src/liblzma/check/sha256.c

   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 }