From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.0 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7CC36C282C4 for ; Mon, 4 Feb 2019 10:52:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 45061217D6 for ; Mon, 4 Feb 2019 10:52:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1549277534; bh=Z6P6k4kC2l3sEg+nTLw7cZCNEMW6pKqxVQT2F9BiDKw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=ytgLIMxNB9YB4A2QopybyClWIbGMS9G2vKjLHpH0ioBIEx7oCo8R9tVP312YqWyHp 7Ql2beqWF9yXoPMsDEprdg/AxUTXU7ENa1MECtY2CUOHd2421vA6i4o9a6MDT5t9+e l7/pxwPhKrzGZKxToK1cl2sXn2LcqgwRoOtp+VsM= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732552AbfBDKwN (ORCPT ); Mon, 4 Feb 2019 05:52:13 -0500 Received: from mail.kernel.org ([198.145.29.99]:49888 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732537AbfBDKwJ (ORCPT ); Mon, 4 Feb 2019 05:52:09 -0500 Received: from localhost (5356596B.cm-6-7b.dynamic.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 15D442070C; Mon, 4 Feb 2019 10:52:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1549277528; bh=Z6P6k4kC2l3sEg+nTLw7cZCNEMW6pKqxVQT2F9BiDKw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=egiVEZYK8UQe4Zydf8rJDG+CXIqaSzumzAkR3u8IH6cPH9M/tHaSG/fHIAZd4VYtE RvuCEVqtdttheVvUMxHQxicxDucVDukODTCv9uM2rYYn+RsI+pRAdVXN4n4eWiP97Y Fp8S9bdmP4Qj2k2661XdUG4CAD5b/cMQ0IKjvxKE= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Colin Ian King , Kees Cook , Shuah Khan Subject: [PATCH 4.20 42/80] selftests/seccomp: Enhance per-arch ptrace syscall skip tests Date: Mon, 4 Feb 2019 11:37:02 +0100 Message-Id: <20190204103625.844879723@linuxfoundation.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190204103620.287366543@linuxfoundation.org> References: <20190204103620.287366543@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review X-Patchwork-Hint: ignore MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 4.20-stable review patch. If anyone has any objections, please let me know. ------------------ From: Kees Cook commit ed5f13261cb65b02c611ae9971677f33581d4286 upstream. Passing EPERM during syscall skipping was confusing since the test wasn't actually exercising the errno evaluation -- it was just passing a literal "1" (EPERM). Instead, expand the tests to check both direct value returns (positive, 45000 in this case), and errno values (negative, -ESRCH in this case) to check both fake success and fake failure during syscall skipping. Reported-by: Colin Ian King Fixes: a33b2d0359a0 ("selftests/seccomp: Add tests for basic ptrace actions") Cc: stable@vger.kernel.org Signed-off-by: Kees Cook Signed-off-by: Shuah Khan Signed-off-by: Greg Kroah-Hartman --- tools/testing/selftests/seccomp/seccomp_bpf.c | 72 ++++++++++++++++++++------ 1 file changed, 57 insertions(+), 15 deletions(-) --- a/tools/testing/selftests/seccomp/seccomp_bpf.c +++ b/tools/testing/selftests/seccomp/seccomp_bpf.c @@ -1563,7 +1563,16 @@ TEST_F(TRACE_poke, getpid_runs_normally) #ifdef SYSCALL_NUM_RET_SHARE_REG # define EXPECT_SYSCALL_RETURN(val, action) EXPECT_EQ(-1, action) #else -# define EXPECT_SYSCALL_RETURN(val, action) EXPECT_EQ(val, action) +# define EXPECT_SYSCALL_RETURN(val, action) \ + do { \ + errno = 0; \ + if (val < 0) { \ + EXPECT_EQ(-1, action); \ + EXPECT_EQ(-(val), errno); \ + } else { \ + EXPECT_EQ(val, action); \ + } \ + } while (0) #endif /* Use PTRACE_GETREGS and PTRACE_SETREGS when available. This is useful for @@ -1602,7 +1611,7 @@ int get_syscall(struct __test_metadata * /* Architecture-specific syscall changing routine. */ void change_syscall(struct __test_metadata *_metadata, - pid_t tracee, int syscall) + pid_t tracee, int syscall, int result) { int ret; ARCH_REGS regs; @@ -1661,7 +1670,7 @@ void change_syscall(struct __test_metada #ifdef SYSCALL_NUM_RET_SHARE_REG TH_LOG("Can't modify syscall return on this architecture"); #else - regs.SYSCALL_RET = EPERM; + regs.SYSCALL_RET = result; #endif #ifdef HAVE_GETREGS @@ -1689,14 +1698,19 @@ void tracer_syscall(struct __test_metada case 0x1002: /* change getpid to getppid. */ EXPECT_EQ(__NR_getpid, get_syscall(_metadata, tracee)); - change_syscall(_metadata, tracee, __NR_getppid); + change_syscall(_metadata, tracee, __NR_getppid, 0); break; case 0x1003: - /* skip gettid. */ + /* skip gettid with valid return code. */ EXPECT_EQ(__NR_gettid, get_syscall(_metadata, tracee)); - change_syscall(_metadata, tracee, -1); + change_syscall(_metadata, tracee, -1, 45000); break; case 0x1004: + /* skip openat with error. */ + EXPECT_EQ(__NR_openat, get_syscall(_metadata, tracee)); + change_syscall(_metadata, tracee, -1, -ESRCH); + break; + case 0x1005: /* do nothing (allow getppid) */ EXPECT_EQ(__NR_getppid, get_syscall(_metadata, tracee)); break; @@ -1729,9 +1743,11 @@ void tracer_ptrace(struct __test_metadat nr = get_syscall(_metadata, tracee); if (nr == __NR_getpid) - change_syscall(_metadata, tracee, __NR_getppid); + change_syscall(_metadata, tracee, __NR_getppid, 0); + if (nr == __NR_gettid) + change_syscall(_metadata, tracee, -1, 45000); if (nr == __NR_openat) - change_syscall(_metadata, tracee, -1); + change_syscall(_metadata, tracee, -1, -ESRCH); } FIXTURE_DATA(TRACE_syscall) { @@ -1748,8 +1764,10 @@ FIXTURE_SETUP(TRACE_syscall) BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_TRACE | 0x1002), BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, __NR_gettid, 0, 1), BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_TRACE | 0x1003), - BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, __NR_getppid, 0, 1), + BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, __NR_openat, 0, 1), BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_TRACE | 0x1004), + BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, __NR_getppid, 0, 1), + BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_TRACE | 0x1005), BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW), }; @@ -1797,15 +1815,26 @@ TEST_F(TRACE_syscall, ptrace_syscall_red EXPECT_NE(self->mypid, syscall(__NR_getpid)); } -TEST_F(TRACE_syscall, ptrace_syscall_dropped) +TEST_F(TRACE_syscall, ptrace_syscall_errno) +{ + /* Swap SECCOMP_RET_TRACE tracer for PTRACE_SYSCALL tracer. */ + teardown_trace_fixture(_metadata, self->tracer); + self->tracer = setup_trace_fixture(_metadata, tracer_ptrace, NULL, + true); + + /* Tracer should skip the open syscall, resulting in ESRCH. */ + EXPECT_SYSCALL_RETURN(-ESRCH, syscall(__NR_openat)); +} + +TEST_F(TRACE_syscall, ptrace_syscall_faked) { /* Swap SECCOMP_RET_TRACE tracer for PTRACE_SYSCALL tracer. */ teardown_trace_fixture(_metadata, self->tracer); self->tracer = setup_trace_fixture(_metadata, tracer_ptrace, NULL, true); - /* Tracer should skip the open syscall, resulting in EPERM. */ - EXPECT_SYSCALL_RETURN(EPERM, syscall(__NR_openat)); + /* Tracer should skip the gettid syscall, resulting fake pid. */ + EXPECT_SYSCALL_RETURN(45000, syscall(__NR_gettid)); } TEST_F(TRACE_syscall, syscall_allowed) @@ -1838,7 +1867,21 @@ TEST_F(TRACE_syscall, syscall_redirected EXPECT_NE(self->mypid, syscall(__NR_getpid)); } -TEST_F(TRACE_syscall, syscall_dropped) +TEST_F(TRACE_syscall, syscall_errno) +{ + long ret; + + ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0); + ASSERT_EQ(0, ret); + + ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->prog, 0, 0); + ASSERT_EQ(0, ret); + + /* openat has been skipped and an errno return. */ + EXPECT_SYSCALL_RETURN(-ESRCH, syscall(__NR_openat)); +} + +TEST_F(TRACE_syscall, syscall_faked) { long ret; @@ -1849,8 +1892,7 @@ TEST_F(TRACE_syscall, syscall_dropped) ASSERT_EQ(0, ret); /* gettid has been skipped and an altered return value stored. */ - EXPECT_SYSCALL_RETURN(EPERM, syscall(__NR_gettid)); - EXPECT_NE(self->mytid, syscall(__NR_gettid)); + EXPECT_SYSCALL_RETURN(45000, syscall(__NR_gettid)); } TEST_F(TRACE_syscall, skip_after_RET_TRACE)