1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * SHA-256, as specified in
4  * http://csrc.nist.gov/groups/STM/cavp/documents/shs/sha256-384-512.pdf
5  *
6  * SHA-256 code by Jean-Luc Cooke <jlcooke@certainkey.com>.
7  *
8  * Copyright (c) Jean-Luc Cooke <jlcooke@certainkey.com>
9  * Copyright (c) Andrew McDonald <andrew@mcdonald.org.uk>
10  * Copyright (c) 2002 James Morris <jmorris@intercode.com.au>
11  * Copyright (c) 2014 Red Hat Inc.
12  */
13 
14 #include <linux/bitops.h>
15 #include <linux/export.h>
16 #include <linux/module.h>
17 #include <linux/string.h>
18 #include <crypto/sha2.h>
19 #include <asm/unaligned.h>
20 
21 static const u32 SHA256_K[] = {
22 	0x428a2f98, 0x71374491, 0xb5c0fbcf, 0xe9b5dba5,
23 	0x3956c25b, 0x59f111f1, 0x923f82a4, 0xab1c5ed5,
24 	0xd807aa98, 0x12835b01, 0x243185be, 0x550c7dc3,
25 	0x72be5d74, 0x80deb1fe, 0x9bdc06a7, 0xc19bf174,
26 	0xe49b69c1, 0xefbe4786, 0x0fc19dc6, 0x240ca1cc,
27 	0x2de92c6f, 0x4a7484aa, 0x5cb0a9dc, 0x76f988da,
28 	0x983e5152, 0xa831c66d, 0xb00327c8, 0xbf597fc7,
29 	0xc6e00bf3, 0xd5a79147, 0x06ca6351, 0x14292967,
30 	0x27b70a85, 0x2e1b2138, 0x4d2c6dfc, 0x53380d13,
31 	0x650a7354, 0x766a0abb, 0x81c2c92e, 0x92722c85,
32 	0xa2bfe8a1, 0xa81a664b, 0xc24b8b70, 0xc76c51a3,
33 	0xd192e819, 0xd6990624, 0xf40e3585, 0x106aa070,
34 	0x19a4c116, 0x1e376c08, 0x2748774c, 0x34b0bcb5,
35 	0x391c0cb3, 0x4ed8aa4a, 0x5b9cca4f, 0x682e6ff3,
36 	0x748f82ee, 0x78a5636f, 0x84c87814, 0x8cc70208,
37 	0x90befffa, 0xa4506ceb, 0xbef9a3f7, 0xc67178f2,
38 };
39 
Ch(u32 x,u32 y,u32 z)40 static inline u32 Ch(u32 x, u32 y, u32 z)
41 {
42 	return z ^ (x & (y ^ z));
43 }
44 
Maj(u32 x,u32 y,u32 z)45 static inline u32 Maj(u32 x, u32 y, u32 z)
46 {
47 	return (x & y) | (z & (x | y));
48 }
49 
50 #define e0(x)       (ror32(x, 2) ^ ror32(x, 13) ^ ror32(x, 22))
51 #define e1(x)       (ror32(x, 6) ^ ror32(x, 11) ^ ror32(x, 25))
52 #define s0(x)       (ror32(x, 7) ^ ror32(x, 18) ^ (x >> 3))
53 #define s1(x)       (ror32(x, 17) ^ ror32(x, 19) ^ (x >> 10))
54 
LOAD_OP(int I,u32 * W,const u8 * input)55 static inline void LOAD_OP(int I, u32 *W, const u8 *input)
56 {
57 	W[I] = get_unaligned_be32((__u32 *)input + I);
58 }
59 
BLEND_OP(int I,u32 * W)60 static inline void BLEND_OP(int I, u32 *W)
61 {
62 	W[I] = s1(W[I-2]) + W[I-7] + s0(W[I-15]) + W[I-16];
63 }
64 
65 #define SHA256_ROUND(i, a, b, c, d, e, f, g, h) do {		\
66 	u32 t1, t2;						\
67 	t1 = h + e1(e) + Ch(e, f, g) + SHA256_K[i] + W[i];	\
68 	t2 = e0(a) + Maj(a, b, c);				\
69 	d += t1;						\
70 	h = t1 + t2;						\
71 } while (0)
72 
sha256_transform(u32 * state,const u8 * input,u32 * W)73 static void sha256_transform(u32 *state, const u8 *input, u32 *W)
74 {
75 	u32 a, b, c, d, e, f, g, h;
76 	int i;
77 
78 	/* load the input */
79 	for (i = 0; i < 16; i += 8) {
80 		LOAD_OP(i + 0, W, input);
81 		LOAD_OP(i + 1, W, input);
82 		LOAD_OP(i + 2, W, input);
83 		LOAD_OP(i + 3, W, input);
84 		LOAD_OP(i + 4, W, input);
85 		LOAD_OP(i + 5, W, input);
86 		LOAD_OP(i + 6, W, input);
87 		LOAD_OP(i + 7, W, input);
88 	}
89 
90 	/* now blend */
91 	for (i = 16; i < 64; i += 8) {
92 		BLEND_OP(i + 0, W);
93 		BLEND_OP(i + 1, W);
94 		BLEND_OP(i + 2, W);
95 		BLEND_OP(i + 3, W);
96 		BLEND_OP(i + 4, W);
97 		BLEND_OP(i + 5, W);
98 		BLEND_OP(i + 6, W);
99 		BLEND_OP(i + 7, W);
100 	}
101 
102 	/* load the state into our registers */
103 	a = state[0];  b = state[1];  c = state[2];  d = state[3];
104 	e = state[4];  f = state[5];  g = state[6];  h = state[7];
105 
106 	/* now iterate */
107 	for (i = 0; i < 64; i += 8) {
108 		SHA256_ROUND(i + 0, a, b, c, d, e, f, g, h);
109 		SHA256_ROUND(i + 1, h, a, b, c, d, e, f, g);
110 		SHA256_ROUND(i + 2, g, h, a, b, c, d, e, f);
111 		SHA256_ROUND(i + 3, f, g, h, a, b, c, d, e);
112 		SHA256_ROUND(i + 4, e, f, g, h, a, b, c, d);
113 		SHA256_ROUND(i + 5, d, e, f, g, h, a, b, c);
114 		SHA256_ROUND(i + 6, c, d, e, f, g, h, a, b);
115 		SHA256_ROUND(i + 7, b, c, d, e, f, g, h, a);
116 	}
117 
118 	state[0] += a; state[1] += b; state[2] += c; state[3] += d;
119 	state[4] += e; state[5] += f; state[6] += g; state[7] += h;
120 }
121 
sha256_update(struct sha256_state * sctx,const u8 * data,unsigned int len)122 void sha256_update(struct sha256_state *sctx, const u8 *data, unsigned int len)
123 {
124 	unsigned int partial, done;
125 	const u8 *src;
126 	u32 W[64];
127 
128 	partial = sctx->count & 0x3f;
129 	sctx->count += len;
130 	done = 0;
131 	src = data;
132 
133 	if ((partial + len) > 63) {
134 		if (partial) {
135 			done = -partial;
136 			memcpy(sctx->buf + partial, data, done + 64);
137 			src = sctx->buf;
138 		}
139 
140 		do {
141 			sha256_transform(sctx->state, src, W);
142 			done += 64;
143 			src = data + done;
144 		} while (done + 63 < len);
145 
146 		memzero_explicit(W, sizeof(W));
147 
148 		partial = 0;
149 	}
150 	memcpy(sctx->buf + partial, src, len - done);
151 }
152 EXPORT_SYMBOL(sha256_update);
153 
sha224_update(struct sha256_state * sctx,const u8 * data,unsigned int len)154 void sha224_update(struct sha256_state *sctx, const u8 *data, unsigned int len)
155 {
156 	sha256_update(sctx, data, len);
157 }
158 EXPORT_SYMBOL(sha224_update);
159 
__sha256_final(struct sha256_state * sctx,u8 * out,int digest_words)160 static void __sha256_final(struct sha256_state *sctx, u8 *out, int digest_words)
161 {
162 	__be32 *dst = (__be32 *)out;
163 	__be64 bits;
164 	unsigned int index, pad_len;
165 	int i;
166 	static const u8 padding[64] = { 0x80, };
167 
168 	/* Save number of bits */
169 	bits = cpu_to_be64(sctx->count << 3);
170 
171 	/* Pad out to 56 mod 64. */
172 	index = sctx->count & 0x3f;
173 	pad_len = (index < 56) ? (56 - index) : ((64+56) - index);
174 	sha256_update(sctx, padding, pad_len);
175 
176 	/* Append length (before padding) */
177 	sha256_update(sctx, (const u8 *)&bits, sizeof(bits));
178 
179 	/* Store state in digest */
180 	for (i = 0; i < digest_words; i++)
181 		put_unaligned_be32(sctx->state[i], &dst[i]);
182 
183 	/* Zeroize sensitive information. */
184 	memzero_explicit(sctx, sizeof(*sctx));
185 }
186 
sha256_final(struct sha256_state * sctx,u8 * out)187 void sha256_final(struct sha256_state *sctx, u8 *out)
188 {
189 	__sha256_final(sctx, out, 8);
190 }
191 EXPORT_SYMBOL(sha256_final);
192 
sha224_final(struct sha256_state * sctx,u8 * out)193 void sha224_final(struct sha256_state *sctx, u8 *out)
194 {
195 	__sha256_final(sctx, out, 7);
196 }
197 EXPORT_SYMBOL(sha224_final);
198 
sha256(const u8 * data,unsigned int len,u8 * out)199 void sha256(const u8 *data, unsigned int len, u8 *out)
200 {
201 	struct sha256_state sctx;
202 
203 	sha256_init(&sctx);
204 	sha256_update(&sctx, data, len);
205 	sha256_final(&sctx, out);
206 }
207 EXPORT_SYMBOL(sha256);
208 
209 MODULE_LICENSE("GPL");
210