[Xen-changelog] [xen stable-4.8] xen/xsm: Introduce new boot parameter xsm

[patchbot@xxxxxxx]

commit 257048fc79aaaa911ccec7b43d8b28f08dec64cd
Author:     Xin Li <talons.lee@xxxxxxxxx>
AuthorDate: Tue Oct 9 17:33:19 2018 +0800
Commit:     Julien Grall <julien.grall@xxxxxxx>
CommitDate: Fri Jun 14 15:46:00 2019 +0100

    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@xxxxxxxxxx>
    Acked-by: Daniel De Graaf <dgdegra@xxxxxxxxxxxxx>
    Acked-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
---
 docs/misc/xen-command-line.markdown | 13 +++++++++++
 xen/common/Kconfig                  | 13 ++++++++++-
 xen/xsm/xsm_core.c                  | 44 ++++++++++++++++++++++++++++++++++++-
 3 files changed, 68 insertions(+), 2 deletions(-)

diff --git a/docs/misc/xen-command-line.markdown 
b/docs/misc/xen-command-line.markdown
index 87ca056726..4396aa2c44 100644
--- a/docs/misc/xen-command-line.markdown
+++ b/docs/misc/xen-command-line.markdown
@@ -776,6 +776,19 @@ 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 f2ecbc43d6..de6308a487 100644
--- 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 08994ee7a1..e78f7d8ca2 100644
--- 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;
 }
--
generated by git-patchbot for /home/xen/git/xen.git#stable-4.8

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