From patchwork Fri Sep 20 08:30:07 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Christian Brauner X-Patchwork-Id: 1165092 X-Patchwork-Delegate: davem@davemloft.net Return-Path: X-Original-To: incoming-bpf@patchwork.ozlabs.org Delivered-To: patchwork-incoming-bpf@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=none (mailfrom) smtp.mailfrom=vger.kernel.org (client-ip=209.132.180.67; helo=vger.kernel.org; envelope-from=bpf-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=none (p=none dis=none) header.from=ubuntu.com Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 46ZRk81bFMz9sCJ for ; Fri, 20 Sep 2019 18:30:40 +1000 (AEST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2437435AbfITIai (ORCPT ); Fri, 20 Sep 2019 04:30:38 -0400 Received: from youngberry.canonical.com ([91.189.89.112]:39516 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2405437AbfITIai (ORCPT ); Fri, 20 Sep 2019 04:30:38 -0400 Received: from static-dcd-cqq-121001.business.bouyguestelecom.com ([212.194.121.1] 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 1iBEJC-0007Va-HJ; Fri, 20 Sep 2019 08:30:30 +0000 From: Christian Brauner To: keescook@chromium.org, luto@amacapital.net Cc: jannh@google.com, wad@chromium.org, shuah@kernel.org, ast@kernel.org, daniel@iogearbox.net, kafai@fb.com, songliubraving@fb.com, yhs@fb.com, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, netdev@vger.kernel.org, bpf@vger.kernel.org, Christian Brauner , Tycho Andersen , Tyler Hicks , stable@vger.kernel.org Subject: [PATCH v2 3/3] seccomp: test SECCOMP_USER_NOTIF_FLAG_CONTINUE Date: Fri, 20 Sep 2019 10:30:07 +0200 Message-Id: <20190920083007.11475-4-christian.brauner@ubuntu.com> X-Mailer: git-send-email 2.23.0 In-Reply-To: <20190920083007.11475-1-christian.brauner@ubuntu.com> References: <20190920083007.11475-1-christian.brauner@ubuntu.com> MIME-Version: 1.0 Sender: bpf-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org Test whether a syscall can be performed after having been intercepted by the seccomp notifier. The test uses dup() and kcmp() since it allows us to nicely test whether the dup() syscall actually succeeded by comparing whether the fds refer to the same underlying struct file. Signed-off-by: Christian Brauner Cc: Kees Cook Cc: Andy Lutomirski Cc: Will Drewry Cc: Shuah Khan Cc: Alexei Starovoitov Cc: Daniel Borkmann Cc: Martin KaFai Lau Cc: Song Liu Cc: Yonghong Song Cc: Tycho Andersen CC: Tyler Hicks Cc: stable@vger.kernel.org Cc: linux-kselftest@vger.kernel.org Cc: netdev@vger.kernel.org Cc: bpf@vger.kernel.org --- /* v2 */ - Shuah Khan : - skip test on missing precondition /* v1 */ Link: https://lore.kernel.org/r/20190919095903.19370-4-christian.brauner@ubuntu.com - Christian Brauner : - adapt to new flag name SECCOMP_USER_NOTIF_FLAG_CONTINUE /* v0 */ Link: https://lore.kernel.org/r/20190918084833.9369-5-christian.brauner@ubuntu.com --- tools/testing/selftests/seccomp/seccomp_bpf.c | 107 ++++++++++++++++++ 1 file changed, 107 insertions(+) diff --git a/tools/testing/selftests/seccomp/seccomp_bpf.c b/tools/testing/selftests/seccomp/seccomp_bpf.c index e996d7b7fd6e..2519377ebda3 100644 --- a/tools/testing/selftests/seccomp/seccomp_bpf.c +++ b/tools/testing/selftests/seccomp/seccomp_bpf.c @@ -44,6 +44,7 @@ #include #include #include +#include #include #include @@ -167,6 +168,10 @@ struct seccomp_metadata { #define SECCOMP_RET_USER_NOTIF 0x7fc00000U +#ifndef SECCOMP_USER_NOTIF_FLAG_CONTINUE +#define SECCOMP_USER_NOTIF_FLAG_CONTINUE 0x00000001 +#endif + #define SECCOMP_IOC_MAGIC '!' #define SECCOMP_IO(nr) _IO(SECCOMP_IOC_MAGIC, nr) #define SECCOMP_IOR(nr, type) _IOR(SECCOMP_IOC_MAGIC, nr, type) @@ -3481,6 +3486,108 @@ TEST(seccomp_get_notif_sizes) EXPECT_EQ(sizes.seccomp_notif_resp, sizeof(struct seccomp_notif_resp)); } +static int filecmp(pid_t pid1, pid_t pid2, int fd1, int fd2) +{ +#ifdef __NR_kcmp + return syscall(__NR_kcmp, pid1, pid2, KCMP_FILE, fd1, fd2); +#else + errno = ENOSYS; + return -1; +#endif +} + +TEST(user_notification_continue) +{ + pid_t pid; + long ret; + int status, listener; + struct seccomp_notif req = {}; + struct seccomp_notif_resp resp = {}; + struct pollfd pollfd; + + ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0); + ASSERT_EQ(0, ret) { + TH_LOG("Kernel does not support PR_SET_NO_NEW_PRIVS!"); + } + + listener = user_trap_syscall(__NR_dup, SECCOMP_FILTER_FLAG_NEW_LISTENER); + ASSERT_GE(listener, 0); + + pid = fork(); + ASSERT_GE(pid, 0); + + if (pid == 0) { + int dup_fd, pipe_fds[2]; + pid_t self; + + ret = pipe(pipe_fds); + if (ret < 0) + exit(1); + + dup_fd = dup(pipe_fds[0]); + if (dup_fd < 0) + exit(1); + + self = getpid(); + + ret = filecmp(self, self, pipe_fds[0], dup_fd); + if (ret) + exit(2); + + exit(0); + } + + pollfd.fd = listener; + pollfd.events = POLLIN | POLLOUT; + + EXPECT_GT(poll(&pollfd, 1, -1), 0); + EXPECT_EQ(pollfd.revents, POLLIN); + + EXPECT_EQ(ioctl(listener, SECCOMP_IOCTL_NOTIF_RECV, &req), 0); + + pollfd.fd = listener; + pollfd.events = POLLIN | POLLOUT; + + EXPECT_GT(poll(&pollfd, 1, -1), 0); + EXPECT_EQ(pollfd.revents, POLLOUT); + + EXPECT_EQ(req.data.nr, __NR_dup); + + resp.id = req.id; + resp.flags = SECCOMP_USER_NOTIF_FLAG_CONTINUE; + + /* + * Verify that setting SECCOMP_USER_NOTIF_FLAG_CONTINUE enforces other + * args be set to 0. + */ + resp.error = 0; + resp.val = USER_NOTIF_MAGIC; + EXPECT_EQ(ioctl(listener, SECCOMP_IOCTL_NOTIF_SEND, &resp), -1); + EXPECT_EQ(errno, EINVAL); + + resp.error = USER_NOTIF_MAGIC; + resp.val = 0; + EXPECT_EQ(ioctl(listener, SECCOMP_IOCTL_NOTIF_SEND, &resp), -1); + EXPECT_EQ(errno, EINVAL); + + resp.error = 0; + resp.val = 0; + EXPECT_EQ(ioctl(listener, SECCOMP_IOCTL_NOTIF_SEND, &resp), 0) { + if (errno == EINVAL) + XFAIL(goto skip, "Kernel does not support SECCOMP_USER_NOTIF_FLAG_CONTINUE"); + } + +skip: + EXPECT_EQ(waitpid(pid, &status, 0), pid); + EXPECT_EQ(true, WIFEXITED(status)); + EXPECT_EQ(0, WEXITSTATUS(status)) { + if (WEXITSTATUS(status) == 2) { + XFAIL(return, "Kernel does not support kcmp() syscall"); + return; + } + } +} + /* * TODO: * - add microbenchmarks