90 lines
2.4 KiB
C
90 lines
2.4 KiB
C
/*
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File: apfs_common.c
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Copyright (C) 2021 Christophe GRENIER <grenier@cgsecurity.org>
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This software 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 2 of the License, or
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(at your option) any later version.
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This program 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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You should have received a copy of the GNU General Public License along
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with this program; if not, write the Free Software Foundation, Inc., 51
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Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
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*/
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#ifdef HAVE_CONFIG_H
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#include <config.h>
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#endif
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#include <stdio.h>
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#ifdef HAVE_STDLIB_H
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#include <stdlib.h>
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#endif
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#ifdef HAVE_STRING_H
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#include <string.h>
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#endif
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#include "types.h"
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#include "common.h"
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#include "apfs_common.h"
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#include "log.h"
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/*@
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@ requires \valid_read(data + (0 .. cnt-1));
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@ assigns \nothing;
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@*/
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static uint64_t fletcher64(const uint32_t *data, const size_t cnt, const uint64_t init)
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{
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size_t k;
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uint64_t sum1 = init & 0xFFFFFFFFU;
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uint64_t sum2 = (init >> 32);
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/*@
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@ loop invariant 0 <= k <= cnt;
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@ loop assigns k, sum1, sum2;
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@*/
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for (k = 0; k < cnt; k++)
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{
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/* @assert k < cnt; */
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sum1 = (sum1 + le32(data[k]));
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sum2 = (sum2 + sum1);
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}
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sum1 = sum1 % 0xFFFFFFFF;
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sum2 = sum2 % 0xFFFFFFFF;
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return (sum2 << 32) | sum1;
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}
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/*@
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@ requires size >= 8;
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@ requires \valid_read((char *)block+ (0 .. size-1));
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@ assigns \nothing;
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@*/
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static uint64_t VerifyBlock(const void *block, const size_t size)
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{
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uint64_t cs;
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const uint32_t *data = (const uint32_t *)block;
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const size_t size4 = size / sizeof(uint32_t);
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cs = fletcher64(data + 2, size4 - 2, 0);
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cs = fletcher64(data, 2, cs);
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return cs;
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}
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int test_APFS(const nx_superblock_t *sb, const partition_t *partition)
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{
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if(le32(sb->nx_magic)!=0x4253584e)
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return 1;
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if((uint64_t)le32(sb->nx_xp_desc_blocks) + le32(sb->nx_xp_data_blocks) > le64(sb->nx_block_count))
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return 2;
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if(le32(sb->nx_block_size) < NX_MINIMUM_BLOCK_SIZE ||
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le32(sb->nx_block_size) > NX_MAXIMUM_BLOCK_SIZE)
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return 3;
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if(VerifyBlock(sb, 4096) != 0)
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return 4;
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return 0;
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}
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