All of XENVER_* have now an XSM check for their sub-ops.
The subop for XENVER_commandline is now a priviliged operation.
To not break guests we still return an string - but it is
just '<denied>\0'.
The rest: XENVER_[version|extraversion|capabilities|
parameters|get_features|page_size|guest_handle|changeset|
compile_info] behave as before - allowed by default for all
guests if using the XSM default policy or with the dummy one.
The admin can choose to change the sub-ops to be denied
as they see fit.
Also we add a local variable block.
Signed-off-by: Konrad Rzeszutek Wilk <konrad.w...@oracle.com>
---
Cc: Daniel De Graaf <dgde...@tycho.nsa.gov>
Cc: Ian Jackson <ian.jack...@eu.citrix.com>
Cc: Stefano Stabellini <stefano.stabell...@eu.citrix.com>
Cc: Wei Liu <wei.l...@citrix.com>
v2: Do XSM check for all the XENVER_ ops.
v3: Add empty data conditions.
v4: Return <denied> for priv subops.
v5: Move extraversion from priv to normal. Drop the XSM check
for the non-priv subops.
v6: Add +1 for strlen(xen_deny()) to include NULL. Move changeset,
compile_info to non-priv subops.
v7: Remove the \0 on xen_deny()
v8: Add new XSM domain for xenver hypercall. Add all subops to it.
v9: Remove the extra line, Add Ack from Daniel
v10: Rename the XSM from xen_version_op to xsm_xen_version.
Prefix the types with 'xen' to distinguish it from another
hypercall performing similar operation. Removed Ack from Daniel
as it was so large. Add local variable block.
---
tools/flask/policy/policy/modules/xen/xen.te | 15 ++++++++
xen/common/kernel.c | 53 +++++++++++++++++++++-------
xen/common/version.c | 15 ++++++++
xen/include/xen/version.h | 2 +-
xen/include/xsm/dummy.h | 22 ++++++++++++
xen/include/xsm/xsm.h | 5 +++
xen/xsm/dummy.c | 1 +
xen/xsm/flask/hooks.c | 43 ++++++++++++++++++++++
xen/xsm/flask/policy/access_vectors | 28 +++++++++++++++
xen/xsm/flask/policy/security_classes | 1 +
10 files changed, 172 insertions(+), 13 deletions(-)
diff --git a/tools/flask/policy/policy/modules/xen/xen.te
b/tools/flask/policy/policy/modules/xen/xen.te
index d35ae22..7e7400d 100644
--- a/tools/flask/policy/policy/modules/xen/xen.te
+++ b/tools/flask/policy/policy/modules/xen/xen.te
@@ -73,6 +73,15 @@ allow dom0_t xen_t:xen2 {
pmu_ctrl
get_symbol
};
+
+# Allow dom0 to use all XENVER_ subops
+# Note that dom0 is part of domain_type so this has duplicates.
+allow dom0_t xen_t:version {
+ xen_version xen_extraversion xen_compile_info xen_capabilities
+ xen_changeset xen_platform_parameters xen_get_features xen_pagesize
+ xen_guest_handle xen_commandline
+};
+
allow dom0_t xen_t:mmu memorymap;
# Allow dom0 to use these domctls on itself. For domctls acting on other
@@ -137,6 +146,12 @@ if (guest_writeconsole) {
# pmu_ctrl is for)
allow domain_type xen_t:xen2 pmu_use;
+# For normal guests all except XENVER_commandline
+allow domain_type xen_t:version {
+ xen_version xen_extraversion xen_compile_info xen_capabilities
+ xen_changeset xen_platform_parameters xen_get_features xen_pagesize
+ xen_guest_handle
+};
###############################################################################
#
# Domain creation
diff --git a/xen/common/kernel.c b/xen/common/kernel.c
index 0618da2..2699ac0 100644
--- a/xen/common/kernel.c
+++ b/xen/common/kernel.c
@@ -13,6 +13,7 @@
#include <xen/nmi.h>
#include <xen/guest_access.h>
#include <xen/hypercall.h>
+#include <xsm/xsm.h>
#include <asm/current.h>
#include <public/nmi.h>
#include <public/version.h>
@@ -223,12 +224,15 @@ void __init do_initcalls(void)
/*
* Simple hypercalls.
*/
-
DO(xen_version)(int cmd, XEN_GUEST_HANDLE_PARAM(void) arg)
{
+ bool_t deny = !!xsm_xen_version(XSM_OTHER, cmd);
+
switch ( cmd )
{
case XENVER_version:
+ if ( deny )
+ return 0;
return (xen_major_version() << 16) | xen_minor_version();
case XENVER_extraversion:
@@ -236,7 +240,7 @@ DO(xen_version)(int cmd, XEN_GUEST_HANDLE_PARAM(void) arg)
xen_extraversion_t extraversion;
memset(extraversion, 0, sizeof(extraversion));
- safe_strcpy(extraversion, xen_extra_version());
+ safe_strcpy(extraversion, deny ? xen_deny() : xen_extra_version());
if ( copy_to_guest(arg, extraversion, ARRAY_SIZE(extraversion)) )
return -EFAULT;
return 0;
@@ -247,10 +251,10 @@ DO(xen_version)(int cmd, XEN_GUEST_HANDLE_PARAM(void) arg)
xen_compile_info_t info;
memset(&info, 0, sizeof(info));
- safe_strcpy(info.compiler, xen_compiler());
- safe_strcpy(info.compile_by, xen_compile_by());
- safe_strcpy(info.compile_domain, xen_compile_domain());
- safe_strcpy(info.compile_date, xen_compile_date());
+ safe_strcpy(info.compiler, deny ? xen_deny() : xen_compiler());
+ safe_strcpy(info.compile_by, deny ? xen_deny() : xen_compile_by());
+ safe_strcpy(info.compile_domain, deny ? xen_deny() :
xen_compile_domain());
+ safe_strcpy(info.compile_date, deny ? xen_deny() :
xen_compile_date());
if ( copy_to_guest(arg, &info, 1) )
return -EFAULT;
return 0;
@@ -261,7 +265,8 @@ DO(xen_version)(int cmd, XEN_GUEST_HANDLE_PARAM(void) arg)
xen_capabilities_info_t info;
memset(info, 0, sizeof(info));
- arch_get_xen_caps(&info);
+ if ( !deny )
+ arch_get_xen_caps(&info);
if ( copy_to_guest(arg, info, ARRAY_SIZE(info)) )
return -EFAULT;
@@ -274,6 +279,9 @@ DO(xen_version)(int cmd, XEN_GUEST_HANDLE_PARAM(void) arg)
.virt_start = HYPERVISOR_VIRT_START
};
+ if ( deny )
+ params.virt_start = 0;
+
if ( copy_to_guest(arg, ¶ms, 1) )
return -EFAULT;
return 0;
@@ -285,7 +293,7 @@ DO(xen_version)(int cmd, XEN_GUEST_HANDLE_PARAM(void) arg)
xen_changeset_info_t chgset;
memset(chgset, 0, sizeof(chgset));
- safe_strcpy(chgset, xen_changeset());
+ safe_strcpy(chgset, deny ? xen_deny() : xen_changeset());
if ( copy_to_guest(arg, chgset, ARRAY_SIZE(chgset)) )
return -EFAULT;
return 0;
@@ -302,6 +310,8 @@ DO(xen_version)(int cmd, XEN_GUEST_HANDLE_PARAM(void) arg)
switch ( fi.submap_idx )
{
case 0:
+ if ( deny )
+ break;
fi.submap = (1U << XENFEAT_memory_op_vnode_supported);
if ( VM_ASSIST(d, pae_extended_cr3) )
fi.submap |= (1U << XENFEAT_pae_pgdir_above_4gb);
@@ -342,19 +352,38 @@ DO(xen_version)(int cmd, XEN_GUEST_HANDLE_PARAM(void) arg)
}
case XENVER_pagesize:
+ if ( deny )
+ return 0;
return (!guest_handle_is_null(arg) ? -EINVAL : PAGE_SIZE);
case XENVER_guest_handle:
- if ( copy_to_guest(arg, current->domain->handle,
- ARRAY_SIZE(current->domain->handle)) )
+ {
+ xen_domain_handle_t hdl;
+ ssize_t len;
+
+ if ( deny )
+ {
+ len = sizeof(hdl);
+ memset(&hdl, 0, len);
+ } else
+ len = ARRAY_SIZE(current->domain->handle);
+
+ if ( copy_to_guest(arg, deny ? hdl : current->domain->handle, len ) )
return -EFAULT;
return 0;
-
+ }
case XENVER_commandline:
- if ( copy_to_guest(arg, saved_cmdline, ARRAY_SIZE(saved_cmdline)) )
+ {
+ size_t len = ARRAY_SIZE(saved_cmdline);
+
+ if ( deny )
+ len = strlen(xen_deny()) + 1;
+
+ if ( copy_to_guest(arg, deny ? xen_deny() : saved_cmdline, len) )
return -EFAULT;
return 0;
}
+ }
return -ENOSYS;
}
diff --git a/xen/common/version.c b/xen/common/version.c
index b152e27..fc9bf42 100644
--- a/xen/common/version.c
+++ b/xen/common/version.c
@@ -55,3 +55,18 @@ const char *xen_banner(void)
{
return XEN_BANNER;
}
+
+const char *xen_deny(void)
+{
+ return "<denied>";
+}
+
+/*
+ * Local variables:
+ * mode: C
+ * c-file-style: "BSD"
+ * c-basic-offset: 4
+ * tab-width: 4
+ * indent-tabs-mode: nil
+ * End:
+ */
diff --git a/xen/include/xen/version.h b/xen/include/xen/version.h
index 81a3c7d..016a56c 100644
--- a/xen/include/xen/version.h
+++ b/xen/include/xen/version.h
@@ -12,5 +12,5 @@ unsigned int xen_minor_version(void);
const char *xen_extra_version(void);
const char *xen_changeset(void);
const char *xen_banner(void);
-
+const char *xen_deny(void);
#endif /* __XEN_VERSION_H__ */
diff --git a/xen/include/xsm/dummy.h b/xen/include/xsm/dummy.h
index 1d13826..94b8855 100644
--- a/xen/include/xsm/dummy.h
+++ b/xen/include/xsm/dummy.h
@@ -727,3 +727,25 @@ static XSM_INLINE int xsm_pmu_op (XSM_DEFAULT_ARG struct
domain *d, unsigned int
}
#endif /* CONFIG_X86 */
+
+#include <public/version.h>
+static XSM_INLINE int xsm_xen_version (XSM_DEFAULT_ARG uint32_t op)
+{
+ XSM_ASSERT_ACTION(XSM_OTHER);
+ switch ( op )
+ {
+ case XENVER_version:
+ case XENVER_extraversion:
+ case XENVER_compile_info:
+ case XENVER_capabilities:
+ case XENVER_changeset:
+ case XENVER_platform_parameters:
+ case XENVER_get_features:
+ case XENVER_pagesize:
+ case XENVER_guest_handle:
+ /* These MUST always be accessible to any guest by default. */
+ return xsm_default_action(XSM_HOOK, current->domain, NULL);
+ default:
+ return xsm_default_action(XSM_PRIV, current->domain, NULL);
+ }
+}
diff --git a/xen/include/xsm/xsm.h b/xen/include/xsm/xsm.h
index 3afed70..db440f6 100644
--- a/xen/include/xsm/xsm.h
+++ b/xen/include/xsm/xsm.h
@@ -193,6 +193,7 @@ struct xsm_operations {
int (*ioport_mapping) (struct domain *d, uint32_t s, uint32_t e, uint8_t
allow);
int (*pmu_op) (struct domain *d, unsigned int op);
#endif
+ int (*xen_version) (uint32_t cmd);
};
#ifdef CONFIG_XSM
@@ -731,6 +732,10 @@ static inline int xsm_pmu_op (xsm_default_t def, struct
domain *d, unsigned int
#endif /* CONFIG_X86 */
+static inline int xsm_xen_version (xsm_default_t def, uint32_t op)
+{
+ return xsm_ops->xen_version(op);
+}
#endif /* XSM_NO_WRAPPERS */
#ifdef CONFIG_MULTIBOOT
diff --git a/xen/xsm/dummy.c b/xen/xsm/dummy.c
index 0f32636..9791ad4 100644
--- a/xen/xsm/dummy.c
+++ b/xen/xsm/dummy.c
@@ -162,4 +162,5 @@ void xsm_fixup_ops (struct xsm_operations *ops)
set_to_dummy_if_null(ops, ioport_mapping);
set_to_dummy_if_null(ops, pmu_op);
#endif
+ set_to_dummy_if_null(ops, xen_version);
}
diff --git a/xen/xsm/flask/hooks.c b/xen/xsm/flask/hooks.c
index 4813623..d1bef43 100644
--- a/xen/xsm/flask/hooks.c
+++ b/xen/xsm/flask/hooks.c
@@ -26,6 +26,7 @@
#include <public/xen.h>
#include <public/physdev.h>
#include <public/platform.h>
+#include <public/version.h>
#include <public/xsm/flask_op.h>
@@ -1620,6 +1621,47 @@ static int flask_pmu_op (struct domain *d, unsigned int
op)
}
#endif /* CONFIG_X86 */
+static int flask_xen_version (uint32_t op)
+{
+ u32 dsid = domain_sid(current->domain);
+
+ switch ( op )
+ {
+ case XENVER_version:
+ return avc_has_perm(dsid, SECINITSID_XEN, SECCLASS_VERSION,
+ VERSION__XEN_VERSION, NULL);
+ case XENVER_extraversion:
+ return avc_has_perm(dsid, SECINITSID_XEN, SECCLASS_VERSION,
+ VERSION__XEN_EXTRAVERSION, NULL);
+ case XENVER_compile_info:
+ return avc_has_perm(dsid, SECINITSID_XEN, SECCLASS_VERSION,
+ VERSION__XEN_COMPILE_INFO, NULL);
+ case XENVER_capabilities:
+ return avc_has_perm(dsid, SECINITSID_XEN, SECCLASS_VERSION,
+ VERSION__XEN_CAPABILITIES, NULL);
+ case XENVER_changeset:
+ return avc_has_perm(dsid, SECINITSID_XEN, SECCLASS_VERSION,
+ VERSION__XEN_CHANGESET, NULL);
+ case XENVER_platform_parameters:
+ return avc_has_perm(dsid, SECINITSID_XEN, SECCLASS_VERSION,
+ VERSION__XEN_PLATFORM_PARAMETERS, NULL);
+ case XENVER_get_features:
+ return avc_has_perm(dsid, SECINITSID_XEN, SECCLASS_VERSION,
+ VERSION__XEN_GET_FEATURES, NULL);
+ case XENVER_pagesize:
+ return avc_has_perm(dsid, SECINITSID_XEN, SECCLASS_VERSION,
+ VERSION__XEN_PAGESIZE, NULL);
+ case XENVER_guest_handle:
+ return avc_has_perm(dsid, SECINITSID_XEN, SECCLASS_VERSION,
+ VERSION__XEN_GUEST_HANDLE, NULL);
+ case XENVER_commandline:
+ return avc_has_perm(dsid, SECINITSID_XEN, SECCLASS_VERSION,
+ VERSION__XEN_COMMANDLINE, NULL);
+ default:
+ return -EPERM;
+ }
+}
+
long do_flask_op(XEN_GUEST_HANDLE_PARAM(xsm_op_t) u_flask_op);
int compat_flask_op(XEN_GUEST_HANDLE_PARAM(xsm_op_t) u_flask_op);
@@ -1758,6 +1800,7 @@ static struct xsm_operations flask_ops = {
.ioport_mapping = flask_ioport_mapping,
.pmu_op = flask_pmu_op,
#endif
+ .xen_version = flask_xen_version,
};
static __init void flask_init(void)
diff --git a/xen/xsm/flask/policy/access_vectors
b/xen/xsm/flask/policy/access_vectors
index effb59f..628dd5c 100644
--- a/xen/xsm/flask/policy/access_vectors
+++ b/xen/xsm/flask/policy/access_vectors
@@ -495,3 +495,31 @@ class security
# remove ocontext label definitions for resources
del_ocontext
}
+
+# Class version is used to describe the XENVER_ hypercall.
+# Each sub-ops is described here - in the default case all of them should
+# be allowed except the XENVER_commandline.
+#
+class version
+{
+# Often called by PV kernels to force an callback.
+ xen_version
+# Extra informations (-unstable).
+ xen_extraversion
+# Compile information of the hypervisor.
+ xen_compile_info
+# Such as "xen-3.0-x86_64 xen-3.0-x86_32p hvm-3.0-x86_32 hvm-3.0-x86_32p
hvm-3.0-x86_64".
+ xen_capabilities
+# Such as the virtual address of where the hypervisor resides.
+ xen_platform_parameters
+# Source code changeset.
+ xen_changeset
+# The features the hypervisor supports.
+ xen_get_features
+# Page size the hypervisor uses.
+ xen_pagesize
+# An value that the control stack can choose.
+ xen_guest_handle
+# Xen command line.
+ xen_commandline
+}
diff --git a/xen/xsm/flask/policy/security_classes
b/xen/xsm/flask/policy/security_classes
index ca191db..cde4e1a 100644
--- a/xen/xsm/flask/policy/security_classes
+++ b/xen/xsm/flask/policy/security_classes
@@ -18,5 +18,6 @@ class shadow
class event
class grant
class security
+class version
# FLASK
