lib/signer.cpp

   1 /*
   2  * Copyright (c) 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 // signer - Signing operation supervisor and controller
  26 //
  27 #include "signer.h"
  28 #include "resources.h"
  29 #include "signerutils.h"
  30 #include "SecCodeSigner.h"
  31 #include <Security/SecIdentity.h>
  32 #include <Security/CMSEncoder.h>
  33 #include <Security/CMSPrivate.h>
  34 #include <CoreFoundation/CFBundlePriv.h>
  35 #include "renum.h"
  36 #include <security_utilities/unix++.h>
  37 #include <security_utilities/unixchild.h>
  38 #include <security_codesigning/cfmunge.h>
  39
  40 namespace Security {
  41 namespace CodeSigning {
  42
  43
  44 //
  45 // Sign some code.
  46 //
  47 void SecCodeSigner::Signer::sign(SecCSFlags flags)
  48 {
  49         // set up access to the subject Code
  50         rep = code->diskRep();
  51
  52         // get the Info.plist out of the rep for some creative defaulting
  53         CFRef<CFDictionaryRef> infoDict;
  54         if (CFRef<CFDataRef> infoData = rep->component(cdInfoSlot))
  55                 infoDict.take(makeCFDictionaryFrom(infoData));
  56
  57         // work out the canonical identifier
  58         identifier = state.mIdentifier;
  59         if (identifier.empty()) {
  60                 identifier = rep->recommendedIdentifier();
  61                 if (identifier.find('.') == string::npos && !state.mIdentifierPrefix.empty())
  62                         identifier = state.mIdentifierPrefix + identifier;
  63                 secdebug("signer", "using default identifier=%s", identifier.c_str());
  64         } else
  65                 secdebug("signer", "using explicit identifier=%s", identifier.c_str());
  66
  67         // work out the CodeDirectory flags word
  68         if (state.mCdFlagsGiven) {
  69                 cdFlags = state.mCdFlags;
  70                 secdebug("signer", "using explicit cdFlags=0x%x", cdFlags);
  71         } else {
  72                 cdFlags = 0;
  73                 if (infoDict)
  74                         if (CFTypeRef csflags = CFDictionaryGetValue(infoDict, CFSTR("CSFlags")))
  75                                 if (CFGetTypeID(csflags) == CFNumberGetTypeID()) {
  76                                         cdFlags = cfNumber<uint32_t>(CFNumberRef(csflags));
  77                                         secdebug("signer", "using numeric cdFlags=0x%x from Info.dict", cdFlags);
  78                                 } else if (CFGetTypeID(csflags) == CFStringGetTypeID()) {
  79                                         cdFlags = CodeDirectory::textFlags(cfString(CFStringRef(csflags)));
  80                                         secdebug("signer", "using text cdFlags=0x%x from Info.dict", cdFlags);
  81                                 } else
  82                                         MacOSError::throwMe(errSecCSBadDictionaryFormat);
  83         }
  84         if (state.mSigner == SecIdentityRef(kCFNull))   // ad-hoc signing requested...
  85                 cdFlags |= kSecCodeSignatureAdhoc;      // ... so allow that
  86
  87         // prepare the resource directory, if any
  88         string rpath = rep->resourcesRootPath();
  89         if (!rpath.empty()) {
  90                 // explicitly given resource rules always win
  91                 CFCopyRef<CFDictionaryRef> resourceRules(state.mResourceRules);
  92
  93                 // embedded resource rules come next
  94                 if (!resourceRules)
  95                         if (CFTypeRef spec = CFDictionaryGetValue(infoDict, _kCFBundleResourceSpecificationKey))
  96                                 if (CFGetTypeID(spec) == CFStringGetTypeID())
  97                                         if (CFRef<CFDataRef> data = cfLoadFile(rpath + "/" + cfString(CFStringRef(spec))))
  98                                                 if (CFRef<CFDictionaryRef> dict = makeCFDictionaryFrom(data))
  99                                                         resourceRules = dict;
 100
 101                 // finally, ask the DiskRep for its default
 102                 if (!resourceRules)
 103                         resourceRules.take(rep->defaultResourceRules());
 104
 105                 // build the resource directory
 106                 ResourceBuilder resources(rpath, cfget<CFDictionaryRef>(resourceRules, "rules"));
 107                 rep->adjustResources(resources);
 108                 CFRef<CFDictionaryRef> rdir = resources.build();
 109                 resourceDirectory.take(CFPropertyListCreateXMLData(NULL, rdir));
 110         }
 111
 112         // screen and set the signing time
 113         CFAbsoluteTime now = CFAbsoluteTimeGetCurrent();
 114         if (state.mSigningTime == CFDateRef(kCFNull)) {
 115                 signingTime = 0;                // no time at all
 116         } else if (!state.mSigningTime) {
 117                 signingTime = now;              // default
 118         } else {
 119                 CFAbsoluteTime time = CFDateGetAbsoluteTime(state.mSigningTime);
 120                 if (time > now) // not allowed to post-date a signature
 121                         MacOSError::throwMe(errSecCSBadDictionaryFormat);
 122                 signingTime = time;
 123         }
 124
 125         pagesize = state.mPageSize ? cfNumber<size_t>(state.mPageSize) : rep->pageSize();
 126
 127         if (Universal *fat = state.mNoMachO ? NULL : rep->mainExecutableImage()) {
 128                 signMachO(fat);
 129         } else {
 130                 signArchitectureAgnostic();
 131         }
 132 }
 133
 134
 135 //
 136 // Sign a Mach-O binary, using liberal dollops of that special Mach-O magic sauce.
 137 // Note that this will deal just fine with non-fat Mach-O binaries, but it will
 138 // treat them as architectural binaries containing (only) one architecture - that
 139 // interpretation is courtesy of the Universal/MachO support classes.
 140 //
 141 void SecCodeSigner::Signer::signMachO(Universal *fat)
 142 {
 143         // Mach-O executable at the core - perform multi-architecture signing
 144         auto_ptr<ArchEditor> editor(state.mDetached
 145                 ? static_cast<ArchEditor *>(new BlobEditor(*fat, *this))
 146                 : new MachOEditor(rep->writer(), *fat, rep->mainExecutablePath()));
 147         assert(editor->count() > 0);
 148         if (!editor->attribute(writerNoGlobal)) // can store architecture-common components
 149                 populate(*editor);
 150
 151         // pass 1: prepare signature blobs and calculate sizes
 152         for (MachOEditor::Iterator it = editor->begin(); it != editor->end(); ++it) {
 153                 MachOEditor::Arch &arch = *it->second;
 154                 arch.source.reset(fat->architecture(it->first));
 155                 arch.ireqs(state.mRequirements, rep->defaultRequirements(&arch.architecture));
 156                 if (editor->attribute(writerNoGlobal))  // can't store globally, add per-arch
 157                         populate(arch);
 158                 populate(arch.cdbuilder, arch, arch.ireqs,
 159                         arch.source->offset(), arch.source->signingExtent());
 160                 // prepare SuperBlob size estimate
 161                 size_t cdSize = arch.cdbuilder.size();
 162                 arch.blobSize = arch.size(cdSize, state.mCMSSize, 0);
 163         }
 164
 165         editor->allocate();
 166
 167         // pass 2: Finish and generate signatures, and write them
 168         for (MachOEditor::Iterator it = editor->begin(); it != editor->end(); ++it) {
 169                 MachOEditor::Arch &arch = *it->second;
 170                 editor->reset(arch);
 171
 172                 // finish CodeDirectory (off new binary) and sign it
 173                 CodeDirectory *cd = arch.cdbuilder.build();
 174                 CFRef<CFDataRef> signature = signCodeDirectory(cd);
 175
 176                 // complete the SuperBlob
 177                 arch.add(cdCodeDirectorySlot, cd);      // takes ownership
 178                 arch.add(cdSignatureSlot, BlobWrapper::alloc(
 179                         CFDataGetBytePtr(signature), CFDataGetLength(signature)));
 180                 if (!state.mDryRun) {
 181                         EmbeddedSignatureBlob *blob = arch.make();
 182                         editor->write(arch, blob);      // takes ownership of blob
 183                 }
 184         }
 185
 186         // done: write edit copy back over the original
 187         if (!state.mDryRun)
 188                 editor->commit();
 189 }
 190
 191
 192 //
 193 // Sign a binary that has no notion of architecture.
 194 // That currently means anything that isn't Mach-O format.
 195 //
 196 void SecCodeSigner::Signer::signArchitectureAgnostic()
 197 {
 198         // non-Mach-O executable - single-instance signing
 199         RefPointer<DiskRep::Writer> writer = state.mDetached ?
 200                 (new DetachedBlobWriter(*this)) : rep->writer();
 201         CodeDirectory::Builder builder;
 202         InternalRequirements ireqs;
 203         ireqs(state.mRequirements, rep->defaultRequirements(NULL));
 204         populate(*writer);
 205         populate(builder, *writer, ireqs, rep->signingBase(), rep->signingLimit());
 206         CodeDirectory *cd = builder.build();
 207         CFRef<CFDataRef> signature = signCodeDirectory(cd);
 208         if (!state.mDryRun) {
 209                 writer->codeDirectory(cd);
 210                 writer->signature(signature);
 211                 writer->flush();
 212         }
 213         ::free(cd);
 214 }
 215
 216
 217 //
 218 // Global populate - send components to destination buffers ONCE
 219 //
 220 void SecCodeSigner::Signer::populate(DiskRep::Writer &writer)
 221 {
 222         if (resourceDirectory)
 223                 writer.component(cdResourceDirSlot, resourceDirectory);
 224 }
 225
 226
 227 //
 228 // Per-architecture populate - send components to per-architecture buffers
 229 // and populate the CodeDirectory for an architecture. In architecture-agnostic
 230 // signing operations, the non-architectural binary is considered one (arbitrary) architecture
 231 // for the purposes of this call.
 232 //
 233 void SecCodeSigner::Signer::populate(CodeDirectory::Builder &builder, DiskRep::Writer &writer,
 234         InternalRequirements &ireqs, size_t offset /* = 0 */, size_t length /* = 0 */)
 235 {
 236         // fill the CodeDirectory
 237         builder.executable(rep->mainExecutablePath(), pagesize, offset, length);
 238         builder.flags(cdFlags);
 239         builder.identifier(identifier);
 240
 241         for (CodeDirectory::Slot slot = cdSlotMax; slot >= 1; --slot)
 242                 switch (slot) {
 243                 case cdRequirementsSlot:
 244                         if (ireqs) {
 245                                 CFRef<CFDataRef> data = makeCFData(*ireqs);
 246                                 writer.component(cdRequirementsSlot, data);
 247                                 builder.special(slot, data);
 248                         }
 249                         break;
 250                 case cdResourceDirSlot:
 251                         if (resourceDirectory)
 252                                 builder.special(slot, resourceDirectory);
 253                         break;
 254                 case cdApplicationSlot:
 255 #if NOT_YET
 256                         if (state.mApplicationData)
 257                                 builder.special(slot, state.mApplicationData);
 258 #endif
 259                         break;
 260                 case cdEntitlementSlot:
 261                         if (state.mEntitlementData) {
 262                                 writer.component(cdEntitlementSlot, state.mEntitlementData);
 263                                 builder.special(slot, state.mEntitlementData);
 264                         }
 265                         break;
 266                 default:
 267                         if (CFDataRef data = rep->component(slot))
 268                                 builder.special(slot, data);
 269                         break;
 270                 }
 271 }
 272
 273
 274 //
 275 // Generate the CMS signature for a (finished) CodeDirectory.
 276 //
 277 CFDataRef SecCodeSigner::Signer::signCodeDirectory(const CodeDirectory *cd)
 278 {
 279         assert(state.mSigner);
 280
 281         // a null signer generates a null signature blob
 282         if (state.mSigner == SecIdentityRef(kCFNull))
 283                 return CFDataCreate(NULL, NULL, 0);
 284
 285         // generate CMS signature
 286         CFRef<CMSEncoderRef> cms;
 287         MacOSError::check(CMSEncoderCreate(&cms.aref()));
 288         MacOSError::check(CMSEncoderSetCertificateChainMode(cms, kCMSCertificateChainWithRoot));
 289         CMSEncoderAddSigners(cms, state.mSigner);
 290         MacOSError::check(CMSEncoderSetHasDetachedContent(cms, true));
 291
 292         if (signingTime) {
 293                 MacOSError::check(CMSEncoderAddSignedAttributes(cms, kCMSAttrSigningTime));
 294                 MacOSError::check(CMSEncoderSetSigningTime(cms, signingTime));
 295         }
 296
 297         MacOSError::check(CMSEncoderUpdateContent(cms, cd, cd->length()));
 298         CFDataRef signature;
 299         MacOSError::check(CMSEncoderCopyEncodedContent(cms, &signature));
 300         return signature;
 301 }
 302
 303
 304 } // end namespace CodeSigning
 305 } // end namespace Security