зеркало из https://github.com/github/putty.git
285 строки
8.4 KiB
C
285 строки
8.4 KiB
C
#include "ssh.h"
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/*
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* MD5 implementation for PuTTY. Written directly from the spec by
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* Simon Tatham.
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*/
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/* ----------------------------------------------------------------------
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* Core MD5 algorithm: processes 16-word blocks into a message digest.
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*/
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#define F(x,y,z) ( ((x) & (y)) | ((~(x)) & (z)) )
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#define G(x,y,z) ( ((x) & (z)) | ((~(z)) & (y)) )
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#define H(x,y,z) ( (x) ^ (y) ^ (z) )
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#define I(x,y,z) ( (y) ^ ( (x) | ~(z) ) )
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#define rol(x,y) ( ((x) << (y)) | (((uint32)x) >> (32-y)) )
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#define subround(f,w,x,y,z,k,s,ti) \
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w = x + rol(w + f(x,y,z) + block[k] + ti, s)
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void MD5_Core_Init(MD5_Core_State * s)
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{
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s->h[0] = 0x67452301;
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s->h[1] = 0xefcdab89;
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s->h[2] = 0x98badcfe;
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s->h[3] = 0x10325476;
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}
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void MD5_Block(MD5_Core_State * s, uint32 * block)
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{
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uint32 a, b, c, d;
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a = s->h[0];
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b = s->h[1];
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c = s->h[2];
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d = s->h[3];
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subround(F, a, b, c, d, 0, 7, 0xd76aa478);
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subround(F, d, a, b, c, 1, 12, 0xe8c7b756);
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subround(F, c, d, a, b, 2, 17, 0x242070db);
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subround(F, b, c, d, a, 3, 22, 0xc1bdceee);
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subround(F, a, b, c, d, 4, 7, 0xf57c0faf);
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subround(F, d, a, b, c, 5, 12, 0x4787c62a);
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subround(F, c, d, a, b, 6, 17, 0xa8304613);
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subround(F, b, c, d, a, 7, 22, 0xfd469501);
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subround(F, a, b, c, d, 8, 7, 0x698098d8);
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subround(F, d, a, b, c, 9, 12, 0x8b44f7af);
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subround(F, c, d, a, b, 10, 17, 0xffff5bb1);
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subround(F, b, c, d, a, 11, 22, 0x895cd7be);
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subround(F, a, b, c, d, 12, 7, 0x6b901122);
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subround(F, d, a, b, c, 13, 12, 0xfd987193);
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subround(F, c, d, a, b, 14, 17, 0xa679438e);
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subround(F, b, c, d, a, 15, 22, 0x49b40821);
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subround(G, a, b, c, d, 1, 5, 0xf61e2562);
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subround(G, d, a, b, c, 6, 9, 0xc040b340);
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subround(G, c, d, a, b, 11, 14, 0x265e5a51);
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subround(G, b, c, d, a, 0, 20, 0xe9b6c7aa);
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subround(G, a, b, c, d, 5, 5, 0xd62f105d);
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subround(G, d, a, b, c, 10, 9, 0x02441453);
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subround(G, c, d, a, b, 15, 14, 0xd8a1e681);
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subround(G, b, c, d, a, 4, 20, 0xe7d3fbc8);
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subround(G, a, b, c, d, 9, 5, 0x21e1cde6);
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subround(G, d, a, b, c, 14, 9, 0xc33707d6);
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subround(G, c, d, a, b, 3, 14, 0xf4d50d87);
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subround(G, b, c, d, a, 8, 20, 0x455a14ed);
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subround(G, a, b, c, d, 13, 5, 0xa9e3e905);
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subround(G, d, a, b, c, 2, 9, 0xfcefa3f8);
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subround(G, c, d, a, b, 7, 14, 0x676f02d9);
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subround(G, b, c, d, a, 12, 20, 0x8d2a4c8a);
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subround(H, a, b, c, d, 5, 4, 0xfffa3942);
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subround(H, d, a, b, c, 8, 11, 0x8771f681);
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subround(H, c, d, a, b, 11, 16, 0x6d9d6122);
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subround(H, b, c, d, a, 14, 23, 0xfde5380c);
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subround(H, a, b, c, d, 1, 4, 0xa4beea44);
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subround(H, d, a, b, c, 4, 11, 0x4bdecfa9);
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subround(H, c, d, a, b, 7, 16, 0xf6bb4b60);
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subround(H, b, c, d, a, 10, 23, 0xbebfbc70);
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subround(H, a, b, c, d, 13, 4, 0x289b7ec6);
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subround(H, d, a, b, c, 0, 11, 0xeaa127fa);
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subround(H, c, d, a, b, 3, 16, 0xd4ef3085);
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subround(H, b, c, d, a, 6, 23, 0x04881d05);
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subround(H, a, b, c, d, 9, 4, 0xd9d4d039);
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subround(H, d, a, b, c, 12, 11, 0xe6db99e5);
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subround(H, c, d, a, b, 15, 16, 0x1fa27cf8);
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subround(H, b, c, d, a, 2, 23, 0xc4ac5665);
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subround(I, a, b, c, d, 0, 6, 0xf4292244);
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subround(I, d, a, b, c, 7, 10, 0x432aff97);
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subround(I, c, d, a, b, 14, 15, 0xab9423a7);
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subround(I, b, c, d, a, 5, 21, 0xfc93a039);
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subround(I, a, b, c, d, 12, 6, 0x655b59c3);
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subround(I, d, a, b, c, 3, 10, 0x8f0ccc92);
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subround(I, c, d, a, b, 10, 15, 0xffeff47d);
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subround(I, b, c, d, a, 1, 21, 0x85845dd1);
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subround(I, a, b, c, d, 8, 6, 0x6fa87e4f);
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subround(I, d, a, b, c, 15, 10, 0xfe2ce6e0);
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subround(I, c, d, a, b, 6, 15, 0xa3014314);
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subround(I, b, c, d, a, 13, 21, 0x4e0811a1);
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subround(I, a, b, c, d, 4, 6, 0xf7537e82);
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subround(I, d, a, b, c, 11, 10, 0xbd3af235);
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subround(I, c, d, a, b, 2, 15, 0x2ad7d2bb);
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subround(I, b, c, d, a, 9, 21, 0xeb86d391);
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s->h[0] += a;
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s->h[1] += b;
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s->h[2] += c;
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s->h[3] += d;
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}
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/* ----------------------------------------------------------------------
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* Outer MD5 algorithm: take an arbitrary length byte string,
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* convert it into 16-word blocks with the prescribed padding at
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* the end, and pass those blocks to the core MD5 algorithm.
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*/
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#define BLKSIZE 64
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void MD5Init(struct MD5Context *s)
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{
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MD5_Core_Init(&s->core);
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s->blkused = 0;
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s->lenhi = s->lenlo = 0;
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}
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void MD5Update(struct MD5Context *s, unsigned char const *p, unsigned len)
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{
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unsigned char *q = (unsigned char *) p;
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uint32 wordblock[16];
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uint32 lenw = len;
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int i;
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/*
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* Update the length field.
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*/
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s->lenlo += lenw;
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s->lenhi += (s->lenlo < lenw);
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if (s->blkused + len < BLKSIZE) {
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/*
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* Trivial case: just add to the block.
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*/
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memcpy(s->block + s->blkused, q, len);
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s->blkused += len;
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} else {
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/*
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* We must complete and process at least one block.
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*/
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while (s->blkused + len >= BLKSIZE) {
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memcpy(s->block + s->blkused, q, BLKSIZE - s->blkused);
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q += BLKSIZE - s->blkused;
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len -= BLKSIZE - s->blkused;
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/* Now process the block. Gather bytes little-endian into words */
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for (i = 0; i < 16; i++) {
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wordblock[i] =
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(((uint32) s->block[i * 4 + 3]) << 24) |
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(((uint32) s->block[i * 4 + 2]) << 16) |
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(((uint32) s->block[i * 4 + 1]) << 8) |
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(((uint32) s->block[i * 4 + 0]) << 0);
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}
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MD5_Block(&s->core, wordblock);
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s->blkused = 0;
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}
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memcpy(s->block, q, len);
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s->blkused = len;
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}
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}
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void MD5Final(unsigned char output[16], struct MD5Context *s)
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{
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int i;
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unsigned pad;
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unsigned char c[64];
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uint32 lenhi, lenlo;
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if (s->blkused >= 56)
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pad = 56 + 64 - s->blkused;
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else
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pad = 56 - s->blkused;
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lenhi = (s->lenhi << 3) | (s->lenlo >> (32 - 3));
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lenlo = (s->lenlo << 3);
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memset(c, 0, pad);
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c[0] = 0x80;
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MD5Update(s, c, pad);
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c[7] = (lenhi >> 24) & 0xFF;
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c[6] = (lenhi >> 16) & 0xFF;
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c[5] = (lenhi >> 8) & 0xFF;
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c[4] = (lenhi >> 0) & 0xFF;
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c[3] = (lenlo >> 24) & 0xFF;
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c[2] = (lenlo >> 16) & 0xFF;
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c[1] = (lenlo >> 8) & 0xFF;
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c[0] = (lenlo >> 0) & 0xFF;
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MD5Update(s, c, 8);
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for (i = 0; i < 4; i++) {
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output[4 * i + 3] = (s->core.h[i] >> 24) & 0xFF;
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output[4 * i + 2] = (s->core.h[i] >> 16) & 0xFF;
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output[4 * i + 1] = (s->core.h[i] >> 8) & 0xFF;
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output[4 * i + 0] = (s->core.h[i] >> 0) & 0xFF;
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}
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}
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/* ----------------------------------------------------------------------
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* The above is the MD5 algorithm itself. Now we implement the
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* HMAC wrapper on it.
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*/
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static struct MD5Context md5_cs_mac_s1, md5_cs_mac_s2;
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static struct MD5Context md5_sc_mac_s1, md5_sc_mac_s2;
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static void md5_key(struct MD5Context *s1, struct MD5Context *s2,
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unsigned char *key, int len)
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{
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unsigned char foo[64];
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int i;
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memset(foo, 0x36, 64);
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for (i = 0; i < len && i < 64; i++)
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foo[i] ^= key[i];
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MD5Init(s1);
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MD5Update(s1, foo, 64);
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memset(foo, 0x5C, 64);
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for (i = 0; i < len && i < 64; i++)
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foo[i] ^= key[i];
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MD5Init(s2);
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MD5Update(s2, foo, 64);
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memset(foo, 0, 64); /* burn the evidence */
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}
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static void md5_cskey(unsigned char *key)
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{
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md5_key(&md5_cs_mac_s1, &md5_cs_mac_s2, key, 16);
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}
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static void md5_sckey(unsigned char *key)
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{
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md5_key(&md5_sc_mac_s1, &md5_sc_mac_s2, key, 16);
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}
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static void md5_do_hmac(struct MD5Context *s1, struct MD5Context *s2,
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unsigned char *blk, int len, unsigned long seq,
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unsigned char *hmac)
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{
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struct MD5Context s;
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unsigned char intermediate[16];
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intermediate[0] = (unsigned char) ((seq >> 24) & 0xFF);
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intermediate[1] = (unsigned char) ((seq >> 16) & 0xFF);
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intermediate[2] = (unsigned char) ((seq >> 8) & 0xFF);
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intermediate[3] = (unsigned char) ((seq) & 0xFF);
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s = *s1; /* structure copy */
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MD5Update(&s, intermediate, 4);
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MD5Update(&s, blk, len);
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MD5Final(intermediate, &s);
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s = *s2; /* structure copy */
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MD5Update(&s, intermediate, 16);
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MD5Final(hmac, &s);
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}
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static void md5_generate(unsigned char *blk, int len, unsigned long seq)
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{
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md5_do_hmac(&md5_cs_mac_s1, &md5_cs_mac_s2, blk, len, seq, blk + len);
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}
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static int md5_verify(unsigned char *blk, int len, unsigned long seq)
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{
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unsigned char correct[16];
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md5_do_hmac(&md5_sc_mac_s1, &md5_sc_mac_s2, blk, len, seq, correct);
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return !memcmp(correct, blk + len, 16);
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}
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const struct ssh_mac ssh_md5 = {
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md5_cskey, md5_sckey,
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md5_generate,
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md5_verify,
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"hmac-md5",
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16
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};
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