cdsa/cdsa_utilities/acl_threshold.h

   1 /*
   2  * Copyright (c) 2000-2001 Apple Computer, Inc. All Rights Reserved.
   3  *
   4  * The contents of this file constitute Original Code as defined in and are
   5  * subject to the Apple Public Source License Version 1.2 (the 'License').
   6  * You may not use this file except in compliance with the License. Please obtain
   7  * a copy of the License at http://www.apple.com/publicsource and read it before
   8  * using this file.
   9  *
  10  * This Original Code and all software distributed under the License are
  11  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESS
  12  * OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, INCLUDING WITHOUT
  13  * LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
  14  * PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT. Please see the License for the
  15  * specific language governing rights and limitations under the License.
  16  */
  17
  18
  19 //
  20 // acl_threshold - Threshold-based group ACL subjects.
  21 //
  22 // This subject type implements threshold (k of n) subjects as per CSSM standard.
  23 // Subsubjects are stored and evaluated in the order received. Any subsubject
  24 // is presented with all subsamples of the corresponding threshold sample, but
  25 // not any other samples possibly present in the credentials. Subsubject evaluation
  26 // stops as soon as the threshold is satisfied, or as soon as it becomes numerically
  27 // impossible to satisfy the threshold with future matches.
  28 // Note that this subject will reject out of hand any threshold sample that
  29 // contains more than <n> subsamples. This defeats "sample stuffing" attacks
  30 // where the attacker provides thousands of samples in the hope that some may
  31 // match by accident. It will however accept threshold samples with fewer than
  32 // <n> subsamples, as long as there are at least <k> subsamples.
  33 //
  34 #ifndef _ACL_THRESHOLD
  35 #define _ACL_THRESHOLD
  36
  37 #include <Security/cssmacl.h>
  38 #include <vector>
  39
  40 #ifdef _CPP_ACL_THRESHOLD
  41 #pragma export on
  42 #endif
  43
  44 namespace Security
  45 {
  46
  47 class ThresholdAclSubject : public SimpleAclSubject {
  48     typedef ObjectAcl::AclSubjectPointer AclSubjectPointer;
  49     typedef vector<AclSubjectPointer> AclSubjectVector;
  50 public:
  51     bool validate(const AclValidationContext &baseCtx, const TypedList &sample) const;
  52     CssmList toList(CssmAllocator &alloc) const;
  53
  54     ThresholdAclSubject(uint32 n, uint32 k, const AclSubjectVector &subSubjects);
  55
  56     void exportBlob(Writer::Counter &pub, Writer::Counter &priv);
  57     void exportBlob(Writer &pub, Writer &priv);
  58
  59         IFDUMP(void debugDump() const);
  60
  61     class Maker : public AclSubject::Maker {
  62     public:
  63         Maker() : AclSubject::Maker(CSSM_ACL_SUBJECT_TYPE_THRESHOLD) { }
  64         ThresholdAclSubject *make(const TypedList &list) const;
  65         ThresholdAclSubject *make(Version, Reader &pub, Reader &priv) const;
  66     };
  67
  68 private:
  69     uint32 minimumNeeded;                               // number of matches needed
  70     uint32 totalSubjects;                               // number of subSubjects
  71     AclSubjectVector elements;                  // sub-subject vector
  72
  73     template <class Action>
  74     void ThresholdAclSubject::exportBlobForm(Action &pub, Action &priv);
  75 };
  76
  77 } // end namespace Security
  78
  79 #ifdef _CPP_ACL_THRESHOLD
  80 #pragma export off
  81 #endif
  82
  83 #endif //_ACL_THRESHOLD