Re: [PATCH v8 3/8] seccomp: add system call filtering using BPF

On Thu, 2012-02-16 at 17:00 -0600, Will Drewry wrote:

On Thu, Feb 16, 2012 at 4:06 PM, H. Peter Anvin [off-list ref] wrote:

quoted

On 02/16/2012 01:51 PM, Will Drewry wrote:

Then syscall_namespace(current, regs) returns
* 0 - SYSCALL_NS_32 (for existing 32 and config_compat)
* 1 - SYSCALL_NS_64 (for existing 64 bit)
* 2 - SYSCALL_NS_X32 (everything after 2 is arch specific)
* ..

This patch series is pegged to x86 right now, so it's not a big deal
to add a simple syscall_namespace to asm/syscall.h.  Of course, the
code is always the easy part.  Even easier would be to only assign 0
and 1 in the seccomp_data for 32-bit or 64-bit, then leave the rest of
the u32 untouched until x32 stabilizes and the TS_COMPAT interactions
are sorted.

I don't know if anyone cares, but include/linux/audit.h tries to expose
this type of information so audit userspace can later piece things back
together.  (we get this info from the syscall entry exit code so we know
which arch it is).

Not sure how x32 is hoping to expose its syscall info, but others are
going to have the same/similar problem.

-Eric