OSX/libsecurity_codesigning/lib/diskrep.h

   1 /*
   2  * Copyright (c) 2006-2007,2011-2012,2014 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 class ResourceBuilder;
  44 class SecCodeSigner;
  45
  46
  47 //
  48 // DiskRep is an abstract interface to code somewhere located by
  49 // a file system path. It presents the ability to read and write
  50 // Code Signing-related information about such code without exposing
  51 // the details of the storage locations or formats.
  52 //
  53 class DiskRep : public RefCount {
  54 public:
  55         class SigningContext;
  56
  57         typedef std::set<OSStatus> ToleratedErrors;
  58
  59 public:
  60         DiskRep();
  61         virtual ~DiskRep();
  62         virtual DiskRep *base();
  63         virtual CFDataRef component(CodeDirectory::SpecialSlot slot) = 0; // fetch component
  64         virtual CFDataRef identification() = 0;                                 // binary lookup identifier
  65         virtual std::string mainExecutablePath() = 0;                   // path to main executable
  66         virtual CFURLRef copyCanonicalPath() = 0;                                       // path to whole code
  67         virtual std::string resourcesRootPath();                                // resource directory if any [none]
  68         virtual void adjustResources(ResourceBuilder &builder); // adjust resource rule set [no change]
  69         virtual void prepareForSigning(SigningContext& context); // pre-adjust signing defaults before argument preparation [none]
  70         virtual Universal *mainExecutableImage();                               // Mach-O image if Mach-O based [null]
  71         virtual size_t signingBase();                                                   // start offset of signed area in main executable [zero]
  72         virtual size_t signingLimit() = 0;                                              // size of signed area in main executable
  73
  74         // The executable segment, if present, denotes which part of the image can be mapped
  75         // into a virtual address space as executable. Not all platforms check this.
  76         virtual size_t execSegBase(const Architecture *arch);                   // start offset of executable segment in main executable [zero]
  77         virtual size_t execSegLimit(const Architecture *arch) = 0;              // size of executable segment in main executable
  78
  79         virtual std::string format() = 0;                                               // human-readable type string
  80         virtual CFArrayRef modifiedFiles();                                             // list of files modified by signing [main execcutable only]
  81         virtual UnixPlusPlus::FileDesc &fd() = 0;                               // a cached file descriptor for main executable file
  82         virtual void flush();                                                                   // flush caches (refetch as needed)
  83     virtual CFDictionaryRef diskRepInformation();           // information from diskrep
  84
  85         virtual void registerStapledTicket();
  86
  87         // default values for signing operations
  88         virtual std::string recommendedIdentifier(const SigningContext &ctx) = 0; // default identifier
  89         virtual CFDictionaryRef defaultResourceRules(const SigningContext &ctx); // default resource rules [none]
  90         virtual const Requirements *defaultRequirements(const Architecture *arch,
  91                 const SigningContext &ctx);                                                     // default internal requirements [none]
  92         virtual size_t pageSize(const SigningContext &ctx);             // default main executable page size [infinite, i.e. no paging]
  93
  94         virtual void strictValidate(const CodeDirectory* cd, const ToleratedErrors& tolerated, SecCSFlags flags); // perform strict validation
  95         virtual CFArrayRef allowedResourceOmissions();                  // allowed (default) resource omission rules
  96
  97         virtual bool appleInternalForcePlatform() const {return false;};
  98
  99         bool mainExecutableIsMachO() { return mainExecutableImage() != NULL; }
 100
 101         // shorthands
 102         CFDataRef signature()           { return component(cdSignatureSlot); }
 103
 104 public:
 105         class Writer;
 106         virtual Writer *writer();                                                               // Writer factory
 107
 108 public:
 109         // optional information that might be used to create a suitable DiskRep. All optional
 110         struct Context {
 111                 Context() : arch(Architecture::none), version(NULL), offset(0), fileOnly(false), inMemory(NULL), size(0) { }
 112                 Architecture arch;                      // explicit architecture (choose amongst universal variants)
 113                 const char *version;            // bundle version (string)
 114                 off_t offset;                           // explicit file offset
 115                 bool fileOnly;                          // only consider single-file representations (no bundles etc.)
 116                 const void *inMemory;           // consider using in-memory copy at this address
 117                 size_t size;                            // size of this mach-o slice
 118         };
 119
 120         static DiskRep *bestGuess(const char *path, const Context *ctx = NULL); // canonical heuristic, any path
 121         static DiskRep *bestFileGuess(const char *path, const Context *ctx = NULL); // ctx (if any) + fileOnly
 122         static DiskRep *bestGuess(const char *path, size_t archOffset); // Mach-O at given file offset only
 123
 124         // versions using std::string paths (merely a convenience)
 125         static DiskRep *bestGuess(const std::string &path, const Context *ctx = NULL)
 126                 { return bestGuess(path.c_str(), ctx); }
 127         static DiskRep *bestGuess(const std::string &path, size_t archOffset) { return bestGuess(path.c_str(), archOffset); }
 128         static DiskRep *bestFileGuess(const std::string &path, const Context *ctx = NULL) { return bestFileGuess(path.c_str(), ctx); }
 129
 130 public:
 131         // see DiskRep::Writer docs for why this is here
 132         class SigningContext {
 133         protected:
 134                 SigningContext() { }
 135
 136         public:
 137                 virtual std::string sdkPath(const std::string &path) const = 0;
 138                 virtual bool isAdhoc() const = 0;
 139                 virtual SecCSFlags signingFlags() const = 0;
 140
 141                 virtual const CodeDirectory::HashAlgorithms &digestAlgorithms() const = 0;
 142                 virtual void setDigestAlgorithms(CodeDirectory::HashAlgorithms types) = 0;
 143
 144                 void setDigestAlgorithm(CodeDirectory::HashAlgorithm type)
 145                 {
 146                         CodeDirectory::HashAlgorithms types;
 147                         types.insert(type);
 148                         setDigestAlgorithms(types);
 149                 }
 150         };
 151
 152 protected:
 153         // canonically derive a suggested signing identifier from some string
 154         static std::string canonicalIdentifier(const std::string &name);
 155
 156 public:
 157         static const size_t segmentedPageSize = 4096;   // default page size for system-paged signatures
 158         static const size_t monolithicPageSize = 0;             // default page size for non-Mach-O executables
 159 };
 160
 161 /*
 162  * Editable Disk Reps allow editing of their existing code signature.
 163  * Specifically, they allow for individual components to be replaced,
 164  * while preserving all other components.
 165  * Lots of restrictions apply, e.g. machO signatures' superblobs may
 166  * not change in size, and components covered by the code directory
 167  * cannot be replaced without adjusting the code directory.
 168  * Replacing or adding CMS blobs (having reserved enough size in the
 169  * superblob beforehand) is the original reason this trait exists.
 170  */
 171 class EditableDiskRep {
 172 public:
 173         typedef std::map<CodeDirectory::Slot, CFCopyRef<CFDataRef>> RawComponentMap;
 174
 175         /* Return all components in raw form.
 176          * Signature editing will add all the components obtained hereby
 177          * back to their specific slots, though some of them may have
 178          * been replaced in the map.
 179          */
 180         virtual RawComponentMap createRawComponents() = 0;
 181 };
 182
 183 //
 184 // Write-access objects.
 185 // At this layer they are quite abstract, carrying just the functionality needed
 186 // for the signing machinery to place data wherever it should go. Each DiskRep subclass
 187 // that supports writing signing data to a place inside the code needs to implement
 188 // a subclass of Writer and return an instance in the DiskRep::writer() method when asked.
 189 //
 190 // The Writer class is subclassed interestingly by the Mach-O multi-architecture signing code,
 191 // which is handled as a special case. This means that not all Writer subclass objects were made
 192 // by DiskRep::writer, and it is unwise to assume so.
 193 //
 194 // Note that the methods that provide defaults for signing operations are in DiskRep rather
 195 // than here. That's because writers abstract data *sending*, and are virtual on management
 196 // of stored data, while DiskRep is virtual on the existing code object, which is where
 197 // we get our defaults from.
 198 //
 199 class DiskRep::Writer : public RefCount {
 200 public:
 201         Writer(uint32_t attrs = 0);
 202         virtual ~Writer();
 203         virtual void component(CodeDirectory::SpecialSlot slot, CFDataRef data) = 0;
 204         virtual uint32_t attributes() const;
 205         virtual void addDiscretionary(CodeDirectory::Builder &builder);
 206         virtual void remove();
 207         virtual void flush();
 208
 209         bool attribute(uint32_t attr) const             { return mAttributes & attr; }
 210
 211         void signature(CFDataRef data)                  { component(cdSignatureSlot, data); }
 212         void codeDirectory(const CodeDirectory *cd, CodeDirectory::SpecialSlot slot)
 213                 { component(slot, CFTempData(cd->data(), cd->length())); }
 214
 215 #if TARGET_OS_OSX
 216         bool getPreserveAFSC()                                  { return mPreserveAFSC; }
 217         void setPreserveAFSC(bool flag)                 { mPreserveAFSC = flag; }
 218 #endif
 219
 220 private:
 221         Architecture mArch;
 222         uint32_t mAttributes;
 223 #if TARGET_OS_OSX
 224         bool mPreserveAFSC = false; // preserve AFSC compression
 225 #endif
 226 };
 227
 228 //
 229 // Writer attributes. Defaults should be off-bits.
 230 //
 231 enum {
 232         writerLastResort = 0x0001,                      // prefers not to store attributes itself
 233         writerNoGlobal = 0x0002,                        // has only per-architecture storage
 234 };
 235
 236
 237 //
 238 // A prefix DiskRep that filters (only) signature-dependent behavior and passes
 239 // all code-dependent behavior off to an underlying (different) DiskRep.
 240 // FilterRep subclasses are typically "stacked" on top of their base DiskRep, and
 241 // then used in their place.
 242 //
 243 class FilterRep : public DiskRep {
 244 public:
 245         FilterRep(DiskRep *orig) : mOriginal(orig) { }
 246
 247         DiskRep *base()                                                 { return mOriginal; }
 248
 249         // things that look at signature components are filtered
 250         CFDataRef component(CodeDirectory::SpecialSlot slot) = 0;
 251
 252         // the rest of the virtual behavior devolves on the original DiskRep
 253         CFDataRef identification()                              { return mOriginal->identification(); }
 254         std::string mainExecutablePath()                { return mOriginal->mainExecutablePath(); }
 255         CFURLRef copyCanonicalPath()                    { return mOriginal->copyCanonicalPath(); }
 256         std::string resourcesRootPath()                 { return mOriginal->resourcesRootPath(); }
 257         void adjustResources(ResourceBuilder &builder) { return mOriginal->adjustResources(builder); }
 258         Universal *mainExecutableImage()                { return mOriginal->mainExecutableImage(); }
 259         size_t signingBase()                                    { return mOriginal->signingBase(); }
 260         size_t signingLimit()                                   { return mOriginal->signingLimit(); }
 261         size_t execSegBase(const Architecture *arch)                                    { return mOriginal->execSegBase(arch); }
 262         size_t execSegLimit(const Architecture *arch)                                   { return mOriginal->execSegLimit(arch); }
 263         std::string format()                                    { return mOriginal->format(); }
 264         CFArrayRef modifiedFiles()                              { return mOriginal->modifiedFiles(); }
 265         UnixPlusPlus::FileDesc &fd()                    { return mOriginal->fd(); }
 266         void flush()                                                    { return mOriginal->flush(); }
 267
 268         std::string recommendedIdentifier(const SigningContext &ctx)
 269                 { return mOriginal->recommendedIdentifier(ctx); }
 270         CFDictionaryRef defaultResourceRules(const SigningContext &ctx)
 271                 { return mOriginal->defaultResourceRules(ctx); }
 272         const Requirements *defaultRequirements(const Architecture *arch, const SigningContext &ctx)
 273                 { return mOriginal->defaultRequirements(arch, ctx); }
 274         size_t pageSize(const SigningContext &ctx) { return mOriginal->pageSize(ctx); }
 275
 276         void strictValidate(const CodeDirectory* cd, const ToleratedErrors& tolerated, SecCSFlags flags) { mOriginal->strictValidate(cd, tolerated, flags); }
 277         CFArrayRef allowedResourceOmissions() { return mOriginal->allowedResourceOmissions(); }
 278
 279 private:
 280         RefPointer<DiskRep> mOriginal;                  // underlying representation
 281 };
 282
 283
 284 } // end namespace CodeSigning
 285 } // end namespace Security
 286
 287 #endif // !_H_DISKREP