lib/diskrep.h

   1 /*
   2  * Copyright (c) 2006-2007 Apple Inc. All Rights Reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License. Please obtain a copy of the License at
  10  * http://www.opensource.apple.com/apsl/ and read it before using this
  11  * file.
  12  *
  13  * The Original Code and all software distributed under the License are
  14  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  15  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  16  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  18  * Please see the License for the specific language governing rights and
  19  * limitations under the License.
  20  *
  21  * @APPLE_LICENSE_HEADER_END@
  22  */
  23
  24 //
  25 // diskrep - disk representations of code
  26 //
  27 #ifndef _H_DISKREP
  28 #define _H_DISKREP
  29
  30 #include "cs.h"
  31 #include "codedirectory.h"
  32 #include "cdbuilder.h"
  33 #include "requirement.h"
  34 #include "resources.h"
  35 #include <security_utilities/macho++.h>         // for class Architecture
  36 #include <security_utilities/refcount.h>
  37 #include <security_utilities/superblob.h>
  38 #include <CoreFoundation/CFData.h>
  39
  40 namespace Security {
  41 namespace CodeSigning {
  42
  43
  44 //
  45 // DiskRep is an abstract interface to code somewhere located by
  46 // a file system path. It presents the ability to read and write
  47 // Code Signing-related information about such code without exposing
  48 // the details of the storage locations or formats.
  49 //
  50 class DiskRep : public RefCount {
  51 public:
  52         DiskRep();
  53         virtual ~DiskRep();
  54         virtual DiskRep *base();
  55         virtual CFDataRef component(CodeDirectory::SpecialSlot slot) = 0; // fetch component
  56         virtual CFDataRef identification() = 0;                                 // binary lookup identifier
  57         virtual std::string mainExecutablePath() = 0;                   // path to main executable
  58         virtual CFURLRef canonicalPath() = 0;                                   // path to whole code
  59         virtual std::string recommendedIdentifier() = 0;                // default identifier
  60         virtual std::string resourcesRootPath();                                // resource directory if any
  61         virtual CFDictionaryRef defaultResourceRules();                 // default resource rules
  62         virtual void adjustResources(ResourceBuilder &builder); // adjust resource rule set
  63         virtual const Requirements *defaultRequirements(const Architecture *arch); // default internal requirements
  64         virtual Universal *mainExecutableImage();                               // binary if Mach-O/Universal
  65         virtual size_t pageSize();                                                              // default main executable page size
  66         virtual size_t signingBase();                                                   // start offset of signed area in main executable
  67         virtual size_t signingLimit() = 0;                                              // size of signed area in main executable
  68         virtual std::string format() = 0;                                               // human-readable type string
  69         virtual CFArrayRef modifiedFiles();                                             // list of files modified by signing
  70         virtual UnixPlusPlus::FileDesc &fd() = 0;                               // a cached fd for main executable file
  71         virtual void flush();                                                                   // flush caches (refetch as needed)
  72
  73         bool mainExecutableIsMachO() { return mainExecutableImage() != NULL; }
  74
  75         // shorthands
  76         CFDataRef codeDirectory()       { return component(cdCodeDirectorySlot); }
  77         CFDataRef signature()           { return component(cdSignatureSlot); }
  78
  79 public:
  80         class Writer;
  81         virtual Writer *writer();
  82
  83 public:
  84         struct Context {
  85                 Context() : arch(Architecture::none), offset(0), fileOnly(false) { }
  86                 Architecture arch;                      // explicit architecture
  87                 off_t offset;                           // explicit file offset
  88                 bool fileOnly;                          // only consider single-file representations
  89         };
  90
  91         static DiskRep *bestGuess(const char *path, const Context *ctx = NULL); // canonical heuristic, any path
  92         static DiskRep *bestFileGuess(const char *path, const Context *ctx = NULL); // ctx (if any) + fileOnly
  93         static DiskRep *bestGuess(const char *path, size_t archOffset); // Mach-O at given file offset only
  94
  95         static DiskRep *bestGuess(const std::string &path, const Context *ctx = NULL)
  96                 { return bestGuess(path.c_str(), ctx); }
  97         static DiskRep *bestGuess(const std::string &path, size_t archOffset) { return bestGuess(path.c_str(), archOffset); }
  98         static DiskRep *bestFileGuess(const std::string &path, const Context *ctx = NULL) { return bestFileGuess(path.c_str(), ctx); }
  99
 100 public:
 101         static const size_t segmentedPageSize = 4096;   // default page size for system-paged signatures
 102         static const size_t monolithicPageSize = 0;             // default page size for non-Mach-O executables
 103 };
 104
 105
 106 //
 107 // Write-access objects.
 108 // At this layer they are quite abstract, carrying just the functionality needed
 109 // for the signing machinery to place data wherever it should go. Each DiskRep subclass
 110 // that supports writing signing data to a place inside the code needs to implement
 111 // a subclass of Writer and return an instance in the DiskRep::writer() method when asked.
 112 //
 113 class DiskRep::Writer : public RefCount {
 114 public:
 115         Writer(uint32_t attrs = 0);
 116         virtual ~Writer();
 117         virtual void component(CodeDirectory::SpecialSlot slot, CFDataRef data) = 0;
 118         virtual uint32_t attributes() const;
 119         virtual void addDiscretionary(CodeDirectory::Builder &builder);
 120         virtual void remove();
 121         virtual void flush();
 122
 123         bool attribute(uint32_t attr) const             { return mAttributes & attr; }
 124
 125         void signature(CFDataRef data)                  { component(cdSignatureSlot, data); }
 126         void codeDirectory(const CodeDirectory *cd)
 127                 { component(cdCodeDirectorySlot, CFTempData(cd->data(), cd->length())); }
 128
 129 private:
 130         Architecture mArch;
 131         uint32_t mAttributes;
 132 };
 133
 134 //
 135 // Writer attributes. Defaults should be off-bits.
 136 //
 137 enum {
 138         writerLastResort = 0x0001,                      // prefers not to store attributes itself
 139         writerNoGlobal = 0x0002,                        // has only per-architecture storage
 140 };
 141
 142
 143 //
 144 // A prefix DiskRep that filters (only) signature-dependent behavior and passes
 145 // all code-dependent behavior off to an underlying (different) DiskRep.
 146 // FilterRep subclasses are typically "stacked" on top of their base DiskRep, and
 147 // then used in their place.
 148 //
 149 class FilterRep : public DiskRep {
 150 public:
 151         FilterRep(DiskRep *orig) : mOriginal(orig) { }
 152
 153         DiskRep *base()                                                 { return mOriginal; }
 154
 155         // things that look at signature components are filtered
 156         CFDataRef component(CodeDirectory::SpecialSlot slot) = 0;
 157
 158         // the rest of the virtual behavior devolves on the original DiskRep
 159         CFDataRef identification()                              { return mOriginal->identification(); }
 160         std::string mainExecutablePath()                { return mOriginal->mainExecutablePath(); }
 161         CFURLRef canonicalPath()                                { return mOriginal->canonicalPath(); }
 162         std::string recommendedIdentifier()             { return mOriginal->recommendedIdentifier(); }
 163         std::string resourcesRootPath()                 { return mOriginal->resourcesRootPath(); }
 164         CFDictionaryRef defaultResourceRules()  { return mOriginal->defaultResourceRules(); }
 165         Universal *mainExecutableImage()                { return mOriginal->mainExecutableImage(); }
 166         size_t signingBase()                                    { return mOriginal->signingBase(); }
 167         size_t signingLimit()                                   { return mOriginal->signingLimit(); }
 168         std::string format()                                    { return mOriginal->format(); }
 169         UnixPlusPlus::FileDesc &fd()                    { return mOriginal->fd(); }
 170         void flush()                                                    { return mOriginal->flush(); }
 171
 172 private:
 173         RefPointer<DiskRep> mOriginal;                  // underlying representation
 174 };
 175
 176
 177 } // end namespace CodeSigning
 178 } // end namespace Security
 179
 180 #endif // !_H_DISKREP