Re: [Bug-tar] leading / included in incremental snapshot rename code

[Nicholas Cole]

Both patches work

Thanks

Nick

On Tue, Oct 02, 2007 at 12:56:59AM +0300, Sergey Poznyakoff wrote:
> Nicholas Cole <address@hidden> ha escrit:
> 
> > This patch causes tar to strip leading / from rename codes during
> > creation. Can you also patch tar to strip leading / from rename
> > codes during extraction? This would prevent odd behaivor when
> > extracting an archive created with an unpatched version of tar and
> > prevent malicious use of rename codes
> 
> Yes, this is reasonable. Here is a patch.
> 
> Regards,
> Sergey
> 
> Index: src/incremen.c
> ===================================================================
> RCS file: /cvsroot/tar/tar/src/incremen.c,v
> retrieving revision 1.58
> diff -p -u -r1.58 incremen.c
> --- src/incremen.c    29 Sep 2007 00:47:59 -0000      1.58
> +++ src/incremen.c    1 Oct 2007 21:54:17 -0000
> @@ -1410,6 +1410,19 @@ try_purge_directory (char const *directo
>         arc += strlen (arc) + 1;
>         dst = arc + 1;
>  
> +       /* Ensure that neither source nor destination are absolute file
> +          names (unless permitted by -P option), and that they do not
> +          contain dubious parts (e.g. ../).
> +
> +          This is an extra safety precaution. Besides, it might be
> +          necessary to extract from archives created with tar versions
> +          prior to 1.19. */
> +       
> +       if (*src)
> +         src = safer_name_suffix (src, false, absolute_names_option);
> +       if (*dst)
> +         dst = safer_name_suffix (dst, false, absolute_names_option);
> +       
>         if (*src == 0)
>           src = temp_stub;
>         else if (*dst == 0)
> 
> 

-- 
Nicholas Cole
address@hidden