1 files changed, 39 insertions, 72 deletions

diff --git a/sandbox-systrace.c b/sandbox-systrace.c
index 04f54a3b6..2d16a627f 100644
--- a/sandbox-systrace.c
+++ b/sandbox-systrace.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: sandbox-systrace.c,v 1.4 2011/07/29 14:42:45 djm Exp $ */
+/* $OpenBSD: sandbox-systrace.c,v 1.6 2012/06/30 14:35:09 markus Exp $ */
 /*
  * Copyright (c) 2011 Damien Miller <djm@mindrot.org>
  *
@@ -17,22 +17,21 @@
 
 #include "includes.h"
 
-#include <sys/types.h>
-
-#include "ssh-sandbox.h"
-
 #ifdef SANDBOX_SYSTRACE
 
+#include <sys/types.h>
 #include <sys/param.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>
@@ -41,6 +40,7 @@
 
 #include "atomicio.h"
 #include "log.h"
+#include "ssh-sandbox.h"
 #include "xmalloc.h"
 
 struct sandbox_policy {
@@ -60,6 +60,7 @@ static const struct sandbox_policy preauth_policy[] = {
         { SYS_madvise, SYSTR_POLICY_PERMIT },
         { SYS_mmap, SYSTR_POLICY_PERMIT },
         { SYS_mprotect, SYSTR_POLICY_PERMIT },
+        { SYS_mquery, SYSTR_POLICY_PERMIT },
         { SYS_poll, SYSTR_POLICY_PERMIT },
         { SYS_munmap, SYSTR_POLICY_PERMIT },
         { SYS_read, SYSTR_POLICY_PERMIT },
@@ -70,69 +71,60 @@ static const struct sandbox_policy preauth_policy[] = {
 };
 
 struct ssh_sandbox {
-        int child_sock;
-        int parent_sock;
         int systrace_fd;
         pid_t child_pid;
+        void (*osigchld)(int);
 };
 
-static int
-sandbox_systrace_probe(void)
-{
-        return 1;
-}
-
-static void *
-sandbox_systrace_init(void)
+struct ssh_sandbox *
+ssh_sandbox_init(void)
 {
         struct ssh_sandbox *box;
-        int s[2];
 
         debug3("%s: preparing systrace sandbox", __func__);
         box = xcalloc(1, sizeof(*box));
-        if (socketpair(AF_UNIX, SOCK_STREAM, 0, s) == -1)
-                fatal("%s: socketpair: %s", __func__, strerror(errno));
-        box->child_sock = s[0];
-        box->parent_sock = s[1];
         box->systrace_fd = -1;
         box->child_pid = 0;
+        box->osigchld = signal(SIGCHLD, SIG_IGN);
 
         return box;
 }
 
-static void
-sandbox_systrace_child(void *vbox)
+void
+ssh_sandbox_child(struct ssh_sandbox *box)
 {
-        struct ssh_sandbox *box = vbox;
-        char whatever = 0;
-
-        close(box->parent_sock);
-        /* Signal parent that we are ready */
         debug3("%s: ready", __func__);
-        if (atomicio(vwrite, box->child_sock, &whatever, 1) != 1)
-                fatal("%s: write: %s", __func__, strerror(errno));
-        /* Wait for parent to signal for us to go */
-        if (atomicio(read, box->child_sock, &whatever, 1) != 1)
-                fatal("%s: read: %s", __func__, strerror(errno));
+        signal(SIGCHLD, box->osigchld);
+        if (kill(getpid(), SIGSTOP) != 0)
+                fatal("%s: kill(%d, SIGSTOP)", __func__, getpid());
         debug3("%s: started", __func__);
-        close(box->child_sock);
 }
 
 static void
-sandbox_systrace_parent(struct ssh_sandbox *box, pid_t child_pid,
+ssh_sandbox_parent(struct ssh_sandbox *box, pid_t child_pid,
     const struct sandbox_policy *allowed_syscalls)
 {
-        int dev_systrace, i, j, found;
-        char whatever = 0;
+        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);
+        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;
-        close(box->child_sock);
-        /* Wait for child to signal that it is ready */
-        if (atomicio(read, box->parent_sock, &whatever, 1) != 1)
-                fatal("%s: read: %s", __func__, strerror(errno));
-        debug3("%s: child %ld ready", __func__, (long)child_pid);
 
         /* Set up systracing of child */
         if ((dev_systrace = open("/dev/systrace", O_RDONLY)) == -1)
@@ -183,16 +175,13 @@ sandbox_systrace_parent(struct ssh_sandbox *box, pid_t child_pid,
 
         /* Signal the child to start running */
         debug3("%s: start child %ld", __func__, (long)child_pid);
-        if (atomicio(vwrite, box->parent_sock, &whatever, 1) != 1)
-                fatal("%s: write: %s", __func__, strerror(errno));
-        close(box->parent_sock);
+        if (kill(box->child_pid, SIGCONT) != 0)
+                fatal("%s: kill(%d, SIGCONT)", __func__, box->child_pid);
 }
 
-static void
-sandbox_systrace_parent_finish(void *vbox)
+void
+ssh_sandbox_parent_finish(struct ssh_sandbox *box)
 {
-        struct ssh_sandbox *box = vbox;
-
         /* Closing this before the child exits will terminate it */
         close(box->systrace_fd);
 
@@ -200,32 +189,10 @@ sandbox_systrace_parent_finish(void *vbox)
         debug3("%s: finished", __func__);
 }
 
-static void
-sandbox_systrace_parent_preauth(void *vbox, pid_t child_pid)
+void
+ssh_sandbox_parent_preauth(struct ssh_sandbox *box, pid_t child_pid)
 {
-        struct ssh_sandbox *box = vbox;
-
         ssh_sandbox_parent(box, child_pid, preauth_policy);
 }
 
-Sandbox ssh_sandbox_systrace = {
-        "systrace",
-        sandbox_systrace_probe,
-        sandbox_systrace_init,
-        sandbox_systrace_child,
-        sandbox_systrace_parent_finish,
-        sandbox_systrace_parent_preauth
-};
-
-#else /* !SANDBOX_SYSTRACE */
-
-Sandbox ssh_sandbox_systrace = {
-        "systrace",
-        NULL,
-        NULL,
-        NULL,
-        NULL,
-        NULL
-};
-
 #endif /* SANDBOX_SYSTRACE */