, 4); |
28 | while (len-- > 0) { |
29 | lenbuf[0] = bignum_byte(b, len); |
30 | SHA_Bytes(s, lenbuf, 1); |
31 | } |
32 | memset(lenbuf, 0, sizeof(lenbuf)); |
33 | } |
34 | |
35 | static void sha512_mpint(SHA512_State * s, Bignum b) |
36 | { |
37 | unsigned char *p; |
38 | unsigned char lenbuf[4]; |
39 | int len; |
40 | len = (bignum_bitcount(b) + 8) / 8; |
41 | PUT_32BIT(lenbuf, len); |
42 | SHA512_Bytes(s, lenbuf, 4); |
43 | while (len-- > 0) { |
44 | lenbuf[0] = bignum_byte(b, len); |
45 | SHA512_Bytes(s, lenbuf, 1); |
46 | } |
47 | memset(lenbuf, 0, sizeof(lenbuf)); |
48 | } |
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49 | |
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50 | static void getstring(char **data, int *datalen, char **p, int *length) |
51 | { |
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52 | *p = NULL; |
53 | if (*datalen < 4) |
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54 | return; |
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55 | *length = GET_32BIT(*data); |
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56 | *datalen -= 4; |
57 | *data += 4; |
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58 | if (*datalen < *length) |
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59 | return; |
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60 | *p = *data; |
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61 | *data += *length; |
62 | *datalen -= *length; |
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63 | } |
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64 | static Bignum getmp(char **data, int *datalen) |
65 | { |
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66 | char *p; |
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67 | int length; |
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68 | Bignum b; |
69 | |
70 | getstring(data, datalen, &p, &length); |
71 | if (!p) |
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72 | return NULL; |
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73 | if (p[0] & 0x80) |
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74 | return NULL; /* negative mp */ |
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75 | b = bignum_from_bytes(p, length); |
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76 | return b; |
77 | } |
78 | |
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79 | static Bignum get160(char **data, int *datalen) |
80 | { |
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81 | Bignum b; |
82 | |
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83 | b = bignum_from_bytes(*data, 20); |
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84 | *data += 20; |
85 | *datalen -= 20; |
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86 | |
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87 | return b; |
88 | } |
89 | |
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90 | static void *dss_newkey(char *data, int len) |
91 | { |
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92 | char *p; |
93 | int slen; |
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94 | struct dss_key *dss; |
95 | |
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96 | dss = smalloc(sizeof(struct dss_key)); |
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97 | if (!dss) |
98 | return NULL; |
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99 | getstring(&data, &len, &p, &slen); |
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100 | |
101 | #ifdef DEBUG_DSS |
102 | { |
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103 | int i; |
104 | printf("key:"); |
105 | for (i = 0; i < len; i++) |
106 | printf(" %02x", (unsigned char) (data[i])); |
107 | printf("\n"); |
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108 | } |
109 | #endif |
110 | |
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111 | if (!p || memcmp(p, "ssh-dss", 7)) { |
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112 | sfree(dss); |
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113 | return NULL; |
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114 | } |
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115 | dss->p = getmp(&data, &len); |
116 | dss->q = getmp(&data, &len); |
117 | dss->g = getmp(&data, &len); |
118 | dss->y = getmp(&data, &len); |
119 | |
120 | return dss; |
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121 | } |
122 | |
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123 | static void dss_freekey(void *key) |
124 | { |
125 | struct dss_key *dss = (struct dss_key *) key; |
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126 | freebn(dss->p); |
127 | freebn(dss->q); |
128 | freebn(dss->g); |
129 | freebn(dss->y); |
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130 | sfree(dss); |
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131 | } |
132 | |
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133 | static char *dss_fmtkey(void *key) |
134 | { |
135 | struct dss_key *dss = (struct dss_key *) key; |
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136 | char *p; |
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137 | int len, i, pos, nibbles; |
138 | static const char hex[] = "0123456789abcdef"; |
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139 | if (!dss->p) |
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140 | return NULL; |
141 | len = 8 + 4 + 1; /* 4 x "0x", punctuation, \0 */ |
142 | len += 4 * (bignum_bitcount(dss->p) + 15) / 16; |
143 | len += 4 * (bignum_bitcount(dss->q) + 15) / 16; |
144 | len += 4 * (bignum_bitcount(dss->g) + 15) / 16; |
145 | len += 4 * (bignum_bitcount(dss->y) + 15) / 16; |
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146 | p = smalloc(len); |
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147 | if (!p) |
148 | return NULL; |
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149 | |
150 | pos = 0; |
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151 | pos += sprintf(p + pos, "0x"); |
152 | nibbles = (3 + bignum_bitcount(dss->p)) / 4; |
153 | if (nibbles < 1) |
154 | nibbles = 1; |
155 | for (i = nibbles; i--;) |
156 | p[pos++] = |
157 | hex[(bignum_byte(dss->p, i / 2) >> (4 * (i % 2))) & 0xF]; |
158 | pos += sprintf(p + pos, ",0x"); |
159 | nibbles = (3 + bignum_bitcount(dss->q)) / 4; |
160 | if (nibbles < 1) |
161 | nibbles = 1; |
162 | for (i = nibbles; i--;) |
163 | p[pos++] = |
164 | hex[(bignum_byte(dss->q, i / 2) >> (4 * (i % 2))) & 0xF]; |
165 | pos += sprintf(p + pos, ",0x"); |
166 | nibbles = (3 + bignum_bitcount(dss->g)) / 4; |
167 | if (nibbles < 1) |
168 | nibbles = 1; |
169 | for (i = nibbles; i--;) |
170 | p[pos++] = |
171 | hex[(bignum_byte(dss->g, i / 2) >> (4 * (i % 2))) & 0xF]; |
172 | pos += sprintf(p + pos, ",0x"); |
173 | nibbles = (3 + bignum_bitcount(dss->y)) / 4; |
174 | if (nibbles < 1) |
175 | nibbles = 1; |
176 | for (i = nibbles; i--;) |
177 | p[pos++] = |
178 | hex[(bignum_byte(dss->y, i / 2) >> (4 * (i % 2))) & 0xF]; |
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179 | p[pos] = '\0'; |
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180 | return p; |
181 | } |
182 | |
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183 | static char *dss_fingerprint(void *key) |
184 | { |
185 | struct dss_key *dss = (struct dss_key *) key; |
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186 | struct MD5Context md5c; |
187 | unsigned char digest[16], lenbuf[4]; |
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188 | char buffer[16 * 3 + 40]; |
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189 | char *ret; |
190 | int numlen, i; |
191 | |
192 | MD5Init(&md5c); |
193 | MD5Update(&md5c, "\0\0\0\7ssh-dss", 11); |
194 | |
195 | #define ADD_BIGNUM(bignum) \ |
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196 | numlen = (bignum_bitcount(bignum)+8)/8; \ |
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197 | PUT_32BIT(lenbuf, numlen); MD5Update(&md5c, lenbuf, 4); \ |
198 | for (i = numlen; i-- ;) { \ |
199 | unsigned char c = bignum_byte(bignum, i); \ |
200 | MD5Update(&md5c, &c, 1); \ |
201 | } |
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202 | ADD_BIGNUM(dss->p); |
203 | ADD_BIGNUM(dss->q); |
204 | ADD_BIGNUM(dss->g); |
205 | ADD_BIGNUM(dss->y); |
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206 | #undef ADD_BIGNUM |
207 | |
208 | MD5Final(digest, &md5c); |
209 | |
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210 | sprintf(buffer, "ssh-dss %d ", bignum_bitcount(dss->p)); |
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211 | for (i = 0; i < 16; i++) |
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212 | sprintf(buffer + strlen(buffer), "%s%02x", i ? ":" : "", |
213 | digest[i]); |
214 | ret = smalloc(strlen(buffer) + 1); |
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215 | if (ret) |
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216 | strcpy(ret, buffer); |
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217 | return ret; |
218 | } |
219 | |
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220 | static int dss_verifysig(void *key, char *sig, int siglen, |
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221 | char *data, int datalen) |
222 | { |
223 | struct dss_key *dss = (struct dss_key *) key; |
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224 | char *p; |
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225 | int slen; |
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226 | char hash[20]; |
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227 | Bignum r, s, w, gu1p, yu2p, gu1yu2p, u1, u2, sha, v; |
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228 | int ret; |
229 | |
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230 | if (!dss->p) |
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231 | return 0; |
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232 | |
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233 | #ifdef DEBUG_DSS |
234 | { |
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235 | int i; |
236 | printf("sig:"); |
237 | for (i = 0; i < siglen; i++) |
238 | printf(" %02x", (unsigned char) (sig[i])); |
239 | printf("\n"); |
9c621433 |
240 | } |
241 | #endif |
7f7837c8 |
242 | /* |
243 | * Commercial SSH (2.0.13) and OpenSSH disagree over the format |
244 | * of a DSA signature. OpenSSH is in line with the IETF drafts: |
245 | * it uses a string "ssh-dss", followed by a 40-byte string |
246 | * containing two 160-bit integers end-to-end. Commercial SSH |
247 | * can't be bothered with the header bit, and considers a DSA |
248 | * signature blob to be _just_ the 40-byte string containing |
249 | * the two 160-bit integers. We tell them apart by measuring |
250 | * the length: length 40 means the commercial-SSH bug, anything |
251 | * else is assumed to be IETF-compliant. |
252 | */ |
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253 | if (siglen != 40) { /* bug not present; read admin fields */ |
254 | getstring(&sig, &siglen, &p, &slen); |
255 | if (!p || slen != 7 || memcmp(p, "ssh-dss", 7)) { |
256 | return 0; |
257 | } |
258 | sig += 4, siglen -= 4; /* skip yet another length field */ |
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259 | } |
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260 | r = get160(&sig, &siglen); |
261 | s = get160(&sig, &siglen); |
262 | if (!r || !s) |
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263 | return 0; |
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264 | |
265 | /* |
266 | * Step 1. w <- s^-1 mod q. |
267 | */ |
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268 | w = modinv(s, dss->q); |
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269 | |
270 | /* |
271 | * Step 2. u1 <- SHA(message) * w mod q. |
272 | */ |
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273 | SHA_Simple(data, datalen, hash); |
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274 | p = hash; |
275 | slen = 20; |
276 | sha = get160(&p, &slen); |
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277 | u1 = modmul(sha, w, dss->q); |
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278 | |
279 | /* |
280 | * Step 3. u2 <- r * w mod q. |
281 | */ |
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282 | u2 = modmul(r, w, dss->q); |
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283 | |
284 | /* |
285 | * Step 4. v <- (g^u1 * y^u2 mod p) mod q. |
286 | */ |
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287 | gu1p = modpow(dss->g, u1, dss->p); |
e055a386 |
288 | yu2p = modpow(dss->y, u2, dss->p); |
e055a386 |
289 | gu1yu2p = modmul(gu1p, yu2p, dss->p); |
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290 | v = modmul(gu1yu2p, One, dss->q); |
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291 | |
292 | /* |
293 | * Step 5. v should now be equal to r. |
294 | */ |
295 | |
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296 | ret = !bignum_cmp(v, r); |
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297 | |
298 | freebn(w); |
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299 | freebn(sha); |
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300 | freebn(gu1p); |
301 | freebn(yu2p); |
302 | freebn(gu1yu2p); |
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303 | freebn(v); |
304 | freebn(r); |
305 | freebn(s); |
306 | |
307 | return ret; |
308 | } |
309 | |
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310 | static unsigned char *dss_public_blob(void *key, int *len) |
311 | { |
312 | struct dss_key *dss = (struct dss_key *) key; |
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313 | int plen, qlen, glen, ylen, bloblen; |
314 | int i; |
315 | unsigned char *blob, *p; |
316 | |
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317 | plen = (bignum_bitcount(dss->p) + 8) / 8; |
318 | qlen = (bignum_bitcount(dss->q) + 8) / 8; |
319 | glen = (bignum_bitcount(dss->g) + 8) / 8; |
320 | ylen = (bignum_bitcount(dss->y) + 8) / 8; |
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321 | |
322 | /* |
323 | * string "ssh-dss", mpint p, mpint q, mpint g, mpint y. Total |
324 | * 27 + sum of lengths. (five length fields, 20+7=27). |
325 | */ |
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326 | bloblen = 27 + plen + qlen + glen + ylen; |
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327 | blob = smalloc(bloblen); |
328 | p = blob; |
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329 | PUT_32BIT(p, 7); |
330 | p += 4; |
331 | memcpy(p, "ssh-dss", 7); |
332 | p += 7; |
333 | PUT_32BIT(p, plen); |
334 | p += 4; |
335 | for (i = plen; i--;) |
336 | *p++ = bignum_byte(dss->p, i); |
337 | PUT_32BIT(p, qlen); |
338 | p += 4; |
339 | for (i = qlen; i--;) |
340 | *p++ = bignum_byte(dss->q, i); |
341 | PUT_32BIT(p, glen); |
342 | p += 4; |
343 | for (i = glen; i--;) |
344 | *p++ = bignum_byte(dss->g, i); |
345 | PUT_32BIT(p, ylen); |
346 | p += 4; |
347 | for (i = ylen; i--;) |
348 | *p++ = bignum_byte(dss->y, i); |
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349 | assert(p == blob + bloblen); |
350 | *len = bloblen; |
351 | return blob; |
352 | } |
353 | |
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354 | static unsigned char *dss_private_blob(void *key, int *len) |
355 | { |
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356 | struct dss_key *dss = (struct dss_key *) key; |
357 | int xlen, bloblen; |
358 | int i; |
359 | unsigned char *blob, *p; |
360 | SHA_State s; |
361 | unsigned char digest[20]; |
362 | |
363 | xlen = (bignum_bitcount(dss->x) + 8) / 8; |
364 | |
365 | /* |
366 | * mpint x, string[20] the SHA of p||q||g. Total 28 + xlen. |
367 | * (two length fields and twenty bytes, 20+8=28). |
368 | */ |
369 | bloblen = 28 + xlen; |
370 | blob = smalloc(bloblen); |
371 | p = blob; |
372 | PUT_32BIT(p, xlen); |
373 | p += 4; |
374 | for (i = xlen; i--;) |
375 | *p++ = bignum_byte(dss->x, i); |
376 | PUT_32BIT(p, 20); |
377 | SHA_Init(&s); |
378 | sha_mpint(&s, dss->p); |
379 | sha_mpint(&s, dss->q); |
380 | sha_mpint(&s, dss->g); |
381 | SHA_Final(&s, digest); |
382 | p += 4; |
383 | for (i = 0; i < 20; i++) |
384 | *p++ = digest[i]; |
385 | assert(p == blob + bloblen); |
386 | *len = bloblen; |
387 | return blob; |
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388 | } |
389 | |
390 | static void *dss_createkey(unsigned char *pub_blob, int pub_len, |
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391 | unsigned char *priv_blob, int priv_len) |
392 | { |
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393 | struct dss_key *dss; |
394 | char *pb = (char *) priv_blob; |
395 | char *hash; |
396 | int hashlen; |
397 | SHA_State s; |
398 | unsigned char digest[20]; |
399 | Bignum ytest; |
400 | |
401 | dss = dss_newkey((char *) pub_blob, pub_len); |
402 | dss->x = getmp(&pb, &priv_len); |
403 | getstring(&pb, &priv_len, &hash, &hashlen); |
404 | |
405 | /* |
406 | * Verify details of the key. First check that the hash is |
407 | * indeed a hash of p||q||g. |
408 | */ |
409 | if (hashlen != 20) { |
410 | dss_freekey(dss); |
411 | return NULL; |
412 | } |
413 | SHA_Init(&s); |
414 | sha_mpint(&s, dss->p); |
415 | sha_mpint(&s, dss->q); |
416 | sha_mpint(&s, dss->g); |
417 | SHA_Final(&s, digest); |
418 | if (0 != memcmp(hash, digest, 20)) { |
419 | dss_freekey(dss); |
420 | return NULL; |
421 | } |
422 | |
423 | /* |
424 | * Now ensure g^x mod p really is y. |
425 | */ |
426 | ytest = modpow(dss->g, dss->x, dss->p); |
427 | if (0 != bignum_cmp(ytest, dss->y)) { |
428 | dss_freekey(dss); |
429 | return NULL; |
430 | } |
431 | freebn(ytest); |
432 | |
433 | return dss; |
65a22376 |
434 | } |
435 | |
32874aea |
436 | static void *dss_openssh_createkey(unsigned char **blob, int *len) |
437 | { |
5c72ca61 |
438 | char **b = (char **) blob; |
439 | struct dss_key *dss; |
440 | |
441 | dss = smalloc(sizeof(struct dss_key)); |
442 | if (!dss) |
443 | return NULL; |
444 | |
445 | dss->p = getmp(b, len); |
446 | dss->q = getmp(b, len); |
447 | dss->g = getmp(b, len); |
448 | dss->y = getmp(b, len); |
449 | dss->x = getmp(b, len); |
450 | |
451 | if (!dss->p || !dss->q || !dss->g || !dss->y || !dss->x) { |
452 | sfree(dss->p); |
453 | sfree(dss->q); |
454 | sfree(dss->g); |
455 | sfree(dss->y); |
456 | sfree(dss->x); |
457 | sfree(dss); |
458 | return NULL; |
459 | } |
460 | |
461 | return dss; |
45cebe79 |
462 | } |
463 | |
32874aea |
464 | static int dss_openssh_fmtkey(void *key, unsigned char *blob, int len) |
465 | { |
5c72ca61 |
466 | struct dss_key *dss = (struct dss_key *) key; |
467 | int bloblen, i; |
468 | |
469 | bloblen = |
470 | ssh2_bignum_length(dss->p) + |
471 | ssh2_bignum_length(dss->q) + |
472 | ssh2_bignum_length(dss->g) + |
473 | ssh2_bignum_length(dss->y) + |
474 | ssh2_bignum_length(dss->x); |
475 | |
476 | if (bloblen > len) |
477 | return bloblen; |
478 | |
479 | bloblen = 0; |
480 | #define ENC(x) \ |
481 | PUT_32BIT(blob+bloblen, ssh2_bignum_length((x))-4); bloblen += 4; \ |
482 | for (i = ssh2_bignum_length((x))-4; i-- ;) blob[bloblen++]=bignum_byte((x),i); |
483 | ENC(dss->p); |
484 | ENC(dss->q); |
485 | ENC(dss->g); |
486 | ENC(dss->y); |
487 | ENC(dss->x); |
488 | |
489 | return bloblen; |
ddecd643 |
490 | } |
491 | |
32874aea |
492 | unsigned char *dss_sign(void *key, char *data, int datalen, int *siglen) |
493 | { |
5c72ca61 |
494 | /* |
495 | * The basic DSS signing algorithm is: |
496 | * |
497 | * - invent a random k between 1 and q-1 (exclusive). |
498 | * - Compute r = (g^k mod p) mod q. |
499 | * - Compute s = k^-1 * (hash + x*r) mod q. |
500 | * |
501 | * This has the dangerous properties that: |
502 | * |
503 | * - if an attacker in possession of the public key _and_ the |
504 | * signature (for example, the host you just authenticated |
505 | * to) can guess your k, he can reverse the computation of s |
506 | * and work out x = r^-1 * (s*k - hash) mod q. That is, he |
507 | * can deduce the private half of your key, and masquerade |
508 | * as you for as long as the key is still valid. |
509 | * |
510 | * - since r is a function purely of k and the public key, if |
511 | * the attacker only has a _range of possibilities_ for k |
512 | * it's easy for him to work through them all and check each |
513 | * one against r; he'll never be unsure of whether he's got |
514 | * the right one. |
515 | * |
516 | * - if you ever sign two different hashes with the same k, it |
517 | * will be immediately obvious because the two signatures |
518 | * will have the same r, and moreover an attacker in |
519 | * possession of both signatures (and the public key of |
520 | * course) can compute k = (hash1-hash2) * (s1-s2)^-1 mod q, |
521 | * and from there deduce x as before. |
522 | * |
523 | * - the Bleichenbacher attack on DSA makes use of methods of |
524 | * generating k which are significantly non-uniformly |
525 | * distributed; in particular, generating a 160-bit random |
526 | * number and reducing it mod q is right out. |
527 | * |
528 | * For this reason we must be pretty careful about how we |
529 | * generate our k. Since this code runs on Windows, with no |
530 | * particularly good system entropy sources, we can't trust our |
531 | * RNG itself to produce properly unpredictable data. Hence, we |
532 | * use a totally different scheme instead. |
533 | * |
534 | * What we do is to take a SHA-512 (_big_) hash of the private |
535 | * key x, and then feed this into another SHA-512 hash that |
536 | * also includes the message hash being signed. That is: |
537 | * |
538 | * proto_k = SHA512 ( SHA512(x) || SHA160(message) ) |
539 | * |
540 | * This number is 512 bits long, so reducing it mod q won't be |
541 | * noticeably non-uniform. So |
542 | * |
543 | * k = proto_k mod q |
544 | * |
545 | * This has the interesting property that it's _deterministic_: |
546 | * signing the same hash twice with the same key yields the |
547 | * same signature. |
548 | * |
549 | * (It doesn't, _per se_, protect against reuse of k. Reuse of |
550 | * k is left to chance; all it does is prevent _excessively |
551 | * high_ chances of reuse of k due to entropy problems.) |
552 | * |
553 | * Thanks to Colin Plumb for the general idea of using x to |
554 | * ensure k is hard to guess, and to the Cambridge University |
555 | * Computer Security Group for helping to argue out all the |
556 | * fine details. |
557 | */ |
558 | struct dss_key *dss = (struct dss_key *) key; |
559 | SHA512_State ss; |
560 | unsigned char digest[20], digest512[64]; |
561 | Bignum proto_k, k, gkp, hash, kinv, hxr, r, s; |
562 | unsigned char *bytes; |
563 | int nbytes, i; |
564 | |
565 | SHA_Simple(data, datalen, digest); |
566 | |
567 | /* |
568 | * Hash some identifying text plus x. |
569 | */ |
570 | SHA512_Init(&ss); |
571 | SHA512_Bytes(&ss, "DSA deterministic k generator", 30); |
572 | sha512_mpint(&ss, dss->x); |
573 | SHA512_Final(&ss, digest512); |
574 | |
575 | /* |
576 | * Now hash that digest plus the message hash. |
577 | */ |
578 | SHA512_Init(&ss); |
579 | SHA512_Bytes(&ss, digest512, sizeof(digest512)); |
580 | SHA512_Bytes(&ss, digest, sizeof(digest)); |
581 | SHA512_Final(&ss, digest512); |
582 | |
583 | memset(&ss, 0, sizeof(ss)); |
584 | |
585 | /* |
586 | * Now convert the result into a bignum, and reduce it mod q. |
587 | */ |
588 | proto_k = bignum_from_bytes(digest512, 64); |
589 | k = bigmod(proto_k, dss->q); |
590 | freebn(proto_k); |
591 | |
592 | memset(digest512, 0, sizeof(digest512)); |
593 | |
594 | /* |
595 | * Now we have k, so just go ahead and compute the signature. |
596 | */ |
597 | gkp = modpow(dss->g, k, dss->p); /* g^k mod p */ |
598 | r = bigmod(gkp, dss->q); /* r = (g^k mod p) mod q */ |
599 | freebn(gkp); |
600 | |
601 | hash = bignum_from_bytes(digest, 20); |
602 | kinv = modinv(k, dss->q); /* k^-1 mod q */ |
603 | hxr = bigmuladd(dss->x, r, hash); /* hash + x*r */ |
604 | s = modmul(kinv, hxr, dss->q); /* s = k^-1 * (hash + x*r) mod q */ |
605 | freebn(hxr); |
606 | freebn(kinv); |
607 | freebn(hash); |
608 | |
609 | /* |
610 | * Signature blob is |
611 | * |
612 | * string "ssh-dss" |
613 | * string two 20-byte numbers r and s, end to end |
614 | * |
615 | * i.e. 4+7 + 4+40 bytes. |
616 | */ |
617 | nbytes = 4 + 7 + 4 + 40; |
618 | bytes = smalloc(nbytes); |
619 | PUT_32BIT(bytes, 7); |
620 | memcpy(bytes + 4, "ssh-dss", 7); |
621 | PUT_32BIT(bytes + 4 + 7, 40); |
622 | for (i = 0; i < 20; i++) { |
623 | bytes[4 + 7 + 4 + i] = bignum_byte(r, 19 - i); |
624 | bytes[4 + 7 + 4 + 20 + i] = bignum_byte(s, 19 - i); |
625 | } |
626 | freebn(r); |
627 | freebn(s); |
628 | |
629 | *siglen = nbytes; |
630 | return bytes; |
e055a386 |
631 | } |
632 | |
65a22376 |
633 | const struct ssh_signkey ssh_dss = { |
e055a386 |
634 | dss_newkey, |
635 | dss_freekey, |
7cca0d81 |
636 | dss_fmtkey, |
65a22376 |
637 | dss_public_blob, |
638 | dss_private_blob, |
639 | dss_createkey, |
45cebe79 |
640 | dss_openssh_createkey, |
ddecd643 |
641 | dss_openssh_fmtkey, |
d5859615 |
642 | dss_fingerprint, |
7cca0d81 |
643 | dss_verifysig, |
e055a386 |
644 | dss_sign, |
d5859615 |
645 | "ssh-dss", |
646 | "dss" |
e5574168 |
647 | }; |