Re: /proc filesystem allows bypassing directory permissions on Linux

[Tony Finch <dot () dotat at>]

On Mon, 26 Oct 2009, Matthew Dempsky wrote:
> On Mon, Oct 26, 2009 at 9:01 AM, Tony Finch <dot () dotat at> wrote:
> > Attacker uses openat() to open and modify the "private" file.
>
> At least with Linux 2.6.18, you still need +x permission on the
> directory to access its contents using openat(2).

According to POSIX, if you open the directory with O_SEARCH then openat()
does not re-check search (+x) permissions.

Tony.
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