Re: /proc filesystem allows bypassing directory permissions on Linux

[Pavel Machek <pavel@xxxxxx>]

On Sat 2009-10-24 01:12:51, Dan Yefimov wrote:
> On 24.10.2009 0:35, Matthew Bergin wrote:
> >doesnt look like the original owner is trying to write to it. Shows it
> >cant, it had guest write to it via the proc folders bad permissions.
> >Looks legitimate
> >
> Please tell me, who issued 'chmod 0666 unwritable_file'? Was that an
> attacker? No, that was the owner of 'unwritable_file', nobody else.
> What the 0666 file mode means? It means, that everybody can write to
> the file, can't he? So why do you believe that pretension
> legitimate?

Original owner did chmod 666... after making sure traditional unix
permissions protect the file. Please look at original mail; it was
subtle but I believe I got it right, and file would not be writable
with /proc unmounted.

                                                                        Pavel
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