ext2fs_block_iterate() on fast symlink

[Jan Kara <jack@suse.cz>]

[-- Attachment #1: Type: text/plain, Size: 514 bytes --]

  Hello,

  when  ext2fs_block_iterate() is called on a fast symlink (and I assume
device inodes would be no different), then random things happen - the
problem is ext2fs_block_iterate() just blindly takes portions of the inode
and treats them as block numbers. Now I agree that garbage went in (it
makes no sence to call this function on such inode) so garbage results but
maybe it would be nicer to handle it more gracefully. Attached patch should
do it.

									Honza
-- 
Jan Kara <jack@suse.cz>
SuSE CR Labs

[-- Attachment #2: e2fsprogs-block_iterate_fix.diff --]
[-- Type: text/x-patch, Size: 878 bytes --]

--- a/lib/ext2fs/inode.c	2007-06-20 13:55:52.000000000 +0200
+++ b/lib/ext2fs/inode.c	2007-06-20 14:11:15.000000000 +0200
@@ -771,6 +771,10 @@ errcode_t ext2fs_get_blocks(ext2_filsys 
 	retval = ext2fs_read_inode(fs, ino, &inode);
 	if (retval)
 		return retval;
+	if (LINUX_S_ISCHR(inode.i_mode) || LINUX_S_ISBLK(inode.i_mode) ||
+	    (LINUX_S_ISLNK(inode.i_mode) &&
+	     ext2fs_inode_data_blocks(fs, &inode) == 0))
+		return EXT2_ET_INVAL_INODE_TYPE;
 	for (i=0; i < EXT2_N_BLOCKS; i++)
 		blocks[i] = inode.i_block[i];
 	return 0;
--- a/lib/ext2fs/ext2_err.et.in	2007-06-20 14:09:18.000000000 +0200
+++ b/lib/ext2fs/ext2_err.et.in	2007-06-20 14:11:25.000000000 +0200
@@ -296,5 +296,8 @@ ec	EXT2_ET_RESIZE_INODE_CORRUPT,
 ec	EXT2_ET_SET_BMAP_NO_IND,
 	"Missing indirect block not present"
 
+ec	EXT2_ET_INVAL_INODE_TYPE,
+	"Invalid inode type for the operation."
+
 	end