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 ///             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 #include "check.h"
  26
  27 #ifndef WORDS_BIGENDIAN
  28 #       include "../../common/bswap.h"
  29 #endif
  30
  31 // At least on x86, GCC is able to optimize this to a rotate instruction.
  32 #define rotr_32(num, amount) ((num) >> (amount) | (num) << (32 - (amount)))
  33
  34 #define blk0(i) (W[i] = 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 & (x | y)))
  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) \
  51         h(i) += S1(e(i)) + Ch(e(i), f(i), g(i)) + SHA256_K[i + j] \
  52                 + (j ? blk2(i) : blk0(i)); \
  53         d(i) += h(i); \
  54         h(i) += S0(a(i)) + Maj(a(i), b(i), c(i))
  55
  56 #define S0(x) (rotr_32(x, 2) ^ rotr_32(x, 13) ^ rotr_32(x, 22))
  57 #define S1(x) (rotr_32(x, 6) ^ rotr_32(x, 11) ^ rotr_32(x, 25))
  58 #define s0(x) (rotr_32(x, 7) ^ rotr_32(x, 18) ^ (x >> 3))
  59 #define s1(x) (rotr_32(x, 17) ^ rotr_32(x, 19) ^ (x >> 10))
  60
  61
  62 static const uint32_t SHA256_K[64] = {
  63         0x428A2F98, 0x71374491, 0xB5C0FBCF, 0xE9B5DBA5,
  64         0x3956C25B, 0x59F111F1, 0x923F82A4, 0xAB1C5ED5,
  65         0xD807AA98, 0x12835B01, 0x243185BE, 0x550C7DC3,
  66         0x72BE5D74, 0x80DEB1FE, 0x9BDC06A7, 0xC19BF174,
  67         0xE49B69C1, 0xEFBE4786, 0x0FC19DC6, 0x240CA1CC,
  68         0x2DE92C6F, 0x4A7484AA, 0x5CB0A9DC, 0x76F988DA,
  69         0x983E5152, 0xA831C66D, 0xB00327C8, 0xBF597FC7,
  70         0xC6E00BF3, 0xD5A79147, 0x06CA6351, 0x14292967,
  71         0x27B70A85, 0x2E1B2138, 0x4D2C6DFC, 0x53380D13,
  72         0x650A7354, 0x766A0ABB, 0x81C2C92E, 0x92722C85,
  73         0xA2BFE8A1, 0xA81A664B, 0xC24B8B70, 0xC76C51A3,
  74         0xD192E819, 0xD6990624, 0xF40E3585, 0x106AA070,
  75         0x19A4C116, 0x1E376C08, 0x2748774C, 0x34B0BCB5,
  76         0x391C0CB3, 0x4ED8AA4A, 0x5B9CCA4F, 0x682E6FF3,
  77         0x748F82EE, 0x78A5636F, 0x84C87814, 0x8CC70208,
  78         0x90BEFFFA, 0xA4506CEB, 0xBEF9A3F7, 0xC67178F2,
  79 };
  80
  81
  82 static void
  83 transform(uint32_t state[static 8], const uint32_t data[static 16])
  84 {
  85         uint32_t W[16];
  86         uint32_t T[8];
  87
  88         // Copy state[] to working vars.
  89         memcpy(T, state, sizeof(T));
  90
  91         // 64 operations, partially loop unrolled
  92         for (unsigned int j = 0; j < 64; j += 16) {
  93                 R( 0); R( 1); R( 2); R( 3);
  94                 R( 4); R( 5); R( 6); R( 7);
  95                 R( 8); R( 9); R(10); R(11);
  96                 R(12); R(13); R(14); R(15);
  97         }
  98
  99         // Add the working vars back into state[].
 100         state[0] += a(0);
 101         state[1] += b(0);
 102         state[2] += c(0);
 103         state[3] += d(0);
 104         state[4] += e(0);
 105         state[5] += f(0);
 106         state[6] += g(0);
 107         state[7] += h(0);
 108 }
 109
 110
 111 static void
 112 process(lzma_check_state *check)
 113 {
 114 #ifdef WORDS_BIGENDIAN
 115         transform(check->state.sha256.state, check->buffer.u32);
 116
 117 #else
 118         uint32_t data[16];
 119
 120         for (size_t i = 0; i < 16; ++i)
 121                 data[i] = bswap_32(check->buffer.u32[i]);
 122
 123         transform(check->state.sha256.state, data);
 124 #endif
 125
 126         return;
 127 }
 128
 129
 130 extern void
 131 lzma_sha256_init(lzma_check_state *check)
 132 {
 133         static const uint32_t s[8] = {
 134                 0x6A09E667, 0xBB67AE85, 0x3C6EF372, 0xA54FF53A,
 135                 0x510E527F, 0x9B05688C, 0x1F83D9AB, 0x5BE0CD19,
 136         };
 137
 138         memcpy(check->state.sha256.state, s, sizeof(s));
 139         check->state.sha256.size = 0;
 140
 141         return;
 142 }
 143
 144
 145 extern void
 146 lzma_sha256_update(const uint8_t *buf, size_t size, lzma_check_state *check)
 147 {
 148         // Copy the input data into a properly aligned temporary buffer.
 149         // This way we can be called with arbitrarily sized buffers
 150         // (no need to be multiple of 64 bytes), and the code works also
 151         // on architectures that don't allow unaligned memory access.
 152         while (size > 0) {
 153                 const size_t copy_start = check->state.sha256.size & 0x3F;
 154                 size_t copy_size = 64 - copy_start;
 155                 if (copy_size > size)
 156                         copy_size = size;
 157
 158                 memcpy(check->buffer.u8 + copy_start, buf, copy_size);
 159
 160                 buf += copy_size;
 161                 size -= copy_size;
 162                 check->state.sha256.size += copy_size;
 163
 164                 if ((check->state.sha256.size & 0x3F) == 0)
 165                         process(check);
 166         }
 167
 168         return;
 169 }
 170
 171
 172 extern void
 173 lzma_sha256_finish(lzma_check_state *check)
 174 {
 175         // Add padding as described in RFC 3174 (it describes SHA-1 but
 176         // the same padding style is used for SHA-256 too).
 177         size_t pos = check->state.sha256.size & 0x3F;
 178         check->buffer.u8[pos++] = 0x80;
 179
 180         while (pos != 64 - 8) {
 181                 if (pos == 64) {
 182                         process(check);
 183                         pos = 0;
 184                 }
 185
 186                 check->buffer.u8[pos++] = 0x00;
 187         }
 188
 189         // Convert the message size from bytes to bits.
 190         check->state.sha256.size *= 8;
 191
 192 #ifdef WORDS_BIGENDIAN
 193         check->buffer.u64[(64 - 8) / 8] = check->state.sha256.size;
 194 #else
 195         check->buffer.u64[(64 - 8) / 8] = bswap_64(check->state.sha256.size);
 196 #endif
 197
 198         process(check);
 199
 200         for (size_t i = 0; i < 8; ++i)
 201 #ifdef WORDS_BIGENDIAN
 202                 check->buffer.u32[i] = check->state.sha256.state[i];
 203 #else
 204                 check->buffer.u32[i] = bswap_32(check->state.sha256.state[i]);
 205 #endif
 206
 207         return;
 208 }