--- /dev/null
+/*
+ * Copyright (c) 2006-2010 Apple Inc. All Rights Reserved.
+ *
+ * @APPLE_LICENSE_HEADER_START@
+ *
+ * This file contains Original Code and/or Modifications of Original Code
+ * as defined in and that are subject to the Apple Public Source License
+ * Version 2.0 (the 'License'). You may not use this file except in
+ * compliance with the License. Please obtain a copy of the License at
+ * http://www.opensource.apple.com/apsl/ and read it before using this
+ * file.
+ *
+ * The Original Code and all software distributed under the License are
+ * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
+ * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
+ * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
+ * Please see the License for the specific language governing rights and
+ * limitations under the License.
+ *
+ * @APPLE_LICENSE_HEADER_END@
+ */
+
+//
+// signerutils - utilities for signature generation
+//
+#include "signerutils.h"
+#include "signer.h"
+#include "SecCodeSigner.h"
+#include <Security/SecIdentity.h>
+#include <Security/CMSEncoder.h>
+#include "renum.h"
+#include "csutilities.h"
+#include "drmaker.h"
+#include <security_utilities/unix++.h>
+#include <security_utilities/unixchild.h>
+#include <vector>
+
+// for helper validation
+#include "Code.h"
+#include <security_utilities/cfmunge.h>
+#include <sys/codesign.h>
+
+
+namespace Security {
+namespace CodeSigning {
+
+
+//
+// About the Mach-O allocation helper
+//
+static const char helperName[] = "codesign_allocate";
+static const char helperPath[] = "/usr/bin/codesign_allocate";
+static const char helperOverride[] = "CODESIGN_ALLOCATE";
+static const size_t csAlign = 16;
+
+
+//
+// BlobWriters
+//
+void BlobWriter::component(CodeDirectory::SpecialSlot slot, CFDataRef data)
+{
+ return EmbeddedSignatureBlob::Maker::component(slot, data);
+}
+
+
+void DetachedBlobWriter::flush()
+{
+ EmbeddedSignatureBlob *blob = this->make();
+ signer.code->detachedSignature(makeCFData(*blob));
+ signer.state.returnDetachedSignature(blob, signer);
+ ::free(blob);
+}
+
+
+//
+// ArchEditor
+//
+ArchEditor::ArchEditor(Universal &code, CodeDirectory::HashAlgorithm hashType, uint32_t attrs)
+ : DiskRep::Writer(attrs)
+{
+ Universal::Architectures archList;
+ code.architectures(archList);
+ for (Universal::Architectures::const_iterator it = archList.begin();
+ it != archList.end(); ++it)
+ architecture[*it] = new Arch(*it, hashType);
+}
+
+
+ArchEditor::~ArchEditor()
+{
+ for (ArchMap::iterator it = begin(); it != end(); ++it)
+ delete it->second;
+}
+
+
+//
+// BlobEditor
+//
+BlobEditor::BlobEditor(Universal &fat, SecCodeSigner::Signer &s)
+ : ArchEditor(fat, s.digestAlgorithm(), 0), signer(s)
+{ }
+
+
+void BlobEditor::component(CodeDirectory::SpecialSlot slot, CFDataRef data)
+{
+ mGlobal.component(slot, data);
+}
+
+void BlobEditor::write(Arch &arch, EmbeddedSignatureBlob *blob)
+{
+ mMaker.add(arch.architecture.cpuType(), blob);
+}
+
+
+void BlobEditor::commit()
+{
+ // create the architecture-global blob and store it into the superblob
+ mMaker.add(0, mGlobal.make()); // takes ownership of blob
+
+ // finish up the superblob and deliver it
+ DetachedSignatureBlob *blob = mMaker.make();
+ signer.state.returnDetachedSignature(blob, signer);
+ ::free(blob);
+}
+
+
+//
+// MachOEditor's allocate() method spawns the codesign_allocate helper tool to
+// "drill up" the Mach-O binary for insertion of Code Signing signature data.
+// After the tool succeeds, we open the new file and are ready to write it.
+//
+MachOEditor::MachOEditor(DiskRep::Writer *w, Universal &code, CodeDirectory::HashAlgorithm hashType, std::string srcPath)
+ : ArchEditor(code, hashType, w->attributes()),
+ writer(w),
+ sourcePath(srcPath),
+ tempPath(srcPath + ".cstemp"),
+ mNewCode(NULL),
+ mTempMayExist(false)
+{
+ if (const char *path = getenv(helperOverride)) {
+ mHelperPath = path;
+ mHelperOverridden = true;
+ } else {
+ mHelperPath = helperPath;
+ mHelperOverridden = false;
+ }
+}
+
+MachOEditor::~MachOEditor()
+{
+ delete mNewCode;
+ if (mTempMayExist)
+ ::remove(tempPath.c_str()); // ignore error (can't do anything about it)
+ this->kill();
+}
+
+
+void MachOEditor::component(CodeDirectory::SpecialSlot slot, CFDataRef data)
+{
+ writer->component(slot, data);
+}
+
+
+void MachOEditor::allocate()
+{
+ // note that we may have a temporary file from now on (for cleanup in the error case)
+ mTempMayExist = true;
+
+ // run codesign_allocate to make room in the executable file
+ fork();
+ wait();
+ if (!Child::succeeded())
+ UnixError::throwMe(ENOEXEC); //@@@ how to signal "it din' work"?
+
+ // open the new (temporary) Universal file
+ {
+ UidGuard guard(0);
+ mFd.open(tempPath, O_RDWR);
+ }
+ mNewCode = new Universal(mFd);
+}
+
+static const unsigned char appleReq[] = {
+ // anchor apple and info["Application-Group"] = "com.apple.tool.codesign_allocate"
+ 0xfa, 0xde, 0x0c, 0x00, 0x00, 0x00, 0x00, 0x58, 0x00, 0x00, 0x00, 0x01, 0x00, 0x00, 0x00, 0x06,
+ 0x00, 0x00, 0x00, 0x03, 0x00, 0x00, 0x00, 0x0a, 0x00, 0x00, 0x00, 0x11, 0x41, 0x70, 0x70, 0x6c,
+ 0x69, 0x63, 0x61, 0x74, 0x69, 0x6f, 0x6e, 0x2d, 0x47, 0x72, 0x6f, 0x75, 0x70, 0x00, 0x00, 0x00,
+ 0x00, 0x00, 0x00, 0x01, 0x00, 0x00, 0x00, 0x20, 0x63, 0x6f, 0x6d, 0x2e, 0x61, 0x70, 0x70, 0x6c,
+ 0x65, 0x2e, 0x74, 0x6f, 0x6f, 0x6c, 0x2e, 0x63, 0x6f, 0x64, 0x65, 0x73, 0x69, 0x67, 0x6e, 0x5f,
+ 0x61, 0x6c, 0x6c, 0x6f, 0x63, 0x61, 0x74, 0x65,
+};
+
+void MachOEditor::parentAction()
+{
+ if (mHelperOverridden) {
+ CODESIGN_ALLOCATE_VALIDATE((char*)mHelperPath, this->pid());
+ // check code identity of an overridden allocation helper
+ SecPointer<SecStaticCode> code = new SecStaticCode(DiskRep::bestGuess(mHelperPath));
+ code->validateDirectory();
+ code->validateExecutable();
+ code->validateResources();
+ code->validateRequirement((const Requirement *)appleReq, errSecCSReqFailed);
+ }
+}
+
+void MachOEditor::childAction()
+{
+ vector<const char *> arguments;
+ arguments.push_back(helperName);
+ arguments.push_back("-i");
+ arguments.push_back(sourcePath.c_str());
+ arguments.push_back("-o");
+ arguments.push_back(tempPath.c_str());
+
+ for (Iterator it = architecture.begin(); it != architecture.end(); ++it) {
+ size_t size = LowLevelMemoryUtilities::alignUp(it->second->blobSize, csAlign);
+ char *ssize; // we'll leak this (execv is coming soon)
+ asprintf(&ssize, "%zd", size);
+
+ if (const char *arch = it->first.name()) {
+ CODESIGN_ALLOCATE_ARCH((char*)arch, size);
+ arguments.push_back("-a");
+ arguments.push_back(arch);
+ } else {
+ CODESIGN_ALLOCATE_ARCHN(it->first.cpuType(), it->first.cpuSubtype(), size);
+ arguments.push_back("-A");
+ char *anum;
+ asprintf(&anum, "%d", it->first.cpuType());
+ arguments.push_back(anum);
+ asprintf(&anum, "%d", it->first.cpuSubtype());
+ arguments.push_back(anum);
+ }
+ arguments.push_back(ssize);
+ }
+ arguments.push_back(NULL);
+
+ if (mHelperOverridden)
+ ::csops(0, CS_EXEC_SET_KILL, NULL, 0); // force code integrity
+ ::seteuid(0); // activate privilege if caller has it; ignore error if not
+ execv(mHelperPath, (char * const *)&arguments[0]);
+}
+
+void MachOEditor::reset(Arch &arch)
+{
+ arch.source.reset(mNewCode->architecture(arch.architecture));
+ arch.cdbuilder.reopen(tempPath,
+ arch.source->offset(), arch.source->signingOffset());
+}
+
+
+//
+// MachOEditor's write() method actually writes the blob into the CODESIGNING section
+// of the executable image file.
+//
+void MachOEditor::write(Arch &arch, EmbeddedSignatureBlob *blob)
+{
+ if (size_t offset = arch.source->signingOffset()) {
+ size_t signingLength = arch.source->signingLength();
+ CODESIGN_ALLOCATE_WRITE((char*)arch.architecture.name(), offset, blob->length(), signingLength);
+ if (signingLength < blob->length())
+ MacOSError::throwMe(errSecCSCMSTooLarge);
+ arch.source->seek(offset);
+ arch.source->writeAll(*blob);
+ ::free(blob); // done with it
+ } else {
+ secdebug("signer", "%p cannot find CODESIGNING section", this);
+ MacOSError::throwMe(errSecCSInternalError);
+ }
+}
+
+
+//
+// Commit the edit.
+// This moves the temporary editor copy over the source image file.
+// Note that the Universal object returned by allocate() is still open
+// and valid; the caller owns it.
+//
+void MachOEditor::commit()
+{
+ // if the file's owned by someone else *and* we can become root...
+ struct stat st;
+ UnixError::check(::stat(sourcePath.c_str(), &st));
+
+ // copy over all the *other* stuff
+ Copyfile copy;
+ int fd = mFd;
+ copy.set(COPYFILE_STATE_DST_FD, &fd);
+ {
+ // perform copy under root or file-owner privileges if available
+ UidGuard guard;
+ if (!guard.seteuid(0))
+ guard.seteuid(st.st_uid);
+
+ // copy metadata from original file...
+ copy(sourcePath.c_str(), NULL, COPYFILE_SECURITY | COPYFILE_METADATA);
+
+ // ... but explicitly update the timestamps since we did change the file
+ char buf;
+ mFd.read(&buf, sizeof(buf), 0);
+ mFd.write(&buf, sizeof(buf), 0);
+
+ // move the new file into place
+ UnixError::check(::rename(tempPath.c_str(), sourcePath.c_str()));
+ mTempMayExist = false; // we renamed it away
+ }
+}
+
+
+//
+// InternalRequirements
+//
+void InternalRequirements::operator () (const Requirements *given, const Requirements *defaulted, const Requirement::Context &context)
+{
+ // first add the default internal requirements
+ if (defaulted) {
+ this->add(defaulted);
+ ::free((void *)defaulted); // was malloc(3)ed by DiskRep
+ }
+
+ // now override them with any requirements explicitly given by the signer
+ if (given)
+ this->add(given);
+
+ // now add the Designated Requirement, if we can make it and it's not been provided
+ if (!this->contains(kSecDesignatedRequirementType)) {
+ DRMaker maker(context);
+ if (Requirement *dr = maker.make()) {
+ this->add(kSecDesignatedRequirementType, dr); // takes ownership of dr
+ }
+ }
+
+ // return the result
+ mReqs = this->make();
+}
+
+
+//
+// Pre-Signing contexts
+//
+PreSigningContext::PreSigningContext(const SecCodeSigner::Signer &signer)
+{
+ // construct a cert chain
+ if (signer.signingIdentity() != SecIdentityRef(kCFNull)) {
+ CFRef<SecCertificateRef> signingCert;
+ MacOSError::check(SecIdentityCopyCertificate(signer.signingIdentity(), &signingCert.aref()));
+ CFRef<SecPolicyRef> policy = SecPolicyCreateWithOID(kSecPolicyAppleCodeSigning);
+ CFRef<SecTrustRef> trust;
+ MacOSError::check(SecTrustCreateWithCertificates(CFArrayRef(signingCert.get()), policy, &trust.aref()));
+ SecTrustResultType result;
+ MacOSError::check(SecTrustEvaluate(trust, &result));
+ CSSM_TP_APPLE_EVIDENCE_INFO *info;
+ MacOSError::check(SecTrustGetResult(trust, &result, &mCerts.aref(), &info));
+ this->certs = mCerts;
+ }
+
+ // other stuff
+ this->identifier = signer.signingIdentifier();
+}
+
+
+} // end namespace CodeSigning
+} // end namespace Security
projects / apple / security.git / blobdiff