1/* vi: set sw=4 ts=4: */ 2/* 3 * check_desc.c --- Check the group descriptors of an ext2 filesystem 4 * 5 * Copyright (C) 1993, 1994, 1995, 1996 Theodore Ts'o. 6 * 7 * %Begin-Header% 8 * This file may be redistributed under the terms of the GNU Public 9 * License. 10 * %End-Header% 11 */ 12 13#include <stdio.h> 14#include <string.h> 15#if HAVE_UNISTD_H 16#include <unistd.h> 17#endif 18#include <fcntl.h> 19#include <time.h> 20#if HAVE_SYS_STAT_H 21#include <sys/stat.h> 22#endif 23#if HAVE_SYS_TYPES_H 24#include <sys/types.h> 25#endif 26 27#include "ext2_fs.h" 28#include "ext2fs.h" 29 30/* 31 * This routine sanity checks the group descriptors 32 */ 33errcode_t ext2fs_check_desc(ext2_filsys fs) 34{ 35 dgrp_t i; 36 blk_t block = fs->super->s_first_data_block; 37 blk_t next; 38 39 EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS); 40 41 for (i = 0; i < fs->group_desc_count; i++) { 42 next = block + fs->super->s_blocks_per_group; 43 /* 44 * Check to make sure block bitmap for group is 45 * located within the group. 46 */ 47 if (fs->group_desc[i].bg_block_bitmap < block || 48 fs->group_desc[i].bg_block_bitmap >= next) 49 return EXT2_ET_GDESC_BAD_BLOCK_MAP; 50 /* 51 * Check to make sure inode bitmap for group is 52 * located within the group 53 */ 54 if (fs->group_desc[i].bg_inode_bitmap < block || 55 fs->group_desc[i].bg_inode_bitmap >= next) 56 return EXT2_ET_GDESC_BAD_INODE_MAP; 57 /* 58 * Check to make sure inode table for group is located 59 * within the group 60 */ 61 if (fs->group_desc[i].bg_inode_table < block || 62 ((fs->group_desc[i].bg_inode_table + 63 fs->inode_blocks_per_group) >= next)) 64 return EXT2_ET_GDESC_BAD_INODE_TABLE; 65 66 block = next; 67 } 68 return 0; 69} 70