1 files changed, 231 insertions, 0 deletions

diff --git a/src/regress/lib/libc/sys/t_ptrace.c b/src/regress/lib/libc/sys/t_ptrace.c
new file mode 100644
index 0000000000..756c9c514e
--- /dev/null
+++ b/src/regress/lib/libc/sys/t_ptrace.c
@@ -0,0 +1,231 @@
+/*      $OpenBSD: t_ptrace.c,v 1.1.1.1 2019/11/19 19:57:04 bluhm Exp $  */
+/*      $NetBSD: t_ptrace.c,v 1.4 2018/05/14 12:44:40 kamil Exp $       */
+
+/*-
+ * Copyright (c) 2016 The NetBSD Foundation, Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
+ * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
+ * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
+ * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "macros.h"
+
+#include <sys/cdefs.h>
+__RCSID("$NetBSD: t_ptrace.c,v 1.4 2018/05/14 12:44:40 kamil Exp $");
+
+#include <sys/param.h>
+#include <sys/types.h>
+#include <sys/ptrace.h>
+#include <sys/stat.h>
+#include <sys/sysctl.h>
+#include <err.h>
+#include <errno.h>
+#include <unistd.h>
+
+#include "atf-c.h"
+
+#include "h_macros.h"
+
+/*
+ * A child process cannot call atf functions and expect them to magically
+ * work like in the parent.
+ * The printf(3) messaging from a child will not work out of the box as well
+ * without estabilishing a communication protocol with its parent. To not
+ * overcomplicate the tests - do not log from a child and use err(3)/errx(3)
+ * wrapped with FORKEE_ASSERT()/FORKEE_ASSERTX() as that is guaranteed to work.
+ */
+#define FORKEE_ASSERTX(x)                                                       \
+do {                                                                            \
+        int ret = (x);                                                          \
+        if (!ret)                                                               \
+                errx(EXIT_FAILURE, "%s:%d %s(): Assertion failed for: %s",      \
+                     __FILE__, __LINE__, __func__, #x);                         \
+} while (0)
+
+#define FORKEE_ASSERT(x)                                                        \
+do {                                                                            \
+        int ret = (x);                                                          \
+        if (!ret)                                                               \
+                err(EXIT_FAILURE, "%s:%d %s(): Assertion failed for: %s",       \
+                     __FILE__, __LINE__, __func__, #x);                         \
+} while (0)
+
+ATF_TC(attach_pid0);
+ATF_TC_HEAD(attach_pid0, tc)
+{
+        atf_tc_set_md_var(tc, "descr",
+            "Assert that a debugger cannot attach to PID 0");
+}
+
+ATF_TC_BODY(attach_pid0, tc)
+{
+        errno = 0;
+        ATF_REQUIRE_ERRNO(EPERM, ptrace(PT_ATTACH, 0, NULL, 0) == -1);
+}
+
+ATF_TC(attach_pid1);
+ATF_TC_HEAD(attach_pid1, tc)
+{
+        atf_tc_set_md_var(tc, "descr",
+            "Assert that a debugger cannot attach to PID 1 (as non-root)");
+
+        atf_tc_set_md_var(tc, "require.user", "unprivileged");
+}
+
+ATF_TC_BODY(attach_pid1, tc)
+{
+        ATF_REQUIRE_ERRNO(EPERM, ptrace(PT_ATTACH, 1, NULL, 0) == -1);
+}
+
+ATF_TC(attach_pid1_securelevel);
+ATF_TC_HEAD(attach_pid1_securelevel, tc)
+{
+        atf_tc_set_md_var(tc, "descr",
+            "Assert that a debugger cannot attach to PID 1 with "
+            "securelevel >= 0 (as root)");
+
+        atf_tc_set_md_var(tc, "require.user", "root");
+}
+
+ATF_TC_BODY(attach_pid1_securelevel, tc)
+{
+        int level;
+        size_t len = sizeof(level);
+
+        ATF_REQUIRE(sysctlbyname("kern.securelevel", &level, &len, NULL, 0)
+            != -1);
+
+        if (level < 0) {
+                atf_tc_skip("Test must be run with securelevel >= 0");
+        }
+
+        ATF_REQUIRE_ERRNO(EPERM, ptrace(PT_ATTACH, 1, NULL, 0) == -1);
+}
+
+ATF_TC(attach_self);
+ATF_TC_HEAD(attach_self, tc)
+{
+        atf_tc_set_md_var(tc, "descr",
+            "Assert that a debugger cannot attach to self (as it's nonsense)");
+}
+
+ATF_TC_BODY(attach_self, tc)
+{
+        ATF_REQUIRE_ERRNO(EINVAL, ptrace(PT_ATTACH, getpid(), NULL, 0) == -1);
+}
+
+ATF_TC(attach_chroot);
+ATF_TC_HEAD(attach_chroot, tc)
+{
+        atf_tc_set_md_var(tc, "descr",
+            "Assert that a debugger cannot trace another process unless the "
+            "process's root directory is at or below the tracing process's "
+            "root");
+
+        atf_tc_set_md_var(tc, "require.user", "root");
+}                    
+
+ATF_TC_BODY(attach_chroot, tc)
+{
+        char buf[PATH_MAX];
+        pid_t child;
+        int fds_toparent[2], fds_fromparent[2];
+        int rv;
+        uint8_t msg = 0xde; /* dummy message for IPC based on pipe(2) */
+
+        (void)memset(buf, '\0', sizeof(buf));
+        ATF_REQUIRE(getcwd(buf, sizeof(buf)) != NULL);
+        (void)strlcat(buf, "/dir", sizeof(buf));
+
+        ATF_REQUIRE(mkdir(buf, 0500) == 0);
+        ATF_REQUIRE(chdir(buf) == 0);
+
+        ATF_REQUIRE(pipe(fds_toparent) == 0);
+        ATF_REQUIRE(pipe(fds_fromparent) == 0);
+        child = atf_utils_fork();
+        if (child == 0) {
+                FORKEE_ASSERT(close(fds_toparent[0]) == 0);
+                FORKEE_ASSERT(close(fds_fromparent[1]) == 0);
+
+                FORKEE_ASSERT(chroot(buf) == 0);
+
+                rv = write(fds_toparent[1], &msg, sizeof(msg));
+                FORKEE_ASSERTX(rv == sizeof(msg));
+
+                ATF_REQUIRE_ERRNO(EPERM,
+                        ptrace(PT_ATTACH, getppid(), NULL, 0) == -1);
+
+                rv = read(fds_fromparent[0], &msg, sizeof(msg));
+                FORKEE_ASSERTX(rv == sizeof(msg));
+
+                _exit(0);
+        }
+        ATF_REQUIRE(close(fds_toparent[1]) == 0);
+        ATF_REQUIRE(close(fds_fromparent[0]) == 0);
+
+        printf("Waiting for chrooting of the child PID %d", child);
+        rv = read(fds_toparent[0], &msg, sizeof(msg));
+        ATF_REQUIRE(rv == sizeof(msg)); 
+
+        printf("Child is ready, it will try to PT_ATTACH to parent\n");
+        rv = write(fds_fromparent[1], &msg, sizeof(msg));
+        ATF_REQUIRE(rv == sizeof(msg));
+
+        printf("fds_fromparent is no longer needed - close it\n");
+        ATF_REQUIRE(close(fds_fromparent[1]) == 0);
+
+        printf("fds_toparent is no longer needed - close it\n");
+        ATF_REQUIRE(close(fds_toparent[0]) == 0);
+}
+
+ATF_TC(traceme_twice);
+ATF_TC_HEAD(traceme_twice, tc)
+{
+        atf_tc_set_md_var(tc, "descr",
+            "Assert that a process cannot mark its parent a debugger twice");
+}
+
+ATF_TC_BODY(traceme_twice, tc)
+{
+
+        printf("Mark the parent process (PID %d) a debugger of PID %d",
+               getppid(), getpid());
+        ATF_REQUIRE(ptrace(PT_TRACE_ME, 0, NULL, 0) == 0);
+
+        printf("Mark the parent process (PID %d) a debugger of PID %d again",
+               getppid(), getpid());
+        ATF_REQUIRE_ERRNO(EBUSY, ptrace(PT_TRACE_ME, 0, NULL, 0) == -1);
+}
+
+ATF_TP_ADD_TCS(tp)
+{
+        setvbuf(stdout, NULL, _IONBF, 0);
+        setvbuf(stderr, NULL, _IONBF, 0);
+        ATF_TP_ADD_TC(tp, attach_pid0);
+        ATF_TP_ADD_TC(tp, attach_pid1);
+        ATF_TP_ADD_TC(tp, attach_pid1_securelevel);
+        ATF_TP_ADD_TC(tp, attach_self);
+        ATF_TP_ADD_TC(tp, attach_chroot);
+        ATF_TP_ADD_TC(tp, traceme_twice);
+
+        return atf_no_error();
+}