xen/xsm: Introduce new boot parameter xsm

Introduce new boot parameter xsm to choose which xsm module is enabled,
and set default to dummy. And add new option in Kconfig to choose the
default XSM implementation.

Signed-off-by: Xin Li <xin.li@citrix.com>
Acked-by: Daniel De Graaf <dgdegra@tycho.nsa.gov>
Acked-by: Andrew Cooper <andrew.cooper3@citrix.com>

diff --git a/docs/misc/xen-command-line.markdown b/docs/misc/xen-command-line.markdown
index 85226212a9b15018c6f738a6959a459290746d16..d03830f837c9bd34f69d0f6f1292313b98cc2be3 100644 (file)
--- a/docs/misc/xen-command-line.markdown
+++ b/docs/misc/xen-command-line.markdown
@@ -790,6 +790,19 @@ hardware domain is architecture dependent.
 Note that specifying zero as domU value means zero, while for dom0 it means
 to use the default.
 
+### xsm
+> `= dummy | flask`
+
+> Default: `dummy`
+
+Specify which XSM module should be enabled.  This option is only available if
+the hypervisor was compiled with XSM support.
+
+* `dummy`: this is the default choice.  Basic restriction for common deployment
+  (the dummy module) will be applied.  It's also used when XSM is compiled out.
+* `flask`: this is the policy based access control.  To choose this, the
+  separated option in kconfig must also be enabled.
+
 ### flask
 > `= permissive | enforcing | late | disabled`
 

diff --git a/xen/common/Kconfig b/xen/common/Kconfig
index dc8e87643986318bfa4d89d026b73ffa53c31b3a..c87422282f49d91899a2a552c1c8fb6bd37fcfa5 100644 (file)
--- a/xen/common/Kconfig
+++ b/xen/common/Kconfig
@@ -99,7 +99,7 @@ config XSM
 
 config FLASK
        def_bool y
-       prompt "FLux Advanced Security Kernel support" if EXPERT = "y"
+       prompt "FLux Advanced Security Kernel support"
        depends on XSM
        ---help---
          Enables FLASK (FLux Advanced Security Kernel) as the access control
@@ -137,6 +137,17 @@ config XSM_POLICY
 
          If unsure, say Y.
 
+choice
+       prompt "Default XSM implementation"
+       depends on XSM
+       default XSM_FLASK_DEFAULT if XSM_FLASK
+       default XSM_DUMMY_DEFAULT
+       config XSM_DUMMY_DEFAULT
+               bool "Match non-XSM behavior"
+       config XSM_FLASK_DEFAULT
+               bool "FLux Advanced Security Kernel" if XSM_FLASK
+endchoice
+
 config LATE_HWDOM
        bool "Dedicated hardware domain"
        default n

diff --git a/xen/xsm/xsm_core.c b/xen/xsm/xsm_core.c
index 08994ee7a131e753097cd56500fcd41ce03da81a..e78f7d8ca2d56ce5086743e893bae930b5198ea9 100644 (file)
--- a/xen/xsm/xsm_core.c
+++ b/xen/xsm/xsm_core.c
@@ -27,6 +27,35 @@
 
 struct xsm_operations *xsm_ops;
 
+enum xsm_bootparam {
+    XSM_BOOTPARAM_DUMMY,
+    XSM_BOOTPARAM_FLASK,
+};
+
+static enum xsm_bootparam __initdata xsm_bootparam =
+#ifdef CONFIG_XSM_FLASK_DEFAULT
+    XSM_BOOTPARAM_FLASK;
+#else
+    XSM_BOOTPARAM_DUMMY;
+#endif
+
+static int __init parse_xsm_param(const char *s)
+{
+    int rc = 0;
+
+    if ( !strcmp(s, "dummy") )
+        xsm_bootparam = XSM_BOOTPARAM_DUMMY;
+#ifdef CONFIG_XSM_FLASK
+    else if ( !strcmp(s, "flask") )
+        xsm_bootparam = XSM_BOOTPARAM_FLASK;
+#endif
+    else
+        rc = -EINVAL;
+
+    return rc;
+}
+custom_param("xsm", parse_xsm_param);
+
 static inline int verify(struct xsm_operations *ops)
 {
     /* verify the security_operations structure exists */
@@ -53,7 +82,20 @@ static int __init xsm_core_init(const void *policy_buffer, size_t policy_size)
     }
 
     xsm_ops = &dummy_xsm_ops;
-    flask_init(policy_buffer, policy_size);
+
+    switch ( xsm_bootparam )
+    {
+    case XSM_BOOTPARAM_DUMMY:
+        break;
+
+    case XSM_BOOTPARAM_FLASK:
+        flask_init(policy_buffer, policy_size);
+        break;
+
+    default:
+        ASSERT_UNREACHABLE();
+        break;
+    }
 
     return 0;
 }