OSX/libsecurity_codesigning/lib/diskrep.cpp

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  10  * http://www.opensource.apple.com/apsl/ and read it before using this
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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 "slcrep.h"
  35 #include "diskimagerep.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 (DiskImageRep::candidate(fd))
 114                         return new DiskImageRep(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 void DiskRep::prepareForSigning(SigningContext &state)
 186 {
 187         // do nothing
 188 }
 189
 190 Universal *DiskRep::mainExecutableImage()
 191 {
 192         return NULL;    // no Mach-O executable
 193 }
 194
 195 size_t DiskRep::signingBase()
 196 {
 197         return 0;               // whole file (start at beginning)
 198 }
 199
 200 CFArrayRef DiskRep::modifiedFiles()
 201 {
 202         // by default, claim (just) the main executable modified
 203         CFRef<CFURLRef> mainURL = makeCFURL(mainExecutablePath());
 204         return makeCFArray(1, mainURL.get());
 205 }
 206
 207 void DiskRep::flush()
 208 {
 209         // nothing cached
 210 }
 211
 212 CFDictionaryRef DiskRep::diskRepInformation()
 213 {
 214     return NULL;
 215 }
 216
 217 CFDictionaryRef DiskRep::defaultResourceRules(const SigningContext &)
 218 {
 219         return NULL;    // none
 220 }
 221
 222 const Requirements *DiskRep::defaultRequirements(const Architecture *, const SigningContext &)
 223 {
 224         return NULL;    // none
 225 }
 226
 227 size_t DiskRep::pageSize(const SigningContext &)
 228 {
 229         return monolithicPageSize;      // unpaged (monolithic)
 230 }
 231
 232
 233 void DiskRep::strictValidate(const CodeDirectory*, const ToleratedErrors& tolerated, SecCSFlags flags)
 234 {
 235         if (flags & kSecCSRestrictToAppLike)
 236                 if (tolerated.find(errSecCSNotAppLike) == tolerated.end())
 237                         MacOSError::throwMe(errSecCSNotAppLike);
 238 }
 239
 240 CFArrayRef DiskRep::allowedResourceOmissions()
 241 {
 242         return NULL;
 243 }
 244
 245
 246 //
 247 // Given some string (usually a pathname), derive a suggested signing identifier
 248 // in a canonical way (so there's some consistency).
 249 //
 250 // This is a heuristic. First we lop off any leading directories and final (non-numeric)
 251 // extension. Then we walk backwards, eliminating numeric extensions except the first one.
 252 // Thus, libfrotz7.3.5.dylib becomes libfrotz7, mumble.77.plugin becomes mumble.77,
 253 // and rumble.rb becomes rumble. This isn't perfect, but it ought to handle 98%+ of
 254 // the common varieties out there. Specify an explicit identifier for the oddballs.
 255 //
 256 // This is called by the various recommendedIdentifier() methods, who are
 257 // free to modify or override it.
 258 //
 259 // Note: We use strchr("...") instead of is*() here because we do not
 260 // wish to be influenced by locale settings.
 261 //
 262 std::string DiskRep::canonicalIdentifier(const std::string &name)
 263 {
 264         string s = name;
 265         string::size_type p;
 266
 267         // lop off any directory prefixes
 268         if ((p = s.rfind('/')) != string::npos)
 269                 s = s.substr(p+1);
 270
 271         // remove any final extension (last dot) unless it's numeric
 272         if ((p = s.rfind('.')) != string::npos && !strchr("0123456789", s[p+1]))
 273                 s = s.substr(0, p);
 274
 275         // eat numeric suffixes except the first one; roughly:
 276         // foo.2.3.4 => foo.2, foo2.3 => foo2, foo.9 => foo.9, foo => foo
 277         if (strchr("0123456789.", s[0]))                        // starts with digit or .
 278                 return s;                                                               // ... so don't mess with it
 279         p = s.size()-1;
 280         // foo3.5^, foo.3.5^, foo3^, foo.3^, foo^
 281         while (strchr("0123456789.", s[p]))
 282                 p--;
 283         // fo^o3.5, fo^o.3.5, fo^o3, fo^o.3, fo^o
 284         p++;
 285         // foo^3.5, foo^.3.5, foo^3, foo^.3, foo^
 286         if (s[p] == '.')
 287                 p++;
 288         // foo^3.5, foo.^3.5, foo^3, foo.^3, foo^
 289         while (p < s.size() && strchr("0123456789", s[p]))
 290                 p++;
 291         // foo3^.5, foo.3^.5, foo3^, foo.3^, foo^
 292         return s.substr(0, p);
 293 }
 294
 295
 296 //
 297 // Writers
 298 //
 299 DiskRep::Writer::Writer(uint32_t attrs)
 300         : mArch(CPU_TYPE_ANY), mAttributes(attrs)
 301 {
 302 }
 303
 304 DiskRep::Writer::~Writer()
 305 { /* virtual */ }
 306
 307 uint32_t DiskRep::Writer::attributes() const
 308 { return mAttributes; }
 309
 310 void DiskRep::Writer::flush()
 311 { /* do nothing */ }
 312
 313 void DiskRep::Writer::remove()
 314 {
 315         MacOSError::throwMe(errSecCSNotSupported);
 316 }
 317
 318
 319 } // end namespace CodeSigning
 320 } // end namespace Security