Security-55163.44.tar.gz

[apple/security.git] / libsecurity_codesigning / lib / slcrep.cpp

diff --git a/libsecurity_codesigning/lib/slcrep.cpp b/libsecurity_codesigning/lib/slcrep.cpp
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+/*
+ * Copyright (c) 2009 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@
+ */
+
+//
+// slcrep - DiskRep representing the Mac OS Shared Library Cache
+//
+#include "slcrep.h"
+
+
+namespace Security {
+namespace CodeSigning {
+
+using namespace UnixPlusPlus;
+
+
+//
+// Object management.
+// We open the file lazily, so nothing much happens on constructions.
+// We can construct directly from a file path, or from an architecture
+// (represented by Context), which will find the file in its usual
+// location on disk.
+//
+DYLDCacheRep::DYLDCacheRep(const char *path)
+       : SingleDiskRep(path), mCache(path)
+{
+       this->setup();
+}
+
+DYLDCacheRep::DYLDCacheRep(const Context *ctx)
+       : SingleDiskRep(DYLDCache::pathFor(((ctx && ctx->arch) ? ctx->arch : Architecture::local()))),
+         mCache(this->path())
+{
+       this->setup();
+}
+
+void DYLDCacheRep::setup()
+{
+       mSigningData = NULL;
+       if (mCache.totalSize() >= mCache.mapSize() + sizeof(BlobCore)) {
+               const EmbeddedSignatureBlob *blob = mCache.at<const EmbeddedSignatureBlob>(mCache.mapSize());
+               if (mCache.totalSize() >= mCache.mapSize() + blob->length())    // entire blob fits in file
+                       mSigningData = blob;
+       }
+       CODESIGN_DISKREP_CREATE_SLC(this, (char*)this->mainExecutablePath().c_str());
+}
+
+
+//
+// Sniffer function for "plausible shared library cache file".
+//
+bool DYLDCacheRep::candidate(FileDesc &fd)
+{
+       return DYLDCache::validate(fd);
+}
+
+
+//
+// Default to system page size for segmented (paged) signatures
+//
+size_t DYLDCacheRep::pageSize(const SigningContext &)
+{
+       return segmentedPageSize;
+}
+
+
+//
+// Retrieve a component from the executable.
+// Our mCache has mapped the entire file, so we just fish the contents out of
+// the mapped area as needed.
+//
+CFDataRef DYLDCacheRep::component(CodeDirectory::SpecialSlot slot)
+{
+       return mSigningData ? mSigningData->component(slot) : NULL;
+}
+
+
+//
+// Provide a (vaguely) human readable characterization of this code
+//
+string DYLDCacheRep::format()
+{
+       if (const char *name = mCache.architecture().name()) {
+               char result[100];
+               snprintf(result, sizeof(result), "OS X Shared Library Cache (%s @ 0x%llx)",
+                       name, mCache.baseAddress());
+               return result;
+       } else
+               return "OS X Shared Library Cache (unknown type)";
+}
+
+
+//
+// DYLDCacheRep::Writers
+//
+DiskRep::Writer *DYLDCacheRep::writer()
+{
+       return new Writer(this);
+}
+
+
+//
+// Write a component.
+//
+void DYLDCacheRep::Writer::component(CodeDirectory::SpecialSlot slot, CFDataRef data)
+{
+       EmbeddedSignatureBlob::Maker::component(slot, data);
+}
+
+
+//
+// Append the superblob we built to the cache file.
+//
+void DYLDCacheRep::Writer::flush()
+{
+       delete mSigningData;                    // ditch previous blob just in case
+       mSigningData = Maker::make();   // assemble new signature SuperBlob
+       fd().seek(rep->mCache.mapSize()); // end of impage proper
+       fd().writeAll(*mSigningData);
+}
+
+
+//
+// The discretionary additions insert a Scatter vector describing the file's mapping table.
+//
+void DYLDCacheRep::Writer::addDiscretionary(CodeDirectory::Builder &builder)
+{
+       unsigned count = rep->mCache.mappingCount();
+       builder.scatter(count);
+       for (unsigned n = 0; n < count; n++) {
+               const DYLDCache::Mapping dmap = rep->mCache.mapping(n);
+               CodeDirectory::Scatter *scatter = builder.scatter() + n;
+               scatter->targetOffset = dmap.address();
+               scatter->base = dmap.offset() / segmentedPageSize;
+               assert(dmap.offset() % segmentedPageSize == 0);
+               scatter->count = dmap.size() / segmentedPageSize;
+               assert(dmap.size() % segmentedPageSize == 0);
+       }
+}
+
+
+} // end namespace CodeSigning
+} // end namespace Security