path: root/lib/sm3.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * SM3_256 Hash Algorithm Implementation for U-Boot
 * based on linux implementation:
 *
 * f83a4f2a4d8c
 *  Merge tag 'erofs-for-6.17-rc6-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/xiang/erofs
 *
 * SM3 secure hash, as specified by OSCCA GM/T 0004-2012 SM3 and described
 * at https://datatracker.ietf.org/doc/html/draft-sca-cfrg-sm3-02
 *
 * Copyright (c) 2025 Heiko Schocher <[email protected]>
 */

#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#include <asm/unaligned.h>
#include <linux/bitops.h>

#include <u-boot/sm3.h>
#ifndef USE_HOSTCC
#include <u-boot/schedule.h>
#endif

static const u32 K[64] = {
	0x79cc4519, 0xf3988a32, 0xe7311465, 0xce6228cb,
	0x9cc45197, 0x3988a32f, 0x7311465e, 0xe6228cbc,
	0xcc451979, 0x988a32f3, 0x311465e7, 0x6228cbce,
	0xc451979c, 0x88a32f39, 0x11465e73, 0x228cbce6,
	0x9d8a7a87, 0x3b14f50f, 0x7629ea1e, 0xec53d43c,
	0xd8a7a879, 0xb14f50f3, 0x629ea1e7, 0xc53d43ce,
	0x8a7a879d, 0x14f50f3b, 0x29ea1e76, 0x53d43cec,
	0xa7a879d8, 0x4f50f3b1, 0x9ea1e762, 0x3d43cec5,
	0x7a879d8a, 0xf50f3b14, 0xea1e7629, 0xd43cec53,
	0xa879d8a7, 0x50f3b14f, 0xa1e7629e, 0x43cec53d,
	0x879d8a7a, 0x0f3b14f5, 0x1e7629ea, 0x3cec53d4,
	0x79d8a7a8, 0xf3b14f50, 0xe7629ea1, 0xcec53d43,
	0x9d8a7a87, 0x3b14f50f, 0x7629ea1e, 0xec53d43c,
	0xd8a7a879, 0xb14f50f3, 0x629ea1e7, 0xc53d43ce,
	0x8a7a879d, 0x14f50f3b, 0x29ea1e76, 0x53d43cec,
	0xa7a879d8, 0x4f50f3b1, 0x9ea1e762, 0x3d43cec5
};

/*
 * Transform the message X which consists of 16 32-bit-words. See
 * GM/T 004-2012 for details.
 */
#define R(i, a, b, c, d, e, f, g, h, t, w1, w2)			\
	do {							\
		ss1 = rol32((rol32((a), 12) + (e) + (t)), 7);	\
		ss2 = ss1 ^ rol32((a), 12);			\
		d += FF ## i(a, b, c) + ss2 + ((w1) ^ (w2));	\
		h += GG ## i(e, f, g) + ss1 + (w1);		\
		b = rol32((b), 9);				\
		f = rol32((f), 19);				\
		h = P0((h));					\
	} while (0)

#define R1(a, b, c, d, e, f, g, h, t, w1, w2) \
	R(1, a, b, c, d, e, f, g, h, t, w1, w2)
#define R2(a, b, c, d, e, f, g, h, t, w1, w2) \
	R(2, a, b, c, d, e, f, g, h, t, w1, w2)

#define FF1(x, y, z)  (x ^ y ^ z)
#define FF2(x, y, z)  ((x & y) | (x & z) | (y & z))

#define GG1(x, y, z)  FF1(x, y, z)
#define GG2(x, y, z)  ((x & y) | (~x & z))

/* Message expansion */
#define P0(x) ((x) ^ rol32((x), 9) ^ rol32((x), 17))
#define P1(x) ((x) ^ rol32((x), 15) ^ rol32((x), 23))
#define I(i)  (W[i] = get_unaligned_be32(data + i * 4))
#define W1(i) (W[i & 0x0f])
#define W2(i) (W[i & 0x0f] =				\
		P1(W[i & 0x0f]				\
			^ W[(i-9) & 0x0f]		\
			^ rol32(W[(i-3) & 0x0f], 15))	\
		^ rol32(W[(i-13) & 0x0f], 7)		\
		^ W[(i-6) & 0x0f])

static void sm3_transform(struct sm3_context *sctx, u8 const *data, u32 W[16])
{
	u32 a, b, c, d, e, f, g, h, ss1, ss2;

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

	R1(a, b, c, d, e, f, g, h, K[0], I(0), I(4));
	R1(d, a, b, c, h, e, f, g, K[1], I(1), I(5));
	R1(c, d, a, b, g, h, e, f, K[2], I(2), I(6));
	R1(b, c, d, a, f, g, h, e, K[3], I(3), I(7));
	R1(a, b, c, d, e, f, g, h, K[4], W1(4), I(8));
	R1(d, a, b, c, h, e, f, g, K[5], W1(5), I(9));
	R1(c, d, a, b, g, h, e, f, K[6], W1(6), I(10));
	R1(b, c, d, a, f, g, h, e, K[7], W1(7), I(11));
	R1(a, b, c, d, e, f, g, h, K[8], W1(8), I(12));
	R1(d, a, b, c, h, e, f, g, K[9], W1(9), I(13));
	R1(c, d, a, b, g, h, e, f, K[10], W1(10), I(14));
	R1(b, c, d, a, f, g, h, e, K[11], W1(11), I(15));
	R1(a, b, c, d, e, f, g, h, K[12], W1(12), W2(16));
	R1(d, a, b, c, h, e, f, g, K[13], W1(13), W2(17));
	R1(c, d, a, b, g, h, e, f, K[14], W1(14), W2(18));
	R1(b, c, d, a, f, g, h, e, K[15], W1(15), W2(19));

	R2(a, b, c, d, e, f, g, h, K[16], W1(16), W2(20));
	R2(d, a, b, c, h, e, f, g, K[17], W1(17), W2(21));
	R2(c, d, a, b, g, h, e, f, K[18], W1(18), W2(22));
	R2(b, c, d, a, f, g, h, e, K[19], W1(19), W2(23));
	R2(a, b, c, d, e, f, g, h, K[20], W1(20), W2(24));
	R2(d, a, b, c, h, e, f, g, K[21], W1(21), W2(25));
	R2(c, d, a, b, g, h, e, f, K[22], W1(22), W2(26));
	R2(b, c, d, a, f, g, h, e, K[23], W1(23), W2(27));
	R2(a, b, c, d, e, f, g, h, K[24], W1(24), W2(28));
	R2(d, a, b, c, h, e, f, g, K[25], W1(25), W2(29));
	R2(c, d, a, b, g, h, e, f, K[26], W1(26), W2(30));
	R2(b, c, d, a, f, g, h, e, K[27], W1(27), W2(31));
	R2(a, b, c, d, e, f, g, h, K[28], W1(28), W2(32));
	R2(d, a, b, c, h, e, f, g, K[29], W1(29), W2(33));
	R2(c, d, a, b, g, h, e, f, K[30], W1(30), W2(34));
	R2(b, c, d, a, f, g, h, e, K[31], W1(31), W2(35));

	R2(a, b, c, d, e, f, g, h, K[32], W1(32), W2(36));
	R2(d, a, b, c, h, e, f, g, K[33], W1(33), W2(37));
	R2(c, d, a, b, g, h, e, f, K[34], W1(34), W2(38));
	R2(b, c, d, a, f, g, h, e, K[35], W1(35), W2(39));
	R2(a, b, c, d, e, f, g, h, K[36], W1(36), W2(40));
	R2(d, a, b, c, h, e, f, g, K[37], W1(37), W2(41));
	R2(c, d, a, b, g, h, e, f, K[38], W1(38), W2(42));
	R2(b, c, d, a, f, g, h, e, K[39], W1(39), W2(43));
	R2(a, b, c, d, e, f, g, h, K[40], W1(40), W2(44));
	R2(d, a, b, c, h, e, f, g, K[41], W1(41), W2(45));
	R2(c, d, a, b, g, h, e, f, K[42], W1(42), W2(46));
	R2(b, c, d, a, f, g, h, e, K[43], W1(43), W2(47));
	R2(a, b, c, d, e, f, g, h, K[44], W1(44), W2(48));
	R2(d, a, b, c, h, e, f, g, K[45], W1(45), W2(49));
	R2(c, d, a, b, g, h, e, f, K[46], W1(46), W2(50));
	R2(b, c, d, a, f, g, h, e, K[47], W1(47), W2(51));

	R2(a, b, c, d, e, f, g, h, K[48], W1(48), W2(52));
	R2(d, a, b, c, h, e, f, g, K[49], W1(49), W2(53));
	R2(c, d, a, b, g, h, e, f, K[50], W1(50), W2(54));
	R2(b, c, d, a, f, g, h, e, K[51], W1(51), W2(55));
	R2(a, b, c, d, e, f, g, h, K[52], W1(52), W2(56));
	R2(d, a, b, c, h, e, f, g, K[53], W1(53), W2(57));
	R2(c, d, a, b, g, h, e, f, K[54], W1(54), W2(58));
	R2(b, c, d, a, f, g, h, e, K[55], W1(55), W2(59));
	R2(a, b, c, d, e, f, g, h, K[56], W1(56), W2(60));
	R2(d, a, b, c, h, e, f, g, K[57], W1(57), W2(61));
	R2(c, d, a, b, g, h, e, f, K[58], W1(58), W2(62));
	R2(b, c, d, a, f, g, h, e, K[59], W1(59), W2(63));
	R2(a, b, c, d, e, f, g, h, K[60], W1(60), W2(64));
	R2(d, a, b, c, h, e, f, g, K[61], W1(61), W2(65));
	R2(c, d, a, b, g, h, e, f, K[62], W1(62), W2(66));
	R2(b, c, d, a, f, g, h, e, K[63], W1(63), W2(67));

	sctx->state[0] ^= a;
	sctx->state[1] ^= b;
	sctx->state[2] ^= c;
	sctx->state[3] ^= d;
	sctx->state[4] ^= e;
	sctx->state[5] ^= f;
	sctx->state[6] ^= g;
	sctx->state[7] ^= h;
}
#undef R
#undef R1
#undef R2
#undef I
#undef W1
#undef W2

static inline void sm3_block(struct sm3_context *sctx,
		u8 const *data, int blocks, u32 W[16])
{
	while (blocks--) {
		sm3_transform(sctx, data, W);
		data += SM3_BLOCK_SIZE;
	}
}

void sm3_init(struct sm3_context *sctx)
{
	memset(sctx, 0, sizeof(*sctx));

	/* Load initial values */
	sctx->state[0] = SM3_IVA;
	sctx->state[1] = SM3_IVB;
	sctx->state[2] = SM3_IVC;
	sctx->state[3] = SM3_IVD;
	sctx->state[4] = SM3_IVE;
	sctx->state[5] = SM3_IVF;
	sctx->state[6] = SM3_IVG;
	sctx->state[7] = SM3_IVH;
	sctx->count = 0;
}

void sm3_update(struct sm3_context *sctx, const uint8_t *input, size_t ilen)
{
	unsigned int partial = sctx->count % SM3_BLOCK_SIZE;
	u32 W[16];

	sctx->count += ilen;

	if ((partial + ilen) >= SM3_BLOCK_SIZE) {
		int blocks;

		if (partial) {
			int p = SM3_BLOCK_SIZE - partial;

			memcpy(sctx->buffer + partial, input, p);
			input += p;
			ilen -= p;

			sm3_block(sctx, sctx->buffer, 1, W);
		}

		blocks = ilen / SM3_BLOCK_SIZE;
		ilen %= SM3_BLOCK_SIZE;

		if (blocks) {
			sm3_block(sctx, input, blocks, W);
			input += blocks * SM3_BLOCK_SIZE;
		}

		memset(W, 0, sizeof(W));

		partial = 0;
	}
	if (ilen)
		memcpy(sctx->buffer + partial, input, ilen);
}

void sm3_final(struct sm3_context *sctx, uint8_t output[SM3_DIGEST_SIZE])
{
	const int bit_offset = SM3_BLOCK_SIZE - sizeof(u64);
	__be64 *bits = (__be64 *)(sctx->buffer + bit_offset);
	__be32 *digest = (__be32 *)&output[0];
	unsigned int partial = sctx->count % SM3_BLOCK_SIZE;
	u32 W[16];
	int i;

	sctx->buffer[partial++] = 0x80;
	if (partial > bit_offset) {
		memset(sctx->buffer + partial, 0, SM3_BLOCK_SIZE - partial - 1);
		partial = 0;

		sm3_block(sctx, sctx->buffer, 1, W);
	}

	memset(sctx->buffer + partial, 0, bit_offset - partial);
	*bits = cpu_to_be64(sctx->count << 3);
	sm3_block(sctx, sctx->buffer, 1, W);

	for (i = 0; i < 8; i++)
		put_unaligned_be32(sctx->state[i], digest++);

	/* Zeroize sensitive information. */
	memset(W, 0, sizeof(W));
	memset(sctx, 0, sizeof(*sctx));
}

/**
 * sm3_hash - Calculate SM3 hash of input data
 * @input: Input data
 * @ilen: Input data length in bytes
 * @output: Output buffer for hash (32 bytes)
 */
void sm3_hash(const uint8_t *input, size_t ilen, uint8_t output[SM3_DIGEST_SIZE])
{
	struct sm3_context sctx;

	sm3_init(&sctx);
	sm3_update(&sctx, input, ilen);
	sm3_final(&sctx, output);
}

/**
 * sm3_csum_wd - Calculate SM3 checksum on memory region using watchdog
 * @addr: Starting address
 * @len: Length in bytes
 * @output: Output buffer for checksum (32 bytes)
 * @flags: Flags for watchdog behavior
 *
 * This is the U-Boot API entry function for SM3 hash calculation
 */
void sm3_csum_wd(const unsigned char *input, uint32_t len,
		 unsigned char *output, unsigned int chunk_sz)
{
	struct sm3_context ctx;
	uint32_t chunk;

	sm3_init(&ctx);

	/* Process data in chunks, kicking watchdog between chunks */
	while (len > 0) {
		chunk = (len > chunk_sz) ? chunk_sz : len;
		sm3_update(&ctx, input, chunk);
		input += chunk;
		len -= chunk;

		schedule();
	}
	sm3_final(&ctx, output);
}