mirror of
https://github.com/CloverHackyColor/CloverBootloader.git
synced 2024-12-27 16:58:09 +01:00
115 lines
2.5 KiB
C
115 lines
2.5 KiB
C
/* crc64.c - crc64 function */
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/*
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* GRUB -- GRand Unified Bootloader
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* Copyright (C) 2008,2011 Free Software Foundation, Inc.
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*
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* GRUB is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* GRUB is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with GRUB. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include <grub/types.h>
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#include <grub/dl.h>
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#include <grub/crypto.h>
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GRUB_MOD_LICENSE ("GPLv3+");
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static grub_uint64_t crc64_table [256];
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/* Helper for init_crc64_table. */
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static grub_uint64_t
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reflect (grub_uint64_t ref, int len)
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{
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grub_uint64_t result = 0;
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int i;
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for (i = 1; i <= len; i++)
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{
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if (ref & 1)
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result |= 1ULL << (len - i);
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ref >>= 1;
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}
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return result;
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}
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static void
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init_crc64_table (void)
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{
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grub_uint64_t polynomial = 0x42f0e1eba9ea3693ULL;
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int i, j;
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for(i = 0; i < 256; i++)
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{
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crc64_table[i] = reflect(i, 8) << 56;
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for (j = 0; j < 8; j++)
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{
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crc64_table[i] = (crc64_table[i] << 1) ^
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(crc64_table[i] & (1ULL << 63) ? polynomial : 0);
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}
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crc64_table[i] = reflect(crc64_table[i], 64);
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}
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}
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static void
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crc64_init (void *context)
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{
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if (! crc64_table[1])
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init_crc64_table ();
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*(grub_uint64_t *) context = 0;
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}
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static void
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crc64_write (void *context, const void *buf, grub_size_t size)
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{
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unsigned i;
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const grub_uint8_t *data = buf;
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grub_uint64_t crc = ~grub_le_to_cpu64 (*(grub_uint64_t *) context);
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for (i = 0; i < size; i++)
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{
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crc = (crc >> 8) ^ crc64_table[(crc & 0xFF) ^ *data];
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data++;
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}
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*(grub_uint64_t *) context = grub_cpu_to_le64 (~crc);
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}
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static grub_uint8_t *
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crc64_read (void *context)
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{
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return context;
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}
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static void
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crc64_final (void *context __attribute__ ((unused)))
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{
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}
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gcry_md_spec_t _gcry_digest_spec_crc64 =
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{
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"CRC64", 0, 0, 0, 8,
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crc64_init, crc64_write, crc64_final, crc64_read,
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sizeof (grub_uint64_t),
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.blocksize = 64
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};
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GRUB_MOD_INIT(crc64)
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{
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grub_md_register (&_gcry_digest_spec_crc64);
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}
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GRUB_MOD_FINI(crc64)
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{
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grub_md_unregister (&_gcry_digest_spec_crc64);
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}
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