+++ /dev/null
-/*
- * Copyright (c) 2000-2006,2011-2012,2014 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_comment - "ignore" ACL subject type.
-//
-// CommentAclSubjects were a bad idea, badly implemented. The code below
-// exists solely to keep existing (external) ACL forms from blowing up the
-// ACL reader machinery and crashing the evaluation host.
-// The original serialization code was not architecture independent - for either
-// pointer sizes(!) or byte ordering. Yes, that was a stupid mistake.
-// The following code is intentionally, wilfully violating the layer separation
-// of the ACL reader/writer machine to deduce enough information about the
-// originating architecture to cleanly consume (just) the bytes making up this
-// ACL's external representation. We make no use of the bytes read; thankfully,
-// the semantics of a CommentAclSubject have always been "never matches."
-// We do not preserve them on write-out; a newly-written ACL will contain no data
-// (and will read cleanly).
-// If you use this code as a template for anything (other than a how-not-to-write-code
-// seminar), your backups shall rot right after your main harddrive crashes, and
-// you have only yourself to blame.
-//
-#include <security_cdsa_utilities/acl_comment.h>
-#include <security_cdsa_utilities/cssmwalkers.h>
-#include <security_cdsa_utilities/cssmlist.h>
-#include <algorithm>
-
-using namespace DataWalkers;
-
-
-//
-// The COMMENT subject matches nothing, no matter how pretty.
-//
-bool CommentAclSubject::validate(const AclValidationContext &) const
-{
- return false;
-}
-
-
-//
-// The list form has no values.
-//
-CssmList CommentAclSubject::toList(Allocator &alloc) const
-{
- return TypedList(Allocator::standard(), CSSM_ACL_SUBJECT_TYPE_COMMENT);
-}
-
-
-//
-// We completely disregard any data contained in CSSM form COMMENT ACLs.
-//
-CommentAclSubject *CommentAclSubject::Maker::make(const TypedList &list) const
-{
- return new CommentAclSubject();
-}
-
-
-//
-// This is the nasty code. We don't really care what data was originally baked
-// into this ACL's external (stream) form, but since there's no external framing
-// to delimit it, we need to figure out how many bytes to consume to keep the
-// reader from going out of sync. And that's not pretty, since the external form
-// contains (stupidly!) a pointer, so we have all permutations of byte order and
-// pointer size to worry about.
-//
-CommentAclSubject *CommentAclSubject::Maker::make(Version, Reader &pub, Reader &) const
-{
- //
- // At this point, the Reader is positioned at data that was once written using
- // this code:
- // pub(ptr); // yes, that's a pointer
- // pub.countedData(ptr, size);
- // We know ptr was a non-NULL pointer (4 or 8 bytes, alas).
- // CountedData writes a 4-byte NBO length followed by that many bytes.
- // The data written starts with a CSSM_LIST structure in native architecture.
- // That in turn begins with a CSSM_LIST_TYPE (4 bytes, native, 0<=type<=2).
- // So to summarize (h=host byte order, n=network byte order), we might be looking at:
- // 32 bits: | P4h | L4n | T4h | (L-4 bytes) |
- // 64 bits: | P8h | L4n | (L bytes) |
- // It's the T4h-or-L4n bytes that save our day, since we know that
- // 0 <= T <= 2 (definition of CSSM_LIST_TYPE)
- // 16M > L >= sizeof(CSSM_LIST) >= 12
- // Phew. I'd rather be lucky than good...
- //
- // So let's get started:
-#ifndef NDEBUG
- static const size_t minCssmList = 12; // min(sizeof(CSSM_LIST)) of all architectures
-#endif
- pub.get<void>(4); // skip first 4 bytes
- uint32_t lop; pub(lop); // read L4n-or-(bottom of)P8h
- uint32_t tol; pub(tol); // read T4h-or-L4n
- if (tol <= 2 || flip(tol) <= 2) { // 32 bits
- // the latter can't be a very big (flipped) L because we know 12 < L < 16M,
- // and you'd have to be a multiple of 2^24 to pass that test
- size_t length = n2h(lop);
- assert(length >= minCssmList);
- pub.get<void>(length - sizeof(tol)); // skip L-4 bytes
- } else { // 64 bits
- size_t length = n2h(tol);
- assert(length >= minCssmList);
- pub.get<void>(length); // skip L bytes
- }
-
- // we've successfully thrown out the garbage. What's left is a data-less subject
- return new CommentAclSubject(); // no data
-}
-
-
-//
-// Export to blob form.
-// This simply writes the smallest form consistent with the heuristic above.
-//
-void CommentAclSubject::exportBlob(Writer::Counter &pub, Writer::Counter &)
-{
- uint32_t zero = 0;
- Endian<uint32_t> length = 12;
- pub(zero); pub(length); pub(zero); pub(zero); pub(zero);
-}
-
-void CommentAclSubject::exportBlob(Writer &pub, Writer &)
-{
- uint32_t zero = 0;
- Endian<uint32_t> length = 12;
- pub(zero); pub(length); pub(zero); pub(zero); pub(zero);
-}
-
-
-#ifdef DEBUGDUMP
-
-void CommentAclSubject::debugDump() const
-{
- Debug::dump("Comment[never]");
-}
-
-#endif //DEBUGDUMP
projects / apple / security.git / blobdiff