| 1 | #include "ssh.h" |
| 2 | |
| 3 | /* |
| 4 | * MD5 implementation for PuTTY. Written directly from the spec by |
| 5 | * Simon Tatham. |
| 6 | */ |
| 7 | |
| 8 | /* ---------------------------------------------------------------------- |
| 9 | * Core MD5 algorithm: processes 16-word blocks into a message digest. |
| 10 | */ |
| 11 | |
| 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) ) ) |
| 16 | |
| 17 | #define rol(x,y) ( ((x) << (y)) | (((uint32)x) >> (32-y)) ) |
| 18 | |
| 19 | #define subround(f,w,x,y,z,k,s,ti) \ |
| 20 | w = x + rol(w + f(x,y,z) + block[k] + ti, s) |
| 21 | |
| 22 | static void MD5_Core_Init(MD5_Core_State * s) |
| 23 | { |
| 24 | s->h[0] = 0x67452301; |
| 25 | s->h[1] = 0xefcdab89; |
| 26 | s->h[2] = 0x98badcfe; |
| 27 | s->h[3] = 0x10325476; |
| 28 | } |
| 29 | |
| 30 | static void MD5_Block(MD5_Core_State * s, uint32 * block) |
| 31 | { |
| 32 | uint32 a, b, c, d; |
| 33 | |
| 34 | a = s->h[0]; |
| 35 | b = s->h[1]; |
| 36 | c = s->h[2]; |
| 37 | d = s->h[3]; |
| 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 | |
| 104 | s->h[0] += a; |
| 105 | s->h[1] += b; |
| 106 | s->h[2] += c; |
| 107 | s->h[3] += d; |
| 108 | } |
| 109 | |
| 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 | */ |
| 115 | |
| 116 | #define BLKSIZE 64 |
| 117 | |
| 118 | void MD5Init(struct MD5Context *s) |
| 119 | { |
| 120 | MD5_Core_Init(&s->core); |
| 121 | s->blkused = 0; |
| 122 | s->lenhi = s->lenlo = 0; |
| 123 | } |
| 124 | |
| 125 | void MD5Update(struct MD5Context *s, unsigned char const *p, unsigned len) |
| 126 | { |
| 127 | unsigned char *q = (unsigned char *) p; |
| 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 | |
| 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; |
| 144 | } else { |
| 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; |
| 165 | } |
| 166 | } |
| 167 | |
| 168 | void MD5Final(unsigned char output[16], struct MD5Context *s) |
| 169 | { |
| 170 | int i; |
| 171 | unsigned pad; |
| 172 | unsigned char c[64]; |
| 173 | uint32 lenhi, lenlo; |
| 174 | |
| 175 | if (s->blkused >= 56) |
| 176 | pad = 56 + 64 - s->blkused; |
| 177 | else |
| 178 | pad = 56 - s->blkused; |
| 179 | |
| 180 | lenhi = (s->lenhi << 3) | (s->lenlo >> (32 - 3)); |
| 181 | lenlo = (s->lenlo << 3); |
| 182 | |
| 183 | memset(c, 0, pad); |
| 184 | c[0] = 0x80; |
| 185 | MD5Update(s, c, pad); |
| 186 | |
| 187 | c[7] = (lenhi >> 24) & 0xFF; |
| 188 | c[6] = (lenhi >> 16) & 0xFF; |
| 189 | c[5] = (lenhi >> 8) & 0xFF; |
| 190 | c[4] = (lenhi >> 0) & 0xFF; |
| 191 | c[3] = (lenlo >> 24) & 0xFF; |
| 192 | c[2] = (lenlo >> 16) & 0xFF; |
| 193 | c[1] = (lenlo >> 8) & 0xFF; |
| 194 | c[0] = (lenlo >> 0) & 0xFF; |
| 195 | |
| 196 | MD5Update(s, c, 8); |
| 197 | |
| 198 | for (i = 0; i < 4; i++) { |
| 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; |
| 203 | } |
| 204 | } |
| 205 | |
| 206 | /* ---------------------------------------------------------------------- |
| 207 | * The above is the MD5 algorithm itself. Now we implement the |
| 208 | * HMAC wrapper on it. |
| 209 | */ |
| 210 | |
| 211 | static void *md5_make_context(void) |
| 212 | { |
| 213 | return snewn(2, struct MD5Context); |
| 214 | } |
| 215 | |
| 216 | static void md5_free_context(void *handle) |
| 217 | { |
| 218 | sfree(handle); |
| 219 | } |
| 220 | |
| 221 | static void md5_key_internal(void *handle, unsigned char *key, int len) |
| 222 | { |
| 223 | struct MD5Context *keys = (struct MD5Context *)handle; |
| 224 | unsigned char foo[64]; |
| 225 | int i; |
| 226 | |
| 227 | memset(foo, 0x36, 64); |
| 228 | for (i = 0; i < len && i < 64; i++) |
| 229 | foo[i] ^= key[i]; |
| 230 | MD5Init(&keys[0]); |
| 231 | MD5Update(&keys[0], foo, 64); |
| 232 | |
| 233 | memset(foo, 0x5C, 64); |
| 234 | for (i = 0; i < len && i < 64; i++) |
| 235 | foo[i] ^= key[i]; |
| 236 | MD5Init(&keys[1]); |
| 237 | MD5Update(&keys[1], foo, 64); |
| 238 | |
| 239 | memset(foo, 0, 64); /* burn the evidence */ |
| 240 | } |
| 241 | |
| 242 | static void md5_key(void *handle, unsigned char *key) |
| 243 | { |
| 244 | md5_key_internal(handle, key, 16); |
| 245 | } |
| 246 | |
| 247 | static void md5_do_hmac(void *handle, unsigned char *blk, int len, |
| 248 | unsigned long seq, unsigned char *hmac) |
| 249 | { |
| 250 | struct MD5Context *keys = (struct MD5Context *)handle; |
| 251 | struct MD5Context s; |
| 252 | unsigned char intermediate[16]; |
| 253 | |
| 254 | intermediate[0] = (unsigned char) ((seq >> 24) & 0xFF); |
| 255 | intermediate[1] = (unsigned char) ((seq >> 16) & 0xFF); |
| 256 | intermediate[2] = (unsigned char) ((seq >> 8) & 0xFF); |
| 257 | intermediate[3] = (unsigned char) ((seq) & 0xFF); |
| 258 | |
| 259 | s = keys[0]; /* structure copy */ |
| 260 | MD5Update(&s, intermediate, 4); |
| 261 | MD5Update(&s, blk, len); |
| 262 | MD5Final(intermediate, &s); |
| 263 | s = keys[1]; /* structure copy */ |
| 264 | MD5Update(&s, intermediate, 16); |
| 265 | MD5Final(hmac, &s); |
| 266 | } |
| 267 | |
| 268 | static void md5_generate(void *handle, unsigned char *blk, int len, |
| 269 | unsigned long seq) |
| 270 | { |
| 271 | md5_do_hmac(handle, blk, len, seq, blk + len); |
| 272 | } |
| 273 | |
| 274 | static int md5_verify(void *handle, unsigned char *blk, int len, |
| 275 | unsigned long seq) |
| 276 | { |
| 277 | unsigned char correct[16]; |
| 278 | md5_do_hmac(handle, blk, len, seq, correct); |
| 279 | return !memcmp(correct, blk + len, 16); |
| 280 | } |
| 281 | |
| 282 | const struct ssh_mac ssh_md5 = { |
| 283 | md5_make_context, md5_free_context, md5_key, |
| 284 | md5_generate, md5_verify, |
| 285 | "hmac-md5", |
| 286 | 16 |
| 287 | }; |