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1 | #include "ssh.h" |
2 | |
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3 | /* |
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4 | * MD5 implementation for PuTTY. Written directly from the spec by |
5 | * Simon Tatham. |
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6 | */ |
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7 | |
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8 | /* ---------------------------------------------------------------------- |
9 | * Core MD5 algorithm: processes 16-word blocks into a message digest. |
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10 | */ |
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11 | |
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12 | #define F(x,y,z) ( ((x) & (y)) | ((~(x)) & (z)) ) |
13 | #define G(x,y,z) ( ((x) & (z)) | ((~(z)) & (y)) ) |
14 | #define H(x,y,z) ( (x) ^ (y) ^ (z) ) |
15 | #define I(x,y,z) ( (y) ^ ( (x) | ~(z) ) ) |
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16 | |
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17 | #define rol(x,y) ( ((x) << (y)) | (((uint32)x) >> (32-y)) ) |
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18 | |
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19 | #define subround(f,w,x,y,z,k,s,ti) \ |
20 | w = x + rol(w + f(x,y,z) + block[k] + ti, s) |
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21 | |
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22 | static void MD5_Core_Init(MD5_Core_State * s) |
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23 | { |
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24 | s->h[0] = 0x67452301; |
25 | s->h[1] = 0xefcdab89; |
26 | s->h[2] = 0x98badcfe; |
27 | s->h[3] = 0x10325476; |
28 | } |
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29 | |
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30 | static void MD5_Block(MD5_Core_State * s, uint32 * block) |
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31 | { |
32 | uint32 a, b, c, d; |
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33 | |
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34 | a = s->h[0]; |
35 | b = s->h[1]; |
36 | c = s->h[2]; |
37 | d = s->h[3]; |
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38 | |
39 | subround(F, a, b, c, d, 0, 7, 0xd76aa478); |
40 | subround(F, d, a, b, c, 1, 12, 0xe8c7b756); |
41 | subround(F, c, d, a, b, 2, 17, 0x242070db); |
42 | subround(F, b, c, d, a, 3, 22, 0xc1bdceee); |
43 | subround(F, a, b, c, d, 4, 7, 0xf57c0faf); |
44 | subround(F, d, a, b, c, 5, 12, 0x4787c62a); |
45 | subround(F, c, d, a, b, 6, 17, 0xa8304613); |
46 | subround(F, b, c, d, a, 7, 22, 0xfd469501); |
47 | subround(F, a, b, c, d, 8, 7, 0x698098d8); |
48 | subround(F, d, a, b, c, 9, 12, 0x8b44f7af); |
49 | subround(F, c, d, a, b, 10, 17, 0xffff5bb1); |
50 | subround(F, b, c, d, a, 11, 22, 0x895cd7be); |
51 | subround(F, a, b, c, d, 12, 7, 0x6b901122); |
52 | subround(F, d, a, b, c, 13, 12, 0xfd987193); |
53 | subround(F, c, d, a, b, 14, 17, 0xa679438e); |
54 | subround(F, b, c, d, a, 15, 22, 0x49b40821); |
55 | subround(G, a, b, c, d, 1, 5, 0xf61e2562); |
56 | subround(G, d, a, b, c, 6, 9, 0xc040b340); |
57 | subround(G, c, d, a, b, 11, 14, 0x265e5a51); |
58 | subround(G, b, c, d, a, 0, 20, 0xe9b6c7aa); |
59 | subround(G, a, b, c, d, 5, 5, 0xd62f105d); |
60 | subround(G, d, a, b, c, 10, 9, 0x02441453); |
61 | subround(G, c, d, a, b, 15, 14, 0xd8a1e681); |
62 | subround(G, b, c, d, a, 4, 20, 0xe7d3fbc8); |
63 | subround(G, a, b, c, d, 9, 5, 0x21e1cde6); |
64 | subround(G, d, a, b, c, 14, 9, 0xc33707d6); |
65 | subround(G, c, d, a, b, 3, 14, 0xf4d50d87); |
66 | subround(G, b, c, d, a, 8, 20, 0x455a14ed); |
67 | subround(G, a, b, c, d, 13, 5, 0xa9e3e905); |
68 | subround(G, d, a, b, c, 2, 9, 0xfcefa3f8); |
69 | subround(G, c, d, a, b, 7, 14, 0x676f02d9); |
70 | subround(G, b, c, d, a, 12, 20, 0x8d2a4c8a); |
71 | subround(H, a, b, c, d, 5, 4, 0xfffa3942); |
72 | subround(H, d, a, b, c, 8, 11, 0x8771f681); |
73 | subround(H, c, d, a, b, 11, 16, 0x6d9d6122); |
74 | subround(H, b, c, d, a, 14, 23, 0xfde5380c); |
75 | subround(H, a, b, c, d, 1, 4, 0xa4beea44); |
76 | subround(H, d, a, b, c, 4, 11, 0x4bdecfa9); |
77 | subround(H, c, d, a, b, 7, 16, 0xf6bb4b60); |
78 | subround(H, b, c, d, a, 10, 23, 0xbebfbc70); |
79 | subround(H, a, b, c, d, 13, 4, 0x289b7ec6); |
80 | subround(H, d, a, b, c, 0, 11, 0xeaa127fa); |
81 | subround(H, c, d, a, b, 3, 16, 0xd4ef3085); |
82 | subround(H, b, c, d, a, 6, 23, 0x04881d05); |
83 | subround(H, a, b, c, d, 9, 4, 0xd9d4d039); |
84 | subround(H, d, a, b, c, 12, 11, 0xe6db99e5); |
85 | subround(H, c, d, a, b, 15, 16, 0x1fa27cf8); |
86 | subround(H, b, c, d, a, 2, 23, 0xc4ac5665); |
87 | subround(I, a, b, c, d, 0, 6, 0xf4292244); |
88 | subround(I, d, a, b, c, 7, 10, 0x432aff97); |
89 | subround(I, c, d, a, b, 14, 15, 0xab9423a7); |
90 | subround(I, b, c, d, a, 5, 21, 0xfc93a039); |
91 | subround(I, a, b, c, d, 12, 6, 0x655b59c3); |
92 | subround(I, d, a, b, c, 3, 10, 0x8f0ccc92); |
93 | subround(I, c, d, a, b, 10, 15, 0xffeff47d); |
94 | subround(I, b, c, d, a, 1, 21, 0x85845dd1); |
95 | subround(I, a, b, c, d, 8, 6, 0x6fa87e4f); |
96 | subround(I, d, a, b, c, 15, 10, 0xfe2ce6e0); |
97 | subround(I, c, d, a, b, 6, 15, 0xa3014314); |
98 | subround(I, b, c, d, a, 13, 21, 0x4e0811a1); |
99 | subround(I, a, b, c, d, 4, 6, 0xf7537e82); |
100 | subround(I, d, a, b, c, 11, 10, 0xbd3af235); |
101 | subround(I, c, d, a, b, 2, 15, 0x2ad7d2bb); |
102 | subround(I, b, c, d, a, 9, 21, 0xeb86d391); |
103 | |
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104 | s->h[0] += a; |
105 | s->h[1] += b; |
106 | s->h[2] += c; |
107 | s->h[3] += d; |
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108 | } |
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109 | |
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110 | /* ---------------------------------------------------------------------- |
111 | * Outer MD5 algorithm: take an arbitrary length byte string, |
112 | * convert it into 16-word blocks with the prescribed padding at |
113 | * the end, and pass those blocks to the core MD5 algorithm. |
114 | */ |
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115 | |
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116 | #define BLKSIZE 64 |
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117 | |
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118 | void MD5Init(struct MD5Context *s) |
119 | { |
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120 | MD5_Core_Init(&s->core); |
121 | s->blkused = 0; |
122 | s->lenhi = s->lenlo = 0; |
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123 | } |
124 | |
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125 | void MD5Update(struct MD5Context *s, unsigned char const *p, unsigned len) |
126 | { |
127 | unsigned char *q = (unsigned char *) p; |
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128 | uint32 wordblock[16]; |
129 | uint32 lenw = len; |
130 | int i; |
131 | |
132 | /* |
133 | * Update the length field. |
134 | */ |
135 | s->lenlo += lenw; |
136 | s->lenhi += (s->lenlo < lenw); |
137 | |
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138 | if (s->blkused + len < BLKSIZE) { |
139 | /* |
140 | * Trivial case: just add to the block. |
141 | */ |
142 | memcpy(s->block + s->blkused, q, len); |
143 | s->blkused += len; |
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144 | } else { |
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145 | /* |
146 | * We must complete and process at least one block. |
147 | */ |
148 | while (s->blkused + len >= BLKSIZE) { |
149 | memcpy(s->block + s->blkused, q, BLKSIZE - s->blkused); |
150 | q += BLKSIZE - s->blkused; |
151 | len -= BLKSIZE - s->blkused; |
152 | /* Now process the block. Gather bytes little-endian into words */ |
153 | for (i = 0; i < 16; i++) { |
154 | wordblock[i] = |
155 | (((uint32) s->block[i * 4 + 3]) << 24) | |
156 | (((uint32) s->block[i * 4 + 2]) << 16) | |
157 | (((uint32) s->block[i * 4 + 1]) << 8) | |
158 | (((uint32) s->block[i * 4 + 0]) << 0); |
159 | } |
160 | MD5_Block(&s->core, wordblock); |
161 | s->blkused = 0; |
162 | } |
163 | memcpy(s->block, q, len); |
164 | s->blkused = len; |
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165 | } |
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166 | } |
167 | |
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168 | void MD5Final(unsigned char output[16], struct MD5Context *s) |
169 | { |
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170 | int i; |
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171 | unsigned pad; |
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172 | unsigned char c[64]; |
173 | uint32 lenhi, lenlo; |
174 | |
175 | if (s->blkused >= 56) |
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176 | pad = 56 + 64 - s->blkused; |
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177 | else |
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178 | pad = 56 - s->blkused; |
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179 | |
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180 | lenhi = (s->lenhi << 3) | (s->lenlo >> (32 - 3)); |
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181 | lenlo = (s->lenlo << 3); |
182 | |
183 | memset(c, 0, pad); |
184 | c[0] = 0x80; |
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185 | MD5Update(s, c, pad); |
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186 | |
187 | c[7] = (lenhi >> 24) & 0xFF; |
188 | c[6] = (lenhi >> 16) & 0xFF; |
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189 | c[5] = (lenhi >> 8) & 0xFF; |
190 | c[4] = (lenhi >> 0) & 0xFF; |
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191 | c[3] = (lenlo >> 24) & 0xFF; |
192 | c[2] = (lenlo >> 16) & 0xFF; |
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193 | c[1] = (lenlo >> 8) & 0xFF; |
194 | c[0] = (lenlo >> 0) & 0xFF; |
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195 | |
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196 | MD5Update(s, c, 8); |
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197 | |
198 | for (i = 0; i < 4; i++) { |
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199 | output[4 * i + 3] = (s->core.h[i] >> 24) & 0xFF; |
200 | output[4 * i + 2] = (s->core.h[i] >> 16) & 0xFF; |
201 | output[4 * i + 1] = (s->core.h[i] >> 8) & 0xFF; |
202 | output[4 * i + 0] = (s->core.h[i] >> 0) & 0xFF; |
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203 | } |
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204 | } |
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205 | |
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206 | void MD5Simple(void const *p, unsigned len, unsigned char output[16]) |
207 | { |
208 | struct MD5Context s; |
209 | |
210 | MD5Init(&s); |
211 | MD5Update(&s, (unsigned char const *)p, len); |
212 | MD5Final(output, &s); |
213 | } |
214 | |
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215 | /* ---------------------------------------------------------------------- |
216 | * The above is the MD5 algorithm itself. Now we implement the |
217 | * HMAC wrapper on it. |
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218 | * |
219 | * Some of these functions are exported directly, because they are |
220 | * useful elsewhere (SOCKS5 CHAP authentication uses HMAC-MD5). |
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221 | */ |
222 | |
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223 | void *hmacmd5_make_context(void) |
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224 | { |
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225 | return snewn(2, struct MD5Context); |
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226 | } |
227 | |
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228 | void hmacmd5_free_context(void *handle) |
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229 | { |
230 | sfree(handle); |
231 | } |
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232 | |
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233 | void hmacmd5_key(void *handle, void const *keyv, int len) |
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234 | { |
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235 | struct MD5Context *keys = (struct MD5Context *)handle; |
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236 | unsigned char foo[64]; |
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237 | unsigned char const *key = (unsigned char const *)keyv; |
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238 | int i; |
239 | |
240 | memset(foo, 0x36, 64); |
241 | for (i = 0; i < len && i < 64; i++) |
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242 | foo[i] ^= key[i]; |
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243 | MD5Init(&keys[0]); |
244 | MD5Update(&keys[0], foo, 64); |
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245 | |
246 | memset(foo, 0x5C, 64); |
247 | for (i = 0; i < len && i < 64; i++) |
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248 | foo[i] ^= key[i]; |
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249 | MD5Init(&keys[1]); |
250 | MD5Update(&keys[1], foo, 64); |
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251 | |
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252 | memset(foo, 0, 64); /* burn the evidence */ |
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253 | } |
254 | |
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255 | static void hmacmd5_key_16(void *handle, unsigned char *key) |
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256 | { |
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257 | hmacmd5_key(handle, key, 16); |
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258 | } |
259 | |
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260 | static void hmacmd5_do_hmac_internal(void *handle, |
261 | unsigned char const *blk, int len, |
262 | unsigned char const *blk2, int len2, |
263 | unsigned char *hmac) |
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264 | { |
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265 | struct MD5Context *keys = (struct MD5Context *)handle; |
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266 | struct MD5Context s; |
267 | unsigned char intermediate[16]; |
268 | |
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269 | s = keys[0]; /* structure copy */ |
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270 | MD5Update(&s, blk, len); |
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271 | if (blk2) MD5Update(&s, blk2, len2); |
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272 | MD5Final(intermediate, &s); |
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273 | s = keys[1]; /* structure copy */ |
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274 | MD5Update(&s, intermediate, 16); |
275 | MD5Final(hmac, &s); |
276 | } |
277 | |
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278 | void hmacmd5_do_hmac(void *handle, unsigned char const *blk, int len, |
279 | unsigned char *hmac) |
280 | { |
281 | hmacmd5_do_hmac_internal(handle, blk, len, NULL, 0, hmac); |
282 | } |
283 | |
284 | static void hmacmd5_do_hmac_ssh(void *handle, unsigned char const *blk, int len, |
285 | unsigned long seq, unsigned char *hmac) |
286 | { |
287 | unsigned char seqbuf[16]; |
288 | |
289 | seqbuf[0] = (unsigned char) ((seq >> 24) & 0xFF); |
290 | seqbuf[1] = (unsigned char) ((seq >> 16) & 0xFF); |
291 | seqbuf[2] = (unsigned char) ((seq >> 8) & 0xFF); |
292 | seqbuf[3] = (unsigned char) ((seq) & 0xFF); |
293 | |
294 | hmacmd5_do_hmac_internal(handle, seqbuf, 4, blk, len, hmac); |
295 | } |
296 | |
297 | static void hmacmd5_generate(void *handle, unsigned char *blk, int len, |
298 | unsigned long seq) |
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299 | { |
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300 | hmacmd5_do_hmac_ssh(handle, blk, len, seq, blk + len); |
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301 | } |
302 | |
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303 | static int hmacmd5_verify(void *handle, unsigned char *blk, int len, |
304 | unsigned long seq) |
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305 | { |
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306 | unsigned char correct[16]; |
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307 | hmacmd5_do_hmac_ssh(handle, blk, len, seq, correct); |
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308 | return !memcmp(correct, blk + len, 16); |
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309 | } |
310 | |
1993f323 |
311 | const struct ssh_mac ssh_hmac_md5 = { |
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312 | hmacmd5_make_context, hmacmd5_free_context, hmacmd5_key_16, |
313 | hmacmd5_generate, hmacmd5_verify, |
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314 | "hmac-md5", |
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315 | 16, |
316 | "HMAC-MD5" |
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317 | }; |