зеркало из https://github.com/github/putty.git
324 строки
9.4 KiB
C
324 строки
9.4 KiB
C
#include <assert.h>
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#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_t)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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static 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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static void MD5_Block(MD5_Core_State *s, uint32_t *block)
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{
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uint32_t 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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static void MD5_BinarySink_write(BinarySink *bs, const void *data, size_t len);
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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->len = 0;
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BinarySink_INIT(s, MD5_BinarySink_write);
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}
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static void MD5_BinarySink_write(BinarySink *bs, const void *data, size_t len)
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{
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struct MD5Context *s = BinarySink_DOWNCAST(bs, struct MD5Context);
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const unsigned char *q = (const unsigned char *)data;
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uint32_t wordblock[16];
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uint32_t lenw = len;
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int i;
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assert(lenw == len);
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/*
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* Update the length field.
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*/
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s->len += 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_t) s->block[i * 4 + 3]) << 24) |
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(((uint32_t) s->block[i * 4 + 2]) << 16) |
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(((uint32_t) s->block[i * 4 + 1]) << 8) |
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(((uint32_t) 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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uint64_t len;
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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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len = (s->len << 3);
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memset(c, 0, pad);
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c[0] = 0x80;
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put_data(s, c, pad);
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PUT_64BIT_LSB_FIRST(c, len);
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put_data(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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void MD5Simple(void const *p, unsigned len, unsigned char output[16])
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{
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struct MD5Context s;
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MD5Init(&s);
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put_data(&s, (unsigned char const *)p, len);
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MD5Final(output, &s);
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smemclr(&s, sizeof(s));
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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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* Some of these functions are exported directly, because they are
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* useful elsewhere (SOCKS5 CHAP authentication uses HMAC-MD5).
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*/
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struct hmacmd5_context {
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struct MD5Context md5[3];
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ssh2_mac mac;
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};
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struct hmacmd5_context *hmacmd5_make_context(void)
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{
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struct hmacmd5_context *ctx = snew(struct hmacmd5_context);
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BinarySink_DELEGATE_INIT(&ctx->mac, &ctx->md5[2]);
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return ctx;
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}
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static ssh2_mac *hmacmd5_ssh2_new(const struct ssh2_macalg *alg,
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ssh2_cipher *cipher)
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{
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struct hmacmd5_context *ctx = hmacmd5_make_context();
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ctx->mac.vt = alg;
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return &ctx->mac;
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}
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void hmacmd5_free_context(struct hmacmd5_context *ctx)
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{
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smemclr(ctx, sizeof(*ctx));
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sfree(ctx);
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}
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static void hmacmd5_ssh2_free(ssh2_mac *mac)
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{
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struct hmacmd5_context *ctx =
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container_of(mac, struct hmacmd5_context, mac);
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hmacmd5_free_context(ctx);
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}
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void hmacmd5_key(struct hmacmd5_context *ctx, void const *keyv, int len)
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{
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unsigned char foo[64];
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unsigned char const *key = (unsigned char const *)keyv;
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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(&ctx->md5[0]);
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put_data(&ctx->md5[0], 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(&ctx->md5[1]);
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put_data(&ctx->md5[1], foo, 64);
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smemclr(foo, 64); /* burn the evidence */
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}
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static void hmacmd5_ssh2_setkey(ssh2_mac *mac, const void *key)
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{
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struct hmacmd5_context *ctx =
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container_of(mac, struct hmacmd5_context, mac);
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hmacmd5_key(ctx, key, ctx->mac.vt->keylen);
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}
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static void hmacmd5_start(ssh2_mac *mac)
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{
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struct hmacmd5_context *ctx =
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container_of(mac, struct hmacmd5_context, mac);
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ctx->md5[2] = ctx->md5[0]; /* structure copy */
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BinarySink_COPIED(&ctx->md5[2]);
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}
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static void hmacmd5_genresult(ssh2_mac *mac, unsigned char *hmac)
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{
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struct hmacmd5_context *ctx =
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container_of(mac, struct hmacmd5_context, mac);
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struct MD5Context s;
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unsigned char intermediate[16];
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s = ctx->md5[2]; /* structure copy */
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BinarySink_COPIED(&s);
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MD5Final(intermediate, &s);
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s = ctx->md5[1]; /* structure copy */
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BinarySink_COPIED(&s);
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put_data(&s, intermediate, 16);
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MD5Final(hmac, &s);
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smemclr(intermediate, sizeof(intermediate));
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}
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void hmacmd5_do_hmac(struct hmacmd5_context *ctx,
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const void *blk, int len, unsigned char *hmac)
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{
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ssh2_mac_start(&ctx->mac);
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put_data(&ctx->mac, blk, len);
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return ssh2_mac_genresult(&ctx->mac, hmac);
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}
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const struct ssh2_macalg ssh_hmac_md5 = {
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hmacmd5_ssh2_new, hmacmd5_ssh2_free, hmacmd5_ssh2_setkey,
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hmacmd5_start, hmacmd5_genresult,
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"hmac-md5", "hmac-md5-etm@openssh.com",
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16, 16,
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"HMAC-MD5"
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};
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