1 ///////////////////////////////////////////////////////////////////////////////
2 //
3 /// \file sha256.c
4 /// \brief SHA-256
5 ///
6 /// \todo Crypto++ has x86 ASM optimizations. They use SSE so if they
7 /// are imported to liblzma, SSE instructions need to be used
8 /// conditionally to keep the code working on older boxes.
9 //
10 // This code is based on the code found from 7-Zip, which has a modified
11 // version of the SHA-256 found from Crypto++ <https://www.cryptopp.com/>.
12 // The code was modified a little to fit into liblzma.
13 //
14 // Authors: Kevin Springle
15 // Wei Dai
16 // Igor Pavlov
17 // Lasse Collin
18 //
19 // This file has been put into the public domain.
20 // You can do whatever you want with this file.
21 //
22 ///////////////////////////////////////////////////////////////////////////////
23
24 #include "check.h"
25
26 // Rotate a uint32_t. GCC can optimize this to a rotate instruction
27 // at least on x86.
28 static inline uint32_t
29 rotr_32(uint32_t num, unsigned amount)
30 {
31 return (num >> amount) | (num << (32 - amount));
32 }
33
34 #define blk0(i) (W[i] = conv32be(data[i]))
35 #define blk2(i) (W[i & 15] += s1(W[(i - 2) & 15]) + W[(i - 7) & 15] \
36 + s0(W[(i - 15) & 15]))
37
38 #define Ch(x, y, z) (z ^ (x & (y ^ z)))
39 #define Maj(x, y, z) ((x & (y ^ z)) + (y & z))
40
41 #define a(i) T[(0 - i) & 7]
42 #define b(i) T[(1 - i) & 7]
43 #define c(i) T[(2 - i) & 7]
44 #define d(i) T[(3 - i) & 7]
45 #define e(i) T[(4 - i) & 7]
46 #define f(i) T[(5 - i) & 7]
47 #define g(i) T[(6 - i) & 7]
48 #define h(i) T[(7 - i) & 7]
49
50 #define R(i, j, blk) \
51 h(i) += S1(e(i)) + Ch(e(i), f(i), g(i)) + SHA256_K[i + j] + blk; \
52 d(i) += h(i); \
53 h(i) += S0(a(i)) + Maj(a(i), b(i), c(i))
54 #define R0(i) R(i, 0, blk0(i))
55 #define R2(i) R(i, j, blk2(i))
56
57 #define S0(x) rotr_32(x ^ rotr_32(x ^ rotr_32(x, 9), 11), 2)
58 #define S1(x) rotr_32(x ^ rotr_32(x ^ rotr_32(x, 14), 5), 6)
59 #define s0(x) (rotr_32(x ^ rotr_32(x, 11), 7) ^ (x >> 3))
60 #define s1(x) (rotr_32(x ^ rotr_32(x, 2), 17) ^ (x >> 10))
61
62
63 static const uint32_t SHA256_K[64] = {
64 0x428A2F98, 0x71374491, 0xB5C0FBCF, 0xE9B5DBA5,
65 0x3956C25B, 0x59F111F1, 0x923F82A4, 0xAB1C5ED5,
66 0xD807AA98, 0x12835B01, 0x243185BE, 0x550C7DC3,
67 0x72BE5D74, 0x80DEB1FE, 0x9BDC06A7, 0xC19BF174,
68 0xE49B69C1, 0xEFBE4786, 0x0FC19DC6, 0x240CA1CC,
69 0x2DE92C6F, 0x4A7484AA, 0x5CB0A9DC, 0x76F988DA,
70 0x983E5152, 0xA831C66D, 0xB00327C8, 0xBF597FC7,
71 0xC6E00BF3, 0xD5A79147, 0x06CA6351, 0x14292967,
72 0x27B70A85, 0x2E1B2138, 0x4D2C6DFC, 0x53380D13,
73 0x650A7354, 0x766A0ABB, 0x81C2C92E, 0x92722C85,
74 0xA2BFE8A1, 0xA81A664B, 0xC24B8B70, 0xC76C51A3,
75 0xD192E819, 0xD6990624, 0xF40E3585, 0x106AA070,
76 0x19A4C116, 0x1E376C08, 0x2748774C, 0x34B0BCB5,
77 0x391C0CB3, 0x4ED8AA4A, 0x5B9CCA4F, 0x682E6FF3,
78 0x748F82EE, 0x78A5636F, 0x84C87814, 0x8CC70208,
79 0x90BEFFFA, 0xA4506CEB, 0xBEF9A3F7, 0xC67178F2,
80 };
81
82
83 static void
84 transform(uint32_t state[8], const uint32_t data[16])
85 {
86 uint32_t W[16];
87 uint32_t T[8];
88
89 // Copy state[] to working vars.
90 memcpy(T, state, sizeof(T));
91
92 // The first 16 operations unrolled
93 R0( 0); R0( 1); R0( 2); R0( 3);
94 R0( 4); R0( 5); R0( 6); R0( 7);
95 R0( 8); R0( 9); R0(10); R0(11);
96 R0(12); R0(13); R0(14); R0(15);
97
98 // The remaining 48 operations partially unrolled
99 for (unsigned int j = 16; j < 64; j += 16) {
100 R2( 0); R2( 1); R2( 2); R2( 3);
101 R2( 4); R2( 5); R2( 6); R2( 7);
102 R2( 8); R2( 9); R2(10); R2(11);
103 R2(12); R2(13); R2(14); R2(15);
104 }
105
106 // Add the working vars back into state[].
107 state[0] += a(0);
108 state[1] += b(0);
109 state[2] += c(0);
110 state[3] += d(0);
111 state[4] += e(0);
112 state[5] += f(0);
113 state[6] += g(0);
114 state[7] += h(0);
115 }
116
117
118 static void
119 process(lzma_check_state *check)
120 {
121 transform(check->state.sha256.state, check->buffer.u32);
122 return;
123 }
124
125
126 extern void
127 lzma_sha256_init(lzma_check_state *check)
128 {
129 static const uint32_t s[8] = {
130 0x6A09E667, 0xBB67AE85, 0x3C6EF372, 0xA54FF53A,
131 0x510E527F, 0x9B05688C, 0x1F83D9AB, 0x5BE0CD19,
132 };
133
134 memcpy(check->state.sha256.state, s, sizeof(s));
135 check->state.sha256.size = 0;
136
137 return;
138 }
139
140
141 extern void
142 lzma_sha256_update(const uint8_t *buf, size_t size, lzma_check_state *check)
143 {
144 // Copy the input data into a properly aligned temporary buffer.
145 // This way we can be called with arbitrarily sized buffers
146 // (no need to be multiple of 64 bytes), and the code works also
147 // on architectures that don't allow unaligned memory access.
148 while (size > 0) {
149 const size_t copy_start = check->state.sha256.size & 0x3F;
150 size_t copy_size = 64 - copy_start;
151 if (copy_size > size)
152 copy_size = size;
153
154 memcpy(check->buffer.u8 + copy_start, buf, copy_size);
155
156 buf += copy_size;
157 size -= copy_size;
158 check->state.sha256.size += copy_size;
159
160 if ((check->state.sha256.size & 0x3F) == 0)
161 process(check);
162 }
163
164 return;
165 }
166
167
168 extern void
169 lzma_sha256_finish(lzma_check_state *check)
170 {
171 // Add padding as described in RFC 3174 (it describes SHA-1 but
172 // the same padding style is used for SHA-256 too).
173 size_t pos = check->state.sha256.size & 0x3F;
174 check->buffer.u8[pos++] = 0x80;
175
176 while (pos != 64 - 8) {
177 if (pos == 64) {
178 process(check);
179 pos = 0;
180 }
181
182 check->buffer.u8[pos++] = 0x00;
183 }
184
185 // Convert the message size from bytes to bits.
186 check->state.sha256.size *= 8;
187
188 check->buffer.u64[(64 - 8) / 8] = conv64be(check->state.sha256.size);
189
190 process(check);
191
192 for (size_t i = 0; i < 8; ++i)
193 check->buffer.u32[i] = conv32be(check->state.sha256.state[i]);
194
195 return;
196 }