| /* SPDX-License-Identifier: LGPL-2.1-or-later */ |
| |
| /* Stolen from glibc and converted to our style. In glibc it comes with the following copyright blurb: */ |
| |
| /* Functions to compute SHA256 message digest of files or memory blocks. |
| according to the definition of SHA256 in FIPS 180-2. |
| Copyright (C) 2007-2022 Free Software Foundation, Inc. |
| This file is part of the GNU C Library. |
| |
| The GNU C Library is free software; you can redistribute it and/or |
| modify it under the terms of the GNU Lesser General Public |
| License as published by the Free Software Foundation; either |
| version 2.1 of the License, or (at your option) any later version. |
| |
| The GNU C Library is distributed in the hope that it will be useful, |
| but WITHOUT ANY WARRANTY; without even the implied warranty of |
| MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| Lesser General Public License for more details. |
| |
| You should have received a copy of the GNU Lesser General Public |
| License along with the GNU C Library; if not, see |
| <https://www.gnu.org/licenses/>. */ |
| |
| #include <stdbool.h> |
| #if SD_BOOT |
| # include "efi-string.h" |
| #else |
| # include <string.h> |
| #endif |
| |
| #include "macro-fundamental.h" |
| #include "sha256.h" |
| #include "unaligned-fundamental.h" |
| |
| #if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__ |
| # define SWAP(n) \ |
| (((n) << 24) | (((n) & 0xff00) << 8) | (((n) >> 8) & 0xff00) | ((n) >> 24)) |
| # define SWAP64(n) \ |
| (((n) << 56) \ |
| | (((n) & 0xff00) << 40) \ |
| | (((n) & 0xff0000) << 24) \ |
| | (((n) & 0xff000000) << 8) \ |
| | (((n) >> 8) & 0xff000000) \ |
| | (((n) >> 24) & 0xff0000) \ |
| | (((n) >> 40) & 0xff00) \ |
| | ((n) >> 56)) |
| #else |
| # define SWAP(n) (n) |
| # define SWAP64(n) (n) |
| #endif |
| |
| /* This array contains the bytes used to pad the buffer to the next |
| 64-byte boundary. (FIPS 180-2:5.1.1) */ |
| static const uint8_t fillbuf[64] = { |
| 0x80, 0 /* , 0, 0, ... */ |
| }; |
| |
| /* Constants for SHA256 from FIPS 180-2:4.2.2. */ |
| static const uint32_t 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 sha256_process_block(const void *, size_t, struct sha256_ctx *); |
| |
| /* Initialize structure containing state of computation. |
| (FIPS 180-2:5.3.2) */ |
| void sha256_init_ctx(struct sha256_ctx *ctx) { |
| assert(ctx); |
| |
| ctx->H[0] = 0x6a09e667; |
| ctx->H[1] = 0xbb67ae85; |
| ctx->H[2] = 0x3c6ef372; |
| ctx->H[3] = 0xa54ff53a; |
| ctx->H[4] = 0x510e527f; |
| ctx->H[5] = 0x9b05688c; |
| ctx->H[6] = 0x1f83d9ab; |
| ctx->H[7] = 0x5be0cd19; |
| |
| ctx->total64 = 0; |
| ctx->buflen = 0; |
| } |
| |
| /* Process the remaining bytes in the internal buffer and the usual |
| prolog according to the standard and write the result to RESBUF. */ |
| uint8_t *sha256_finish_ctx(struct sha256_ctx *ctx, uint8_t resbuf[static SHA256_DIGEST_SIZE]) { |
| /* Take yet unprocessed bytes into account. */ |
| uint32_t bytes = ctx->buflen; |
| size_t pad; |
| |
| assert(ctx); |
| assert(resbuf); |
| |
| /* Now count remaining bytes. */ |
| ctx->total64 += bytes; |
| |
| pad = bytes >= 56 ? 64 + 56 - bytes : 56 - bytes; |
| memcpy(&ctx->buffer[bytes], fillbuf, pad); |
| |
| /* Put the 64-bit file length in *bits* at the end of the buffer. */ |
| ctx->buffer32[(bytes + pad + 4) / 4] = SWAP(ctx->total[TOTAL64_low] << 3); |
| ctx->buffer32[(bytes + pad) / 4] = SWAP((ctx->total[TOTAL64_high] << 3) |
| | (ctx->total[TOTAL64_low] >> 29)); |
| |
| /* Process last bytes. */ |
| sha256_process_block(ctx->buffer, bytes + pad + 8, ctx); |
| |
| /* Put result from CTX in first 32 bytes following RESBUF. */ |
| for (size_t i = 0; i < 8; ++i) |
| unaligned_write_ne32(resbuf + i * sizeof(uint32_t), SWAP(ctx->H[i])); |
| return resbuf; |
| } |
| |
| void sha256_process_bytes(const void *buffer, size_t len, struct sha256_ctx *ctx) { |
| assert(buffer); |
| assert(ctx); |
| |
| /* When we already have some bits in our internal buffer concatenate |
| both inputs first. */ |
| |
| if (ctx->buflen != 0) { |
| size_t left_over = ctx->buflen; |
| size_t add = 128 - left_over > len ? len : 128 - left_over; |
| |
| memcpy(&ctx->buffer[left_over], buffer, add); |
| ctx->buflen += add; |
| |
| if (ctx->buflen > 64) { |
| sha256_process_block(ctx->buffer, ctx->buflen & ~63, ctx); |
| |
| ctx->buflen &= 63; |
| /* The regions in the following copy operation cannot overlap. */ |
| memcpy(ctx->buffer, &ctx->buffer[(left_over + add) & ~63], |
| ctx->buflen); |
| } |
| |
| buffer = (const char *) buffer + add; |
| len -= add; |
| } |
| |
| /* Process available complete blocks. */ |
| if (len >= 64) { |
| if (IS_ALIGNED32(buffer)) { |
| sha256_process_block(buffer, len & ~63, ctx); |
| buffer = (const char *) buffer + (len & ~63); |
| len &= 63; |
| } else |
| while (len > 64) { |
| memcpy(ctx->buffer, buffer, 64); |
| sha256_process_block(ctx->buffer, 64, ctx); |
| buffer = (const char *) buffer + 64; |
| len -= 64; |
| } |
| } |
| |
| /* Move remaining bytes into internal buffer. */ |
| if (len > 0) { |
| size_t left_over = ctx->buflen; |
| |
| memcpy(&ctx->buffer[left_over], buffer, len); |
| left_over += len; |
| if (left_over >= 64) { |
| sha256_process_block(ctx->buffer, 64, ctx); |
| left_over -= 64; |
| memcpy(ctx->buffer, &ctx->buffer[64], left_over); |
| } |
| ctx->buflen = left_over; |
| } |
| } |
| |
| /* Process LEN bytes of BUFFER, accumulating context into CTX. |
| It is assumed that LEN % 64 == 0. */ |
| static void sha256_process_block(const void *buffer, size_t len, struct sha256_ctx *ctx) { |
| const uint32_t *words = ASSERT_PTR(buffer); |
| size_t nwords = len / sizeof(uint32_t); |
| |
| assert(ctx); |
| |
| uint32_t a = ctx->H[0]; |
| uint32_t b = ctx->H[1]; |
| uint32_t c = ctx->H[2]; |
| uint32_t d = ctx->H[3]; |
| uint32_t e = ctx->H[4]; |
| uint32_t f = ctx->H[5]; |
| uint32_t g = ctx->H[6]; |
| uint32_t h = ctx->H[7]; |
| |
| /* First increment the byte count. FIPS 180-2 specifies the possible |
| length of the file up to 2^64 bits. Here we only compute the |
| number of bytes. */ |
| ctx->total64 += len; |
| |
| /* Process all bytes in the buffer with 64 bytes in each round of |
| the loop. */ |
| while (nwords > 0) { |
| uint32_t W[64]; |
| uint32_t a_save = a; |
| uint32_t b_save = b; |
| uint32_t c_save = c; |
| uint32_t d_save = d; |
| uint32_t e_save = e; |
| uint32_t f_save = f; |
| uint32_t g_save = g; |
| uint32_t h_save = h; |
| |
| /* Operators defined in FIPS 180-2:4.1.2. */ |
| #define Ch(x, y, z) ((x & y) ^ (~x & z)) |
| #define Maj(x, y, z) ((x & y) ^ (x & z) ^ (y & z)) |
| #define S0(x) (CYCLIC (x, 2) ^ CYCLIC (x, 13) ^ CYCLIC (x, 22)) |
| #define S1(x) (CYCLIC (x, 6) ^ CYCLIC (x, 11) ^ CYCLIC (x, 25)) |
| #define R0(x) (CYCLIC (x, 7) ^ CYCLIC (x, 18) ^ (x >> 3)) |
| #define R1(x) (CYCLIC (x, 17) ^ CYCLIC (x, 19) ^ (x >> 10)) |
| |
| /* It is unfortunate that C does not provide an operator for |
| cyclic rotation. Hope the C compiler is smart enough. */ |
| #define CYCLIC(w, s) ((w >> s) | (w << (32 - s))) |
| |
| /* Compute the message schedule according to FIPS 180-2:6.2.2 step 2. */ |
| for (size_t t = 0; t < 16; ++t) { |
| W[t] = SWAP (*words); |
| ++words; |
| } |
| for (size_t t = 16; t < 64; ++t) |
| W[t] = R1 (W[t - 2]) + W[t - 7] + R0 (W[t - 15]) + W[t - 16]; |
| |
| /* The actual computation according to FIPS 180-2:6.2.2 step 3. */ |
| for (size_t t = 0; t < 64; ++t) { |
| uint32_t T1 = h + S1 (e) + Ch (e, f, g) + K[t] + W[t]; |
| uint32_t T2 = S0 (a) + Maj (a, b, c); |
| h = g; |
| g = f; |
| f = e; |
| e = d + T1; |
| d = c; |
| c = b; |
| b = a; |
| a = T1 + T2; |
| } |
| |
| /* Add the starting values of the context according to FIPS 180-2:6.2.2 |
| step 4. */ |
| a += a_save; |
| b += b_save; |
| c += c_save; |
| d += d_save; |
| e += e_save; |
| f += f_save; |
| g += g_save; |
| h += h_save; |
| |
| /* Prepare for the next round. */ |
| nwords -= 16; |
| } |
| |
| /* Put checksum in context given as argument. */ |
| ctx->H[0] = a; |
| ctx->H[1] = b; |
| ctx->H[2] = c; |
| ctx->H[3] = d; |
| ctx->H[4] = e; |
| ctx->H[5] = f; |
| ctx->H[6] = g; |
| ctx->H[7] = h; |
| } |
| |
| uint8_t* sha256_direct(const void *buffer, size_t sz, uint8_t result[static SHA256_DIGEST_SIZE]) { |
| struct sha256_ctx ctx; |
| sha256_init_ctx(&ctx); |
| sha256_process_bytes(buffer, sz, &ctx); |
| return sha256_finish_ctx(&ctx, result); |
| } |