lib/diskrep.cpp

   1 /*
   2  * Copyright (c) 2006-2007 Apple Inc. All Rights Reserved.
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   8  * Version 2.0 (the 'License'). You may not use this file except in
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  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,
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  18  * Please see the License for the specific language governing rights and
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  23
  24 //
  25 // diskrep - disk representations of code
  26 //
  27 #include "diskrep.h"
  28 #include <sys/stat.h>
  29 #include <CoreFoundation/CFBundlePriv.h>
  30
  31 // specific disk representations created by the bestGuess() function
  32 #include "filediskrep.h"
  33 #include "bundlediskrep.h"
  34 #include "cfmdiskrep.h"
  35 #include "slcrep.h"
  36
  37
  38 namespace Security {
  39 namespace CodeSigning {
  40
  41 using namespace UnixPlusPlus;
  42
  43
  44 //
  45 // Abstract features
  46 //
  47 DiskRep::DiskRep()
  48 {
  49 }
  50
  51 DiskRep::~DiskRep()
  52 {
  53         CODESIGN_DISKREP_DESTROY(this);
  54 }
  55
  56
  57 //
  58 // Normal DiskReps are their own base.
  59 //
  60 DiskRep *DiskRep::base()
  61 {
  62         return this;
  63 }
  64
  65
  66 //
  67 // By default, DiskReps are read-only.
  68 //
  69 DiskRep::Writer *DiskRep::writer()
  70 {
  71         MacOSError::throwMe(errSecCSUnimplemented);
  72 }
  73
  74
  75 void DiskRep::Writer::addDiscretionary(CodeDirectory::Builder &)
  76 {
  77         // do nothing
  78 }
  79
  80
  81 //
  82 // Given a file system path, come up with the most likely correct
  83 // disk representation for what's there.
  84 // This is, strictly speaking, a heuristic that could be fooled - there's
  85 // no fool-proof rule for figuring this out. But we'd expect this to work
  86 // fine in ordinary use. If you happen to know what you're looking at
  87 // (say, a bundle), then just create the suitable subclass of DiskRep directly.
  88 // That's quite legal.
  89 // The optional context argument can provide additional information that guides the guess.
  90 //
  91 DiskRep *DiskRep::bestGuess(const char *path, const Context *ctx)
  92 {
  93         try {
  94                 if (!(ctx && ctx->fileOnly)) {
  95                         struct stat st;
  96                         if (::stat(path, &st))
  97                                 UnixError::throwMe();
  98
  99                         // if it's a directory, assume it's a bundle
 100                         if ((st.st_mode & S_IFMT) == S_IFDIR)   // directory - assume bundle
 101                                 return new BundleDiskRep(path, ctx);
 102
 103                         // see if it's the main executable of a recognized bundle
 104                         if (CFRef<CFURLRef> pathURL = makeCFURL(path))
 105                                 if (CFRef<CFBundleRef> bundle = _CFBundleCreateWithExecutableURLIfMightBeBundle(NULL, pathURL))
 106                                                 return new BundleDiskRep(bundle, ctx);
 107                 }
 108
 109                 // try the various single-file representations
 110                 AutoFileDesc fd(path, O_RDONLY);
 111                 if (MachORep::candidate(fd))
 112                         return new MachORep(path, ctx);
 113                 if (CFMDiskRep::candidate(fd))
 114                         return new CFMDiskRep(path);
 115                 if (DYLDCacheRep::candidate(fd))
 116                         return new DYLDCacheRep(path);
 117
 118                 // ultimate fallback - the generic file representation
 119                 return new FileDiskRep(path);
 120
 121         } catch (const CommonError &error) {
 122                 switch (error.unixError()) {
 123                 case ENOENT:
 124                         MacOSError::throwMe(errSecCSStaticCodeNotFound);
 125                 default:
 126                         throw;
 127                 }
 128         }
 129 }
 130
 131
 132 DiskRep *DiskRep::bestFileGuess(const char *path, const Context *ctx)
 133 {
 134         Context dctx;
 135         if (ctx)
 136                 dctx = *ctx;
 137         dctx.fileOnly = true;
 138         return bestGuess(path, &dctx);
 139 }
 140
 141
 142 //
 143 // Given a main executable known to be a Mach-O binary, and an offset into
 144 // the file of the actual architecture desired (of a Universal file),
 145 // produce a suitable MachORep.
 146 // This function does not consider non-MachO binaries. It does however handle
 147 // bundles with Mach-O main executables correctly.
 148 //
 149 DiskRep *DiskRep::bestGuess(const char *path, size_t archOffset)
 150 {
 151         try {
 152                 // is it the main executable of a bundle?
 153                 if (CFRef<CFURLRef> pathURL = makeCFURL(path))
 154                         if (CFRef<CFBundleRef> bundle = _CFBundleCreateWithExecutableURLIfMightBeBundle(NULL, pathURL)) {
 155                                 Context ctx; ctx.offset = archOffset;
 156                                 return new BundleDiskRep(bundle, &ctx); // ask bundle to make bundle-with-MachO-at-offset
 157                         }
 158                 // else, must be a Mach-O binary
 159                 Context ctx; ctx.offset = archOffset;
 160                 return new MachORep(path, &ctx);
 161         } catch (const CommonError &error) {
 162                 switch (error.unixError()) {
 163                 case ENOENT:
 164                         MacOSError::throwMe(errSecCSStaticCodeNotFound);
 165                 default:
 166                         throw;
 167                 }
 168         }
 169 }
 170
 171
 172 //
 173 // Default behaviors of DiskRep
 174 //
 175 string DiskRep::resourcesRootPath()
 176 {
 177         return "";              // has no resources directory
 178 }
 179
 180 void DiskRep::adjustResources(ResourceBuilder &builder)
 181 {
 182         // do nothing
 183 }
 184
 185 Universal *DiskRep::mainExecutableImage()
 186 {
 187         return NULL;    // no Mach-O executable
 188 }
 189
 190 size_t DiskRep::signingBase()
 191 {
 192         return 0;               // whole file (start at beginning)
 193 }
 194
 195 CFArrayRef DiskRep::modifiedFiles()
 196 {
 197         // by default, claim (just) the main executable modified
 198         CFRef<CFURLRef> mainURL = makeCFURL(mainExecutablePath());
 199         return makeCFArray(1, mainURL.get());
 200 }
 201
 202 void DiskRep::flush()
 203 {
 204         // nothing cached
 205 }
 206
 207
 208 CFDictionaryRef DiskRep::defaultResourceRules(const SigningContext &)
 209 {
 210         return NULL;    // none
 211 }
 212
 213 const Requirements *DiskRep::defaultRequirements(const Architecture *, const SigningContext &)
 214 {
 215         return NULL;    // none
 216 }
 217
 218 size_t DiskRep::pageSize(const SigningContext &)
 219 {
 220         return monolithicPageSize;      // unpaged (monolithic)
 221 }
 222
 223
 224 //
 225 // Given some string (usually a pathname), derive a suggested signing identifier
 226 // in a canonical way (so there's some consistency).
 227 //
 228 // This is a heuristic. First we lop off any leading directories and final (non-numeric)
 229 // extension. Then we walk backwards, eliminating numeric extensions except the first one.
 230 // Thus, libfrotz7.3.5.dylib becomes libfrotz7, mumble.77.plugin becomes mumble.77,
 231 // and rumble.rb becomes rumble. This isn't perfect, but it ought to handle 98%+ of
 232 // the common varieties out there. Specify an explicit identifier for the oddballs.
 233 //
 234 // This is called by the various recommendedIdentifier() methods, who are
 235 // free to modify or override it.
 236 //
 237 // Note: We use strchr("...") instead of is*() here because we do not
 238 // wish to be influenced by locale settings.
 239 //
 240 std::string DiskRep::canonicalIdentifier(const std::string &name)
 241 {
 242         string s = name;
 243         string::size_type p;
 244
 245         // lop off any directory prefixes
 246         if ((p = s.rfind('/')) != string::npos)
 247                 s = s.substr(p+1);
 248
 249         // remove any final extension (last dot) unless it's numeric
 250         if ((p = s.rfind('.')) != string::npos && !strchr("0123456789", s[p+1]))
 251                 s = s.substr(0, p);
 252
 253         // eat numeric suffixes except the first one; roughly:
 254         // foo.2.3.4 => foo.2, foo2.3 => foo2, foo.9 => foo.9, foo => foo
 255         if (strchr("0123456789.", s[0]))                        // starts with digit or .
 256                 return s;                                                               // ... so don't mess with it
 257         p = s.size()-1;
 258         // foo3.5^, foo.3.5^, foo3^, foo.3^, foo^
 259         while (strchr("0123456789.", s[p]))
 260                 p--;
 261         // fo^o3.5, fo^o.3.5, fo^o3, fo^o.3, fo^o
 262         p++;
 263         // foo^3.5, foo^.3.5, foo^3, foo^.3, foo^
 264         if (s[p] == '.')
 265                 p++;
 266         // foo^3.5, foo.^3.5, foo^3, foo.^3, foo^
 267         while (p < s.size() && strchr("0123456789", s[p]))
 268                 p++;
 269         // foo3^.5, foo.3^.5, foo3^, foo.3^, foo^
 270         return s.substr(0, p);
 271 }
 272
 273
 274 //
 275 // Writers
 276 //
 277 DiskRep::Writer::Writer(uint32_t attrs)
 278         : mArch(CPU_TYPE_ANY), mAttributes(attrs)
 279 {
 280 }
 281
 282 DiskRep::Writer::~Writer()
 283 { /* virtual */ }
 284
 285 uint32_t DiskRep::Writer::attributes() const
 286 { return mAttributes; }
 287
 288 void DiskRep::Writer::flush()
 289 { /* do nothing */ }
 290
 291 void DiskRep::Writer::remove()
 292 {
 293         MacOSError::throwMe(errSecCSNotSupported);
 294 }
 295
 296
 297 } // end namespace CodeSigning
 298 } // end namespace Security