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From Ben Laurie <...@gonzo.ben.algroup.co.uk>
Subject Re: Yet another URL-encoding bug
Date Fri, 13 Oct 1995 16:49:01 GMT
> 
> Yet another URL-encoding bug:
> Redirect /wibble/ http://aserver/dir/
> 
> accessing http://myserver/wibble/heelo%25.html
> generates a redirect to the Location: http://aserver/dir/heelo%.html
> 
> mod_alias.c was not re-escaping the incoming URL for the redirect.
> 
> I've uploaded 26_redirect2.0.8.14.patch to hyperreal.com in the
> for_Apache_0.8.14 directory (for the lack of a better place).
> This patch calls escape_uri to fix the problem.
> 
> I would rather use os_escape_path() to escape the URI, but unfortunately, that
> would break on requests with a ':' - e.g.
> http://myserver/wibble/hello:.html would return a Location: of
> http://aserver/dir/./hello:.html
> 
> My preferred solution would be to change os_escape_path() so that it escapes
> ':' - that way it can be called on both relative and absolute paths.
> I think that is much neater than having two routines.

Well, there are (at least) two answers to this. Answer one is to escape the
new path _after_ you have assembled the parts (not strictly correct, I'll
agree). Answer two is that a ./ is _removed_ anyway (see RFC 1808), so
can't affect the path. Answer three (probably the best) is to tell
os_escape_path whether the path is absolute or relative, by prepending a '/',
i.e. you pass it "/hello:.html" to escape, then it doesn't put the ./ in.

BTW, the relevant bit of RFC 1808 is:

Step 6: The last segment of the base URL's path (anything
           following the rightmost slash "/", or the entire path if no
           slash is present) is removed and the embedded URL's path is
           appended in its place.  The following operations are
           then applied, in order, to the new path:

           a) All occurrences of "./", where "." is a complete path
              segment, are removed.


> 
> I've also copied across the QNX port patch.
> 
>  David.
> 
> 26_redirect2.0.8.14.patch:
>   From: drtr@ast.cam.ac.uk (David Robinson)
>   Subject: Fix handling of % in Redirect command
>   Affects: mod_alias.c
>   ChangeLog: Escape the URI before generating the redirect.
> 
> 27_qnx.0.8.14.patch:
>   Subject: QNX Port
>   Affects: alloc.c conf.h http_main.c rfc931.c util.c Configuration
>   Changelog: QNX Port
>   Comments: This patch also removes some redundant headers (not gratuitously,
>           they had to go on QNX anyway, and were already included in some other
>           local header). It also adds a debugging convenience; SIGSEGV and
>           SIGBUS are not caught when in debug mode (-X flag). This makes
>           running under some debuggers better.
> 

-- 
Ben Laurie                  Phone: +44 (181) 994 6435
Freelance Consultant        Fax:   +44 (181) 994 6472
and Technical Director      Email: ben@algroup.co.uk
A.L. Digital Ltd,
London, England.

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