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StaticCode.cpp
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StaticCode.cpp
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/*
* Copyright (c) 2006-2015 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@
*/
//
// StaticCode - SecStaticCode API objects
//
#include "StaticCode.h"
#include "SecTask.h"
#include "Code.h"
#include "reqmaker.h"
#include "machorep.h"
#if TARGET_OS_OSX
#include "drmaker.h"
#include "notarization.h"
#endif
#include "reqdumper.h"
#include "reqparser.h"
#include "sigblob.h"
#include "resources.h"
#include "detachedrep.h"
#include "signerutils.h"
#if TARGET_OS_OSX
#include "csdatabase.h"
#endif
#include "dirscanner.h"
#include <CoreFoundation/CFURLAccess.h>
#include <Security/SecPolicyPriv.h>
#include <Security/SecTrustPriv.h>
#include <Security/SecCertificatePriv.h>
#if TARGET_OS_OSX
#include <Security/CMSPrivate.h>
#endif
#import <Security/SecCMS.h>
#include <Security/SecCmsContentInfo.h>
#include <Security/SecCmsSignerInfo.h>
#include <Security/SecCmsSignedData.h>
#if TARGET_OS_OSX
#include <Security/cssmapplePriv.h>
#endif
#include <security_utilities/unix++.h>
#include <security_utilities/cfmunge.h>
#include <security_utilities/casts.h>
#include <Security/CMSDecoder.h>
#include <security_utilities/logging.h>
#include <dirent.h>
#include <sys/xattr.h>
#include <sstream>
#include <IOKit/storage/IOStorageDeviceCharacteristics.h>
#include <dispatch/private.h>
#include <os/assumes.h>
#include <os/feature_private.h>
#include <os/variant_private.h>
#include <regex.h>
#import <utilities/entitlements.h>
#define CORE_ENTITLEMENTS_I_KNOW_WHAT_IM_DOING
#include <CoreEntitlements/CoreEntitlementsPriv.h>
#include <CoreEntitlements/EntitlementsPriv.h>
#import <CoreEntitlements/FoundationUtils.h>
#import "LWCRHelper.h"
#include <kern/cs_blobs.h>
namespace Security {
namespace CodeSigning {
using namespace UnixPlusPlus;
// A requirement representing a Mac or iOS dev cert, a Mac or iOS distribution cert, or a developer ID
static const char WWDRRequirement[] = "anchor apple generic and certificate leaf[field.1.2.840.113635.100.6.1.2] exists";
static const char MACWWDRRequirement[] = "anchor apple generic and certificate leaf[field.1.2.840.113635.100.6.1.12] exists";
static const char developerID[] = "anchor apple generic and certificate 1[field.1.2.840.113635.100.6.2.6] exists"
" and certificate leaf[field.1.2.840.113635.100.6.1.13] exists";
static const char distributionCertificate[] = "anchor apple generic and certificate leaf[field.1.2.840.113635.100.6.1.7] exists";
static const char iPhoneDistributionCert[] = "anchor apple generic and certificate leaf[field.1.2.840.113635.100.6.1.4] exists";
//
// Map a component slot number to a suitable error code for a failure
//
static inline OSStatus errorForSlot(CodeDirectory::SpecialSlot slot)
{
switch (slot) {
case cdInfoSlot:
return errSecCSInfoPlistFailed;
case cdResourceDirSlot:
return errSecCSResourceDirectoryFailed;
default:
return errSecCSSignatureFailed;
}
}
#if TARGET_OS_OSX
/// Determines if the current process is marked as platform, cached with dispatch_once.
static bool isCurrentProcessPlatform(void)
{
static dispatch_once_t sOnceToken;
static bool sIsPlatform = false;
dispatch_once(&sOnceToken, ^{
SecTaskRef task = SecTaskCreateFromSelf(NULL);
if (task) {
uint32_t flags = SecTaskGetCodeSignStatus(task);
if (flags & kSecCodeStatusPlatform) {
sIsPlatform = true;
}
CFRelease(task);
}
});
return sIsPlatform;
}
#endif // TARGET_OS_OSX
/// Determines if the item qualifies for a resource validity exemption based on its filesystem location.
static bool itemQualifiesForResourceExemption(string &item)
{
if (isOnRootFilesystem(item.c_str())) {
return true;
}
if (os_variant_allows_internal_security_policies("com.apple.security.codesigning")) {
if (isPathPrefix("/AppleInternal/", item) ||
isPathPrefix("/System/Volumes/Data/AppleInternal/", item) ||
isPathPrefix("/System/AppleInternal/", item) ||
isPathPrefix("/usr/local/", item) ||
isPathPrefix("/usr/appleinternal/", item)) {
return true;
}
}
return false;
}
//
// Construct a SecStaticCode object given a disk representation object
//
SecStaticCode::SecStaticCode(DiskRep *rep, uint32_t flags)
: mCheckfix30814861builder1(NULL),
mRep(rep),
mValidated(false), mExecutableValidated(false), mResourcesValidated(false), mResourcesValidContext(NULL),
mProgressQueue("com.apple.security.validation-progress", false, QOS_CLASS_UNSPECIFIED),
mOuterScope(NULL), mResourceScope(NULL),
mDesignatedReq(NULL), mGotResourceBase(false), mMonitor(NULL), mLimitedAsync(NULL),
mFlags(flags), mNotarizationChecked(false), mStaplingChecked(false), mNotarizationDate(NAN),
mNetworkEnabledByDefault(true), mTrustedSigningCertChain(false), mValidationCategory(CS_VALIDATION_CATEGORY_INVALID)
{
CODESIGN_STATIC_CREATE(this, rep);
#if TARGET_OS_OSX
checkForSystemSignature();
// By default, platform code will no longer use the network.
if (os_feature_enabled(Security, SecCodeOCSPDefault)) {
if (isCurrentProcessPlatform()) {
mNetworkEnabledByDefault = false;
}
}
secinfo("staticCode", "SecStaticCode network default: %s", mNetworkEnabledByDefault ? "YES" : "NO");
#endif
}
//
// Clean up a SecStaticCode object
//
SecStaticCode::~SecStaticCode() _NOEXCEPT
try {
CEReleaseManagedContext(&mCEQueryContext);
::free(const_cast<Requirement *>(mDesignatedReq));
delete mResourcesValidContext;
delete mLimitedAsync;
delete mCheckfix30814861builder1;
} catch (...) {
return;
}
//
// Initialize a nested SecStaticCode object from its parent
//
void SecStaticCode::initializeFromParent(const SecStaticCode& parent) {
mOuterScope = &parent;
setMonitor(parent.monitor());
if (parent.mLimitedAsync)
mLimitedAsync = new LimitedAsync(*parent.mLimitedAsync);
}
//
// CF-level comparison of SecStaticCode objects compares CodeDirectory hashes if signed,
// and falls back on comparing canonical paths if (both are) not.
//
bool SecStaticCode::equal(SecCFObject &secOther)
{
SecStaticCode *other = static_cast<SecStaticCode *>(&secOther);
CFDataRef mine = this->cdHash();
CFDataRef his = other->cdHash();
if (mine || his)
return mine && his && CFEqual(mine, his);
else
return CFEqual(CFRef<CFURLRef>(this->copyCanonicalPath()), CFRef<CFURLRef>(other->copyCanonicalPath()));
}
CFHashCode SecStaticCode::hash()
{
if (CFDataRef h = this->cdHash())
return CFHash(h);
else
return CFHash(CFRef<CFURLRef>(this->copyCanonicalPath()));
}
//
// Invoke a stage monitor if registered
//
CFTypeRef SecStaticCode::reportEvent(CFStringRef stage, CFDictionaryRef info)
{
if (mMonitor)
return mMonitor(this->handle(false), stage, info);
else
return NULL;
}
void SecStaticCode::prepareProgress(unsigned int workload)
{
dispatch_sync(mProgressQueue, ^{
mCancelPending = false; // not canceled
});
if (mValidationFlags & kSecCSReportProgress) {
mCurrentWork = 0; // nothing done yet
mTotalWork = workload; // totally fake - we don't know how many files we'll get to chew
}
}
void SecStaticCode::reportProgress(unsigned amount /* = 1 */)
{
if (mMonitor && (mValidationFlags & kSecCSReportProgress)) {
// update progress and report
__block bool cancel = false;
dispatch_sync(mProgressQueue, ^{
if (mCancelPending)
cancel = true;
mCurrentWork += amount;
mMonitor(this->handle(false), CFSTR("progress"), CFTemp<CFDictionaryRef>("{current=%d,total=%d}", mCurrentWork, mTotalWork));
});
// if cancellation is pending, abort now
if (cancel)
MacOSError::throwMe(errSecCSCancelled);
}
}
//
// Set validation conditions for fine-tuning legacy tolerance
//
static void addError(CFTypeRef cfError, void* context)
{
if (CFGetTypeID(cfError) == CFNumberGetTypeID()) {
int64_t error;
CFNumberGetValue(CFNumberRef(cfError), kCFNumberSInt64Type, (void*)&error);
MacOSErrorSet* errors = (MacOSErrorSet*)context;
errors->insert(OSStatus(error));
}
}
void SecStaticCode::setValidationModifiers(CFDictionaryRef conditions)
{
if (conditions) {
CFDictionary source(conditions, errSecCSDbCorrupt);
mAllowOmissions = source.get<CFArrayRef>("omissions");
if (CFArrayRef errors = source.get<CFArrayRef>("errors"))
CFArrayApplyFunction(errors, CFRangeMake(0, CFArrayGetCount(errors)), addError, &this->mTolerateErrors);
}
}
//
// Request cancellation of a validation in progress.
// We do this by posting an abort flag that is checked periodically.
//
void SecStaticCode::cancelValidation()
{
if (!(mValidationFlags & kSecCSReportProgress)) // not using progress reporting; cancel won't make it through
MacOSError::throwMe(errSecCSInvalidFlags);
dispatch_assert_queue(mProgressQueue);
mCancelPending = true;
}
//
// Attach a detached signature.
//
void SecStaticCode::detachedSignature(CFDataRef sigData)
{
if (sigData) {
mDetachedSig = sigData;
mRep = new DetachedRep(sigData, mRep->base(), "explicit detached");
CODESIGN_STATIC_ATTACH_EXPLICIT(this, mRep);
} else {
mDetachedSig = NULL;
mRep = mRep->base();
CODESIGN_STATIC_ATTACH_EXPLICIT(this, NULL);
}
}
//
// Consult the system detached signature database to see if it contains
// a detached signature for this StaticCode. If it does, fetch and attach it.
// We do this only if the code has no signature already attached.
//
void SecStaticCode::checkForSystemSignature()
{
#if TARGET_OS_OSX
if (!this->isSigned()) {
SignatureDatabase db;
if (db.isOpen())
try {
if (RefPointer<DiskRep> dsig = db.findCode(mRep)) {
CODESIGN_STATIC_ATTACH_SYSTEM(this, dsig);
mRep = dsig;
}
} catch (...) {
}
}
#else
MacOSError::throwMe(errSecUnimplemented);
#endif
}
//
// Return a descriptive string identifying the source of the code signature
//
string SecStaticCode::signatureSource()
{
if (!isSigned())
return "unsigned";
if (DetachedRep *rep = dynamic_cast<DetachedRep *>(mRep.get()))
return rep->source();
return "embedded";
}
//
// Do ::required, but convert incoming SecCodeRefs to their SecStaticCodeRefs
// (if possible).
//
SecStaticCode *SecStaticCode::requiredStatic(SecStaticCodeRef ref)
{
SecCFObject *object = SecCFObject::required(ref, errSecCSInvalidObjectRef);
if (SecStaticCode *scode = dynamic_cast<SecStaticCode *>(object))
return scode;
else if (SecCode *code = dynamic_cast<SecCode *>(object))
return code->staticCode();
else // neither (a SecSomethingElse)
MacOSError::throwMe(errSecCSInvalidObjectRef);
}
SecCode *SecStaticCode::optionalDynamic(SecStaticCodeRef ref)
{
SecCFObject *object = SecCFObject::required(ref, errSecCSInvalidObjectRef);
if (dynamic_cast<SecStaticCode *>(object))
return NULL;
else if (SecCode *code = dynamic_cast<SecCode *>(object))
return code;
else // neither (a SecSomethingElse)
MacOSError::throwMe(errSecCSInvalidObjectRef);
}
//
// Void all cached validity data.
//
// We also throw out cached components, because the new signature data may have
// a different idea of what components should be present. We could reconcile the
// cached data instead, if performance seems to be impacted.
//
void SecStaticCode::resetValidity()
{
CODESIGN_EVAL_STATIC_RESET(this);
mValidated = false;
mExecutableValidated = mResourcesValidated = false;
if (mResourcesValidContext) {
delete mResourcesValidContext;
mResourcesValidContext = NULL;
}
mDir = NULL;
mCodeDirectories.clear();
mSignature = NULL;
for (unsigned n = 0; n < cdSlotCount; n++)
mCache[n] = NULL;
mInfoDict = NULL;
mEntitlements = NULL;
mResourceDict = NULL;
mDesignatedReq = NULL;
mCDHash = NULL;
mGotResourceBase = false;
mTrust = NULL;
mCertChain = NULL;
mNotarizationChecked = false;
mStaplingChecked = false;
mNotarizationDate = NAN;
mRep->flush();
mCEReconstitutedEnts = NULL;
CEReleaseManagedContext(&mCEQueryContext);
#if TARGET_OS_OSX
// we may just have updated the system database, so check again
checkForSystemSignature();
#endif
}
//
// Retrieve a sealed component by special slot index.
// If the CodeDirectory has already been validated, validate against that.
// Otherwise, retrieve the component without validation (but cache it). Validation
// will go through the cache and validate all cached components.
//
CFDataRef SecStaticCode::component(CodeDirectory::SpecialSlot slot, OSStatus fail /* = errSecCSSignatureFailed */)
{
assert(slot <= cdSlotMax);
CFRef<CFDataRef> &cache = mCache[slot];
if (!cache) {
if (CFRef<CFDataRef> data = mRep->component(slot)) {
if (validated()) { // if the directory has been validated...
if (!codeDirectory()->slotIsPresent(-slot))
return NULL;
if (!codeDirectory()->validateSlot(CFDataGetBytePtr(data), // ... and it's no good
CFDataGetLength(data), -slot, false))
MacOSError::throwMe(errorForSlot(slot)); // ... then bail
}
cache = data; // it's okay, cache it
} else { // absent, mark so
if (validated()) // if directory has been validated...
if (codeDirectory()->slotIsPresent(-slot)) // ... and the slot is NOT missing
MacOSError::throwMe(errorForSlot(slot)); // was supposed to be there
if (slot == cdEntitlementDERSlot) {
// if we have a regular slot we can fake this one up
if (CFDataRef entitlementData = component(cdEntitlementSlot)) {
validateComponent(cdEntitlementSlot);
const EntitlementBlob *blob = reinterpret_cast<const EntitlementBlob *>(CFDataGetBytePtr(entitlementData));
if (blob->validateBlob()) {
CFRef<CFDictionaryRef> xmlEnts = blob->entitlements();
CFDataRef fakeDER = NULL;
if (CE_OK(CESerializeCFDictionary(CECRuntime, (CFDictionaryRef)xmlEnts, &fakeDER))) {
// Great success
cache.take(EntitlementDERBlob::blobify(fakeDER));
CFRelease(fakeDER);
goto done;
} else {
secinfo("staticCode", "%p the XML cannot be converted to valid DER", this);
}
}
}
}
cache = CFDataRef(kCFNull); // assume null for now, maybe we can transmute
}
}
done:
return (cache == CFDataRef(kCFNull)) ? NULL : cache.get();
}
//
// Get the CodeDirectories.
// Throws (if check==true) or returns NULL (check==false) if there are none.
// Always throws if the CodeDirectories exist but are invalid.
// NEVER validates against the signature.
//
const SecStaticCode::CodeDirectoryMap *
SecStaticCode::codeDirectories(bool check /* = true */) const
{
if (mCodeDirectories.empty()) {
try {
loadCodeDirectories(mCodeDirectories);
} catch (...) {
if (check)
throw;
// We wanted a NON-checked peek and failed to safely decode the existing CodeDirectories.
// Pretend this is unsigned, but make sure we didn't somehow cache an invalid CodeDirectory.
if (!mCodeDirectories.empty()) {
assert(false);
Syslog::warning("code signing internal problem: mCodeDirectories set despite exception exit");
MacOSError::throwMe(errSecCSInternalError);
}
}
} else {
return &mCodeDirectories;
}
if (!mCodeDirectories.empty()) {
return &mCodeDirectories;
}
if (check) {
MacOSError::throwMe(errSecCSUnsigned);
}
return NULL;
}
//
// Get the CodeDirectory.
// Throws (if check==true) or returns NULL (check==false) if there is none.
// Always throws if the CodeDirectory exists but is invalid.
// NEVER validates against the signature.
//
const CodeDirectory *SecStaticCode::codeDirectory(bool check /* = true */) const
{
if (!mDir) {
// pick our favorite CodeDirectory from the choices we've got
try {
CodeDirectoryMap const *candidates = codeDirectories(check);
if (candidates != NULL) {
CodeDirectory::HashAlgorithm type = CodeDirectory::bestHashOf(mHashAlgorithms);
mDir = candidates->at(type); // and the winner is...
}
} catch (...) {
if (check)
throw;
// We wanted a NON-checked peek and failed to safely decode the existing CodeDirectory.
// Pretend this is unsigned, but make sure we didn't somehow cache an invalid CodeDirectory.
if (mDir) {
assert(false);
Syslog::warning("code signing internal problem: mDir set despite exception exit");
MacOSError::throwMe(errSecCSInternalError);
}
}
}
if (mDir)
return reinterpret_cast<const CodeDirectory *>(CFDataGetBytePtr(mDir));
if (check)
MacOSError::throwMe(errSecCSUnsigned);
return NULL;
}
//
// Fetch an array of all available CodeDirectories.
// Returns false if unsigned (no classic CD slot), true otherwise.
//
bool SecStaticCode::loadCodeDirectories(CodeDirectoryMap& cdMap) const
{
__block CodeDirectoryMap candidates;
__block CodeDirectory::HashAlgorithms hashAlgorithms;
__block CFRef<CFDataRef> baseDir;
auto add = ^bool (CodeDirectory::SpecialSlot slot){
CFRef<CFDataRef> cdData = diskRep()->component(slot);
if (!cdData)
return false;
const CodeDirectory* cd = reinterpret_cast<const CodeDirectory*>(CFDataGetBytePtr(cdData));
if (!cd->validateBlob(CFDataGetLength(cdData)))
MacOSError::throwMe(errSecCSSignatureFailed); // no recovery - any suspect CD fails
cd->checkIntegrity();
auto result = candidates.insert(make_pair(cd->hashType, cdData.get()));
if (!result.second)
MacOSError::throwMe(errSecCSSignatureInvalid); // duplicate hashType, go to heck
hashAlgorithms.insert(cd->hashType);
if (slot == cdCodeDirectorySlot)
baseDir = cdData;
return true;
};
if (!add(cdCodeDirectorySlot))
return false; // no classic slot CodeDirectory -> unsigned
for (CodeDirectory::SpecialSlot slot = cdAlternateCodeDirectorySlots; slot < cdAlternateCodeDirectoryLimit; slot++)
if (!add(slot)) // no CodeDirectory at this slot -> end of alternates
break;
if (candidates.empty())
MacOSError::throwMe(errSecCSSignatureFailed); // no viable CodeDirectory in sight
// commit to cached values
cdMap.swap(candidates);
mHashAlgorithms.swap(hashAlgorithms);
mBaseDir = baseDir;
return true;
}
//
// Get the hash of the CodeDirectory.
// Returns NULL if there is none.
//
CFDataRef SecStaticCode::cdHash()
{
if (!mCDHash) {
if (const CodeDirectory *cd = codeDirectory(false)) {
mCDHash.take(cd->cdhash());
CODESIGN_STATIC_CDHASH(this, CFDataGetBytePtr(mCDHash), (unsigned int)CFDataGetLength(mCDHash));
}
}
return mCDHash;
}
//
// Get an array of the cdhashes for all digest types in this signature
// The array is sorted by cd->hashType.
//
CFArrayRef SecStaticCode::cdHashes()
{
if (!mCDHashes) {
CFRef<CFMutableArrayRef> cdList = makeCFMutableArray(0);
for (auto it = mCodeDirectories.begin(); it != mCodeDirectories.end(); ++it) {
const CodeDirectory *cd = (const CodeDirectory *)CFDataGetBytePtr(it->second);
if (CFRef<CFDataRef> hash = cd->cdhash())
CFArrayAppendValue(cdList, hash);
}
mCDHashes = cdList.get();
}
return mCDHashes;
}
//
// Get a dictionary of untruncated cdhashes for all digest types in this signature.
//
CFDictionaryRef SecStaticCode::cdHashesFull()
{
if (!mCDHashFullDict) {
CFRef<CFMutableDictionaryRef> cdDict = makeCFMutableDictionary();
for (auto const &it : mCodeDirectories) {
CodeDirectory::HashAlgorithm alg = it.first;
const CodeDirectory *cd = (const CodeDirectory *)CFDataGetBytePtr(it.second);
CFRef<CFDataRef> hash = cd->cdhash(false);
if (hash) {
CFDictionaryAddValue(cdDict, CFTempNumber(alg), hash);
}
}
mCDHashFullDict = cdDict.get();
}
return mCDHashFullDict;
}
//
// Return the CMS signature blob; NULL if none found.
//
CFDataRef SecStaticCode::signature()
{
if (!mSignature)
mSignature.take(mRep->signature());
if (mSignature)
return mSignature;
MacOSError::throwMe(errSecCSUnsigned);
}
//
// Verify the signature on the CodeDirectory.
// If this succeeds (doesn't throw), the CodeDirectory is statically trustworthy.
// Any outcome (successful or not) is cached for the lifetime of the StaticCode.
//
void SecStaticCode::validateDirectory()
{
// echo previous outcome, if any
// track revocation separately, as it may not have been checked
// during the initial validation
if (!validated() || ((mValidationFlags & kSecCSEnforceRevocationChecks) && !revocationChecked()))
try {
// perform validation (or die trying)
CODESIGN_EVAL_STATIC_DIRECTORY(this);
mValidationExpired = verifySignature();
if (mValidationFlags & kSecCSEnforceRevocationChecks)
mRevocationChecked = true;
for (CodeDirectory::SpecialSlot slot = codeDirectory()->maxSpecialSlot(); slot >= 1; --slot)
if (mCache[slot]) // if we already loaded that resource...
validateComponent(slot, errorForSlot(slot)); // ... then check it now
mValidated = true; // we've done the deed...
mValidationResult = errSecSuccess; // ... and it was good
} catch (const CommonError &err) {
mValidated = true;
mValidationResult = err.osStatus();
throw;
} catch (...) {
secinfo("staticCode", "%p validation threw non-common exception", this);
mValidated = true;
Syslog::notice("code signing internal problem: unknown exception thrown by validation");
mValidationResult = errSecCSInternalError;
throw;
}
assert(validated());
// XXX: Embedded doesn't have CSSMERR_TP_CERT_EXPIRED so we can't throw it
// XXX: This should be implemented for embedded once we implement
// XXX: verifySignature and see how we're going to handle expired certs
#if TARGET_OS_OSX
if (mValidationResult == errSecSuccess) {
if (mValidationExpired)
if ((mValidationFlags & kSecCSConsiderExpiration)
|| (codeDirectory()->flags & kSecCodeSignatureForceExpiration))
MacOSError::throwMe(CSSMERR_TP_CERT_EXPIRED);
} else
MacOSError::throwMe(mValidationResult);
#endif
}
//
// Load and validate the CodeDirectory and all components *except* those related to the resource envelope.
// Those latter components are checked by validateResources().
//
void SecStaticCode::validateNonResourceComponents()
{
this->validateDirectory();
for (CodeDirectory::SpecialSlot slot = codeDirectory()->maxSpecialSlot(); slot >= 1; --slot)
switch (slot) {
case cdResourceDirSlot: // validated by validateResources
break;
default:
this->component(slot); // loads and validates
break;
}
}
//
// Check that any "top index" sealed into the signature conforms to what's actually here.
//
void SecStaticCode::validateTopDirectory()
{
assert(mDir); // must already have loaded CodeDirectories
if (CFDataRef topDirectory = component(cdTopDirectorySlot)) {
const auto topData = (const Endian<uint32_t> *)CFDataGetBytePtr(topDirectory);
const auto topDataEnd = topData + CFDataGetLength(topDirectory) / sizeof(*topData);
std::vector<uint32_t> signedVector(topData, topDataEnd);
std::vector<uint32_t> foundVector;
foundVector.push_back(cdCodeDirectorySlot); // mandatory
for (CodeDirectory::Slot slot = 1; slot <= cdSlotMax; ++slot) {
if (slot == cdEntitlementDERSlot && !codeDirectory()->slotIsPresent(-cdEntitlementDERSlot)) {
// The DER entitlement slot is special and gets fabricated from XML entitlements via the component
// accessor. For that slot, directly check if its present in the code directory.
continue;
}
if (component(slot)) {
foundVector.push_back(slot);
}
}
int alternateCount = int(mCodeDirectories.size() - 1); // one will go into cdCodeDirectorySlot
for (int n = 0; n < alternateCount; n++) {
foundVector.push_back(cdAlternateCodeDirectorySlots + n);
}
foundVector.push_back(cdSignatureSlot); // mandatory (may be empty)
if (signedVector != foundVector) {
MacOSError::throwMe(errSecCSSignatureFailed);
}
}
}
//
// Get the (signed) signing date from the code signature.
// Sadly, we need to validate the signature to get the date (as a side benefit).
// This means that you can't get the signing time for invalidly signed code.
//
// We could run the decoder "almost to" verification to avoid this, but there seems
// little practical point to such a duplication of effort.
//
CFAbsoluteTime SecStaticCode::signingTime()
{
validateDirectory();
return mSigningTime;
}
CFAbsoluteTime SecStaticCode::signingTimestamp()
{
validateDirectory();
return mSigningTimestamp;
}
#if TARGET_OS_OSX
#define kSecSHA256HashSize 32
// subject:/C=US/ST=California/L=San Jose/O=Adobe Systems Incorporated/OU=Information Systems/OU=Digital ID Class 3 - Microsoft Software Validation v2/CN=Adobe Systems Incorporated
// issuer :/C=US/O=VeriSign, Inc./OU=VeriSign Trust Network/OU=Terms of use at https://www.verisign.com/rpa (c)10/CN=VeriSign Class 3 Code Signing 2010 CA
// Not Before: Dec 15 00:00:00 2010 GMT
// Not After : Dec 14 23:59:59 2012 GMT
static const unsigned char ASI_CS_12[] = {
0x77,0x82,0x9C,0x64,0x33,0x45,0x2E,0x4A,0xD3,0xA8,0xE4,0x6F,0x00,0x6C,0x27,0xEA,
0xFB,0xD3,0xF2,0x6D,0x50,0xF3,0x6F,0xE0,0xE9,0x6D,0x06,0x59,0x19,0xB5,0x46,0xFF
};
bool SecStaticCode::checkfix41082220(OSStatus cssmTrustResult)
{
// only applicable to revoked results
if (cssmTrustResult != CSSMERR_TP_CERT_REVOKED) {
return false;
}
// only this leaf certificate
if (CFArrayGetCount(mCertChain) == 0) {
return false;
}
CFRef<CFDataRef> leafHash(SecCertificateCopySHA256Digest((SecCertificateRef)CFArrayGetValueAtIndex(mCertChain, 0)));
if (memcmp(ASI_CS_12, CFDataGetBytePtr(leafHash), kSecSHA256HashSize) != 0) {
return false;
}
// detached dmg signature
if (!isDetached() || format() != std::string("disk image")) {
return false;
}
// sha-1 signed
if (hashAlgorithms().size() != 1 || hashAlgorithm() != kSecCodeSignatureHashSHA1) {
return false;
}
// not a privileged binary - no TeamID and no entitlements
if (component(cdEntitlementSlot) || teamID() || component(cdEntitlementDERSlot)) {
return false;
}
// no flags and old version
if (codeDirectory()->version != 0x20100 || codeDirectory()->flags != 0) {
return false;
}
Security::Syslog::warning("CodeSigning: Check-fix enabled for dmg '%s' with identifier '%s' signed with revoked certificates",
mainExecutablePath().c_str(), identifier().c_str());
return true;
}
#endif // TARGET_OS_OSX
//
// Verify the CMS signature.
// This performs the cryptographic tango. It returns if the signature is valid,
// or throws if it is not. As a side effect, a successful return sets up the
// cached certificate chain for future use.
// Returns true if the signature is expired (the X.509 sense), false if it's not.
// Expiration is fatal (throws) if a secure timestamp is included, but not otherwise.
//
bool SecStaticCode::verifySignature()
{
// ad-hoc signed code is considered validly signed by definition
if (flag(kSecCodeSignatureAdhoc)) {
CODESIGN_EVAL_STATIC_SIGNATURE_ADHOC(this);
return false;
}
DTRACK(CODESIGN_EVAL_STATIC_SIGNATURE, this, (char*)this->mainExecutablePath().c_str());
#if TARGET_OS_OSX
if (!(mValidationFlags & kSecCSApplyEmbeddedPolicy)) {
// decode CMS and extract SecTrust for verification
CFRef<CMSDecoderRef> cms;
MacOSError::check(CMSDecoderCreate(&cms.aref())); // create decoder
CFDataRef sig = this->signature();
MacOSError::check(CMSDecoderUpdateMessage(cms, CFDataGetBytePtr(sig), CFDataGetLength(sig)));
this->codeDirectory(); // load CodeDirectory (sets mDir)
MacOSError::check(CMSDecoderSetDetachedContent(cms, mBaseDir));
MacOSError::check(CMSDecoderFinalizeMessage(cms));
MacOSError::check(CMSDecoderSetSearchKeychain(cms, cfEmptyArray()));
CFRef<CFArrayRef> vf_policies(createVerificationPolicies());
CFRef<CFArrayRef> ts_policies(createTimeStampingAndRevocationPolicies());
CMSSignerStatus status;
MacOSError::check(CMSDecoderCopySignerStatus(cms, 0, vf_policies,
false, &status, &mTrust.aref(), NULL));
if (status != kCMSSignerValid) {
const char *reason;
switch (status) {
case kCMSSignerUnsigned: reason="kCMSSignerUnsigned"; break;
case kCMSSignerNeedsDetachedContent: reason="kCMSSignerNeedsDetachedContent"; break;
case kCMSSignerInvalidSignature: reason="kCMSSignerInvalidSignature"; break;
case kCMSSignerInvalidCert: reason="kCMSSignerInvalidCert"; break;
case kCMSSignerInvalidIndex: reason="kCMSSignerInvalidIndex"; break;
default: reason="unknown"; break;
}
Security::Syslog::error("CMSDecoderCopySignerStatus failed with %s error (%d)",
reason, (int)status);
MacOSError::throwMe(errSecCSSignatureFailed);
}
// retrieve auxiliary v1 data bag and verify against current state
CFRef<CFDataRef> hashAgilityV1;
switch (OSStatus rc = CMSDecoderCopySignerAppleCodesigningHashAgility(cms, 0, &hashAgilityV1.aref())) {
case noErr:
if (hashAgilityV1) {
CFRef<CFDictionaryRef> hashDict = makeCFDictionaryFrom(hashAgilityV1);
CFArrayRef cdList = CFArrayRef(CFDictionaryGetValue(hashDict, CFSTR("cdhashes")));
CFArrayRef myCdList = this->cdHashes();
/* Note that this is not very "agile": There's no way to calculate the exact
* list for comparison if it contains hash algorithms we don't know yet... */
if (cdList == NULL || !CFEqual(cdList, myCdList))
MacOSError::throwMe(errSecCSSignatureFailed);
}
break;
case -1: /* CMS used to return this for "no attribute found", so tolerate it. Now returning noErr/NULL */
break;
default:
MacOSError::throwMe(rc);
}
// retrieve auxiliary v2 data bag and verify against current state
CFRef<CFDictionaryRef> hashAgilityV2;
switch (OSStatus rc = CMSDecoderCopySignerAppleCodesigningHashAgilityV2(cms, 0, &hashAgilityV2.aref())) {
case noErr:
if (hashAgilityV2) {
/* Require number of code directoris and entries in the hash agility
* dict to be the same size (no stripping out code directories).
*/
if (CFDictionaryGetCount(hashAgilityV2) != mCodeDirectories.size()) {
MacOSError::throwMe(errSecCSSignatureFailed);
}
/* Require every cdhash of every code directory whose hash
* algorithm we know to be in the agility dictionary.
*
* We check untruncated cdhashes here because we can.
*/
bool foundOurs = false;
for (auto& entry : mCodeDirectories) {
SECOidTag tag = CodeDirectorySet::SECOidTagForAlgorithm(entry.first);
if (tag == SEC_OID_UNKNOWN) {
// Unknown hash algorithm, ignore.
continue;
}
CFRef<CFNumberRef> key = makeCFNumber(int(tag));
CFRef<CFDataRef> entryCdhash;
entryCdhash = (CFDataRef)CFDictionaryGetValue(hashAgilityV2, (void*)key.get());
CodeDirectory const *cd = (CodeDirectory const*)CFDataGetBytePtr(entry.second);
CFRef<CFDataRef> ourCdhash = cd->cdhash(false); // Untruncated cdhash!
if (!CFEqual(entryCdhash, ourCdhash)) {
MacOSError::throwMe(errSecCSSignatureFailed);
}
if (entry.first == this->hashAlgorithm()) {
foundOurs = true;
}
}
/* Require the cdhash of our chosen code directory to be in the dictionary.
* In theory, the dictionary could be full of unsupported cdhashes, but we
* really want ours, which is bound to be supported, to be covered.
*/
if (!foundOurs) {
MacOSError::throwMe(errSecCSSignatureFailed);
}
}
break;
case -1: /* CMS used to return this for "no attribute found", so tolerate it. Now returning noErr/NULL */
break;
default:
MacOSError::throwMe(rc);
}
// internal signing time (as specified by the signer; optional)
mSigningTime = 0; // "not present" marker (nobody could code sign on Jan 1, 2001 :-)
switch (OSStatus rc = CMSDecoderCopySignerSigningTime(cms, 0, &mSigningTime)) {
case errSecSuccess:
case errSecSigningTimeMissing:
break;
default:
Security::Syslog::error("Could not get signing time (error %d)", (int)rc);
MacOSError::throwMe(rc);
}
// certified signing time (as specified by a TSA; optional)
mSigningTimestamp = 0;
switch (OSStatus rc = CMSDecoderCopySignerTimestampWithPolicy(cms, ts_policies, 0, &mSigningTimestamp)) {
case errSecSuccess:
case errSecTimestampMissing:
break;
default:
Security::Syslog::error("Could not get timestamp (error %d)", (int)rc);
MacOSError::throwMe(rc);
}
// set up the environment for SecTrust
if (validationCannotUseNetwork()) {
MacOSError::check(SecTrustSetNetworkFetchAllowed(mTrust, false)); // no network?
}
MacOSError::check(SecTrustSetKeychainsAllowed(mTrust, false));
CSSM_APPLE_TP_ACTION_DATA actionData = {
CSSM_APPLE_TP_ACTION_VERSION, // version of data structure
0 // action flags
};
if (!(mValidationFlags & kSecCSCheckTrustedAnchors)) {