Re: [PATCH 2/2] doc: warn about following symlinks recursively in chown/chgrp

[Bernhard Voelker]

Hi Michael,

thank for that 2nd patch as well.

On 12/28/2017 09:52 PM, Michael Orlitzky wrote:
> --- a/doc/coreutils.texi
> +++ b/doc/coreutils.texi
> @@ -1427,6 +1427,9 @@ a command line argument is a symbolic link to a 
> directory, traverse it.
>   @cindex symbolic link to directory, traverse each that is encountered
>   In a recursive traversal, traverse every symbolic link to a directory
>   that is encountered.
> +This option creates a security risk: an attacker may be able to
> +introduce a symlink that reorders the directory traversal, resulting
> +in the operation being performed on an arbitrary path of his choosing.

I'm not an English native-speaker, and somehow this "reorders the directory
traversal" thing confuses me, so I doubt that a regular user will find this
sufficiently explanatory.

The point is that the attacker can create a symlink during the run of
chown/chgrp which would then be followed and chown/chgrp would operate
on the symlink target ... which in turn may not be what the calling user
- usually 'root' on GNU/Linux systems - was expecting when starting the tool.
Can you find some better words along the above lines?

Thanks & have a nice day,
Berny