X-Git-Url: https://git.saurik.com/apple/security.git/blobdiff_plain/80e2389990082500d76eb566d4946be3e786c3ef..d8f41ccd20de16f8ebe2ccc84d47bf1cb2b26bbb:/Security/libsecurity_cdsa_utilities/lib/acl_threshold.cpp

diff --git a/Security/libsecurity_cdsa_utilities/lib/acl_threshold.cpp b/Security/libsecurity_cdsa_utilities/lib/acl_threshold.cpp
new file mode 100644
index 00000000..17e568f9
--- /dev/null
+++ b/Security/libsecurity_cdsa_utilities/lib/acl_threshold.cpp
@@ -0,0 +1,180 @@
+/*
+ * Copyright (c) 2000-2004,2006,2011,2014 Apple Inc. All Rights Reserved.
+ * 
+ * @APPLE_LICENSE_HEADER_START@
+ * 
+ * This file contains Original Code and/or Modifications of Original Code
+ * as defined in and that are subject to the Apple Public Source License
+ * Version 2.0 (the 'License'). You may not use this file except in
+ * compliance with the License. Please obtain a copy of the License at
+ * http://www.opensource.apple.com/apsl/ and read it before using this
+ * file.
+ * 
+ * The Original Code and all software distributed under the License are
+ * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
+ * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
+ * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
+ * Please see the License for the specific language governing rights and
+ * limitations under the License.
+ * 
+ * @APPLE_LICENSE_HEADER_END@
+ */
+
+
+//
+// acl_threshold - Threshold-based group ACL subjects
+//
+#include <security_cdsa_utilities/acl_threshold.h>
+#include <algorithm>
+#include <security_utilities/endian.h>
+
+
+//
+// Validate a credential set against this subject.
+//
+// With STRICTCOUNTING set, we assume that every match in the threshold ACL
+// "consumes" one sample in the corresponding threshold sample. This will not
+// work as expected for subject types that may succeed without a sample (e.g. ANY)
+// or subject types that may multiply match against a single sample. You have been
+// warned.
+//
+class SublistValidationContext : public AclValidationContext {
+public:
+    SublistValidationContext(const AclValidationContext &ctx, const TypedList &list)
+    : AclValidationContext(ctx), sampleList(list) { }
+    
+    uint32 count() const { return sampleList.length() - 1; }
+    const TypedList &sample(uint32 n) const
+    { return TypedList::overlay(sampleList[n+1].list()); }
+
+	void matched(const TypedList *) const { }	//@@@ ignore sub-matches for now
+
+    const TypedList &sampleList;
+};
+
+bool ThresholdAclSubject::validate(const AclValidationContext &baseCtx,
+    const TypedList &sample) const
+{
+#ifdef STRICTCOUNTING
+    // Pre-screen for reasonable number of subsamples.
+    // We could more strictly require subSampleCount == elements.length();
+    // this is more flexible in that it allows the caller to abbreviate.
+    uint32 subSampleCount = sample.length() - 1;	// (drop type header)
+    if (subSampleCount < minimumNeeded)	// can't possibly satisfy
+		CssmError::throwMe(CSSM_ERRCODE_INVALID_SAMPLE_VALUE);
+    if (subSampleCount > totalSubjects)	// reject attempt at sample stuffing
+		CssmError::throwMe(CSSM_ERRCODE_INVALID_SAMPLE_VALUE);
+#endif //STRICTCOUNTING
+
+    // evaluate
+    SublistValidationContext ctx(baseCtx, sample);
+    uint32 matched = 0;
+    for (uint32 n = 0; n < totalSubjects; n++) {
+		if ((matched += elements[n]->validate(ctx)) >= minimumNeeded)
+            return true;
+#ifdef STRICTCOUNTING
+        else if (matched + subSampleCount - n <= minimumNeeded)
+            return false;	// can't get there anymore
+#endif //STRICTCOUNTING
+    }
+	return false;
+}
+
+
+//
+// Make a copy of this subject in CSSM_LIST form
+//
+CssmList ThresholdAclSubject::toList(Allocator &alloc) const
+{
+	TypedList result(alloc, CSSM_ACL_SUBJECT_TYPE_THRESHOLD,
+		new(alloc) ListElement(minimumNeeded),
+		new(alloc) ListElement(totalSubjects));
+    for (uint32 n = 0; n < totalSubjects; n++)
+		result += new(alloc) ListElement(elements[n]->toList(alloc));
+	return result;
+}
+
+
+//
+// Create a ThresholdAclSubject
+//
+ThresholdAclSubject *ThresholdAclSubject::Maker::make(const TypedList &list) const
+{
+    // pick apart the input list
+    if (list.length() < 4)	// head + "n" + "k" + at least one subSubject
+        CssmError::throwMe(CSSM_ERRCODE_INVALID_ACL_SUBJECT_VALUE);
+    uint32 minimumNeeded = getWord(list[1], 1);
+    uint32 totalSubjects = getWord(list[2], minimumNeeded);
+    if (list.length() != 3 + totalSubjects)
+        CssmError::throwMe(CSSM_ERRCODE_INVALID_ACL_SUBJECT_VALUE);
+
+    // now compile the subSubjects
+    AclSubjectVector elements(totalSubjects);
+    const ListElement *subSubject = &list[3];
+    for (uint32 n = 0; n < totalSubjects; n++, subSubject = subSubject->next())
+        elements[n] = ObjectAcl::make(subSubject->typedList());
+	return new ThresholdAclSubject(totalSubjects, minimumNeeded, elements);
+}
+
+ThresholdAclSubject *ThresholdAclSubject::Maker::make(Version, Reader &pub, Reader &priv) const
+{
+    Endian<uint32> totalSubjects; pub(totalSubjects);
+    Endian<uint32> minimumNeeded; pub(minimumNeeded);
+    AclSubjectVector subSubjects(totalSubjects);
+    for (uint32 n = 0; n < totalSubjects; n++)
+		subSubjects[n] = ObjectAcl::importSubject(pub, priv);
+	return new ThresholdAclSubject(totalSubjects, minimumNeeded, subSubjects);
+}
+
+ThresholdAclSubject::ThresholdAclSubject(uint32 n, uint32 k,
+    const AclSubjectVector &subSubjects)
+: SimpleAclSubject(CSSM_ACL_SUBJECT_TYPE_THRESHOLD),
+  minimumNeeded(k), totalSubjects(n), elements(subSubjects)
+{
+}
+
+
+//
+// Export the subject to a memory blob
+//
+template <class Action>
+void ThresholdAclSubject::exportBlobForm(Action &pub, Action &priv)
+{
+    pub(h2n(totalSubjects));
+    pub(h2n(minimumNeeded));
+    for (uint32 n = 0; n < totalSubjects; n++)
+		ObjectAcl::exportSubject(elements[n], pub, priv);
+}
+
+void ThresholdAclSubject::exportBlob(Writer::Counter &pub, Writer::Counter &priv)
+{ exportBlobForm(pub, priv); }
+
+void ThresholdAclSubject::exportBlob(Writer &pub, Writer &priv)
+{ exportBlobForm(pub, priv); }
+
+
+void ThresholdAclSubject::add(AclSubject *subject, unsigned beforePosition)
+{
+	secdebug("threshacl", "adding subject %p before position %u",
+		subject, beforePosition);
+	elements.insert(elements.begin() + beforePosition, subject);
+	totalSubjects++;
+}
+
+
+#ifdef DEBUGDUMP
+
+void ThresholdAclSubject::debugDump() const
+{
+	Debug::dump("Threshold(%u of %u)", minimumNeeded, totalSubjects);
+	for (unsigned int n = 0; n < elements.size(); n++) {
+		Debug::dump(" [");
+		if (Version v = elements[n]->version())
+			Debug::dump("V=%d ", v);
+		elements[n]->debugDump();
+		Debug::dump("]");
+	}
+}
+
+#endif //DEBUGDUMP