Re: Fw: seccomp selftest on s390

From: Kees Cook
Date: Fri Aug 21 2015 - 12:56:37 EST


On Fri, Aug 21, 2015 at 5:20 AM, Jan Willeke <willeke@xxxxxxxxxxxxxxxxxx> wrote:
> On Fri, 2015-08-20 at 23:33 , Kees Cook wrote:
>> Hi!
>>
>> I don't have access to s390 running a modern kernel, so I've not been able
>> to meaningfully run the seccomp selftest suite. In a quick review, I think
>> the following is close to the missing pieces, but I can't verify it. :)
>>
>> Can someone let me know if this works, or otherwise check that the
>> tools/testing/selftests/seccomp suite passes on s390?
>>
>> Thanks!
>>
>> -Kees
>>
>> --- seccomp_bpf.c.orig 2015-08-20 21:13:17.735789007 +0000
>> +++ seccomp_bpf.c 2015-08-20 21:09:49.547879621 +0000
>> @@ -1210,6 +1211,10 @@
>> # define ARCH_REGS struct pt_regs
>> # define SYSCALL_NUM gpr[0]
>> # define SYSCALL_RET gpr[3]
>> +#elif defined(__s390__)
>> +# define ARCH_REGS s390_regs
>> +# define SYSCALL_NUM gprs[1]
>> +# define SYSCALL_RET gprs[2]
>> #else
>> # error "Do not know how to find your architecture's registers and
>> syscalls"
>> #endif
>> @@ -1243,7 +1248,7 @@
>> ret = ptrace(PTRACE_GETREGSET, tracee, NT_PRSTATUS, &iov);
>> EXPECT_EQ(0, ret);
>>
>> -#if defined(__x86_64__) || defined(__i386__) || defined(__aarch64__) ||
>> defined(__powerpc__)
>> +#if defined(__x86_64__) || defined(__i386__) || defined(__aarch64__) ||
>> defined(__powerpc__) || defined(__s390__)
>> {
>> regs.SYSCALL_NUM = syscall;
>> }
>>
>> --
>> Kees Cook
>> Chrome OS Security
>>
>>
>
>
> Hi Kees,
> to compile the code warning free I added:
>
> @@ -1409,6 +1413,8 @@ TEST_F(TRACE_syscall, syscall_dropped)
> # define __NR_seccomp 277
> # elif defined(__powerpc__)
> # define __NR_seccomp 358
> +# elif defined(__s390__)
> +# define __NR_seccomp 348
> # else
> # warning "seccomp syscall number unknown for this architecture"
> # define __NR_seccomp 0xffff

Ah, yes. Whoops that got left off my cut/paste. :)

>
> than I run the testcase on the linux next kernel, result:
>
> ./seccomp_bpf
> [==========] Running 48 tests from 1 test cases.
> ...
> [ OK ] TRACE_syscall.syscall_allowed
> [ RUN ] TRACE_syscall.syscall_redirected
> seccomp_bpf.c:1386:TRACE_syscall.syscall_redirected:Expected
> self->parent (2774548873216) == syscall(20) (686)
> seccomp_bpf.c:1387:TRACE_syscall.syscall_redirected:Expected self->mypid
> (2946347565056) != syscall(20) (686)
> [ FAIL ] TRACE_syscall.syscall_redirected
> [ RUN ] TRACE_syscall.syscall_dropped
> [ OK ] TRACE_syscall.syscall_dropped
> ...
> [ RUN ] TSYNC.two_siblings_not_under_filter
> [ OK ] TSYNC.two_siblings_not_under_filter
> [ RUN ] global.syscall_restart
> seccomp_bpf.c:2063:global.syscall_restart:Expected 168 (721554505728) ==
> get_syscall(_metadata, child_pid) (14965540365812105216)
> seccomp_bpf.c:2104:global.syscall_restart:Expected 7 (30064771072) ==
> ret (18446744072899020716)
> [ FAIL ] global.syscall_restart
> [==========] 46 / 48 tests passed.
> [ FAILED ]
>
> I hope that helps you.

It does, thanks! 46 of 48 is very close. :) I'll study this output to
see if I can figure out what's needed next.

-Kees

>
> regards Jan
>
> Linux on z Systems Development
> ----------------------------------------------------
> IBM Deutschland Research & Development GmbH, Vorsitzende des
> Aufsichtsrats:
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>



--
Kees Cook
Chrome OS Security
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