lists  /  announce  owl-users  owl-dev  john-users  john-dev  passwdqc-users  yescrypt  popa3d-users  /  oss-security  kernel-hardening  musl  sabotage  tlsify  passwords  /  crypt-dev  xvendor  /  Bugtraq  Full-Disclosure  linux-kernel  linux-netdev  linux-ext4  linux-hardening  linux-cve-announce  PHC 
Open Source and information security mailing list archives
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Date:   Wed, 8 May 2019 16:09:43 -0700
From:   Alexei Starovoitov <>
To:     Eric Dumazet <>
Cc:     Alexei Starovoitov <>,
        Daniel Borkmann <>,
        netdev <>,
Subject: Re: Question about seccomp / bpf

On Wed, May 08, 2019 at 02:21:52PM -0700, Eric Dumazet wrote:
> Hi Alexei and Daniel
> I have a question about seccomp.
> It seems that after this patch, seccomp no longer needs a helper
> (seccomp_bpf_load())
> Are we detecting that a particular JIT code needs to call at least one
> function from the kernel at all ?

Currently we don't track such things and trying very hard to avoid
any special cases for classic vs extended.

> If the filter contains self-contained code (no call, just inline
> code), then we could use any room in whole vmalloc space,
> not only from the modules (which is something like 2GB total on x86_64)

I believe there was an effort to make bpf progs and other executable things
to be everywhere too, but I lost the track of it.
It's not that hard to tweak x64 jit to emit 64-bit calls to helpers
when delta between call insn and a helper is more than 32-bit that fits
into call insn. iirc there was even such patch floating around.

but what motivated you question? do you see 2GB space being full?!

Powered by blists - more mailing lists