[Ocfs2-tools-devel] [PATCH] libocfs2: Prevent endian swapping from scribbling over memory.

[Tao Ma]

Hi Joel,
	The idea is cool. Just one small comment.

Joel Becker wrote:
<snip>
> +static void ocfs2_swap_xattr_entries_to_cpu(ocfs2_filesys *fs, void *obj,
> +					    size_t objsize,
> +					    struct ocfs2_xattr_header *xh)
>  {
>  	uint16_t i;
> +	char *value;
> +	ocfs2_filesys fake_fs = {
> +		.fs_blocksize = objsize,
> +	};
>  
>  	if (cpu_is_little_endian)
>  		return;
> @@ -116,23 +133,40 @@ static void ocfs2_swap_xattr_entries_to_cpu(struct ocfs2_xattr_header *xh)
>  	for (i = 0; i < xh->xh_count; i++) {
>  		struct ocfs2_xattr_entry *xe = &xh->xh_entries[i];
>  
> +		if (ocfs2_swap_barrier(&fake_fs, obj, xe,
> +				       sizeof(struct ocfs2_xattr_entry)))
> +			break;
> +
>  		ocfs2_swap_xattr_entry(xe);
>  
> +		value = (char *)xh + xe->xe_name_offset +
> +			OCFS2_XATTR_SIZE(xe->xe_name_len);
> +
>  		if (!ocfs2_xattr_is_local(xe)) {
>  			struct ocfs2_xattr_value_root *xr =
> -				(struct ocfs2_xattr_value_root *)
> -				((char *)xh + xe->xe_name_offset +
> -				OCFS2_XATTR_SIZE(xe->xe_name_len));
> +				(struct ocfs2_xattr_value_root *)value;
> +
> +			if (ocfs2_swap_barrier(&fake_fs, obj, xr,
> +					       OCFS2_XATTR_ROOT_SIZE))
> +				break;
>  
>  			ocfs2_swap_xattr_value_root(xr);
> -			ocfs2_swap_extent_list_to_cpu(&xr->xr_list);
> -		}
> +			ocfs2_swap_extent_list_to_cpu(fs, xh, &xr->xr_list);
> +		} else if (ocfs2_swap_barrier(&fake_fs, obj, value,
> +					      xe->xe_value_size))
here we may need to use OCFS2_XATTR_SIZE(xe->xe_value_size) since 
actually it is aligned. The same goes for ocfs2_swap_xattr_entries_from_cpu.

Regards,
Tao