Adding upstream version 1:8.4p1.upstream/1%8.4p1upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 218 insertions, 0 deletions

diff --git a/sandbox-systrace.c b/sandbox-systrace.c
new file mode 100644
index 0000000..e61d581
--- /dev/null
+++ b/sandbox-systrace.c
@@ -0,0 +1,218 @@
+/* $OpenBSD: sandbox-systrace.c,v 1.18 2015/10/02 01:39:26 deraadt Exp $ */
+/*
+ * Copyright (c) 2011 Damien Miller <djm@mindrot.org>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#include "includes.h"
+
+#ifdef SANDBOX_SYSTRACE
+
+#include <sys/types.h>
+#include <sys/ioctl.h>
+#include <sys/syscall.h>
+#include <sys/socket.h>
+#include <sys/wait.h>
+
+#include <dev/systrace.h>
+
+#include <errno.h>
+#include <fcntl.h>
+#include <limits.h>
+#include <signal.h>
+#include <stdarg.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#include "atomicio.h"
+#include "log.h"
+#include "ssh-sandbox.h"
+#include "xmalloc.h"
+
+struct sandbox_policy {
+	int syscall;
+	int action;
+};
+
+/* Permitted syscalls in preauth. Unlisted syscalls get SYSTR_POLICY_KILL */
+static const struct sandbox_policy preauth_policy[] = {
+	{ SYS_exit, SYSTR_POLICY_PERMIT },
+#ifdef SYS_kbind
+	{ SYS_kbind, SYSTR_POLICY_PERMIT },
+#endif
+
+	{ SYS_getpid, SYSTR_POLICY_PERMIT },
+	{ SYS_getpgid, SYSTR_POLICY_PERMIT },
+	{ SYS_clock_gettime, SYSTR_POLICY_PERMIT },
+	{ SYS_gettimeofday, SYSTR_POLICY_PERMIT },
+	{ SYS_nanosleep, SYSTR_POLICY_PERMIT },
+	{ SYS_sigprocmask, SYSTR_POLICY_PERMIT },
+
+#ifdef SYS_getentropy
+	/* OpenBSD 5.6 and newer use getentropy(2) to seed arc4random(3). */
+	{ SYS_getentropy, SYSTR_POLICY_PERMIT },
+#else
+	/* Previous releases used sysctl(3)'s kern.arnd variable. */
+	{ SYS___sysctl, SYSTR_POLICY_PERMIT },
+#endif
+#ifdef SYS_sendsyslog
+	{ SYS_sendsyslog, SYSTR_POLICY_PERMIT },
+#endif
+
+	{ SYS_madvise, SYSTR_POLICY_PERMIT },
+	{ SYS_mmap, SYSTR_POLICY_PERMIT },
+	{ SYS_mprotect, SYSTR_POLICY_PERMIT },
+	{ SYS_mquery, SYSTR_POLICY_PERMIT },
+	{ SYS_munmap, SYSTR_POLICY_PERMIT },
+
+	{ SYS_poll, SYSTR_POLICY_PERMIT },
+	{ SYS_select, SYSTR_POLICY_PERMIT },
+	{ SYS_read, SYSTR_POLICY_PERMIT },
+	{ SYS_write, SYSTR_POLICY_PERMIT },
+	{ SYS_shutdown, SYSTR_POLICY_PERMIT },
+	{ SYS_close, SYSTR_POLICY_PERMIT },
+
+	{ SYS_open, SYSTR_POLICY_NEVER },
+
+	{ -1, -1 }
+};
+
+struct ssh_sandbox {
+	int systrace_fd;
+	pid_t child_pid;
+	void (*osigchld)(int);
+};
+
+struct ssh_sandbox *
+ssh_sandbox_init(struct monitor *monitor)
+{
+	struct ssh_sandbox *box;
+
+	debug3("%s: preparing systrace sandbox", __func__);
+	box = xcalloc(1, sizeof(*box));
+	box->systrace_fd = -1;
+	box->child_pid = 0;
+	box->osigchld = ssh_signal(SIGCHLD, SIG_IGN);
+
+	return box;
+}
+
+void
+ssh_sandbox_child(struct ssh_sandbox *box)
+{
+	debug3("%s: ready", __func__);
+	ssh_signal(SIGCHLD, box->osigchld);
+	if (kill(getpid(), SIGSTOP) != 0)
+		fatal("%s: kill(%d, SIGSTOP)", __func__, getpid());
+	debug3("%s: started", __func__);
+}
+
+static void
+ssh_sandbox_parent(struct ssh_sandbox *box, pid_t child_pid,
+    const struct sandbox_policy *allowed_syscalls)
+{
+	int dev_systrace, i, j, found, status;
+	pid_t pid;
+	struct systrace_policy policy;
+
+	/* Wait for the child to send itself a SIGSTOP */
+	debug3("%s: wait for child %ld", __func__, (long)child_pid);
+	do {
+		pid = waitpid(child_pid, &status, WUNTRACED);
+	} while (pid == -1 && errno == EINTR);
+	ssh_signal(SIGCHLD, box->osigchld);
+	if (!WIFSTOPPED(status)) {
+		if (WIFSIGNALED(status))
+			fatal("%s: child terminated with signal %d",
+			    __func__, WTERMSIG(status));
+		if (WIFEXITED(status))
+			fatal("%s: child exited with status %d",
+			    __func__, WEXITSTATUS(status));
+		fatal("%s: child not stopped", __func__);
+	}
+	debug3("%s: child %ld stopped", __func__, (long)child_pid);
+	box->child_pid = child_pid;
+
+	/* Set up systracing of child */
+	if ((dev_systrace = open("/dev/systrace", O_RDONLY)) == -1)
+		fatal("%s: open(\"/dev/systrace\"): %s", __func__,
+		    strerror(errno));
+	if (ioctl(dev_systrace, STRIOCCLONE, &box->systrace_fd) == -1)
+		fatal("%s: ioctl(STRIOCCLONE, %d): %s", __func__,
+		    dev_systrace, strerror(errno));
+	close(dev_systrace);
+	debug3("%s: systrace attach, fd=%d", __func__, box->systrace_fd);
+	if (ioctl(box->systrace_fd, STRIOCATTACH, &child_pid) == -1)
+		fatal("%s: ioctl(%d, STRIOCATTACH, %d): %s", __func__,
+		    box->systrace_fd, child_pid, strerror(errno));
+
+	/* Allocate and assign policy */
+	memset(&policy, 0, sizeof(policy));
+	policy.strp_op = SYSTR_POLICY_NEW;
+	policy.strp_maxents = SYS_MAXSYSCALL;
+	if (ioctl(box->systrace_fd, STRIOCPOLICY, &policy) == -1)
+		fatal("%s: ioctl(%d, STRIOCPOLICY (new)): %s", __func__,
+		    box->systrace_fd, strerror(errno));
+
+	policy.strp_op = SYSTR_POLICY_ASSIGN;
+	policy.strp_pid = box->child_pid;
+	if (ioctl(box->systrace_fd, STRIOCPOLICY, &policy) == -1)
+		fatal("%s: ioctl(%d, STRIOCPOLICY (assign)): %s",
+		    __func__, box->systrace_fd, strerror(errno));
+
+	/* Set per-syscall policy */
+	for (i = 0; i < SYS_MAXSYSCALL; i++) {
+		found = 0;
+		for (j = 0; allowed_syscalls[j].syscall != -1; j++) {
+			if (allowed_syscalls[j].syscall == i) {
+				found = 1;
+				break;
+			}
+		}
+		policy.strp_op = SYSTR_POLICY_MODIFY;
+		policy.strp_code = i;
+		policy.strp_policy = found ?
+		    allowed_syscalls[j].action : SYSTR_POLICY_KILL;
+		if (found)
+			debug3("%s: policy: enable syscall %d", __func__, i);
+		if (ioctl(box->systrace_fd, STRIOCPOLICY, &policy) == -1)
+			fatal("%s: ioctl(%d, STRIOCPOLICY (modify)): %s",
+			    __func__, box->systrace_fd, strerror(errno));
+	}
+
+	/* Signal the child to start running */
+	debug3("%s: start child %ld", __func__, (long)child_pid);
+	if (kill(box->child_pid, SIGCONT) != 0)
+		fatal("%s: kill(%d, SIGCONT)", __func__, box->child_pid);
+}
+
+void
+ssh_sandbox_parent_finish(struct ssh_sandbox *box)
+{
+	/* Closing this before the child exits will terminate it */
+	close(box->systrace_fd);
+
+	free(box);
+	debug3("%s: finished", __func__);
+}
+
+void
+ssh_sandbox_parent_preauth(struct ssh_sandbox *box, pid_t child_pid)
+{
+	ssh_sandbox_parent(box, child_pid, preauth_policy);
+}
+
+#endif /* SANDBOX_SYSTRACE */