From: Kees Cook <keescook@chromium.org>
To: Will Deacon <will@kernel.org>
Cc: Keno Fischer <keno@juliacomputing.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Oleg Nesterov <oleg@redhat.com>,
Andy Lutomirski <luto@amacapital.net>,
Will Drewry <wad@chromium.org>
Subject: Re: ptrace: seccomp: Return value when the call was already invalid
Date: Fri, 3 Jul 2020 08:52:05 -0700 [thread overview]
Message-ID: <202007030851.D11F1EFA@keescook> (raw)
In-Reply-To: <20200703154426.GA19406@willie-the-truck>
On Fri, Jul 03, 2020 at 04:44:27PM +0100, Will Deacon wrote:
> On Fri, Jul 03, 2020 at 08:17:19AM -0700, Kees Cook wrote:
> > On Fri, Jul 03, 2020 at 09:39:14AM +0100, Will Deacon wrote:
> > > diff --git a/arch/arm64/kernel/syscall.c b/arch/arm64/kernel/syscall.c
> > > index 5f5b868292f5..a13661f44818 100644
> > > --- a/arch/arm64/kernel/syscall.c
> > > +++ b/arch/arm64/kernel/syscall.c
> > > @@ -121,12 +121,10 @@ static void el0_svc_common(struct pt_regs *regs, int scno, int sc_nr,
> > > user_exit();
> > >
> > > if (has_syscall_work(flags)) {
> > > - /* set default errno for user-issued syscall(-1) */
> > > - if (scno == NO_SYSCALL)
> > > - regs->regs[0] = -ENOSYS;
> > > - scno = syscall_trace_enter(regs);
> > > - if (scno == NO_SYSCALL)
> > > + if (syscall_trace_enter(regs))
> > > goto trace_exit;
> > > +
> > > + scno = regs->syscallno;
> > > }
> > >
> > > invoke_syscall(regs, scno, sc_nr, syscall_table);
> >
> > What effect do either of these patches have on the existing seccomp
> > selftests: tools/testing/selftests/seccomp/seccomp_bpf ?
>
> Tests! Thanks, I'll have a look.
Thanks!
(And either way, that this behavioral difference went unnoticed means we
need to add a test to the selftests for this patch.)
--
Kees Cook
next prev parent reply other threads:[~2020-07-03 15:52 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-23 1:01 ptrace: seccomp: Return value when the call was already invalid Keno Fischer
2020-07-03 8:39 ` Will Deacon
2020-07-03 15:17 ` Kees Cook
2020-07-03 15:44 ` Will Deacon
2020-07-03 15:52 ` Kees Cook [this message]
2020-07-04 12:33 ` Will Deacon
2020-07-05 4:56 ` Kees Cook
2020-07-06 8:15 ` Will Deacon
2020-07-06 21:40 ` Kees Cook
2020-07-10 12:42 ` Will Deacon
2020-07-10 16:14 ` Kees Cook
2020-07-03 20:27 ` Keno Fischer
2020-07-04 12:50 ` Will Deacon
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