[PATCH v5 1/4] xen/xsm: remove unnecessary #define

[PATCH v5 1/4] xen/xsm: remove unnecessary #define

[Xin Li]

this #define is unnecessary since XSM_INLINE is redefined in
xsm/dummy.h, it's a risk of build breakage, so remove it.

Signed-off-by: Xin Li <xin.li@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>

---
CC: Daniel De Graaf <dgdegra@tycho.nsa.gov>
CC: George Dunlap <George.Dunlap@eu.citrix.com>
CC: Jan Beulich <JBeulich@suse.com>
CC: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
CC: Stefano Stabellini <sstabellini@kernel.org>
CC: Tim Deegan <tim@xen.org>
CC: Wei Liu <wei.liu2@citrix.com>
CC: Sergey Dyasli <sergey.dyasli@citrix.com>
CC: Andrew Cooper <andrew.cooper3@citrix.com>
CC: Ming Lu <ming.lu@citrix.com>

v5:
1. move the removal of #define to this new patch.
2. fix wrong git author

---
 xen/xsm/dummy.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/xen/xsm/dummy.c b/xen/xsm/dummy.c
index 3290d04527..06a674fad0 100644
--- a/xen/xsm/dummy.c
+++ b/xen/xsm/dummy.c
@@ -11,7 +11,6 @@
  */
 
 #define XSM_NO_WRAPPERS
-#define XSM_INLINE /* */
 #include <xsm/dummy.h>
 
 struct xsm_operations dummy_xsm_ops;
-- 
2.18.0


_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xenproject.org
https://lists.xenproject.org/mailman/listinfo/xen-devel

[PATCH v5 2/4] xen/xsm: Introduce new boot parameter xsm

[Xin Li]

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>

---
CC: Daniel De Graaf <dgdegra@tycho.nsa.gov>
CC: George Dunlap <George.Dunlap@eu.citrix.com>
CC: Jan Beulich <JBeulich@suse.com>
CC: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
CC: Stefano Stabellini <sstabellini@kernel.org>
CC: Tim Deegan <tim@xen.org>
CC: Wei Liu <wei.liu2@citrix.com>
CC: Sergey Dyasli <sergey.dyasli@citrix.com>
CC: Andrew Cooper <andrew.cooper3@citrix.com>
CC: Ming Lu <ming.lu@citrix.com>

v5:
1. wording and style refine.
2. use ASSERT_UNREACHABLE() instead of unreachable printk.

---
 docs/misc/xen-command-line.markdown | 13 ++++++++
 xen/common/Kconfig                  | 13 +++++++-
 xen/xsm/xsm_core.c                  | 47 ++++++++++++++++++++++++++++-
 3 files changed, 71 insertions(+), 2 deletions(-)

diff --git a/docs/misc/xen-command-line.markdown b/docs/misc/xen-command-line.markdown
index 1ffd586224..67e062ecd7 100644
--- a/docs/misc/xen-command-line.markdown
+++ b/docs/misc/xen-command-line.markdown
@@ -899,6 +899,19 @@ 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 1a6d6281c1..f802efb625 100644
--- a/xen/common/Kconfig
+++ b/xen/common/Kconfig
@@ -116,7 +116,7 @@ config XSM
 
 config XSM_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
@@ -154,6 +154,17 @@ config XSM_FLASK_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 9645e244c3..9e5c1b07a2 100644
--- a/xen/xsm/xsm_core.c
+++ b/xen/xsm/xsm_core.c
@@ -31,6 +31,38 @@
 
 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
+    {
+        printk("XSM: Unknown boot parameter xsm=%s\n", s);
+        rc = -EINVAL;
+    }
+
+    return rc;
+}
+custom_param("xsm", parse_xsm_param);
+
 static inline int verify(struct xsm_operations *ops)
 {
     /* verify the security_operations structure exists */
@@ -57,7 +89,20 @@ 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;
 }
-- 
2.18.0


_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xenproject.org
https://lists.xenproject.org/mailman/listinfo/xen-devel

[PATCH v5 3/4] xen/xsm: Add new SILO mode for XSM

[Xin Li]

When SILO is enabled, there would be no page-sharing or event notifications
between unprivileged VMs (no grant tables or event channels).

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

---
CC: Daniel De Graaf <dgdegra@tycho.nsa.gov>
CC: George Dunlap <George.Dunlap@eu.citrix.com>
CC: Jan Beulich <JBeulich@suse.com>
CC: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
CC: Stefano Stabellini <sstabellini@kernel.org>
CC: Tim Deegan <tim@xen.org>
CC: Wei Liu <wei.liu2@citrix.com>
CC: Sergey Dyasli <sergey.dyasli@citrix.com>
CC: Andrew Cooper <andrew.cooper3@citrix.com>
CC: Ming Lu <ming.lu@citrix.com>

v5:
1. use __maybe_unused instead of __attribute__ ((unused)), and remove
unnecessary #ifdef CONFIG_XSM_SILO.
2. rename cur_dom to currd.
3. move the removal of #define in dummy.c to a seperate patch.
4. remove a blank line in silo.c.

---
 docs/misc/xen-command-line.markdown |   5 +-
 xen/common/Kconfig                  |  15 ++++
 xen/include/xsm/dummy.h             |   3 +-
 xen/include/xsm/xsm.h               |   6 ++
 xen/xsm/Makefile                    |   1 +
 xen/xsm/silo.c                      | 108 ++++++++++++++++++++++++++++
 xen/xsm/xsm_core.c                  |  11 +++
 7 files changed, 147 insertions(+), 2 deletions(-)
 create mode 100644 xen/xsm/silo.c

diff --git a/docs/misc/xen-command-line.markdown b/docs/misc/xen-command-line.markdown
index 67e062ecd7..2c7046eb86 100644
--- a/docs/misc/xen-command-line.markdown
+++ b/docs/misc/xen-command-line.markdown
@@ -900,7 +900,7 @@ Note that specifying zero as domU value means zero, while for dom0 it means
 to use the default.
 
 ### xsm
-> `= dummy | flask`
+> `= dummy | flask | silo`
 
 > Default: `dummy`
 
@@ -911,6 +911,9 @@ the hypervisor was compiled with XSM support.
   (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.
+* `silo`: this will deny any unmediated communication channels between
+  unprivileged VMs.  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 f802efb625..ce965fbf17 100644
--- a/xen/common/Kconfig
+++ b/xen/common/Kconfig
@@ -154,15 +154,30 @@ config XSM_FLASK_POLICY
 
 	  If unsure, say Y.
 
+config XSM_SILO
+	def_bool y
+	prompt "SILO support"
+	depends on XSM
+	---help---
+	  Enables SILO as the access control mechanism used by the XSM framework.
+	  This is not the default module, add boot parameter xsm=silo to choose
+	  it. This will deny any unmediated communication channels (grant tables
+	  and event channels) between unprivileged VMs.
+
+	  If unsure, say Y.
+
 choice
 	prompt "Default XSM implementation"
 	depends on XSM
 	default XSM_FLASK_DEFAULT if XSM_FLASK
+	default XSM_SILO_DEFAULT if XSM_SILO
 	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
+	config XSM_SILO_DEFAULT
+		bool "SILO" if XSM_SILO
 endchoice
 
 config LATE_HWDOM
diff --git a/xen/include/xsm/dummy.h b/xen/include/xsm/dummy.h
index b0ac1f66b3..ae971822d5 100644
--- a/xen/include/xsm/dummy.h
+++ b/xen/include/xsm/dummy.h
@@ -48,7 +48,8 @@ void __xsm_action_mismatch_detected(void);
  * There is no xsm_default_t argument available, so the value from the assertion
  * is used to initialize the variable.
  */
-#define XSM_INLINE /* */
+#define XSM_INLINE __maybe_unused
+
 #define XSM_DEFAULT_ARG /* */
 #define XSM_DEFAULT_VOID void
 #define XSM_ASSERT_ACTION(def) xsm_default_t action = def; (void)action
diff --git a/xen/include/xsm/xsm.h b/xen/include/xsm/xsm.h
index 3d67962493..3b192b5c31 100644
--- a/xen/include/xsm/xsm.h
+++ b/xen/include/xsm/xsm.h
@@ -733,6 +733,12 @@ extern const unsigned char xsm_flask_init_policy[];
 extern const unsigned int xsm_flask_init_policy_size;
 #endif
 
+#ifdef CONFIG_XSM_SILO
+extern void silo_init(void);
+#else
+static inline void silo_init(void) {}
+#endif
+
 #else /* CONFIG_XSM */
 
 #include <xsm/dummy.h>
diff --git a/xen/xsm/Makefile b/xen/xsm/Makefile
index 8bb4a24f09..e4d581e065 100644
--- a/xen/xsm/Makefile
+++ b/xen/xsm/Makefile
@@ -1,5 +1,6 @@
 obj-y += xsm_core.o
 obj-$(CONFIG_XSM) += xsm_policy.o
 obj-$(CONFIG_XSM) += dummy.o
+obj-$(CONFIG_XSM_SILO) += silo.o
 
 subdir-$(CONFIG_XSM_FLASK) += flask
diff --git a/xen/xsm/silo.c b/xen/xsm/silo.c
new file mode 100644
index 0000000000..4850756a3d
--- /dev/null
+++ b/xen/xsm/silo.c
@@ -0,0 +1,108 @@
+/******************************************************************************
+ * xsm/silo.c
+ *
+ * SILO module for XSM (Xen Security Modules)
+ *
+ * Copyright (c) 2018 Citrix Systems Ltd.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program; If not, see <http://www.gnu.org/licenses/>.
+ */
+#define XSM_NO_WRAPPERS
+#include <xsm/dummy.h>
+
+/*
+ * Check if inter-domain communication is allowed.
+ * Return true when pass check.
+ */
+static bool silo_mode_dom_check(const struct domain *ldom,
+                                const struct domain *rdom)
+{
+    const struct domain *currd = current->domain;
+
+    return (is_control_domain(currd) || is_control_domain(ldom) ||
+            is_control_domain(rdom) || ldom == rdom);
+}
+
+static int silo_evtchn_unbound(struct domain *d1, struct evtchn *chn,
+                               domid_t id2)
+{
+    int rc = -EPERM;
+    struct domain *d2 = rcu_lock_domain_by_any_id(id2);
+
+    if ( d2 == NULL )
+        rc = -ESRCH;
+    else
+    {
+        if ( silo_mode_dom_check(d1, d2) )
+            rc = xsm_evtchn_unbound(d1, chn, id2);
+        rcu_unlock_domain(d2);
+    }
+
+    return rc;
+}
+
+static int silo_evtchn_interdomain(struct domain *d1, struct evtchn *chan1,
+                                   struct domain *d2, struct evtchn *chan2)
+{
+    if ( silo_mode_dom_check(d1, d2) )
+        return xsm_evtchn_interdomain(d1, chan1, d2, chan2);
+    return -EPERM;
+}
+
+static int silo_grant_mapref(struct domain *d1, struct domain *d2,
+                             uint32_t flags)
+{
+    if ( silo_mode_dom_check(d1, d2) )
+        return xsm_grant_mapref(d1, d2, flags);
+    return -EPERM;
+}
+
+static int silo_grant_transfer(struct domain *d1, struct domain *d2)
+{
+    if ( silo_mode_dom_check(d1, d2) )
+        return xsm_grant_transfer(d1, d2);
+    return -EPERM;
+}
+
+static int silo_grant_copy(struct domain *d1, struct domain *d2)
+{
+    if ( silo_mode_dom_check(d1, d2) )
+        return xsm_grant_copy(d1, d2);
+    return -EPERM;
+}
+
+static struct xsm_operations silo_xsm_ops = {
+    .evtchn_unbound = silo_evtchn_unbound,
+    .evtchn_interdomain = silo_evtchn_interdomain,
+    .grant_mapref = silo_grant_mapref,
+    .grant_transfer = silo_grant_transfer,
+    .grant_copy = silo_grant_copy,
+};
+
+void __init silo_init(void)
+{
+    printk("Initialising XSM SILO mode\n");
+
+    if ( register_xsm(&silo_xsm_ops) )
+        panic("SILO: Unable to register with XSM\n");
+}
+
+/*
+ * Local variables:
+ * mode: C
+ * c-file-style: "BSD"
+ * c-basic-offset: 4
+ * tab-width: 4
+ * indent-tabs-mode: nil
+ * End:
+ */
diff --git a/xen/xsm/xsm_core.c b/xen/xsm/xsm_core.c
index 9e5c1b07a2..66e5987c27 100644
--- a/xen/xsm/xsm_core.c
+++ b/xen/xsm/xsm_core.c
@@ -34,11 +34,14 @@ struct xsm_operations *xsm_ops;
 enum xsm_bootparam {
     XSM_BOOTPARAM_DUMMY,
     XSM_BOOTPARAM_FLASK,
+    XSM_BOOTPARAM_SILO,
 };
 
 static enum xsm_bootparam __initdata xsm_bootparam =
 #ifdef CONFIG_XSM_FLASK_DEFAULT
     XSM_BOOTPARAM_FLASK;
+#elif CONFIG_XSM_SILO_DEFAULT
+    XSM_BOOTPARAM_SILO;
 #else
     XSM_BOOTPARAM_DUMMY;
 #endif
@@ -52,6 +55,10 @@ static int __init parse_xsm_param(const char *s)
 #ifdef CONFIG_XSM_FLASK
     else if ( !strcmp(s, "flask") )
         xsm_bootparam = XSM_BOOTPARAM_FLASK;
+#endif
+#ifdef CONFIG_XSM_SILO
+    else if ( !strcmp(s, "silo") )
+        xsm_bootparam = XSM_BOOTPARAM_SILO;
 #endif
     else
     {
@@ -99,6 +106,10 @@ static int __init xsm_core_init(const void *policy_buffer, size_t policy_size)
         flask_init(policy_buffer, policy_size);
         break;
 
+    case XSM_BOOTPARAM_SILO:
+        silo_init();
+        break;
+
     default:
         ASSERT_UNREACHABLE();
         break;
-- 
2.18.0


_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xenproject.org
https://lists.xenproject.org/mailman/listinfo/xen-devel

[PATCH v5 4/4] xen/xsm: Remove printing from set_to_dummy_if_null()

[Xin Li]

Filling dummy module's hook to null value of xsm_operations structure
will generate debug message. This becomes boot time spew for module
like silo, which only sets a few hooks of itself. So remove the printing
to avoid boot time spew.

Signed-off-by: Xin Li <xin.li@citrix.com>

---
CC: Daniel De Graaf <dgdegra@tycho.nsa.gov>
CC: George Dunlap <George.Dunlap@eu.citrix.com>
CC: Jan Beulich <JBeulich@suse.com>
CC: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
CC: Stefano Stabellini <sstabellini@kernel.org>
CC: Tim Deegan <tim@xen.org>
CC: Wei Liu <wei.liu2@citrix.com>
CC: Sergey Dyasli <sergey.dyasli@citrix.com>
CC: Andrew Cooper <andrew.cooper3@citrix.com>
CC: Ming Lu <ming.lu@citrix.com>

v5:
1. new change to avoid boot time spew.
---
 xen/xsm/dummy.c | 5 -----
 1 file changed, 5 deletions(-)

diff --git a/xen/xsm/dummy.c b/xen/xsm/dummy.c
index 06a674fad0..5701047c06 100644
--- a/xen/xsm/dummy.c
+++ b/xen/xsm/dummy.c
@@ -18,12 +18,7 @@ struct xsm_operations dummy_xsm_ops;
 #define set_to_dummy_if_null(ops, function)                            \
     do {                                                               \
         if ( !ops->function )                                          \
-        {                                                              \
             ops->function = xsm_##function;                            \
-            if (ops != &dummy_xsm_ops)                                 \
-                dprintk(XENLOG_DEBUG, "Had to override the " #function \
-                    " security operation with the dummy one.\n");      \
-        }                                                              \
     } while (0)
 
 void __init xsm_fixup_ops (struct xsm_operations *ops)
-- 
2.18.0


_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xenproject.org
https://lists.xenproject.org/mailman/listinfo/xen-devel

Re: [PATCH v5 1/4] xen/xsm: remove unnecessary #define

[Jan Beulich]

>>> On 08.11.18 at 04:14, <talons.lee@gmail.com> wrote:
> this #define is unnecessary since XSM_INLINE is redefined in
> xsm/dummy.h, it's a risk of build breakage, so remove it.
> 
> Signed-off-by: Xin Li <xin.li@citrix.com>
> Reviewed-by: Jan Beulich <jbeulich@suse.com>

I'm confused - this and patches 2 and 3 went in already, didn't they?
And quite some time ago.

Jan



_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xenproject.org
https://lists.xenproject.org/mailman/listinfo/xen-devel