lib/signerutils.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 // signerutils - utilities for signature generation
  26 //
  27 #ifndef _H_SIGNERUTILS
  28 #define _H_SIGNERUTILS
  29
  30 #include "CodeSigner.h"
  31 #include "sigblob.h"
  32 #include "cdbuilder.h"
  33 #include <security_utilities/utilities.h>
  34 #include <security_utilities/blob.h>
  35 #include <security_utilities/unix++.h>
  36 #include <security_utilities/unixchild.h>
  37
  38 extern "C" {
  39 #include <copyfile.h>
  40 }
  41
  42 namespace Security {
  43 namespace CodeSigning {
  44
  45
  46 //
  47 // A helper to deal with the magic merger logic of internal requirements
  48 //
  49 class InternalRequirements : public Requirements::Maker {
  50 public:
  51         InternalRequirements() : mReqs(NULL) { }
  52         ~InternalRequirements() { ::free((void *)mReqs); }
  53         void operator () (const Requirements *given, const Requirements *defaulted);
  54         operator const Requirements * () const { return mReqs; }
  55
  56 private:
  57         const Requirements *mReqs;
  58 };
  59
  60
  61 //
  62 // A DiskRep::Writer that assembles data in a SuperBlob (in memory)
  63 //
  64 class BlobWriter : public DiskRep::Writer, public EmbeddedSignatureBlob::Maker {
  65 public:
  66         void component(CodeDirectory::SpecialSlot slot, CFDataRef data);
  67 };
  68
  69
  70 class DetachedBlobWriter : public BlobWriter {
  71 public:
  72         DetachedBlobWriter(SecCodeSigner::Signer &s) : signer(s) { }
  73
  74         SecCodeSigner::Signer &signer;
  75
  76         void flush();
  77 };
  78
  79
  80 //
  81 // A multi-architecture editing assistant.
  82 // ArchEditor collects (Mach-O) architectures in use, and maintains per-archtitecture
  83 // data structures. It must be subclassed to express a particular way to handle the signing
  84 // data.
  85 //
  86 class ArchEditor : public DiskRep::Writer {
  87 public:
  88         ArchEditor(Universal &fat, uint32_t attrs = 0);
  89         virtual ~ArchEditor();
  90
  91 public:
  92         //
  93         // One architecture's signing construction element.
  94         // This also implements DispRep::Writer so generic writing code
  95         // can work with both Mach-O and other files.
  96         //
  97         struct Arch : public BlobWriter {
  98                 Architecture architecture;              // our architecture
  99                 auto_ptr<MachO> source;                 // Mach-O object to be signed
 100                 CodeDirectory::Builder cdbuilder; // builder for CodeDirectory
 101                 InternalRequirements ireqs;             // consolidated internal requirements
 102                 size_t blobSize;                                // calculated SuperBlob size
 103
 104                 Arch(const Architecture &arch) : architecture(arch) { }
 105         };
 106
 107         //
 108         // Our callers access the architectural universe through a map
 109         // from Architectures to Arch objects.
 110         //
 111         typedef std::map<Architecture, Arch *> ArchMap;
 112         typedef ArchMap::iterator Iterator;
 113         ArchMap::iterator begin()               { return architecture.begin(); }
 114         ArchMap::iterator end()                 { return architecture.end(); }
 115         unsigned count() const                  { return architecture.size(); }
 116
 117         // methods needed for an actual implementation
 118         virtual void allocate() = 0;                    // interpass allocations
 119         virtual void reset(Arch &arch) = 0;             // pass 2 prep
 120         virtual void write(Arch &arch, EmbeddedSignatureBlob *blob) = 0; // takes ownership of blob
 121         virtual void commit() = 0;                              // write/flush result
 122
 123 protected:
 124         ArchMap architecture;
 125 };
 126
 127
 128 //
 129 // An ArchEditor that collects all architectures into a single SuperBlob,
 130 // usually for writing a detached multi-architecture signature.
 131 //
 132 class BlobEditor : public ArchEditor {
 133 public:
 134         BlobEditor(Universal &fat, SecCodeSigner::Signer &s) : ArchEditor(fat), signer(s) { }
 135         ~BlobEditor() { }
 136
 137         SecCodeSigner::Signer &signer;
 138
 139         void component(CodeDirectory::SpecialSlot slot, CFDataRef data);
 140         void allocate() { }
 141         void reset(Arch &arch) { }
 142         void write(Arch &arch, EmbeddedSignatureBlob *blob);
 143         void commit();
 144
 145 private:
 146         DetachedSignatureBlob::Maker mMaker;
 147         EmbeddedSignatureBlob::Maker mGlobal;
 148 };
 149
 150
 151 //
 152 // An ArchEditor that writes its signatures into a (fat) binary file.
 153 //
 154 class MachOEditor : public ArchEditor, private UnixPlusPlus::Child {
 155 public:
 156         MachOEditor(DiskRep::Writer *w, Universal &code, std::string srcPath);
 157         ~MachOEditor();
 158
 159         const RefPointer<DiskRep::Writer> writer;
 160         const std::string sourcePath;
 161         const std::string tempPath;
 162
 163         void component(CodeDirectory::SpecialSlot slot, CFDataRef data);
 164         void allocate();
 165         void reset(Arch &arch);
 166         void write(Arch &arch, EmbeddedSignatureBlob *blob);
 167         void commit();
 168
 169 private:
 170         void childAction();
 171         Universal *mNewCode;
 172         UnixPlusPlus::AutoFileDesc mFd;
 173         bool mTempMayExist;
 174 };
 175
 176
 177 //
 178 // Encapsulation of the copyfile(3) API.
 179 // This is slated to go into utilities once stable.
 180 //
 181 class Copyfile {
 182 public:
 183         Copyfile();
 184         ~Copyfile()     { copyfile_state_free(mState); }
 185
 186         operator copyfile_state_t () const { return mState; }
 187
 188         void set(uint32_t flag, const void *value);
 189         void get(uint32_t flag, void *value);
 190
 191         void operator () (const char *src, const char *dst, copyfile_flags_t flags);
 192
 193 private:
 194         void check(int rc);
 195
 196 private:
 197         copyfile_state_t mState;
 198 };
 199
 200
 201 //
 202 // A reliable uid set/reset bracket
 203 //
 204 class UidGuard {
 205 public:
 206         UidGuard() : mPrevious(-1) { }
 207         UidGuard(uid_t uid) : mPrevious(-1) { seteuid(uid); }
 208         ~UidGuard()
 209         {
 210                 if (active())
 211                         UnixError::check(::seteuid(mPrevious));
 212         }
 213
 214         bool seteuid(uid_t uid)
 215         {
 216                 if (uid == geteuid())
 217                         return true;    // no change, don't bother the kernel
 218                 if (!active())
 219                         mPrevious = ::geteuid();
 220                 return ::seteuid(uid) == 0;
 221         }
 222
 223         bool active() const { return mPrevious != uid_t(-1); }
 224         operator bool () const { return active(); }
 225         uid_t saved() const { assert(active()); return mPrevious; }
 226
 227 private:
 228         uid_t mPrevious;
 229 };
 230
 231
 232 } // end namespace CodeSigning
 233 } // end namespace Security
 234
 235 #endif // !_H_SIGNERUTILS