Re: [PATCH v2 2/2] rusage: allow 64-bit times ru_utime/ru_stime

* Eric W. Biederman [off-list ref] wrote:

Ingo Molnar [off-list ref] writes:

quoted

* Eric W. Biederman [off-list ref] wrote:

quoted

The trouble with attributes is that means you can't filter your system
call arguments with seccomp. [...]

There's nothing keeping seccomp from securely fetching those arguments and 
extending filtering to them as well ...

Allowing that would make sense for a lot of other system calls as
well.

Possibly.  The challenge is that if the fetch for the kernel to use
those arguments is different from the fetch of seccomp to test those
arguments you have a time of test vs time of use race.

Those fetched values should obviously then be used to call permitted system calls.

Given the location of the seccomp hook at the kernel user space border
there is no easy way for seccomp to share the fetch with the system
call itself.

So I don't see how seccomp could perform the fetch securely.

Looks like more of a seccomp mis-design/mis-implementation than some fundamental 
problem.

Mis-designed security features should not hinder system call design.

Thanks,

	Ingo
_______________________________________________
Y2038 mailing list
Y2038@lists.linaro.org
https://lists.linaro.org/mailman/listinfo/y2038