[Xen-devel] [PATCH][ACM] Add support for resource labeling

["Bryan D. Payne" <bdpayne@xxxxxxxxxx>]

This patch provides the framework needed for resource labeling.  
Subsequent patches will follow in the coming weeks that will enable Xen 
ACM to control assignment of resources (e.g., block devices and 
networking) to virtual machines based on resource labels and the active 
security policy.
Signed-off-by: Bryan D. Payne <bdpayne@xxxxxxxxxx>
Signed-off-by: Reiner Sailer <sailer@xxxxxxxxxx>
---
tools/python/xen/util/security.py                   |   41 ++++++++++----
tools/python/xen/xm/addlabel.py                     |    2
tools/python/xen/xm/create.py                       |    2
tools/security/Makefile                             |    2
tools/security/python/xensec_gen/cgi-bin/policy.cgi |    2
tools/security/python/xensec_tools/acm_getdecision  |   55 
--------------------
tools/security/secpol_xml2bin.c                     |    6 +-
7 files changed, 38 insertions(+), 72 deletions(-)

Index: xen-unstable.hg-shype/tools/python/xen/util/security.py
===================================================================
--- xen-unstable.hg-shype.orig/tools/python/xen/util/security.py
+++ xen-unstable.hg-shype/tools/python/xen/util/security.py
@@ -52,7 +52,8 @@ empty_line_re = re.compile("^\s*$")
binary_name_re = re.compile(".*[chwall|ste|chwall_ste].*\.bin", 
re.IGNORECASE)
policy_name_re = re.compile(".*[chwall|ste|chwall_ste].*", re.IGNORECASE)

-
+#other global variables
+NULL_SSIDREF = 0

log = logging.getLogger("xend.util.security")

@@ -255,6 +256,8 @@ def ssidref2label(ssidref_var):
   #2. get labelnames for both ssidref parts
   pri_ssid = ssidref & 0xffff
   sec_ssid = ssidref >> 16
+    pri_null_ssid = NULL_SSIDREF & 0xffff
+    sec_null_ssid = NULL_SSIDREF >> 16
   pri_labels = []
   sec_labels = []
   labels = []
@@ -270,7 +273,11 @@ def ssidref2label(ssidref_var):
   f.close()

   #3. get the label that is in both lists (combination must be a 
single label)
-    if secondary == "NULL":
+    if (primary == "CHWALL") and (pri_ssid == pri_null_ssid) and 
(sec_ssid != sec_null_ssid):
+        labels = sec_labels
+    elif (secondary == "CHWALL") and (pri_ssid != pri_null_ssid) and 
(sec_ssid == sec_null_ssid):
+        labels = pri_labels
+    elif secondary == "NULL":
       labels = pri_labels
   else:
       for i in pri_labels:
@@ -285,7 +292,7 @@ def ssidref2label(ssidref_var):



-def label2ssidref(labelname, policyname):
+def label2ssidref(labelname, policyname, type):
   """
   returns ssidref corresponding to labelname;
   maps current policy to default directory
@@ -294,6 +301,14 @@ def label2ssidref(labelname, policyname)
   if policyname in ['NULL', 'INACTIVE', 'DEFAULT']:
       err("Cannot translate labels for \'" + policyname + "\' policy.")

+    allowed_types = ['ANY']
+    if type == 'dom':
+        allowed_types.append('VM')
+    elif type == 'res':
+        allowed_types.append('RES')
+    else:
+        err("Invalid type.  Must specify 'dom' or 'res'.")
+
   (primary, secondary, f, pol_exists) = getmapfile(policyname)

   #2. get labelnames for ssidref parts and find a common label
@@ -303,11 +318,15 @@ def label2ssidref(labelname, policyname)
       l = line.split()
       if (len(l) < 5) or (l[0] != "LABEL->SSID"):
           continue
-        if primary and (l[2] == primary) and (l[3] == labelname):
+        if primary and (l[1] in allowed_types) and (l[2] == primary) 
and (l[3] == labelname):
           pri_ssid.append(int(l[4], 16))
-        if secondary and (l[2] == secondary) and (l[3] == labelname):
+        if secondary and (l[1] in allowed_types) and (l[2] == 
secondary) and (l[3] == labelname):
           sec_ssid.append(int(l[4], 16))
   f.close()
+    if (type == 'res') and (primary == "CHWALL") and (len(pri_ssid) == 0):
+        pri_ssid.append(NULL_SSIDREF)
+    elif (type == 'res') and (secondary == "CHWALL") and (len(sec_ssid) 
== 0):
+        sec_ssid.append(NULL_SSIDREF)

   #3. sanity check and composition of ssidref
   if (len(pri_ssid) == 0) or ((len(sec_ssid) == 0) and (secondary != 
"NULL")):
@@ -360,7 +379,7 @@ def refresh_ssidref(config):
       err("Policy \'" + policyname + "\' in label does not match 
active policy \'"
           + active_policy +"\'!")

-    new_ssidref = label2ssidref(labelname, policyname)
+    new_ssidref = label2ssidref(labelname, policyname, 'dom')
   if not new_ssidref:
       err("SSIDREF refresh failed!")

@@ -409,7 +428,7 @@ def get_decision(arg1, arg2):
   enables domains to retrieve access control decisions from
   the hypervisor Access Control Module.
   IN: args format = ['domid', id] or ['ssidref', ssidref]
-    or ['access_control', ['policy', policy], ['label', label]]
+    or ['access_control', ['policy', policy], ['label', label], 
['type', type]]
   """

   if not on():
@@ -417,14 +436,14 @@ def get_decision(arg1, arg2):

   #translate labels before calling low-level function
   if arg1[0] == 'access_control':
-        if (arg1[1][0] != 'policy') or (arg1[2][0] != 'label') :
+        if (arg1[1][0] != 'policy') or (arg1[2][0] != 'label') or 
(arg1[3][0] != 'type'):
           err("Argument type not supported.")
-        ssidref = label2ssidref(arg1[2][1], arg1[1][1])
+        ssidref = label2ssidref(arg1[2][1], arg1[1][1], arg1[3][1])
       arg1 = ['ssidref', str(ssidref)]
   if arg2[0] == 'access_control':
-        if (arg2[1][0] != 'policy') or (arg2[2][0] != 'label') :
+        if (arg2[1][0] != 'policy') or (arg2[2][0] != 'label') or 
(arg2[3][0] != 'type'):
           err("Argument type not supported.")
-        ssidref = label2ssidref(arg2[2][1], arg2[1][1])
+        ssidref = label2ssidref(arg2[2][1], arg2[1][1], arg2[3][1])
       arg2 = ['ssidref', str(ssidref)]

   # accept only int or string types for domid and ssidref
Index: xen-unstable.hg-shype/tools/python/xen/xm/addlabel.py
===================================================================
--- xen-unstable.hg-shype.orig/tools/python/xen/xm/addlabel.py
+++ xen-unstable.hg-shype/tools/python/xen/xm/addlabel.py
@@ -50,7 +50,7 @@ def main(argv):
           err("No active policy. Policy must be specified in command 
line.")
       #sanity checks: make sure this label can be instantiated later on
-        ssidref = label2ssidref(label, policyref)
+        ssidref = label2ssidref(label, policyref, 'dom')

       new_label = "access_control = ['policy=%s,label=%s']\n" % 
(policyref, label)
       if not os.path.isfile(configfile):
Index: xen-unstable.hg-shype/tools/python/xen/xm/create.py
===================================================================
--- xen-unstable.hg-shype.orig/tools/python/xen/xm/create.py
+++ xen-unstable.hg-shype/tools/python/xen/xm/create.py
@@ -533,7 +533,7 @@ def configure_security(config, vals):
       if sxp.child_value(config, 'ssidref'):
           err("ERROR: SSIDREF and access_control are mutually 
exclusive but both specified!")
       #else calculate ssidre from label
-        ssidref = security.label2ssidref(label, policy)
+        ssidref = security.label2ssidref(label, policy, 'dom')
       if not ssidref :
           err("ERROR calculating ssidref from access_control.")
       security_label = ['security', [ config_access_control, 
['ssidref' , ssidref ] ] ]
Index: xen-unstable.hg-shype/tools/security/Makefile
===================================================================
--- xen-unstable.hg-shype.orig/tools/security/Makefile
+++ xen-unstable.hg-shype/tools/security/Makefile
@@ -33,7 +33,7 @@ OBJS_XML2BIN := $(patsubst %.c,%.o,$(fil

ACM_INST_TOOLS    = xensec_tool xensec_xml2bin xensec_gen
ACM_OBJS          = $(OBJS_TOOL) $(OBJS_XML2BIN) $(OBJS_GETD)
-ACM_SCRIPTS       = python/xensec_tools/acm_getlabel 
python/xensec_tools/acm_getdecision
+ACM_SCRIPTS       = python/xensec_tools/acm_getlabel

ACM_CONFIG_DIR    = /etc/xen/acm-security
ACM_POLICY_DIR    = $(ACM_CONFIG_DIR)/policies
Index: 
xen-unstable.hg-shype/tools/security/python/xensec_gen/cgi-bin/policy.cgi
===================================================================
--- 
xen-unstable.hg-shype.orig/tools/security/python/xensec_gen/cgi-bin/policy.cgi 

+++ 
xen-unstable.hg-shype/tools/security/python/xensec_gen/cgi-bin/policy.cgi
@@ -406,7 +406,7 @@ def parsePolicyXml( ):
                   msg = msg + 'Please validate the Policy file used.'
                   formatXmlError( msg )

-                    allCSMTypes[csName][1] = csMemberList
+                allCSMTypes[csName][1] = csMemberList

   if pOrder != '':
       formPolicyOrder[1] = pOrder
Index: 
xen-unstable.hg-shype/tools/security/python/xensec_tools/acm_getdecision
===================================================================
--- 
xen-unstable.hg-shype.orig/tools/security/python/xensec_tools/acm_getdecision 

+++ /dev/null
@@ -1,55 +0,0 @@
-#!/usr/bin/env python
-#  -*- mode: python; -*-
-import sys
-import traceback
-import getopt
-
-# add fallback path for non-native python path installs if needed
-sys.path.insert(-1, '/usr/lib/python')
-sys.path.insert(-1, '/usr/lib64/python')
-
-from xen.util.security import ACMError, err, get_decision, active_policy
-
-def usage():
-    print "Usage: acm_getdecision -i domainid --label labelname"
-    print "  Test program illustrating the retrieval of"
-    print "  access control decisions from Xen. At this time,"
-    print "  only sharing (STE) policy decisions are supported."
-    print "  Arguments are two paramters in any combination:"
-    print "\t -i domain_id or --domid domain_id"
-    print "\t -l labelname or --label labelname"
-    print "  Return value:"
-    print "\t PERMITTED if access is permitted"
-    print "\t DENIED if access is denied"
-    print "\t ACMError -- e.g., unknown label or domain id"
-    err("Usage")
-
-try:
-
-    if len(sys.argv) != 5:
-        usage()
-
-    decision_args = []
-
-    for idx in range(1, len(sys.argv), 2):
-        if sys.argv[idx] in ['-i', '--domid']:
-            decision_args.append(['domid', sys.argv[idx+1]])
-        elif sys.argv[idx] in ['-l', '--label']:
-            decision_args.append(['access_control',
-                                  ['policy', active_policy],
-                                  ['label', sys.argv[idx+1]]
-                                  ])
-        else:
-            print "unknown argument %s" % sys.argv[idx]
-            usage()
-
-    if len(decision_args) != 2:
-        print "too many arguments"
-        usage()
-
-    print get_decision(decision_args[0], decision_args[1])
-
-except ACMError:
-    pass
-except:
-    traceback.print_exc(limit=1)
Index: xen-unstable.hg-shype/tools/security/secpol_xml2bin.c
===================================================================
--- xen-unstable.hg-shype.orig/tools/security/secpol_xml2bin.c
+++ xen-unstable.hg-shype/tools/security/secpol_xml2bin.c
@@ -44,6 +44,8 @@

#define DEBUG    0

+#define NULL_LABEL_NAME "__NULL_LABEL__"
+
/* primary / secondary policy component setting */
enum policycomponent { CHWALL, STE, NULLPOLICY }
   primary = NULLPOLICY, secondary = NULLPOLICY;
@@ -467,7 +469,7 @@ int init_ssid_queues(void)
       return -ENOMEM;

   /* default chwall ssid */
-    default_ssid_chwall->name = "DEFAULT";
+    default_ssid_chwall->name = NULL_LABEL_NAME;
   default_ssid_chwall->num = max_chwall_ssids++;
   default_ssid_chwall->is_ref = 0;
   default_ssid_chwall->type = ANY;
@@ -484,7 +486,7 @@ int init_ssid_queues(void)
   max_chwall_labels++;

   /* default ste ssid */
-    default_ssid_ste->name = "DEFAULT";
+    default_ssid_ste->name = NULL_LABEL_NAME;
   default_ssid_ste->num = max_ste_ssids++;
   default_ssid_ste->is_ref = 0;
   default_ssid_ste->type = ANY;



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