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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 | void MD5_Core_Init(MD5_Core_State *s) { |
23 | s->h[0] = 0x67452301; |
24 | s->h[1] = 0xefcdab89; |
25 | s->h[2] = 0x98badcfe; |
26 | s->h[3] = 0x10325476; |
27 | } |
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28 | |
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29 | void MD5_Block(MD5_Core_State *s, uint32 *block) { |
30 | uint32 a,b,c,d; |
31 | |
32 | a = s->h[0]; b = s->h[1]; c = s->h[2]; d = s->h[3]; |
33 | |
34 | subround(F, a, b, c, d, 0, 7, 0xd76aa478); |
35 | subround(F, d, a, b, c, 1, 12, 0xe8c7b756); |
36 | subround(F, c, d, a, b, 2, 17, 0x242070db); |
37 | subround(F, b, c, d, a, 3, 22, 0xc1bdceee); |
38 | subround(F, a, b, c, d, 4, 7, 0xf57c0faf); |
39 | subround(F, d, a, b, c, 5, 12, 0x4787c62a); |
40 | subround(F, c, d, a, b, 6, 17, 0xa8304613); |
41 | subround(F, b, c, d, a, 7, 22, 0xfd469501); |
42 | subround(F, a, b, c, d, 8, 7, 0x698098d8); |
43 | subround(F, d, a, b, c, 9, 12, 0x8b44f7af); |
44 | subround(F, c, d, a, b, 10, 17, 0xffff5bb1); |
45 | subround(F, b, c, d, a, 11, 22, 0x895cd7be); |
46 | subround(F, a, b, c, d, 12, 7, 0x6b901122); |
47 | subround(F, d, a, b, c, 13, 12, 0xfd987193); |
48 | subround(F, c, d, a, b, 14, 17, 0xa679438e); |
49 | subround(F, b, c, d, a, 15, 22, 0x49b40821); |
50 | subround(G, a, b, c, d, 1, 5, 0xf61e2562); |
51 | subround(G, d, a, b, c, 6, 9, 0xc040b340); |
52 | subround(G, c, d, a, b, 11, 14, 0x265e5a51); |
53 | subround(G, b, c, d, a, 0, 20, 0xe9b6c7aa); |
54 | subround(G, a, b, c, d, 5, 5, 0xd62f105d); |
55 | subround(G, d, a, b, c, 10, 9, 0x02441453); |
56 | subround(G, c, d, a, b, 15, 14, 0xd8a1e681); |
57 | subround(G, b, c, d, a, 4, 20, 0xe7d3fbc8); |
58 | subround(G, a, b, c, d, 9, 5, 0x21e1cde6); |
59 | subround(G, d, a, b, c, 14, 9, 0xc33707d6); |
60 | subround(G, c, d, a, b, 3, 14, 0xf4d50d87); |
61 | subround(G, b, c, d, a, 8, 20, 0x455a14ed); |
62 | subround(G, a, b, c, d, 13, 5, 0xa9e3e905); |
63 | subround(G, d, a, b, c, 2, 9, 0xfcefa3f8); |
64 | subround(G, c, d, a, b, 7, 14, 0x676f02d9); |
65 | subround(G, b, c, d, a, 12, 20, 0x8d2a4c8a); |
66 | subround(H, a, b, c, d, 5, 4, 0xfffa3942); |
67 | subround(H, d, a, b, c, 8, 11, 0x8771f681); |
68 | subround(H, c, d, a, b, 11, 16, 0x6d9d6122); |
69 | subround(H, b, c, d, a, 14, 23, 0xfde5380c); |
70 | subround(H, a, b, c, d, 1, 4, 0xa4beea44); |
71 | subround(H, d, a, b, c, 4, 11, 0x4bdecfa9); |
72 | subround(H, c, d, a, b, 7, 16, 0xf6bb4b60); |
73 | subround(H, b, c, d, a, 10, 23, 0xbebfbc70); |
74 | subround(H, a, b, c, d, 13, 4, 0x289b7ec6); |
75 | subround(H, d, a, b, c, 0, 11, 0xeaa127fa); |
76 | subround(H, c, d, a, b, 3, 16, 0xd4ef3085); |
77 | subround(H, b, c, d, a, 6, 23, 0x04881d05); |
78 | subround(H, a, b, c, d, 9, 4, 0xd9d4d039); |
79 | subround(H, d, a, b, c, 12, 11, 0xe6db99e5); |
80 | subround(H, c, d, a, b, 15, 16, 0x1fa27cf8); |
81 | subround(H, b, c, d, a, 2, 23, 0xc4ac5665); |
82 | subround(I, a, b, c, d, 0, 6, 0xf4292244); |
83 | subround(I, d, a, b, c, 7, 10, 0x432aff97); |
84 | subround(I, c, d, a, b, 14, 15, 0xab9423a7); |
85 | subround(I, b, c, d, a, 5, 21, 0xfc93a039); |
86 | subround(I, a, b, c, d, 12, 6, 0x655b59c3); |
87 | subround(I, d, a, b, c, 3, 10, 0x8f0ccc92); |
88 | subround(I, c, d, a, b, 10, 15, 0xffeff47d); |
89 | subround(I, b, c, d, a, 1, 21, 0x85845dd1); |
90 | subround(I, a, b, c, d, 8, 6, 0x6fa87e4f); |
91 | subround(I, d, a, b, c, 15, 10, 0xfe2ce6e0); |
92 | subround(I, c, d, a, b, 6, 15, 0xa3014314); |
93 | subround(I, b, c, d, a, 13, 21, 0x4e0811a1); |
94 | subround(I, a, b, c, d, 4, 6, 0xf7537e82); |
95 | subround(I, d, a, b, c, 11, 10, 0xbd3af235); |
96 | subround(I, c, d, a, b, 2, 15, 0x2ad7d2bb); |
97 | subround(I, b, c, d, a, 9, 21, 0xeb86d391); |
98 | |
99 | s->h[0] += a; s->h[1] += b; s->h[2] += c; s->h[3] += d; |
100 | } |
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101 | |
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102 | /* ---------------------------------------------------------------------- |
103 | * Outer MD5 algorithm: take an arbitrary length byte string, |
104 | * convert it into 16-word blocks with the prescribed padding at |
105 | * the end, and pass those blocks to the core MD5 algorithm. |
106 | */ |
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107 | |
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108 | #define BLKSIZE 64 |
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109 | |
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110 | void MD5Init(struct MD5Context *s) { |
111 | MD5_Core_Init(&s->core); |
112 | s->blkused = 0; |
113 | s->lenhi = s->lenlo = 0; |
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114 | } |
115 | |
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116 | void MD5Update(struct MD5Context *s, unsigned char const *p, |
117 | unsigned len) { |
118 | unsigned char *q = (unsigned char *)p; |
119 | uint32 wordblock[16]; |
120 | uint32 lenw = len; |
121 | int i; |
122 | |
123 | /* |
124 | * Update the length field. |
125 | */ |
126 | s->lenlo += lenw; |
127 | s->lenhi += (s->lenlo < lenw); |
128 | |
129 | if (s->blkused+len < BLKSIZE) { |
130 | /* |
131 | * Trivial case: just add to the block. |
132 | */ |
133 | memcpy(s->block + s->blkused, q, len); |
134 | s->blkused += len; |
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135 | } else { |
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136 | /* |
137 | * We must complete and process at least one block. |
138 | */ |
139 | while (s->blkused + len >= BLKSIZE) { |
140 | memcpy(s->block + s->blkused, q, BLKSIZE - s->blkused); |
141 | q += BLKSIZE - s->blkused; |
142 | len -= BLKSIZE - s->blkused; |
143 | /* Now process the block. Gather bytes little-endian into words */ |
144 | for (i = 0; i < 16; i++) { |
145 | wordblock[i] = |
146 | ( ((uint32)s->block[i*4+3]) << 24 ) | |
147 | ( ((uint32)s->block[i*4+2]) << 16 ) | |
148 | ( ((uint32)s->block[i*4+1]) << 8 ) | |
149 | ( ((uint32)s->block[i*4+0]) << 0 ); |
150 | } |
151 | MD5_Block(&s->core, wordblock); |
152 | s->blkused = 0; |
153 | } |
154 | memcpy(s->block, q, len); |
155 | s->blkused = len; |
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156 | } |
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157 | } |
158 | |
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159 | void MD5Final(unsigned char output[16], struct MD5Context *s) { |
160 | int i; |
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161 | unsigned pad; |
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162 | unsigned char c[64]; |
163 | uint32 lenhi, lenlo; |
164 | |
165 | if (s->blkused >= 56) |
166 | pad = 56 + 64 - s->blkused; |
167 | else |
168 | pad = 56 - s->blkused; |
169 | |
170 | lenhi = (s->lenhi << 3) | (s->lenlo >> (32-3)); |
171 | lenlo = (s->lenlo << 3); |
172 | |
173 | memset(c, 0, pad); |
174 | c[0] = 0x80; |
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175 | MD5Update(s, c, pad); |
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176 | |
177 | c[7] = (lenhi >> 24) & 0xFF; |
178 | c[6] = (lenhi >> 16) & 0xFF; |
179 | c[5] = (lenhi >> 8) & 0xFF; |
180 | c[4] = (lenhi >> 0) & 0xFF; |
181 | c[3] = (lenlo >> 24) & 0xFF; |
182 | c[2] = (lenlo >> 16) & 0xFF; |
183 | c[1] = (lenlo >> 8) & 0xFF; |
184 | c[0] = (lenlo >> 0) & 0xFF; |
185 | |
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186 | MD5Update(s, c, 8); |
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187 | |
188 | for (i = 0; i < 4; i++) { |
189 | output[4*i+3] = (s->core.h[i] >> 24) & 0xFF; |
190 | output[4*i+2] = (s->core.h[i] >> 16) & 0xFF; |
191 | output[4*i+1] = (s->core.h[i] >> 8) & 0xFF; |
192 | output[4*i+0] = (s->core.h[i] >> 0) & 0xFF; |
193 | } |
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194 | } |
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195 | |
196 | /* ---------------------------------------------------------------------- |
197 | * The above is the MD5 algorithm itself. Now we implement the |
198 | * HMAC wrapper on it. |
199 | */ |
200 | |
201 | static struct MD5Context md5_cs_mac_s1, md5_cs_mac_s2; |
202 | static struct MD5Context md5_sc_mac_s1, md5_sc_mac_s2; |
203 | |
204 | static void md5_key(struct MD5Context *s1, struct MD5Context *s2, |
205 | unsigned char *key, int len) { |
206 | unsigned char foo[64]; |
207 | int i; |
208 | |
209 | memset(foo, 0x36, 64); |
210 | for (i = 0; i < len && i < 64; i++) |
211 | foo[i] ^= key[i]; |
212 | MD5Init(s1); |
213 | MD5Update(s1, foo, 64); |
214 | |
215 | memset(foo, 0x5C, 64); |
216 | for (i = 0; i < len && i < 64; i++) |
217 | foo[i] ^= key[i]; |
218 | MD5Init(s2); |
219 | MD5Update(s2, foo, 64); |
220 | |
221 | memset(foo, 0, 64); /* burn the evidence */ |
222 | } |
223 | |
224 | static void md5_cskey(unsigned char *key) { |
225 | md5_key(&md5_cs_mac_s1, &md5_cs_mac_s2, key, 16); |
226 | } |
227 | |
228 | static void md5_sckey(unsigned char *key) { |
229 | md5_key(&md5_sc_mac_s1, &md5_sc_mac_s2, key, 16); |
230 | } |
231 | |
232 | static void md5_do_hmac(struct MD5Context *s1, struct MD5Context *s2, |
233 | unsigned char *blk, int len, unsigned long seq, |
234 | unsigned char *hmac) { |
235 | struct MD5Context s; |
236 | unsigned char intermediate[16]; |
237 | |
238 | intermediate[0] = (unsigned char)((seq >> 24) & 0xFF); |
239 | intermediate[1] = (unsigned char)((seq >> 16) & 0xFF); |
240 | intermediate[2] = (unsigned char)((seq >> 8) & 0xFF); |
241 | intermediate[3] = (unsigned char)((seq ) & 0xFF); |
242 | |
243 | s = *s1; /* structure copy */ |
244 | MD5Update(&s, intermediate, 4); |
245 | MD5Update(&s, blk, len); |
246 | MD5Final(intermediate, &s); |
247 | s = *s2; /* structure copy */ |
248 | MD5Update(&s, intermediate, 16); |
249 | MD5Final(hmac, &s); |
250 | } |
251 | |
252 | static void md5_generate(unsigned char *blk, int len, unsigned long seq) { |
253 | md5_do_hmac(&md5_cs_mac_s1, &md5_cs_mac_s2, blk, len, seq, blk+len); |
254 | } |
255 | |
256 | static int md5_verify(unsigned char *blk, int len, unsigned long seq) { |
257 | unsigned char correct[16]; |
258 | md5_do_hmac(&md5_sc_mac_s1, &md5_sc_mac_s2, blk, len, seq, correct); |
259 | return !memcmp(correct, blk+len, 16); |
260 | } |
261 | |
262 | struct ssh_mac ssh_md5 = { |
263 | md5_cskey, md5_sckey, |
264 | md5_generate, |
265 | md5_verify, |
266 | "hmac-md5", |
267 | 16 |
268 | }; |