busybox/libbb/hash_sha.c

/* vi: set sw=4 ts=4: */
/*
 * Based on shasum from http://www.netsw.org/crypto/hash/
 * Majorly hacked up to use Dr Brian Gladman's sha1 code
 *
 * Copyright (C) 2002 Dr Brian Gladman <brg@gladman.me.uk>, Worcester, UK.
 * Copyright (C) 2003 Glenn L. McGrath
 * Copyright (C) 2003 Erik Andersen
 *
 * Licensed under GPLv2 or later, see file LICENSE in this source tree.
 *
 * ---------------------------------------------------------------------------
 * Issue Date: 10/11/2002
 *
 * This is a byte oriented version of SHA1 that operates on arrays of bytes
 * stored in memory. It runs at 22 cycles per byte on a Pentium P4 processor
 *
 * ---------------------------------------------------------------------------
 *
 * SHA256 and SHA512 parts are:
 * Released into the Public Domain by Ulrich Drepper <drepper@redhat.com>.
 * Shrank by Denys Vlasenko.
 *
 * ---------------------------------------------------------------------------
 *
 * The best way to test random blocksizes is to go to coreutils/md5_sha1_sum.c
 * and replace "4096" with something like "2000 + time(NULL) % 2097",
 * then rebuild and compare "shaNNNsum bigfile" results.
 */

#include "libbb.h"

/* gcc 4.2.1 optimizes rotr64 better with inline than with macro
 * (for rotX32, there is no difference). Why? My guess is that
 * macro requires clever common subexpression elimination heuristics
 * in gcc, while inline basically forces it to happen.
 */
//#define rotl32(x,n) (((x) << (n)) | ((x) >> (32 - (n))))
static ALWAYS_INLINE uint32_t rotl32(uint32_t x, unsigned n)
{
	return (x << n) | (x >> (32 - n));
}
//#define rotr32(x,n) (((x) >> (n)) | ((x) << (32 - (n))))
static ALWAYS_INLINE uint32_t rotr32(uint32_t x, unsigned n)
{
	return (x >> n) | (x << (32 - n));
}
/* rotr64 in needed for sha512 only: */
//#define rotr64(x,n) (((x) >> (n)) | ((x) << (64 - (n))))
static ALWAYS_INLINE uint64_t rotr64(uint64_t x, unsigned n)
{
	return (x >> n) | (x << (64 - n));
}
#if BB_LITTLE_ENDIAN
/* ALWAYS_INLINE below would hurt code size, using plain inline: */
static inline uint64_t hton64(uint64_t v)
{
	return (((uint64_t)htonl(v)) << 32) | htonl(v >> 32);
}
#else
#define hton64(v) (v)
#endif
#define ntoh64(v) hton64(v)


/* Some arch headers have conflicting defines */
#undef ch
#undef parity
#undef maj
#undef rnd

static void FAST_FUNC sha1_process_block64(sha1_ctx_t *ctx)
{
	unsigned t;
	uint32_t W[80], a, b, c, d, e;
	const uint32_t *words = (uint32_t*) ctx->wbuffer;

	for (t = 0; t < 16; ++t)
		W[t] = ntohl(words[t]);
	for (/*t = 16*/; t < 80; ++t) {
		uint32_t T = W[t - 3] ^ W[t - 8] ^ W[t - 14] ^ W[t - 16];
		W[t] = rotl32(T, 1);
	}

	a = ctx->hash[0];
	b = ctx->hash[1];
	c = ctx->hash[2];
	d = ctx->hash[3];
	e = ctx->hash[4];

/* Reverse byte order in 32-bit words   */
#define ch(x,y,z)        ((z) ^ ((x) & ((y) ^ (z))))
#define parity(x,y,z)    ((x) ^ (y) ^ (z))
#define maj(x,y,z)       (((x) & (y)) | ((z) & ((x) | (y))))
/* A normal version as set out in the FIPS. This version uses   */
/* partial loop unrolling and is optimised for the Pentium 4    */
#define rnd(f,k) \
	do { \
		uint32_t T = a; \
		a = rotl32(a, 5) + f(b, c, d) + e + k + W[t]; \
		e = d; \
		d = c; \
		c = rotl32(b, 30); \
		b = T; \
	} while (0)

	for (t = 0; t < 20; ++t)
		rnd(ch, 0x5a827999);

	for (/*t = 20*/; t < 40; ++t)
		rnd(parity, 0x6ed9eba1);

	for (/*t = 40*/; t < 60; ++t)
		rnd(maj, 0x8f1bbcdc);

	for (/*t = 60*/; t < 80; ++t)
		rnd(parity, 0xca62c1d6);
#undef ch
#undef parity
#undef maj
#undef rnd

	ctx->hash[0] += a;
	ctx->hash[1] += b;
	ctx->hash[2] += c;
	ctx->hash[3] += d;
	ctx->hash[4] += e;
}

/* Constants for SHA512 from FIPS 180-2:4.2.3.
 * SHA256 constants from FIPS 180-2:4.2.2
 * are the most significant half of first 64 elements
 * of the same array.
 */
static const uint64_t sha_K[80] = {
	0x428a2f98d728ae22ULL, 0x7137449123ef65cdULL,
	0xb5c0fbcfec4d3b2fULL, 0xe9b5dba58189dbbcULL,
	0x3956c25bf348b538ULL, 0x59f111f1b605d019ULL,
	0x923f82a4af194f9bULL, 0xab1c5ed5da6d8118ULL,
	0xd807aa98a3030242ULL, 0x12835b0145706fbeULL,
	0x243185be4ee4b28cULL, 0x550c7dc3d5ffb4e2ULL,
	0x72be5d74f27b896fULL, 0x80deb1fe3b1696b1ULL,
	0x9bdc06a725c71235ULL, 0xc19bf174cf692694ULL,
	0xe49b69c19ef14ad2ULL, 0xefbe4786384f25e3ULL,
	0x0fc19dc68b8cd5b5ULL, 0x240ca1cc77ac9c65ULL,
	0x2de92c6f592b0275ULL, 0x4a7484aa6ea6e483ULL,
	0x5cb0a9dcbd41fbd4ULL, 0x76f988da831153b5ULL,
	0x983e5152ee66dfabULL, 0xa831c66d2db43210ULL,
	0xb00327c898fb213fULL, 0xbf597fc7beef0ee4ULL,
	0xc6e00bf33da88fc2ULL, 0xd5a79147930aa725ULL,
	0x06ca6351e003826fULL, 0x142929670a0e6e70ULL,
	0x27b70a8546d22ffcULL, 0x2e1b21385c26c926ULL,
	0x4d2c6dfc5ac42aedULL, 0x53380d139d95b3dfULL,
	0x650a73548baf63deULL, 0x766a0abb3c77b2a8ULL,
	0x81c2c92e47edaee6ULL, 0x92722c851482353bULL,
	0xa2bfe8a14cf10364ULL, 0xa81a664bbc423001ULL,
	0xc24b8b70d0f89791ULL, 0xc76c51a30654be30ULL,
	0xd192e819d6ef5218ULL, 0xd69906245565a910ULL,
	0xf40e35855771202aULL, 0x106aa07032bbd1b8ULL,
	0x19a4c116b8d2d0c8ULL, 0x1e376c085141ab53ULL,
	0x2748774cdf8eeb99ULL, 0x34b0bcb5e19b48a8ULL,
	0x391c0cb3c5c95a63ULL, 0x4ed8aa4ae3418acbULL,
	0x5b9cca4f7763e373ULL, 0x682e6ff3d6b2b8a3ULL,
	0x748f82ee5defb2fcULL, 0x78a5636f43172f60ULL,
	0x84c87814a1f0ab72ULL, 0x8cc702081a6439ecULL,
	0x90befffa23631e28ULL, 0xa4506cebde82bde9ULL,
	0xbef9a3f7b2c67915ULL, 0xc67178f2e372532bULL,
	0xca273eceea26619cULL, 0xd186b8c721c0c207ULL, /* [64]+ are used for sha512 only */
	0xeada7dd6cde0eb1eULL, 0xf57d4f7fee6ed178ULL,
	0x06f067aa72176fbaULL, 0x0a637dc5a2c898a6ULL,
	0x113f9804bef90daeULL, 0x1b710b35131c471bULL,
	0x28db77f523047d84ULL, 0x32caab7b40c72493ULL,
	0x3c9ebe0a15c9bebcULL, 0x431d67c49c100d4cULL,
	0x4cc5d4becb3e42b6ULL, 0x597f299cfc657e2aULL,
	0x5fcb6fab3ad6faecULL, 0x6c44198c4a475817ULL
};

#undef Ch
#undef Maj
#undef S0
#undef S1
#undef R0
#undef R1

static void FAST_FUNC sha256_process_block64(sha256_ctx_t *ctx)
{
	unsigned t;
	uint32_t W[64], a, b, c, d, e, f, g, h;
	const uint32_t *words = (uint32_t*) ctx->wbuffer;

	/* Operators defined in FIPS 180-2:4.1.2.  */
#define Ch(x, y, z) ((x & y) ^ (~x & z))
#define Maj(x, y, z) ((x & y) ^ (x & z) ^ (y & z))
#define S0(x) (rotr32(x, 2) ^ rotr32(x, 13) ^ rotr32(x, 22))
#define S1(x) (rotr32(x, 6) ^ rotr32(x, 11) ^ rotr32(x, 25))
#define R0(x) (rotr32(x, 7) ^ rotr32(x, 18) ^ (x >> 3))
#define R1(x) (rotr32(x, 17) ^ rotr32(x, 19) ^ (x >> 10))

	/* Compute the message schedule according to FIPS 180-2:6.2.2 step 2.  */
	for (t = 0; t < 16; ++t)
		W[t] = ntohl(words[t]);
	for (/*t = 16*/; t < 64; ++t)
		W[t] = R1(W[t - 2]) + W[t - 7] + R0(W[t - 15]) + W[t - 16];

	a = ctx->hash[0];
	b = ctx->hash[1];
	c = ctx->hash[2];
	d = ctx->hash[3];
	e = ctx->hash[4];
	f = ctx->hash[5];
	g = ctx->hash[6];
	h = ctx->hash[7];

	/* The actual computation according to FIPS 180-2:6.2.2 step 3.  */
	for (t = 0; t < 64; ++t) {
		/* Need to fetch upper half of sha_K[t]
		 * (I hope compiler is clever enough to just fetch
		 * upper half)
		 */
		uint32_t K_t = sha_K[t] >> 32;
		uint32_t T1 = h + S1(e) + Ch(e, f, g) + K_t + W[t];
		uint32_t T2 = S0(a) + Maj(a, b, c);
		h = g;
		g = f;
		f = e;
		e = d + T1;
		d = c;
		c = b;
		b = a;
		a = T1 + T2;
	}
#undef Ch
#undef Maj
#undef S0
#undef S1
#undef R0
#undef R1
	/* Add the starting values of the context according to FIPS 180-2:6.2.2
	   step 4.  */
	ctx->hash[0] += a;
	ctx->hash[1] += b;
	ctx->hash[2] += c;
	ctx->hash[3] += d;
	ctx->hash[4] += e;
	ctx->hash[5] += f;
	ctx->hash[6] += g;
	ctx->hash[7] += h;
}

static void FAST_FUNC sha512_process_block128(sha512_ctx_t *ctx)
{
	unsigned t;
	uint64_t W[80];
	/* On i386, having assignments here (not later as sha256 does)
	 * produces 99 bytes smaller code with gcc 4.3.1
	 */
	uint64_t a = ctx->hash[0];
	uint64_t b = ctx->hash[1];
	uint64_t c = ctx->hash[2];
	uint64_t d = ctx->hash[3];
	uint64_t e = ctx->hash[4];
	uint64_t f = ctx->hash[5];
	uint64_t g = ctx->hash[6];
	uint64_t h = ctx->hash[7];
	const uint64_t *words = (uint64_t*) ctx->wbuffer;

	/* Operators defined in FIPS 180-2:4.1.2.  */
#define Ch(x, y, z) ((x & y) ^ (~x & z))
#define Maj(x, y, z) ((x & y) ^ (x & z) ^ (y & z))
#define S0(x) (rotr64(x, 28) ^ rotr64(x, 34) ^ rotr64(x, 39))
#define S1(x) (rotr64(x, 14) ^ rotr64(x, 18) ^ rotr64(x, 41))
#define R0(x) (rotr64(x, 1) ^ rotr64(x, 8) ^ (x >> 7))
#define R1(x) (rotr64(x, 19) ^ rotr64(x, 61) ^ (x >> 6))

	/* Compute the message schedule according to FIPS 180-2:6.3.2 step 2.  */
	for (t = 0; t < 16; ++t)
		W[t] = ntoh64(words[t]);
	for (/*t = 16*/; t < 80; ++t)
		W[t] = R1(W[t - 2]) + W[t - 7] + R0(W[t - 15]) + W[t - 16];

	/* The actual computation according to FIPS 180-2:6.3.2 step 3.  */
	for (t = 0; t < 80; ++t) {
		uint64_t T1 = h + S1(e) + Ch(e, f, g) + sha_K[t] + W[t];
		uint64_t T2 = S0(a) + Maj(a, b, c);
		h = g;
		g = f;
		f = e;
		e = d + T1;
		d = c;
		c = b;
		b = a;
		a = T1 + T2;
	}
#undef Ch
#undef Maj
#undef S0
#undef S1
#undef R0
#undef R1
	/* Add the starting values of the context according to FIPS 180-2:6.3.2
	   step 4.  */
	ctx->hash[0] += a;
	ctx->hash[1] += b;
	ctx->hash[2] += c;
	ctx->hash[3] += d;
	ctx->hash[4] += e;
	ctx->hash[5] += f;
	ctx->hash[6] += g;
	ctx->hash[7] += h;
}


void FAST_FUNC sha1_begin(sha1_ctx_t *ctx)
{
	ctx->hash[0] = 0x67452301;
	ctx->hash[1] = 0xefcdab89;
	ctx->hash[2] = 0x98badcfe;
	ctx->hash[3] = 0x10325476;
	ctx->hash[4] = 0xc3d2e1f0;
	ctx->total64 = 0;
	ctx->process_block = sha1_process_block64;
}

static const uint32_t init256[] = {
	0x6a09e667,
	0xbb67ae85,
	0x3c6ef372,
	0xa54ff53a,
	0x510e527f,
	0x9b05688c,
	0x1f83d9ab,
	0x5be0cd19,
	0,
	0,
};
static const uint32_t init512_lo[] = {
	0xf3bcc908,
	0x84caa73b,
	0xfe94f82b,
	0x5f1d36f1,
	0xade682d1,
	0x2b3e6c1f,
	0xfb41bd6b,
	0x137e2179,
	0,
	0,
};

/* Initialize structure containing state of computation.
   (FIPS 180-2:5.3.2)  */
void FAST_FUNC sha256_begin(sha256_ctx_t *ctx)
{
	memcpy(ctx->hash, init256, sizeof(init256));
	/*ctx->total64 = 0; - done by extending init256 with two 32-bit zeros */
	ctx->process_block = sha256_process_block64;
}

/* Initialize structure containing state of computation.
   (FIPS 180-2:5.3.3)  */
void FAST_FUNC sha512_begin(sha512_ctx_t *ctx)
{
	int i;
	/* Two extra iterations zero out ctx->total64[] */
	for (i = 0; i < 8+2; i++)
		ctx->hash[i] = ((uint64_t)(init256[i]) << 32) + init512_lo[i];
	/*ctx->total64[0] = ctx->total64[1] = 0; - already done */
}


/* Used also for sha256 */
void FAST_FUNC sha1_hash(sha1_ctx_t *ctx, const void *buffer, size_t len)
{
	unsigned bufpos = ctx->total64 & 63;
	unsigned remaining;

	ctx->total64 += len;
#if 0
	remaining = 64 - bufpos;

	/* Hash whole blocks */
	while (len >= remaining) {
		memcpy(ctx->wbuffer + bufpos, buffer, remaining);
		buffer = (const char *)buffer + remaining;
		len -= remaining;
		remaining = 64;
		bufpos = 0;
		ctx->process_block(ctx);
	}

	/* Save last, partial blosk */
	memcpy(ctx->wbuffer + bufpos, buffer, len);
#else
	/* Tiny bit smaller code */
	while (1) {
		remaining = 64 - bufpos;
		if (remaining > len)
			remaining = len;
		/* Copy data into aligned buffer */
		memcpy(ctx->wbuffer + bufpos, buffer, remaining);
		len -= remaining;
		buffer = (const char *)buffer + remaining;
		bufpos += remaining;
		/* clever way to do "if (bufpos != 64) break; ... ; bufpos = 0;" */
		bufpos -= 64;
		if (bufpos != 0)
			break;
		/* Buffer is filled up, process it */
		ctx->process_block(ctx);
		/*bufpos = 0; - already is */
	}
#endif
}

void FAST_FUNC sha512_hash(sha512_ctx_t *ctx, const void *buffer, size_t len)
{
	unsigned bufpos = ctx->total64[0] & 127;
	unsigned remaining;

	/* First increment the byte count.  FIPS 180-2 specifies the possible
	   length of the file up to 2^128 _bits_.
	   We compute the number of _bytes_ and convert to bits later.  */
	ctx->total64[0] += len;
	if (ctx->total64[0] < len)
		ctx->total64[1]++;
#if 0
	remaining = 128 - bufpos;

	/* Hash whole blocks */
	while (len >= remaining) {
		memcpy(ctx->wbuffer + bufpos, buffer, remaining);
		buffer = (const char *)buffer + remaining;
		len -= remaining;
		remaining = 128;
		bufpos = 0;
		sha512_process_block128(ctx);
	}

	/* Save last, partial blosk */
	memcpy(ctx->wbuffer + bufpos, buffer, len);
#else
	while (1) {
		remaining = 128 - bufpos;
		if (remaining > len)
			remaining = len;
		/* Copy data into aligned buffer */
		memcpy(ctx->wbuffer + bufpos, buffer, remaining);
		len -= remaining;
		buffer = (const char *)buffer + remaining;
		bufpos += remaining;
		/* clever way to do "if (bufpos != 128) break; ... ; bufpos = 0;" */
		bufpos -= 128;
		if (bufpos != 0)
			break;
		/* Buffer is filled up, process it */
		sha512_process_block128(ctx);
		/*bufpos = 0; - already is */
	}
#endif
}


/* Used also for sha256 */
void FAST_FUNC sha1_end(sha1_ctx_t *ctx, void *resbuf)
{
	unsigned bufpos = ctx->total64 & 63;

	/* Pad the buffer to the next 64-byte boundary with 0x80,0,0,0... */
	ctx->wbuffer[bufpos++] = 0x80;

	/* This loop iterates either once or twice, no more, no less */
	while (1) {
		unsigned remaining = 64 - bufpos;
		memset(ctx->wbuffer + bufpos, 0, remaining);
		/* Do we have enough space for the length count? */
		if (remaining >= 8) {
			/* Store the 64-bit counter of bits in the buffer in BE format */
			uint64_t t = ctx->total64 << 3;
			t = hton64(t);
			/* wbuffer is suitably aligned for this */
			*(uint64_t *) (&ctx->wbuffer[64 - 8]) = t;
		}
		ctx->process_block(ctx);
		if (remaining >= 8)
			break;
		bufpos = 0;
	}

	bufpos = (ctx->process_block == sha1_process_block64) ? 5 : 8;
	/* This way we do not impose alignment constraints on resbuf: */
	if (BB_LITTLE_ENDIAN) {
		unsigned i;
		for (i = 0; i < bufpos; ++i)
			ctx->hash[i] = htonl(ctx->hash[i]);
	}
	memcpy(resbuf, ctx->hash, sizeof(ctx->hash[0]) * bufpos);
}

void FAST_FUNC sha512_end(sha512_ctx_t *ctx, void *resbuf)
{
	unsigned bufpos = ctx->total64[0] & 127;

	/* Pad the buffer to the next 128-byte boundary with 0x80,0,0,0... */
	ctx->wbuffer[bufpos++] = 0x80;

	while (1) {
		unsigned remaining = 128 - bufpos;
		memset(ctx->wbuffer + bufpos, 0, remaining);
		if (remaining >= 16) {
			/* Store the 128-bit counter of bits in the buffer in BE format */
			uint64_t t;
			t = ctx->total64[0] << 3;
			t = hton64(t);
			*(uint64_t *) (&ctx->wbuffer[128 - 8]) = t;
			t = (ctx->total64[1] << 3) | (ctx->total64[0] >> 61);
			t = hton64(t);
			*(uint64_t *) (&ctx->wbuffer[128 - 16]) = t;
		}
		sha512_process_block128(ctx);
		if (remaining >= 16)
			break;
		bufpos = 0;
	}

	if (BB_LITTLE_ENDIAN) {
		unsigned i;
		for (i = 0; i < ARRAY_SIZE(ctx->hash); ++i)
			ctx->hash[i] = hton64(ctx->hash[i]);
	}
	memcpy(resbuf, ctx->hash, sizeof(ctx->hash));
}