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Diffstat (limited to '')
| -rw-r--r-- | src/liblzma/check/sha256.c | 196 |
1 files changed, 196 insertions, 0 deletions
diff --git a/src/liblzma/check/sha256.c b/src/liblzma/check/sha256.c new file mode 100644 index 0000000..6feb342 --- /dev/null +++ b/src/liblzma/check/sha256.c @@ -0,0 +1,196 @@ +/////////////////////////////////////////////////////////////////////////////// +// +/// \file sha256.c +/// \brief SHA-256 +/// +/// \todo Crypto++ has x86 ASM optimizations. They use SSE so if they +/// are imported to liblzma, SSE instructions need to be used +/// conditionally to keep the code working on older boxes. +// +// This code is based on the code found from 7-Zip, which has a modified +// version of the SHA-256 found from Crypto++ <https://www.cryptopp.com/>. +// The code was modified a little to fit into liblzma. +// +// Authors: Kevin Springle +// Wei Dai +// Igor Pavlov +// Lasse Collin +// +// This file has been put into the public domain. +// You can do whatever you want with this file. +// +/////////////////////////////////////////////////////////////////////////////// + +#include "check.h" + +// Rotate a uint32_t. GCC can optimize this to a rotate instruction +// at least on x86. +static inline uint32_t +rotr_32(uint32_t num, unsigned amount) +{ + return (num >> amount) | (num << (32 - amount)); +} + +#define blk0(i) (W[i] = conv32be(data[i])) +#define blk2(i) (W[i & 15] += s1(W[(i - 2) & 15]) + W[(i - 7) & 15] \ + + s0(W[(i - 15) & 15])) + +#define Ch(x, y, z) (z ^ (x & (y ^ z))) +#define Maj(x, y, z) ((x & (y ^ z)) + (y & z)) + +#define a(i) T[(0 - i) & 7] +#define b(i) T[(1 - i) & 7] +#define c(i) T[(2 - i) & 7] +#define d(i) T[(3 - i) & 7] +#define e(i) T[(4 - i) & 7] +#define f(i) T[(5 - i) & 7] +#define g(i) T[(6 - i) & 7] +#define h(i) T[(7 - i) & 7] + +#define R(i, j, blk) \ + h(i) += S1(e(i)) + Ch(e(i), f(i), g(i)) + SHA256_K[i + j] + blk; \ + d(i) += h(i); \ + h(i) += S0(a(i)) + Maj(a(i), b(i), c(i)) +#define R0(i) R(i, 0, blk0(i)) +#define R2(i) R(i, j, blk2(i)) + +#define S0(x) rotr_32(x ^ rotr_32(x ^ rotr_32(x, 9), 11), 2) +#define S1(x) rotr_32(x ^ rotr_32(x ^ rotr_32(x, 14), 5), 6) +#define s0(x) (rotr_32(x ^ rotr_32(x, 11), 7) ^ (x >> 3)) +#define s1(x) (rotr_32(x ^ rotr_32(x, 2), 17) ^ (x >> 10)) + + +static const uint32_t SHA256_K[64] = { + 0x428A2F98, 0x71374491, 0xB5C0FBCF, 0xE9B5DBA5, + 0x3956C25B, 0x59F111F1, 0x923F82A4, 0xAB1C5ED5, + 0xD807AA98, 0x12835B01, 0x243185BE, 0x550C7DC3, + 0x72BE5D74, 0x80DEB1FE, 0x9BDC06A7, 0xC19BF174, + 0xE49B69C1, 0xEFBE4786, 0x0FC19DC6, 0x240CA1CC, + 0x2DE92C6F, 0x4A7484AA, 0x5CB0A9DC, 0x76F988DA, + 0x983E5152, 0xA831C66D, 0xB00327C8, 0xBF597FC7, + 0xC6E00BF3, 0xD5A79147, 0x06CA6351, 0x14292967, + 0x27B70A85, 0x2E1B2138, 0x4D2C6DFC, 0x53380D13, + 0x650A7354, 0x766A0ABB, 0x81C2C92E, 0x92722C85, + 0xA2BFE8A1, 0xA81A664B, 0xC24B8B70, 0xC76C51A3, + 0xD192E819, 0xD6990624, 0xF40E3585, 0x106AA070, + 0x19A4C116, 0x1E376C08, 0x2748774C, 0x34B0BCB5, + 0x391C0CB3, 0x4ED8AA4A, 0x5B9CCA4F, 0x682E6FF3, + 0x748F82EE, 0x78A5636F, 0x84C87814, 0x8CC70208, + 0x90BEFFFA, 0xA4506CEB, 0xBEF9A3F7, 0xC67178F2, +}; + + +static void +transform(uint32_t state[8], const uint32_t data[16]) +{ + uint32_t W[16]; + uint32_t T[8]; + + // Copy state[] to working vars. + memcpy(T, state, sizeof(T)); + + // The first 16 operations unrolled + R0( 0); R0( 1); R0( 2); R0( 3); + R0( 4); R0( 5); R0( 6); R0( 7); + R0( 8); R0( 9); R0(10); R0(11); + R0(12); R0(13); R0(14); R0(15); + + // The remaining 48 operations partially unrolled + for (unsigned int j = 16; j < 64; j += 16) { + R2( 0); R2( 1); R2( 2); R2( 3); + R2( 4); R2( 5); R2( 6); R2( 7); + R2( 8); R2( 9); R2(10); R2(11); + R2(12); R2(13); R2(14); R2(15); + } + + // Add the working vars back into state[]. + state[0] += a(0); + state[1] += b(0); + state[2] += c(0); + state[3] += d(0); + state[4] += e(0); + state[5] += f(0); + state[6] += g(0); + state[7] += h(0); +} + + +static void +process(lzma_check_state *check) +{ + transform(check->state.sha256.state, check->buffer.u32); + return; +} + + +extern void +lzma_sha256_init(lzma_check_state *check) +{ + static const uint32_t s[8] = { + 0x6A09E667, 0xBB67AE85, 0x3C6EF372, 0xA54FF53A, + 0x510E527F, 0x9B05688C, 0x1F83D9AB, 0x5BE0CD19, + }; + + memcpy(check->state.sha256.state, s, sizeof(s)); + check->state.sha256.size = 0; + + return; +} + + +extern void +lzma_sha256_update(const uint8_t *buf, size_t size, lzma_check_state *check) +{ + // Copy the input data into a properly aligned temporary buffer. + // This way we can be called with arbitrarily sized buffers + // (no need to be multiple of 64 bytes), and the code works also + // on architectures that don't allow unaligned memory access. + while (size > 0) { + const size_t copy_start = check->state.sha256.size & 0x3F; + size_t copy_size = 64 - copy_start; + if (copy_size > size) + copy_size = size; + + memcpy(check->buffer.u8 + copy_start, buf, copy_size); + + buf += copy_size; + size -= copy_size; + check->state.sha256.size += copy_size; + + if ((check->state.sha256.size & 0x3F) == 0) + process(check); + } + + return; +} + + +extern void +lzma_sha256_finish(lzma_check_state *check) +{ + // Add padding as described in RFC 3174 (it describes SHA-1 but + // the same padding style is used for SHA-256 too). + size_t pos = check->state.sha256.size & 0x3F; + check->buffer.u8[pos++] = 0x80; + + while (pos != 64 - 8) { + if (pos == 64) { + process(check); + pos = 0; + } + + check->buffer.u8[pos++] = 0x00; + } + + // Convert the message size from bytes to bits. + check->state.sha256.size *= 8; + + check->buffer.u64[(64 - 8) / 8] = conv64be(check->state.sha256.size); + + process(check); + + for (size_t i = 0; i < 8; ++i) + check->buffer.u32[i] = conv32be(check->state.sha256.state[i]); + + return; +} |