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 /// We could also support using some external libary for SHA-256. 10 // 11 // This code is based on the code found from 7-Zip, which has a modified 12 // version of the SHA-256 found from Crypto++ <http://www.cryptopp.com/>. 13 // The code was modified a little to fit into liblzma. 14 // 15 // Authors: Kevin Springle 16 // Wei Dai 17 // Igor Pavlov 18 // Lasse Collin 19 // 20 // This file has been put into the public domain. 21 // You can do whatever you want with this file. 22 // 23 /////////////////////////////////////////////////////////////////////////////// 24 25 // Avoid bogus warnings in transform(). 26 #if (__GNUC__ == 4 && __GNUC_MINOR__ >= 2) || __GNUC__ > 4 27 # pragma GCC diagnostic ignored "-Wuninitialized" 28 #endif 29 30 #include "check.h" 31 32 // At least on x86, GCC is able to optimize this to a rotate instruction. 33 #define rotr_32(num, amount) ((num) >> (amount) | (num) << (32 - (amount))) 34 35 #define blk0(i) (W[i] = data[i]) 36 #define blk2(i) (W[i & 15] += s1(W[(i - 2) & 15]) + W[(i - 7) & 15] \ 37 + s0(W[(i - 15) & 15])) 38 39 #define Ch(x, y, z) (z ^ (x & (y ^ z))) 40 #define Maj(x, y, z) ((x & y) | (z & (x | y))) 41 42 #define a(i) T[(0 - i) & 7] 43 #define b(i) T[(1 - i) & 7] 44 #define c(i) T[(2 - i) & 7] 45 #define d(i) T[(3 - i) & 7] 46 #define e(i) T[(4 - i) & 7] 47 #define f(i) T[(5 - i) & 7] 48 #define g(i) T[(6 - i) & 7] 49 #define h(i) T[(7 - i) & 7] 50 51 #define R(i) \ 52 h(i) += S1(e(i)) + Ch(e(i), f(i), g(i)) + SHA256_K[i + j] \ 53 + (j ? blk2(i) : blk0(i)); \ 54 d(i) += h(i); \ 55 h(i) += S0(a(i)) + Maj(a(i), b(i), c(i)) 56 57 #define S0(x) (rotr_32(x, 2) ^ rotr_32(x, 13) ^ rotr_32(x, 22)) 58 #define S1(x) (rotr_32(x, 6) ^ rotr_32(x, 11) ^ rotr_32(x, 25)) 59 #define s0(x) (rotr_32(x, 7) ^ rotr_32(x, 18) ^ (x >> 3)) 60 #define s1(x) (rotr_32(x, 17) ^ rotr_32(x, 19) ^ (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[static 8], const uint32_t data[static 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 // 64 operations, partially loop unrolled 93 for (unsigned int j = 0; j < 64; j += 16) { 94 R( 0); R( 1); R( 2); R( 3); 95 R( 4); R( 5); R( 6); R( 7); 96 R( 8); R( 9); R(10); R(11); 97 R(12); R(13); R(14); R(15); 98 } 99 100 // Add the working vars back into state[]. 101 state[0] += a(0); 102 state[1] += b(0); 103 state[2] += c(0); 104 state[3] += d(0); 105 state[4] += e(0); 106 state[5] += f(0); 107 state[6] += g(0); 108 state[7] += h(0); 109 } 110 111 112 static void 113 process(lzma_check_state *check) 114 { 115 #ifdef WORDS_BIGENDIAN 116 transform(check->state.sha256.state, check->buffer.u32); 117 118 #else 119 uint32_t data[16]; 120 121 for (size_t i = 0; i < 16; ++i) 122 data[i] = bswap32(check->buffer.u32[i]); 123 124 transform(check->state.sha256.state, data); 125 #endif 126 127 return; 128 } 129 130 131 extern void 132 lzma_sha256_init(lzma_check_state *check) 133 { 134 static const uint32_t s[8] = { 135 0x6A09E667, 0xBB67AE85, 0x3C6EF372, 0xA54FF53A, 136 0x510E527F, 0x9B05688C, 0x1F83D9AB, 0x5BE0CD19, 137 }; 138 139 memcpy(check->state.sha256.state, s, sizeof(s)); 140 check->state.sha256.size = 0; 141 142 return; 143 } 144 145 146 extern void 147 lzma_sha256_update(const uint8_t *buf, size_t size, lzma_check_state *check) 148 { 149 // Copy the input data into a properly aligned temporary buffer. 150 // This way we can be called with arbitrarily sized buffers 151 // (no need to be multiple of 64 bytes), and the code works also 152 // on architectures that don't allow unaligned memory access. 153 while (size > 0) { 154 const size_t copy_start = check->state.sha256.size & 0x3F; 155 size_t copy_size = 64 - copy_start; 156 if (copy_size > size) 157 copy_size = size; 158 159 memcpy(check->buffer.u8 + copy_start, buf, copy_size); 160 161 buf += copy_size; 162 size -= copy_size; 163 check->state.sha256.size += copy_size; 164 165 if ((check->state.sha256.size & 0x3F) == 0) 166 process(check); 167 } 168 169 return; 170 } 171 172 173 extern void 174 lzma_sha256_finish(lzma_check_state *check) 175 { 176 // Add padding as described in RFC 3174 (it describes SHA-1 but 177 // the same padding style is used for SHA-256 too). 178 size_t pos = check->state.sha256.size & 0x3F; 179 check->buffer.u8[pos++] = 0x80; 180 181 while (pos != 64 - 8) { 182 if (pos == 64) { 183 process(check); 184 pos = 0; 185 } 186 187 check->buffer.u8[pos++] = 0x00; 188 } 189 190 // Convert the message size from bytes to bits. 191 check->state.sha256.size *= 8; 192 193 check->buffer.u64[(64 - 8) / 8] = conv64be(check->state.sha256.size); 194 195 process(check); 196 197 for (size_t i = 0; i < 8; ++i) 198 check->buffer.u32[i] = conv32be(check->state.sha256.state[i]); 199 200 return; 201 } 202