1 | /* vi: set sw=4 ts=4: */
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2 | /*
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3 | * check_desc.c --- Check the group descriptors of an ext2 filesystem
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4 | *
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5 | * Copyright (C) 1993, 1994, 1995, 1996 Theodore Ts'o.
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6 | *
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7 | * %Begin-Header%
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8 | * This file may be redistributed under the terms of the GNU Public
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9 | * License.
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10 | * %End-Header%
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11 | */
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12 |
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13 | #include <stdio.h>
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14 | #include <string.h>
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15 | #if HAVE_UNISTD_H
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16 | #include <unistd.h>
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17 | #endif
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18 | #include <fcntl.h>
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19 | #include <time.h>
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20 | #if HAVE_SYS_STAT_H
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21 | #include <sys/stat.h>
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22 | #endif
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23 | #if HAVE_SYS_TYPES_H
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24 | #include <sys/types.h>
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25 | #endif
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26 |
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27 | #include "ext2_fs.h"
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28 | #include "ext2fs.h"
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29 |
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30 | /*
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31 | * This routine sanity checks the group descriptors
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32 | */
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33 | errcode_t ext2fs_check_desc(ext2_filsys fs)
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34 | {
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35 | dgrp_t i;
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36 | blk_t block = fs->super->s_first_data_block;
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37 | blk_t next;
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38 |
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39 | EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
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40 |
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41 | for (i = 0; i < fs->group_desc_count; i++) {
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42 | next = block + fs->super->s_blocks_per_group;
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43 | /*
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44 | * Check to make sure block bitmap for group is
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45 | * located within the group.
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46 | */
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47 | if (fs->group_desc[i].bg_block_bitmap < block ||
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48 | fs->group_desc[i].bg_block_bitmap >= next)
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49 | return EXT2_ET_GDESC_BAD_BLOCK_MAP;
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50 | /*
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51 | * Check to make sure inode bitmap for group is
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52 | * located within the group
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53 | */
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54 | if (fs->group_desc[i].bg_inode_bitmap < block ||
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55 | fs->group_desc[i].bg_inode_bitmap >= next)
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56 | return EXT2_ET_GDESC_BAD_INODE_MAP;
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57 | /*
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58 | * Check to make sure inode table for group is located
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59 | * within the group
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60 | */
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61 | if (fs->group_desc[i].bg_inode_table < block ||
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62 | ((fs->group_desc[i].bg_inode_table +
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63 | fs->inode_blocks_per_group) >= next))
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64 | return EXT2_ET_GDESC_BAD_INODE_TABLE;
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65 |
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66 | block = next;
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67 | }
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68 | return 0;
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69 | }
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