Messages in this thread | | | Date | Tue, 8 Nov 2011 15:17:52 -0800 | From | Andrew Morton <> | Subject | Re: [PATCH] proc: restrict access to /proc/$PID/{sched,schedstat} |
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On Tue, 8 Nov 2011 15:59:00 +0400 Vasiliy Kulikov <segoon@openwall.com> wrote:
> (CC'ed l-k)
security@kernel.org isn't working, btw.
> On Sat, Nov 05, 2011 at 14:48 +0400, Vasiliy Kulikov wrote: > > /proc/$PID/{sched,schedstat} contain debugging scheduler counters, which > > should not be world readable. They may be used to gather private information > > about processes' activity. E.g. it can be used to count the number of > > characters typed in gksu dialog: > > > > http://www.openwall.com/lists/oss-security/2011/11/05/3 > > > > This infoleak is similar to io (1d1221f375c) and stat's eip/esp (f83ce3e6b02d) > > infoleaks. Probably other 0644/0444 procfs files are vulnerable to > > similar infoleaks.
Grumble.
The obvious issue with this patch is its non-back-compatibility. What existing code will break, in what manner and what is the seriousness of the breakage?
You *know* this is the main issue, yet you didn't address it at all! You just leave the issue out there for other people to work out, and to ask the obvious questions.
This happens over and over and I'm getting rather tired of the charade.
So I'm going to ignore this patch and I ask that you and other security people never do this again.
If you're going to submit a patch which you know will change kernel interfaces in a non-backward-compatible fashion then don't just pretend that it didn't happen! Please provide us with a complete description of the breakage and at least some analysis of the downstream implications of the change. So that we are better able to decide whether the security improvements justify the disruption.
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