libsecurity_codesigning/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,
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  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 class ResourceBuilder;
  44
  45
  46 //
  47 // DiskRep is an abstract interface to code somewhere located by
  48 // a file system path. It presents the ability to read and write
  49 // Code Signing-related information about such code without exposing
  50 // the details of the storage locations or formats.
  51 //
  52 class DiskRep : public RefCount {
  53 public:
  54         class SigningContext;
  55
  56 public:
  57         DiskRep();
  58         virtual ~DiskRep();
  59         virtual DiskRep *base();
  60         virtual CFDataRef component(CodeDirectory::SpecialSlot slot) = 0; // fetch component
  61         virtual CFDataRef identification() = 0;                                 // binary lookup identifier
  62         virtual std::string mainExecutablePath() = 0;                   // path to main executable
  63         virtual CFURLRef canonicalPath() = 0;                                   // path to whole code
  64         virtual std::string resourcesRootPath();                                // resource directory if any [none]
  65         virtual void adjustResources(ResourceBuilder &builder); // adjust resource rule set [no change]
  66         virtual Universal *mainExecutableImage();                               // Mach-O image if Mach-O based [null]
  67         virtual size_t signingBase();                                                   // start offset of signed area in main executable [zero]
  68         virtual size_t signingLimit() = 0;                                              // size of signed area in main executable
  69         virtual std::string format() = 0;                                               // human-readable type string
  70         virtual CFArrayRef modifiedFiles();                                             // list of files modified by signing [main execcutable only]
  71         virtual UnixPlusPlus::FileDesc &fd() = 0;                               // a cached file descriptor for main executable file
  72         virtual void flush();                                                                   // flush caches (refetch as needed)
  73
  74         // default values for signing operations
  75         virtual std::string recommendedIdentifier(const SigningContext &ctx) = 0; // default identifier
  76         virtual CFDictionaryRef defaultResourceRules(const SigningContext &ctx); // default resource rules [none]
  77         virtual const Requirements *defaultRequirements(const Architecture *arch,
  78                 const SigningContext &ctx);                                                     // default internal requirements [none]
  79         virtual size_t pageSize(const SigningContext &ctx);             // default main executable page size [infinite, i.e. no paging]
  80
  81         bool mainExecutableIsMachO() { return mainExecutableImage() != NULL; }
  82
  83         // shorthands
  84         CFDataRef codeDirectory()       { return component(cdCodeDirectorySlot); }
  85         CFDataRef signature()           { return component(cdSignatureSlot); }
  86
  87 public:
  88         class Writer;
  89         virtual Writer *writer();                                                               // Writer factory
  90
  91 public:
  92         // optional information that might be used to create a suitable DiskRep. All optional
  93         struct Context {
  94                 Context() : arch(Architecture::none), version(NULL), offset(0), fileOnly(false), inMemory(NULL) { }
  95                 Architecture arch;                      // explicit architecture (choose amongst universal variants)
  96                 const char *version;            // bundle version (string)
  97                 off_t offset;                           // explicit file offset
  98                 bool fileOnly;                          // only consider single-file representations (no bundles etc.)
  99                 const void *inMemory;           // consider using in-memory copy at this address
 100         };
 101
 102         static DiskRep *bestGuess(const char *path, const Context *ctx = NULL); // canonical heuristic, any path
 103         static DiskRep *bestFileGuess(const char *path, const Context *ctx = NULL); // ctx (if any) + fileOnly
 104         static DiskRep *bestGuess(const char *path, size_t archOffset); // Mach-O at given file offset only
 105
 106         // versions using std::string paths (merely a convenience)
 107         static DiskRep *bestGuess(const std::string &path, const Context *ctx = NULL)
 108                 { return bestGuess(path.c_str(), ctx); }
 109         static DiskRep *bestGuess(const std::string &path, size_t archOffset) { return bestGuess(path.c_str(), archOffset); }
 110         static DiskRep *bestFileGuess(const std::string &path, const Context *ctx = NULL) { return bestFileGuess(path.c_str(), ctx); }
 111
 112 public:
 113         // see DiskRep::Writer docs for why this is here
 114         class SigningContext {
 115         protected:
 116                 SigningContext() { }
 117
 118         public:
 119                 virtual std::string sdkPath(const std::string &path) const = 0;
 120                 virtual bool isAdhoc() const = 0;
 121                 virtual SecCSFlags signingFlags() const = 0;
 122         };
 123
 124 protected:
 125         // canonically derive a suggested signing identifier from some string
 126         static std::string canonicalIdentifier(const std::string &name);
 127
 128 public:
 129         static const size_t segmentedPageSize = 4096;   // default page size for system-paged signatures
 130         static const size_t monolithicPageSize = 0;             // default page size for non-Mach-O executables
 131 };
 132
 133
 134 //
 135 // Write-access objects.
 136 // At this layer they are quite abstract, carrying just the functionality needed
 137 // for the signing machinery to place data wherever it should go. Each DiskRep subclass
 138 // that supports writing signing data to a place inside the code needs to implement
 139 // a subclass of Writer and return an instance in the DiskRep::writer() method when asked.
 140 //
 141 // The Writer class is subclassed interestingly by the Mach-O multi-architecture signing code,
 142 // which is handled as a special case. This means that not all Writer subclass objects were made
 143 // by DiskRep::writer, and it is unwise to assume so.
 144 //
 145 // Note that the methods that provide defaults for signing operations are in DiskRep rather
 146 // than here. That's because writers abstract data *sending*, and are virtual on management
 147 // of stored data, while DiskRep is virtual on the existing code object, which is where
 148 // we get our defaults from.
 149 //
 150 class DiskRep::Writer : public RefCount {
 151 public:
 152         Writer(uint32_t attrs = 0);
 153         virtual ~Writer();
 154         virtual void component(CodeDirectory::SpecialSlot slot, CFDataRef data) = 0;
 155         virtual uint32_t attributes() const;
 156         virtual void addDiscretionary(CodeDirectory::Builder &builder);
 157         virtual void remove();
 158         virtual void flush();
 159
 160         bool attribute(uint32_t attr) const             { return mAttributes & attr; }
 161
 162         void signature(CFDataRef data)                  { component(cdSignatureSlot, data); }
 163         void codeDirectory(const CodeDirectory *cd)
 164                 { component(cdCodeDirectorySlot, CFTempData(cd->data(), cd->length())); }
 165
 166 private:
 167         Architecture mArch;
 168         uint32_t mAttributes;
 169 };
 170
 171 //
 172 // Writer attributes. Defaults should be off-bits.
 173 //
 174 enum {
 175         writerLastResort = 0x0001,                      // prefers not to store attributes itself
 176         writerNoGlobal = 0x0002,                        // has only per-architecture storage
 177 };
 178
 179
 180 //
 181 // A prefix DiskRep that filters (only) signature-dependent behavior and passes
 182 // all code-dependent behavior off to an underlying (different) DiskRep.
 183 // FilterRep subclasses are typically "stacked" on top of their base DiskRep, and
 184 // then used in their place.
 185 //
 186 class FilterRep : public DiskRep {
 187 public:
 188         FilterRep(DiskRep *orig) : mOriginal(orig) { }
 189
 190         DiskRep *base()                                                 { return mOriginal; }
 191
 192         // things that look at signature components are filtered
 193         CFDataRef component(CodeDirectory::SpecialSlot slot) = 0;
 194
 195         // the rest of the virtual behavior devolves on the original DiskRep
 196         CFDataRef identification()                              { return mOriginal->identification(); }
 197         std::string mainExecutablePath()                { return mOriginal->mainExecutablePath(); }
 198         CFURLRef canonicalPath()                                { return mOriginal->canonicalPath(); }
 199         std::string resourcesRootPath()                 { return mOriginal->resourcesRootPath(); }
 200         void adjustResources(ResourceBuilder &builder) { return mOriginal->adjustResources(builder); }
 201         Universal *mainExecutableImage()                { return mOriginal->mainExecutableImage(); }
 202         size_t signingBase()                                    { return mOriginal->signingBase(); }
 203         size_t signingLimit()                                   { return mOriginal->signingLimit(); }
 204         std::string format()                                    { return mOriginal->format(); }
 205         CFArrayRef modifiedFiles()                              { return mOriginal->modifiedFiles(); }
 206         UnixPlusPlus::FileDesc &fd()                    { return mOriginal->fd(); }
 207         void flush()                                                    { return mOriginal->flush(); }
 208
 209         std::string recommendedIdentifier(const SigningContext &ctx)
 210                 { return mOriginal->recommendedIdentifier(ctx); }
 211         CFDictionaryRef defaultResourceRules(const SigningContext &ctx)
 212                 { return mOriginal->defaultResourceRules(ctx); }
 213
 214 private:
 215         RefPointer<DiskRep> mOriginal;                  // underlying representation
 216 };
 217
 218
 219 } // end namespace CodeSigning
 220 } // end namespace Security
 221
 222 #endif // !_H_DISKREP