1 files changed, 68 insertions, 0 deletions
diff --git a/e2fsprogs/ext2fs/check_desc.c b/e2fsprogs/ext2fs/check_desc.c
new file mode 100644
index 0000000..2a754c7
--- /dev/null
+++ b/e2fsprogs/ext2fs/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)
+{
+	dgrp_t 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;
+}