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-rw-r--r--e2fslib/check_desc.c68
1 files changed, 68 insertions, 0 deletions
diff --git a/e2fslib/check_desc.c b/e2fslib/check_desc.c
new file mode 100644
index 0000000..902c4b6
--- /dev/null
+++ b/e2fslib/check_desc.c
@@ -0,0 +1,68 @@
+/*
+ * check_desc.c --- Check the group descriptors of an ext2 filesystem
+ *
+ * Copyright (C) 1993, 1994, 1995, 1996 Theodore Ts'o.
+ *
+ * %Begin-Header%
+ * This file may be redistributed under the terms of the GNU Public
+ * License.
+ * %End-Header%
+ */
+
+#include <stdio.h>
+#include <string.h>
+#if HAVE_UNISTD_H
+#include <unistd.h>
+#endif
+#include <fcntl.h>
+#include <time.h>
+#if HAVE_SYS_STAT_H
+#include <sys/stat.h>
+#endif
+#if HAVE_SYS_TYPES_H
+#include <sys/types.h>
+#endif
+
+#include "ext2_fs.h"
+#include "ext2fs.h"
+
+/*
+ * This routine sanity checks the group descriptors
+ */
+errcode_t ext2fs_check_desc(ext2_filsys fs)
+{
+ int i;
+ blk_t block = fs->super->s_first_data_block;
+ blk_t next;
+
+ EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
+
+ for (i = 0; i < fs->group_desc_count; i++) {
+ next = block + fs->super->s_blocks_per_group;
+ /*
+ * Check to make sure block bitmap for group is
+ * located within the group.
+ */
+ if (fs->group_desc[i].bg_block_bitmap < block ||
+ fs->group_desc[i].bg_block_bitmap >= next)
+ return EXT2_ET_GDESC_BAD_BLOCK_MAP;
+ /*
+ * Check to make sure inode bitmap for group is
+ * located within the group
+ */
+ if (fs->group_desc[i].bg_inode_bitmap < block ||
+ fs->group_desc[i].bg_inode_bitmap >= next)
+ return EXT2_ET_GDESC_BAD_INODE_MAP;
+ /*
+ * Check to make sure inode table for group is located
+ * within the group
+ */
+ if (fs->group_desc[i].bg_inode_table < block ||
+ ((fs->group_desc[i].bg_inode_table +
+ fs->inode_blocks_per_group) >= next))
+ return EXT2_ET_GDESC_BAD_INODE_TABLE;
+
+ block = next;
+ }
+ return 0;
+}