Re: d_path() truncating excessive long path name vulnerability

[Solar Designer <solar () openwall com>]

On Wed, Nov 27, 2002 at 01:04:04PM +1100, Paul Szabo wrote:
> Back in March 2002, Wojciech Purczynski <cliph () isec pl> wrote (original
> article at http://online.securityfocus.com/archive/1/264117 ):
>
> > Name:               Linux kernel
> > Version:    up to 2.2.20 and 2.4.18
> > ...
> > In case of excessively long path names d_path kernel internal function
> > returns truncated trailing components of a path name instead of an error
> > value. As this function is called by getcwd(2) system call and
> > do_proc_readlink() function, false information may be returned to
> > user-space processes.
>
> The problem is still present in Debian 2.4.19 kernel. I have not tried 2.5,
> but see nothing relevant in the Changelogs at http://www.kernel.org/ .

FWIW, I've included a workaround for this (covering the getcwd(2) case
only, not other uses of d_path() by the kernel or modules) in 2.2.21-ow1
patch and it went into 2.2.22 release in September.

This kind of proves the need for double-checking newer kernel branches
(2.4.x and 2.5.x currently) for fixes going into what many consider
stable kernels.

-- 
/sd