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From "Roy T. Fielding" <field...@apache.org>
Subject Re: [1.3 PATCH/QUESTION] Win32 ap_os_is_filename_valid()
Date Wed, 13 Mar 2002 21:30:23 GMT
On Wed, Mar 13, 2002 at 02:12:18PM -0500, Jeff Trawick wrote:
> Jeff Trawick <trawick@attglobal.net> writes:
> 
> > This function is checking for several characters which, at least in
> > ASCII, are supposedly not valid characters for filenames.  But some of
> > these same characters can appear in valid non-ASCII filenames, and the
> > logic to check for these characters breaks Apache's ability to serve
> > those files.
> > 
> > A user reported the inability to request a file with the Chinese
> > character %b5%7c in the name.  The %7c byte tripped up the check for
> > invalid ASCII characters.
> 
> I think this is an accurate statement regarding the use of non-ASCII
> characters in filenames with Apache 1.3 on Win32.  Comments?
> 
> -------------------cut here------------------
> Names of file-based resources with Apache 1.3 on Win32
> 
> Apache 1.3 on Win32 assumes that the names of files served are comprised 
> solely of characters from the US-ASCII character set.  It has no logic to
> determine whether or not a possible file name contains invalid non-ASCII
> characters.  It has no logic to properly match actual non-ASCII file names 
> with names specified in the Apache configuration file.  Because Apache
> does not verify that the characters in file names are all ASCII, files
> files containing various non-ASCII characters in their names can be 
> successfully served by Apache.  However, this is not recommended for the
> following reasons:

No, it doesn't.  It treats all names as raw bytes, regardless of charset,
but the filtering process of preventing some filesystem-specific magic
characters from creating security holes on a server prevents the use
of unfiltered 16-bit Unicode or similar wide character sets from being used
directly.  This is true in general for the Web -- wide character encodings
are not allowed to appear in URI under any circumstances.

The solution is to use UTF-8 encoding for non-ASCII characters and not
allow any access via wide character function calls.

....Roy

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