From patchwork Tue Jun 30 16:47:39 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Thadeu Lima de Souza Cascardo X-Patchwork-Id: 1320007 Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from lists.ozlabs.org (lists.ozlabs.org [203.11.71.2]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 49x9M41Wjyz9sQx for ; Wed, 1 Jul 2020 02:49:52 +1000 (AEST) Authentication-Results: ozlabs.org; dmarc=fail (p=none dis=none) header.from=canonical.com Received: from bilbo.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 49x9M32GW3zDqkc for ; Wed, 1 Jul 2020 02:49:51 +1000 (AEST) X-Original-To: linuxppc-dev@lists.ozlabs.org Delivered-To: linuxppc-dev@lists.ozlabs.org Authentication-Results: lists.ozlabs.org; spf=none (no SPF record) smtp.mailfrom=canonical.com (client-ip=91.189.89.112; helo=youngberry.canonical.com; envelope-from=cascardo@canonical.com; receiver=) Authentication-Results: lists.ozlabs.org; dmarc=fail (p=none dis=none) header.from=canonical.com Received: from youngberry.canonical.com (youngberry.canonical.com [91.189.89.112]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 49x9KM46S1zDqJh for ; Wed, 1 Jul 2020 02:48:22 +1000 (AEST) Received: from 1.general.cascardo.us.vpn ([10.172.70.58] helo=localhost.localdomain) by youngberry.canonical.com with esmtpsa (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.86_2) (envelope-from ) id 1jqJQc-0001jJ-S7; Tue, 30 Jun 2020 16:48:15 +0000 From: Thadeu Lima de Souza Cascardo To: linux-kselftest@vger.kernel.org Subject: [PATCH] selftests/seccomp: fix ptrace tests on powerpc Date: Tue, 30 Jun 2020 13:47:39 -0300 Message-Id: <20200630164739.1268222-1-cascardo@canonical.com> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Thadeu Lima de Souza Cascardo , Shuah Khan , Oleg Nesterov , Kees Cook , linuxppc-dev@lists.ozlabs.org Errors-To: linuxppc-dev-bounces+patchwork-incoming=ozlabs.org@lists.ozlabs.org Sender: "Linuxppc-dev" As pointed out by Michael Ellerman, the ptrace ABI on powerpc does not allow or require the return code to be set on syscall entry when skipping the syscall. It will always return ENOSYS and the return code must be set on syscall exit. This code does that, behaving more similarly to strace. It still sets the return code on entry, which is overridden on powerpc, and it will always repeat the same on exit. Also, on powerpc, the errno is not inverted, and depends on ccr.so being set. This has been tested on powerpc and amd64. Cc: Michael Ellerman Cc: Kees Cook Signed-off-by: Thadeu Lima de Souza Cascardo --- tools/testing/selftests/seccomp/seccomp_bpf.c | 24 +++++++++++++++---- 1 file changed, 20 insertions(+), 4 deletions(-) diff --git a/tools/testing/selftests/seccomp/seccomp_bpf.c b/tools/testing/selftests/seccomp/seccomp_bpf.c index 252140a52553..b90a9190ba88 100644 --- a/tools/testing/selftests/seccomp/seccomp_bpf.c +++ b/tools/testing/selftests/seccomp/seccomp_bpf.c @@ -1738,6 +1738,14 @@ void change_syscall(struct __test_metadata *_metadata, TH_LOG("Can't modify syscall return on this architecture"); #else regs.SYSCALL_RET = result; +# if defined(__powerpc__) + if (result < 0) { + regs.SYSCALL_RET = -result; + regs.ccr |= 0x10000000; + } else { + regs.ccr &= ~0x10000000; + } +# endif #endif #ifdef HAVE_GETREGS @@ -1796,6 +1804,7 @@ void tracer_ptrace(struct __test_metadata *_metadata, pid_t tracee, int ret, nr; unsigned long msg; static bool entry; + int *syscall_nr = args; /* * The traditional way to tell PTRACE_SYSCALL entry/exit @@ -1809,10 +1818,15 @@ void tracer_ptrace(struct __test_metadata *_metadata, pid_t tracee, EXPECT_EQ(entry ? PTRACE_EVENTMSG_SYSCALL_ENTRY : PTRACE_EVENTMSG_SYSCALL_EXIT, msg); - if (!entry) + if (!entry && !syscall_nr) return; - nr = get_syscall(_metadata, tracee); + if (entry) + nr = get_syscall(_metadata, tracee); + else + nr = *syscall_nr; + if (syscall_nr) + *syscall_nr = nr; if (nr == __NR_getpid) change_syscall(_metadata, tracee, __NR_getppid, 0); @@ -1889,9 +1903,10 @@ TEST_F(TRACE_syscall, ptrace_syscall_redirected) TEST_F(TRACE_syscall, ptrace_syscall_errno) { + int syscall_nr = -1; /* Swap SECCOMP_RET_TRACE tracer for PTRACE_SYSCALL tracer. */ teardown_trace_fixture(_metadata, self->tracer); - self->tracer = setup_trace_fixture(_metadata, tracer_ptrace, NULL, + self->tracer = setup_trace_fixture(_metadata, tracer_ptrace, &syscall_nr, true); /* Tracer should skip the open syscall, resulting in ESRCH. */ @@ -1900,9 +1915,10 @@ TEST_F(TRACE_syscall, ptrace_syscall_errno) TEST_F(TRACE_syscall, ptrace_syscall_faked) { + int syscall_nr = -1; /* Swap SECCOMP_RET_TRACE tracer for PTRACE_SYSCALL tracer. */ teardown_trace_fixture(_metadata, self->tracer); - self->tracer = setup_trace_fixture(_metadata, tracer_ptrace, NULL, + self->tracer = setup_trace_fixture(_metadata, tracer_ptrace, &syscall_nr, true); /* Tracer should skip the gettid syscall, resulting fake pid. */