#include "ssh.h" /* * MD5 implementation for PuTTY. Written directly from the spec by * Simon Tatham. */ /* ---------------------------------------------------------------------- * Core MD5 algorithm: processes 16-word blocks into a message digest. */ #define F(x,y,z) ( ((x) & (y)) | ((~(x)) & (z)) ) #define G(x,y,z) ( ((x) & (z)) | ((~(z)) & (y)) ) #define H(x,y,z) ( (x) ^ (y) ^ (z) ) #define I(x,y,z) ( (y) ^ ( (x) | ~(z) ) ) #define rol(x,y) ( ((x) << (y)) | (((uint32)x) >> (32-y)) ) #define subround(f,w,x,y,z,k,s,ti) \ w = x + rol(w + f(x,y,z) + block[k] + ti, s) static void MD5_Core_Init(MD5_Core_State * s) { s->h[0] = 0x67452301; s->h[1] = 0xefcdab89; s->h[2] = 0x98badcfe; s->h[3] = 0x10325476; } static void MD5_Block(MD5_Core_State * s, uint32 * block) { uint32 a, b, c, d; a = s->h[0]; b = s->h[1]; c = s->h[2]; d = s->h[3]; subround(F, a, b, c, d, 0, 7, 0xd76aa478); subround(F, d, a, b, c, 1, 12, 0xe8c7b756); subround(F, c, d, a, b, 2, 17, 0x242070db); subround(F, b, c, d, a, 3, 22, 0xc1bdceee); subround(F, a, b, c, d, 4, 7, 0xf57c0faf); subround(F, d, a, b, c, 5, 12, 0x4787c62a); subround(F, c, d, a, b, 6, 17, 0xa8304613); subround(F, b, c, d, a, 7, 22, 0xfd469501); subround(F, a, b, c, d, 8, 7, 0x698098d8); subround(F, d, a, b, c, 9, 12, 0x8b44f7af); subround(F, c, d, a, b, 10, 17, 0xffff5bb1); subround(F, b, c, d, a, 11, 22, 0x895cd7be); subround(F, a, b, c, d, 12, 7, 0x6b901122); subround(F, d, a, b, c, 13, 12, 0xfd987193); subround(F, c, d, a, b, 14, 17, 0xa679438e); subround(F, b, c, d, a, 15, 22, 0x49b40821); subround(G, a, b, c, d, 1, 5, 0xf61e2562); subround(G, d, a, b, c, 6, 9, 0xc040b340); subround(G, c, d, a, b, 11, 14, 0x265e5a51); subround(G, b, c, d, a, 0, 20, 0xe9b6c7aa); subround(G, a, b, c, d, 5, 5, 0xd62f105d); subround(G, d, a, b, c, 10, 9, 0x02441453); subround(G, c, d, a, b, 15, 14, 0xd8a1e681); subround(G, b, c, d, a, 4, 20, 0xe7d3fbc8); subround(G, a, b, c, d, 9, 5, 0x21e1cde6); subround(G, d, a, b, c, 14, 9, 0xc33707d6); subround(G, c, d, a, b, 3, 14, 0xf4d50d87); subround(G, b, c, d, a, 8, 20, 0x455a14ed); subround(G, a, b, c, d, 13, 5, 0xa9e3e905); subround(G, d, a, b, c, 2, 9, 0xfcefa3f8); subround(G, c, d, a, b, 7, 14, 0x676f02d9); subround(G, b, c, d, a, 12, 20, 0x8d2a4c8a); subround(H, a, b, c, d, 5, 4, 0xfffa3942); subround(H, d, a, b, c, 8, 11, 0x8771f681); subround(H, c, d, a, b, 11, 16, 0x6d9d6122); subround(H, b, c, d, a, 14, 23, 0xfde5380c); subround(H, a, b, c, d, 1, 4, 0xa4beea44); subround(H, d, a, b, c, 4, 11, 0x4bdecfa9); subround(H, c, d, a, b, 7, 16, 0xf6bb4b60); subround(H, b, c, d, a, 10, 23, 0xbebfbc70); subround(H, a, b, c, d, 13, 4, 0x289b7ec6); subround(H, d, a, b, c, 0, 11, 0xeaa127fa); subround(H, c, d, a, b, 3, 16, 0xd4ef3085); subround(H, b, c, d, a, 6, 23, 0x04881d05); subround(H, a, b, c, d, 9, 4, 0xd9d4d039); subround(H, d, a, b, c, 12, 11, 0xe6db99e5); subround(H, c, d, a, b, 15, 16, 0x1fa27cf8); subround(H, b, c, d, a, 2, 23, 0xc4ac5665); subround(I, a, b, c, d, 0, 6, 0xf4292244); subround(I, d, a, b, c, 7, 10, 0x432aff97); subround(I, c, d, a, b, 14, 15, 0xab9423a7); subround(I, b, c, d, a, 5, 21, 0xfc93a039); subround(I, a, b, c, d, 12, 6, 0x655b59c3); subround(I, d, a, b, c, 3, 10, 0x8f0ccc92); subround(I, c, d, a, b, 10, 15, 0xffeff47d); subround(I, b, c, d, a, 1, 21, 0x85845dd1); subround(I, a, b, c, d, 8, 6, 0x6fa87e4f); subround(I, d, a, b, c, 15, 10, 0xfe2ce6e0); subround(I, c, d, a, b, 6, 15, 0xa3014314); subround(I, b, c, d, a, 13, 21, 0x4e0811a1); subround(I, a, b, c, d, 4, 6, 0xf7537e82); subround(I, d, a, b, c, 11, 10, 0xbd3af235); subround(I, c, d, a, b, 2, 15, 0x2ad7d2bb); subround(I, b, c, d, a, 9, 21, 0xeb86d391); s->h[0] += a; s->h[1] += b; s->h[2] += c; s->h[3] += d; } /* ---------------------------------------------------------------------- * Outer MD5 algorithm: take an arbitrary length byte string, * convert it into 16-word blocks with the prescribed padding at * the end, and pass those blocks to the core MD5 algorithm. */ #define BLKSIZE 64 void MD5Init(struct MD5Context *s) { MD5_Core_Init(&s->core); s->blkused = 0; s->lenhi = s->lenlo = 0; } void MD5Update(struct MD5Context *s, unsigned char const *p, unsigned len) { unsigned char *q = (unsigned char *) p; uint32 wordblock[16]; uint32 lenw = len; int i; /* * Update the length field. */ s->lenlo += lenw; s->lenhi += (s->lenlo < lenw); if (s->blkused + len < BLKSIZE) { /* * Trivial case: just add to the block. */ memcpy(s->block + s->blkused, q, len); s->blkused += len; } else { /* * We must complete and process at least one block. */ while (s->blkused + len >= BLKSIZE) { memcpy(s->block + s->blkused, q, BLKSIZE - s->blkused); q += BLKSIZE - s->blkused; len -= BLKSIZE - s->blkused; /* Now process the block. Gather bytes little-endian into words */ for (i = 0; i < 16; i++) { wordblock[i] = (((uint32) s->block[i * 4 + 3]) << 24) | (((uint32) s->block[i * 4 + 2]) << 16) | (((uint32) s->block[i * 4 + 1]) << 8) | (((uint32) s->block[i * 4 + 0]) << 0); } MD5_Block(&s->core, wordblock); s->blkused = 0; } memcpy(s->block, q, len); s->blkused = len; } } void MD5Final(unsigned char output[16], struct MD5Context *s) { int i; unsigned pad; unsigned char c[64]; uint32 lenhi, lenlo; if (s->blkused >= 56) pad = 56 + 64 - s->blkused; else pad = 56 - s->blkused; lenhi = (s->lenhi << 3) | (s->lenlo >> (32 - 3)); lenlo = (s->lenlo << 3); memset(c, 0, pad); c[0] = 0x80; MD5Update(s, c, pad); c[7] = (lenhi >> 24) & 0xFF; c[6] = (lenhi >> 16) & 0xFF; c[5] = (lenhi >> 8) & 0xFF; c[4] = (lenhi >> 0) & 0xFF; c[3] = (lenlo >> 24) & 0xFF; c[2] = (lenlo >> 16) & 0xFF; c[1] = (lenlo >> 8) & 0xFF; c[0] = (lenlo >> 0) & 0xFF; MD5Update(s, c, 8); for (i = 0; i < 4; i++) { output[4 * i + 3] = (s->core.h[i] >> 24) & 0xFF; output[4 * i + 2] = (s->core.h[i] >> 16) & 0xFF; output[4 * i + 1] = (s->core.h[i] >> 8) & 0xFF; output[4 * i + 0] = (s->core.h[i] >> 0) & 0xFF; } } void MD5Simple(void const *p, unsigned len, unsigned char output[16]) { struct MD5Context s; MD5Init(&s); MD5Update(&s, (unsigned char const *)p, len); MD5Final(output, &s); } /* ---------------------------------------------------------------------- * The above is the MD5 algorithm itself. Now we implement the * HMAC wrapper on it. * * Some of these functions are exported directly, because they are * useful elsewhere (SOCKS5 CHAP authentication uses HMAC-MD5). */ void *hmacmd5_make_context(void) { return snewn(3, struct MD5Context); } void hmacmd5_free_context(void *handle) { sfree(handle); } void hmacmd5_key(void *handle, void const *keyv, int len) { struct MD5Context *keys = (struct MD5Context *)handle; unsigned char foo[64]; unsigned char const *key = (unsigned char const *)keyv; int i; memset(foo, 0x36, 64); for (i = 0; i < len && i < 64; i++) foo[i] ^= key[i]; MD5Init(&keys[0]); MD5Update(&keys[0], foo, 64); memset(foo, 0x5C, 64); for (i = 0; i < len && i < 64; i++) foo[i] ^= key[i]; MD5Init(&keys[1]); MD5Update(&keys[1], foo, 64); memset(foo, 0, 64); /* burn the evidence */ } static void hmacmd5_key_16(void *handle, unsigned char *key) { hmacmd5_key(handle, key, 16); } static void hmacmd5_start(void *handle) { struct MD5Context *keys = (struct MD5Context *)handle; keys[2] = keys[0]; /* structure copy */ } static void hmacmd5_bytes(void *handle, unsigned char const *blk, int len) { struct MD5Context *keys = (struct MD5Context *)handle; MD5Update(&keys[2], blk, len); } static void hmacmd5_genresult(void *handle, unsigned char *hmac) { struct MD5Context *keys = (struct MD5Context *)handle; struct MD5Context s; unsigned char intermediate[16]; s = keys[2]; /* structure copy */ MD5Final(intermediate, &s); s = keys[1]; /* structure copy */ MD5Update(&s, intermediate, 16); MD5Final(hmac, &s); } static int hmacmd5_verresult(void *handle, unsigned char const *hmac) { unsigned char correct[16]; hmacmd5_genresult(handle, correct); return !memcmp(correct, hmac, 16); } static void hmacmd5_do_hmac_internal(void *handle, unsigned char const *blk, int len, unsigned char const *blk2, int len2, unsigned char *hmac) { hmacmd5_start(handle); hmacmd5_bytes(handle, blk, len); if (blk2) hmacmd5_bytes(handle, blk2, len2); hmacmd5_genresult(handle, hmac); } void hmacmd5_do_hmac(void *handle, unsigned char const *blk, int len, unsigned char *hmac) { hmacmd5_do_hmac_internal(handle, blk, len, NULL, 0, hmac); } static void hmacmd5_do_hmac_ssh(void *handle, unsigned char const *blk, int len, unsigned long seq, unsigned char *hmac) { unsigned char seqbuf[16]; seqbuf[0] = (unsigned char) ((seq >> 24) & 0xFF); seqbuf[1] = (unsigned char) ((seq >> 16) & 0xFF); seqbuf[2] = (unsigned char) ((seq >> 8) & 0xFF); seqbuf[3] = (unsigned char) ((seq) & 0xFF); hmacmd5_do_hmac_internal(handle, seqbuf, 4, blk, len, hmac); } static void hmacmd5_generate(void *handle, unsigned char *blk, int len, unsigned long seq) { hmacmd5_do_hmac_ssh(handle, blk, len, seq, blk + len); } static int hmacmd5_verify(void *handle, unsigned char *blk, int len, unsigned long seq) { unsigned char correct[16]; hmacmd5_do_hmac_ssh(handle, blk, len, seq, correct); return !memcmp(correct, blk + len, 16); } const struct ssh_mac ssh_hmac_md5 = { hmacmd5_make_context, hmacmd5_free_context, hmacmd5_key_16, hmacmd5_generate, hmacmd5_verify, hmacmd5_start, hmacmd5_bytes, hmacmd5_genresult, hmacmd5_verresult, "hmac-md5", 16, "HMAC-MD5" };