Add a sandbox fallback mechanism, so that behaviour on Linux depends on

whether the running system's kernel has seccomp_filter support, not the
build system's kernel (forwarded upstream as
https://bugzilla.mindrot.org/show_bug.cgi?id=2011).

1 files changed, 44 insertions, 11 deletions

diff --git a/sandbox-systrace.c b/sandbox-systrace.c
index 5a39f4fe1..04f54a3b6 100644
--- a/sandbox-systrace.c
+++ b/sandbox-systrace.c
@@ -17,9 +17,12 @@
 
 #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>
@@ -38,7 +41,6 @@
 
 #include "atomicio.h"
 #include "log.h"
-#include "ssh-sandbox.h"
 #include "xmalloc.h"
 
 struct sandbox_policy {
@@ -74,8 +76,14 @@ struct ssh_sandbox {
         pid_t child_pid;
 };
 
-struct ssh_sandbox *
-ssh_sandbox_init(void)
+static int
+sandbox_systrace_probe(void)
+{
+        return 1;
+}
+
+static void *
+sandbox_systrace_init(void)
 {
         struct ssh_sandbox *box;
         int s[2];
@@ -92,9 +100,10 @@ ssh_sandbox_init(void)
         return box;
 }
 
-void
-ssh_sandbox_child(struct ssh_sandbox *box)
+static void
+sandbox_systrace_child(void *vbox)
 {
+        struct ssh_sandbox *box = vbox;
         char whatever = 0;
 
         close(box->parent_sock);
@@ -110,7 +119,7 @@ ssh_sandbox_child(struct ssh_sandbox *box)
 }
 
 static void
-ssh_sandbox_parent(struct ssh_sandbox *box, pid_t child_pid,
+sandbox_systrace_parent(struct ssh_sandbox *box, pid_t child_pid,
     const struct sandbox_policy *allowed_syscalls)
 {
         int dev_systrace, i, j, found;
@@ -179,9 +188,11 @@ ssh_sandbox_parent(struct ssh_sandbox *box, pid_t child_pid,
         close(box->parent_sock);
 }
 
-void
-ssh_sandbox_parent_finish(struct ssh_sandbox *box)
+static void
+sandbox_systrace_parent_finish(void *vbox)
 {
+        struct ssh_sandbox *box = vbox;
+
         /* Closing this before the child exits will terminate it */
         close(box->systrace_fd);
 
@@ -189,10 +200,32 @@ ssh_sandbox_parent_finish(struct ssh_sandbox *box)
         debug3("%s: finished", __func__);
 }
 
-void
-ssh_sandbox_parent_preauth(struct ssh_sandbox *box, pid_t child_pid)
+static void
+sandbox_systrace_parent_preauth(void *vbox, 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 */