lib/ext2fs/check_desc.c

   1 /*
   2  * check_desc.c --- Check the group descriptors of an ext2 filesystem
   3  *
   4  * Copyright (C) 1993, 1994, 1995, 1996 Theodore Ts'o.
   5  *
   6  * %Begin-Header%
   7  * This file may be redistributed under the terms of the GNU Public
   8  * License.
   9  * %End-Header%
  10  */
  11
  12 #include <stdio.h>
  13 #include <string.h>
  14 #if HAVE_UNISTD_H
  15 #include <unistd.h>
  16 #endif
  17 #include <fcntl.h>
  18 #include <time.h>
  19 #if HAVE_SYS_STAT_H
  20 #include <sys/stat.h>
  21 #endif
  22 #if HAVE_SYS_TYPES_H
  23 #include <sys/types.h>
  24 #endif
  25
  26 #include "ext2_fs.h"
  27 #include "ext2fs.h"
  28
  29 /*
  30  * This routine sanity checks the group descriptors
  31  */
  32 errcode_t ext2fs_check_desc(ext2_filsys fs)
  33 {
  34         dgrp_t i;
  35         blk_t first_block = fs->super->s_first_data_block;
  36         blk_t last_block;
  37
  38         EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
  39
  40         for (i = 0; i < fs->group_desc_count; i++) {
  41                 first_block = ext2fs_group_first_block(fs, i);
  42                 last_block = ext2fs_group_last_block(fs, i);
  43
  44                 /*
  45                  * Check to make sure block bitmap for group is
  46                  * located within the group.
  47                  */
  48                 if (fs->group_desc[i].bg_block_bitmap < first_block ||
  49                     fs->group_desc[i].bg_block_bitmap > last_block)
  50                         return EXT2_ET_GDESC_BAD_BLOCK_MAP;
  51                 /*
  52                  * Check to make sure inode bitmap for group is
  53                  * located within the group
  54                  */
  55                 if (fs->group_desc[i].bg_inode_bitmap < first_block ||
  56                     fs->group_desc[i].bg_inode_bitmap > last_block)
  57                         return EXT2_ET_GDESC_BAD_INODE_MAP;
  58                 /*
  59                  * Check to make sure inode table for group is located
  60                  * within the group
  61                  */
  62                 if (fs->group_desc[i].bg_inode_table < first_block ||
  63                     ((fs->group_desc[i].bg_inode_table +
  64                       fs->inode_blocks_per_group - 1) > last_block))
  65                         return EXT2_ET_GDESC_BAD_INODE_TABLE;
  66         }
  67         return 0;
  68 }