crypto: sm3 - create SM3 stand-alone library

Stand-alone implementation of the SM3 algorithm. It is designed
to have as little dependencies as possible. In other cases you
should generally use the hash APIs from include/crypto/hash.h.
Especially when hashing large amounts of data as those APIs may
be hw-accelerated. In the new SM3 stand-alone library,
sm3_transform() has also been optimized, instead of simply using
the code in sm3_generic.

Signed-off-by: Tianjia Zhang <[e-mail]>
Reviewed-by: Gilad Ben-Yossef <[e-mail]>
Signed-off-by: Herbert Xu <[e-mail]>

include/crypto/sm3.h

···
+/* SPDX-License-Identifier: GPL-2.0-only */
 /*
  * Common values for SM3 algorithm
+ *
+ * Copyright (C) 2017 ARM Limited or its affiliates.
+ * Copyright (C) 2017 Gilad Ben-Yossef <[e-mail]>
+ * Copyright (C) 2021 Tianjia Zhang <[e-mail]>
  */
 
 #ifndef _CRYPTO_SM3_H
···
 
 extern int crypto_sm3_finup(struct shash_desc *desc, const u8 *data,
 			     unsigned int len, u8 *hash);
+
+/*
+ * Stand-alone implementation of the SM3 algorithm. It is designed to
+ * have as little dependencies as possible so it can be used in the
+ * kexec_file purgatory. In other cases you should generally use the
+ * hash APIs from include/crypto/hash.h. Especially when hashing large
+ * amounts of data as those APIs may be hw-accelerated.
+ *
+ * For details see lib/crypto/sm3.c
+ */
+
+static inline void sm3_init(struct sm3_state *sctx)
+{
+	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_state *sctx, const u8 *data, unsigned int len);
+void sm3_final(struct sm3_state *sctx, u8 *out);
+
 #endif

lib/crypto/Kconfig

···
 config CRYPTO_LIB_SHA256
 	tristate
 
+config CRYPTO_LIB_SM3
+	tristate
+
 config CRYPTO_LIB_SM4
 	tristate
 

lib/crypto/Makefile

···
 obj-$(CONFIG_CRYPTO_LIB_SHA256)			+= libsha256.o
 libsha256-y					:= sha256.o
 
+obj-$(CONFIG_CRYPTO_LIB_SM3)			+= libsm3.o
+libsm3-y					:= sm3.o
+
 obj-$(CONFIG_CRYPTO_LIB_SM4)			+= libsm4.o
 libsm4-y					:= sm4.o
 

lib/crypto/sm3.c

···
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * 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) 2017 ARM Limited or its affiliates.
+ * Copyright (C) 2017 Gilad Ben-Yossef <[e-mail]>
+ * Copyright (C) 2021 Tianjia Zhang <[e-mail]>
+ */
+
+#include <linux/module.h>
+#include <asm/unaligned.h>
+#include <crypto/sm3.h>
+
+static const u32 ____cacheline_aligned 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_state *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_state *sctx,
+		u8 const *data, int blocks, u32 W[16])
+{
+	while (blocks--) {
+		sm3_transform(sctx, data, W);
+		data += SM3_BLOCK_SIZE;
+	}
+}
+
+void sm3_update(struct sm3_state *sctx, const u8 *data, unsigned int len)
+{
+	unsigned int partial = sctx->count % SM3_BLOCK_SIZE;
+	u32 W[16];
+
+	sctx->count += len;
+
+	if ((partial + len) >= SM3_BLOCK_SIZE) {
+		int blocks;
+
+		if (partial) {
+			int p = SM3_BLOCK_SIZE - partial;
+
+			memcpy(sctx->buffer + partial, data, p);
+			data += p;
+			len -= p;
+
+			sm3_block(sctx, sctx->buffer, 1, W);
+		}
+
+		blocks = len / SM3_BLOCK_SIZE;
+		len %= SM3_BLOCK_SIZE;
+
+		if (blocks) {
+			sm3_block(sctx, data, blocks, W);
+			data += blocks * SM3_BLOCK_SIZE;
+		}
+
+		memzero_explicit(W, sizeof(W));
+
+		partial = 0;
+	}
+	if (len)
+		memcpy(sctx->buffer + partial, data, len);
+}
+EXPORT_SYMBOL_GPL(sm3_update);
+
+void sm3_final(struct sm3_state *sctx, u8 *out)
+{
+	const int bit_offset = SM3_BLOCK_SIZE - sizeof(u64);
+	__be64 *bits = (__be64 *)(sctx->buffer + bit_offset);
+	__be32 *digest = (__be32 *)out;
+	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);
+		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. */
+	memzero_explicit(W, sizeof(W));
+	memzero_explicit(sctx, sizeof(*sctx));
+}
+EXPORT_SYMBOL_GPL(sm3_final);
+
+MODULE_DESCRIPTION("Generic SM3 library");
+MODULE_LICENSE("GPL v2");