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