// // Perform common argument normalizations for update operations // static void normalizeTarget(CFRef<CFTypeRef> &target, CFDictionary &context, std::string *signUnsigned) { // turn CFURLs into (designated) SecRequirements if (target && CFGetTypeID(target) == CFURLGetTypeID()) { CFRef<SecStaticCodeRef> code; MacOSError::check(SecStaticCodeCreateWithPath(target.as<CFURLRef>(), kSecCSDefaultFlags, &code.aref())); switch (OSStatus rc = SecCodeCopyDesignatedRequirement(code, kSecCSDefaultFlags, (SecRequirementRef *)&target.aref())) { case noErr: { // use the *default* DR to avoid unreasonably wide DRs opening up Gatekeeper to attack CFRef<CFDictionaryRef> info; MacOSError::check(SecCodeCopySigningInformation(code, kSecCSRequirementInformation, &info.aref())); target = CFDictionaryGetValue(info, kSecCodeInfoImplicitDesignatedRequirement); } break; case errSecCSUnsigned: if (signUnsigned) { // Ad-hoc sign the code temporarily so we can get its code requirement CFRef<CFDataRef> signature = CFDataCreateMutable(NULL, 0); CFRef<SecCodeSignerRef> signer; CFTemp<CFDictionaryRef> arguments("{%O=%O, %O=#N}", kSecCodeSignerDetached, signature.get(), kSecCodeSignerIdentity); MacOSError::check(SecCodeSignerCreate(arguments, kSecCSDefaultFlags, &signer.aref())); MacOSError::check(SecCodeSignerAddSignature(signer, code, kSecCSDefaultFlags)); MacOSError::check(SecCodeSetDetachedSignature(code, signature, kSecCSDefaultFlags)); MacOSError::check(SecCodeCopyDesignatedRequirement(code, kSecCSDefaultFlags, (SecRequirementRef *)&target.aref())); CFRef<CFDictionaryRef> info; MacOSError::check(SecCodeCopySigningInformation(code, kSecCSInternalInformation, &info.aref())); if (CFDataRef cdData = CFDataRef(CFDictionaryGetValue(info, kSecCodeInfoCodeDirectory))) *signUnsigned = ((const CodeDirectory *)CFDataGetBytePtr(cdData))->screeningCode(); break; } MacOSError::check(rc); case errSecCSSignatureFailed: // recover certain cases of broken signatures (well, try) if (codeInvalidityExceptions(code, NULL)) { // Ad-hoc sign the code in place (requiring a writable subject). This requires root privileges. CFRef<SecCodeSignerRef> signer; CFTemp<CFDictionaryRef> arguments("{%O=#N}", kSecCodeSignerIdentity); MacOSError::check(SecCodeSignerCreate(arguments, kSecCSDefaultFlags, &signer.aref())); MacOSError::check(SecCodeSignerAddSignature(signer, code, kSecCSDefaultFlags)); MacOSError::check(SecCodeCopyDesignatedRequirement(code, kSecCSDefaultFlags, (SecRequirementRef *)&target.aref())); break; } MacOSError::check(rc); default: MacOSError::check(rc); } if (context.get(kSecAssessmentUpdateKeyRemarks) == NULL) { // no explicit remarks; add one with the path CFRef<CFURLRef> path; MacOSError::check(SecCodeCopyPath(code, kSecCSDefaultFlags, &path.aref())); CFMutableDictionaryRef dict = makeCFMutableDictionary(context.get()); CFDictionaryAddValue(dict, kSecAssessmentUpdateKeyRemarks, CFTempString(cfString(path))); context.take(dict); } } }
// // Process special overrides for invalidly signed code. // This is the (hopefully minimal) concessions we make to keep hurting our customers // for our own prior mistakes... // static bool codeInvalidityExceptions(SecStaticCodeRef code, CFMutableDictionaryRef result) { if (OSAIsRecognizedExecutableURL) { CFRef<CFDictionaryRef> info; MacOSError::check(SecCodeCopySigningInformation(code, kSecCSDefaultFlags, &info.aref())); if (CFURLRef executable = CFURLRef(CFDictionaryGetValue(info, kSecCodeInfoMainExecutable))) { SInt32 error; if (OSAIsRecognizedExecutableURL(executable, &error)) { if (result) CFDictionaryAddValue(result, kSecAssessmentAssessmentAuthorityOverride, CFSTR("ignoring known invalid applet signature")); return true; } } } return false; }
// // Take an assessment outcome and record it in the object cache // void PolicyEngine::recordOutcome(SecStaticCodeRef code, bool allow, AuthorityType type, double expires, SQLite::int64 authority) { CFRef<CFDictionaryRef> info; MacOSError::check(SecCodeCopySigningInformation(code, kSecCSDefaultFlags, &info.aref())); CFDataRef cdHash = CFDataRef(CFDictionaryGetValue(info, kSecCodeInfoUnique)); assert(cdHash); // was signed CFRef<CFURLRef> path; MacOSError::check(SecCodeCopyPath(code, kSecCSDefaultFlags, &path.aref())); assert(expires); SQLite::Transaction xact(*this, SQLite3::Transaction::deferred, "caching"); SQLite::Statement insert(*this, "INSERT OR REPLACE INTO object (type, allow, hash, expires, path, authority)" " VALUES (:type, :allow, :hash, :expires, :path," " CASE :authority WHEN 0 THEN (SELECT id FROM authority WHERE label = 'No Matching Rule') ELSE :authority END" " );"); insert.bind(":type").integer(type); insert.bind(":allow").integer(allow); insert.bind(":hash") = cdHash; insert.bind(":expires") = expires; insert.bind(":path") = cfString(path); insert.bind(":authority").integer(authority); insert.execute(); xact.commit(); }
// // The executable path is a bit annoying to get, but not quite // annoying enough to cache the result. // string OSXCodeWrap::executablePath() const { CFRef<CFDictionaryRef> info; MacOSError::check(SecCodeCopySigningInformation(mCode, kSecCSDefaultFlags, &info.aref())); return cfString(CFURLRef(CFDictionaryGetValue(info, kSecCodeInfoMainExecutable))); }
// // Executable code. // Read from disk, evaluate properly, cache as indicated. The whole thing, so far. // void PolicyEngine::evaluateCode(CFURLRef path, AuthorityType type, SecAssessmentFlags flags, CFDictionaryRef context, CFMutableDictionaryRef result, bool handleUnsignedCode /* = true */) { FileQuarantine qtn(cfString(path).c_str()); if (qtn.flag(QTN_FLAG_HARD)) MacOSError::throwMe(errSecCSFileHardQuarantined); CFRef<SecStaticCodeRef> code; MacOSError::check(SecStaticCodeCreateWithPath(path, kSecCSDefaultFlags, &code.aref())); OSStatus rc = noErr; // last validation error const SecCSFlags validationFlags = kSecCSEnforceRevocationChecks; WhitelistPrescreen whitelistScreen(code); // pre-screening filter for whitelist pre-screening (only) SQLite::Statement query(*this, "SELECT allow, requirement, id, label, expires, flags, disabled, filter_unsigned, remarks FROM scan_authority" " WHERE type = :type" " ORDER BY priority DESC;"); query.bind(":type").integer(type); SQLite3::int64 latentID = 0; // first (highest priority) disabled matching ID std::string latentLabel; // ... and associated label, if any while (query.nextRow()) { bool allow = int(query[0]); const char *reqString = query[1]; SQLite3::int64 id = query[2]; const char *label = query[3]; double expires = query[4]; sqlite3_int64 ruleFlags = query[5]; SQLite3::int64 disabled = query[6]; const char *filter = query[7]; const char *remarks = query[8]; CFRef<SecRequirementRef> requirement; MacOSError::check(SecRequirementCreateWithString(CFTempString(reqString), kSecCSDefaultFlags, &requirement.aref())); rc = SecStaticCodeCheckValidity(code, validationFlags, requirement); // ad-hoc sign unsigned code, skip of Gatekeeper is off or the rule is disabled; but always do it for whitelist recording if (rc == errSecCSUnsigned && handleUnsignedCode && (!(disabled || overrideAssessment()) || SYSPOLICY_RECORDER_MODE_ENABLED())) { if (!SYSPOLICY_RECORDER_MODE_ENABLED()) { // apply whitelist pre-screening to speed things up for non-matches if (ruleFlags & kAuthorityFlagDefault) // can't ever match standard rules with unsigned code continue; if (whitelistScreen.reject(filter, remarks)) // apply whitelist pre-filter continue; } try { // ad-hoc sign the code and attach the signature CFRef<CFDataRef> signature = CFDataCreateMutable(NULL, 0); CFTemp<CFDictionaryRef> arguments("{%O=%O, %O=#N}", kSecCodeSignerDetached, signature.get(), kSecCodeSignerIdentity); CFRef<SecCodeSignerRef> signer; MacOSError::check(SecCodeSignerCreate(arguments, kSecCSDefaultFlags, &signer.aref())); MacOSError::check(SecCodeSignerAddSignature(signer, code, kSecCSDefaultFlags)); MacOSError::check(SecCodeSetDetachedSignature(code, signature, kSecCSDefaultFlags)); // if we're in GKE recording mode, save that signature and report its location if (SYSPOLICY_RECORDER_MODE_ENABLED()) { int status = recorder_code_unable; // ephemeral signature (not recorded) if (geteuid() == 0) { CFRef<CFUUIDRef> uuid = CFUUIDCreate(NULL); std::string sigfile = RECORDER_DIR + cfStringRelease(CFUUIDCreateString(NULL, uuid)) + ".tsig"; try { UnixPlusPlus::AutoFileDesc fd(sigfile, O_WRONLY | O_CREAT); fd.write(CFDataGetBytePtr(signature), CFDataGetLength(signature)); status = recorder_code_adhoc; // recorded signature SYSPOLICY_RECORDER_MODE_ADHOC_PATH(cfString(path).c_str(), type, sigfile.c_str()); } catch (...) { } } // now report the D probe itself CFRef<CFDictionaryRef> info; MacOSError::check(SecCodeCopySigningInformation(code, kSecCSDefaultFlags, &info.aref())); CFDataRef cdhash = CFDataRef(CFDictionaryGetValue(info, kSecCodeInfoUnique)); SYSPOLICY_RECORDER_MODE(cfString(path).c_str(), type, "", cdhash ? CFDataGetBytePtr(cdhash) : NULL, status); } // rerun the validation to update state rc = SecStaticCodeCheckValidity(code, validationFlags | kSecCSBasicValidateOnly, requirement); } catch (...) { } } switch (rc) { case noErr: // well signed and satisfies requirement... break; // ... continue below case errSecCSSignatureFailed: if (!codeInvalidityExceptions(code, result)) { if (SYSPOLICY_ASSESS_OUTCOME_BROKEN_ENABLED()) SYSPOLICY_ASSESS_OUTCOME_BROKEN(cfString(path).c_str(), type, false); MacOSError::throwMe(rc); } if (SYSPOLICY_ASSESS_OUTCOME_BROKEN_ENABLED()) SYSPOLICY_ASSESS_OUTCOME_BROKEN(cfString(path).c_str(), type, true); // treat as unsigned to fix problems in the field case errSecCSUnsigned: if (handleUnsignedCode) { cfadd(result, "{%O=#F}", kSecAssessmentAssessmentVerdict); addAuthority(result, "no usable signature"); } return; case errSecCSReqFailed: // requirement missed, but otherwise okay continue; default: // broken in some way; all tests will fail like this so bail out MacOSError::throwMe(rc); } if (disabled) { if (latentID == 0) { latentID = id; if (label) latentLabel = label; } continue; // the loop } CFRef<CFDictionaryRef> info; // as needed if (flags & kSecAssessmentFlagRequestOrigin) { if (!info) MacOSError::check(SecCodeCopySigningInformation(code, kSecCSSigningInformation, &info.aref())); if (CFArrayRef chain = CFArrayRef(CFDictionaryGetValue(info, kSecCodeInfoCertificates))) setOrigin(chain, result); } if (!(ruleFlags & kAuthorityFlagInhibitCache) && !(flags & kSecAssessmentFlagNoCache)) { // cache inhibit if (!info) MacOSError::check(SecCodeCopySigningInformation(code, kSecCSSigningInformation, &info.aref())); if (SecTrustRef trust = SecTrustRef(CFDictionaryGetValue(info, kSecCodeInfoTrust))) { CFRef<CFDictionaryRef> xinfo; MacOSError::check(SecTrustCopyExtendedResult(trust, &xinfo.aref())); if (CFDateRef limit = CFDateRef(CFDictionaryGetValue(xinfo, kSecTrustExpirationDate))) { this->recordOutcome(code, allow, type, min(expires, dateToJulian(limit)), id); } } } if (allow) { if (SYSPOLICY_ASSESS_OUTCOME_ACCEPT_ENABLED()) { if (!info) MacOSError::check(SecCodeCopySigningInformation(code, kSecCSSigningInformation, &info.aref())); CFDataRef cdhash = CFDataRef(CFDictionaryGetValue(info, kSecCodeInfoUnique)); SYSPOLICY_ASSESS_OUTCOME_ACCEPT(cfString(path).c_str(), type, label, cdhash ? CFDataGetBytePtr(cdhash) : NULL); } } else { if (SYSPOLICY_ASSESS_OUTCOME_DENY_ENABLED() || SYSPOLICY_RECORDER_MODE_ENABLED()) { if (!info) MacOSError::check(SecCodeCopySigningInformation(code, kSecCSSigningInformation, &info.aref())); CFDataRef cdhash = CFDataRef(CFDictionaryGetValue(info, kSecCodeInfoUnique)); std::string cpath = cfString(path); const void *hashp = cdhash ? CFDataGetBytePtr(cdhash) : NULL; SYSPOLICY_ASSESS_OUTCOME_DENY(cpath.c_str(), type, label, hashp); SYSPOLICY_RECORDER_MODE(cpath.c_str(), type, label, hashp, recorder_code_untrusted); } } cfadd(result, "{%O=%B}", kSecAssessmentAssessmentVerdict, allow); addAuthority(result, label, id); return; } if (rc == errSecCSUnsigned) { // skipped all applicable rules due to pre-screening cfadd(result, "{%O=#F}", kSecAssessmentAssessmentVerdict); addAuthority(result, "no usable signature"); return; } // no applicable authority (but signed, perhaps temporarily). Deny by default CFRef<CFDictionaryRef> info; MacOSError::check(SecCodeCopySigningInformation(code, kSecCSSigningInformation, &info.aref())); if (flags & kSecAssessmentFlagRequestOrigin) { if (CFArrayRef chain = CFArrayRef(CFDictionaryGetValue(info, kSecCodeInfoCertificates))) setOrigin(chain, result); } if (SYSPOLICY_ASSESS_OUTCOME_DEFAULT_ENABLED() || SYSPOLICY_RECORDER_MODE_ENABLED()) { CFDataRef cdhash = CFDataRef(CFDictionaryGetValue(info, kSecCodeInfoUnique)); const void *hashp = cdhash ? CFDataGetBytePtr(cdhash) : NULL; std::string cpath = cfString(path); SYSPOLICY_ASSESS_OUTCOME_DEFAULT(cpath.c_str(), type, latentLabel.c_str(), hashp); SYSPOLICY_RECORDER_MODE(cpath.c_str(), type, latentLabel.c_str(), hashp, 0); } if (!(flags & kSecAssessmentFlagNoCache)) this->recordOutcome(code, false, type, this->julianNow() + NEGATIVE_HOLD, latentID); cfadd(result, "{%O=%B}", kSecAssessmentAssessmentVerdict, false); addAuthority(result, latentLabel.c_str(), latentID); }
bool PolicyEngine::temporarySigning(SecStaticCodeRef code, AuthorityType type, CFURLRef path, SecAssessmentFlags matchFlags) { if (matchFlags == 0) { // playback; consult authority table for matches DiskRep *rep = SecStaticCode::requiredStatic(code)->diskRep(); std::string screen; if (CFRef<CFDataRef> info = rep->component(cdInfoSlot)) { SHA1 hash; hash.update(CFDataGetBytePtr(info), CFDataGetLength(info)); screen = createWhitelistScreen('I', hash); } else if (rep->mainExecutableImage()) { screen = "N"; } else { SHA1 hash; hashFileData(rep->mainExecutablePath().c_str(), &hash); screen = createWhitelistScreen('M', hash); } SQLite::Statement query(*this, "SELECT flags FROM authority " "WHERE type = :type" " AND NOT flags & :flag" " AND CASE WHEN filter_unsigned IS NULL THEN remarks = :remarks ELSE filter_unsigned = :screen END"); query.bind(":type").integer(type); query.bind(":flag").integer(kAuthorityFlagDefault); query.bind(":screen") = screen; query.bind(":remarks") = cfString(path); if (!query.nextRow()) // guaranteed no matching rule return false; matchFlags = SQLite3::int64(query[0]); } try { // ad-hoc sign the code and attach the signature CFRef<CFDataRef> signature = CFDataCreateMutable(NULL, 0); CFTemp<CFDictionaryRef> arguments("{%O=%O, %O=#N}", kSecCodeSignerDetached, signature.get(), kSecCodeSignerIdentity); CFRef<SecCodeSignerRef> signer; MacOSError::check(SecCodeSignerCreate(arguments, (matchFlags & kAuthorityFlagWhitelistV2) ? kSecCSSignOpaque : kSecCSSignV1, &signer.aref())); MacOSError::check(SecCodeSignerAddSignature(signer, code, kSecCSDefaultFlags)); MacOSError::check(SecCodeSetDetachedSignature(code, signature, kSecCSDefaultFlags)); SecRequirementRef dr = NULL; SecCodeCopyDesignatedRequirement(code, kSecCSDefaultFlags, &dr); CFStringRef drs = NULL; SecRequirementCopyString(dr, kSecCSDefaultFlags, &drs); // if we're in GKE recording mode, save that signature and report its location if (SYSPOLICY_RECORDER_MODE_ENABLED()) { int status = recorder_code_unable; // ephemeral signature (not recorded) if (geteuid() == 0) { CFRef<CFUUIDRef> uuid = CFUUIDCreate(NULL); std::string sigfile = RECORDER_DIR + cfStringRelease(CFUUIDCreateString(NULL, uuid)) + ".tsig"; try { UnixPlusPlus::AutoFileDesc fd(sigfile, O_WRONLY | O_CREAT); fd.write(CFDataGetBytePtr(signature), CFDataGetLength(signature)); status = recorder_code_adhoc; // recorded signature SYSPOLICY_RECORDER_MODE_ADHOC_PATH(cfString(path).c_str(), type, sigfile.c_str()); } catch (...) { } } // now report the D probe itself CFRef<CFDictionaryRef> info; MacOSError::check(SecCodeCopySigningInformation(code, kSecCSDefaultFlags, &info.aref())); CFDataRef cdhash = CFDataRef(CFDictionaryGetValue(info, kSecCodeInfoUnique)); SYSPOLICY_RECORDER_MODE(cfString(path).c_str(), type, "", cdhash ? CFDataGetBytePtr(cdhash) : NULL, status); } return true; // it worked; we're now (well) signed } catch (...) { } return false; }
void PolicyEngine::evaluateCodeItem(SecStaticCodeRef code, CFURLRef path, AuthorityType type, SecAssessmentFlags flags, bool nested, CFMutableDictionaryRef result) { SQLite::Statement query(*this, "SELECT allow, requirement, id, label, expires, flags, disabled, filter_unsigned, remarks FROM scan_authority" " WHERE type = :type" " ORDER BY priority DESC;"); query.bind(":type").integer(type); SQLite3::int64 latentID = 0; // first (highest priority) disabled matching ID std::string latentLabel; // ... and associated label, if any while (query.nextRow()) { bool allow = int(query[0]); const char *reqString = query[1]; SQLite3::int64 id = query[2]; const char *label = query[3]; double expires = query[4]; sqlite3_int64 ruleFlags = query[5]; SQLite3::int64 disabled = query[6]; // const char *filter = query[7]; // const char *remarks = query[8]; CFRef<SecRequirementRef> requirement; MacOSError::check(SecRequirementCreateWithString(CFTempString(reqString), kSecCSDefaultFlags, &requirement.aref())); switch (OSStatus rc = SecStaticCodeCheckValidity(code, kSecCSBasicValidateOnly, requirement)) { case errSecSuccess: break; // rule match; process below case errSecCSReqFailed: continue; // rule does not apply case errSecCSVetoed: return; // nested code has failed to pass default: MacOSError::throwMe(rc); // general error; pass to caller } // if this rule is disabled, skip it but record the first matching one for posterity if (disabled && latentID == 0) { latentID = id; latentLabel = label ? label : ""; continue; } // current rule is first rule (in priority order) that matched. Apply it if (nested) // success, nothing to record return; CFRef<CFDictionaryRef> info; // as needed if (flags & kSecAssessmentFlagRequestOrigin) { if (!info) MacOSError::check(SecCodeCopySigningInformation(code, kSecCSSigningInformation, &info.aref())); if (CFArrayRef chain = CFArrayRef(CFDictionaryGetValue(info, kSecCodeInfoCertificates))) setOrigin(chain, result); } if (!(ruleFlags & kAuthorityFlagInhibitCache) && !(flags & kSecAssessmentFlagNoCache)) { // cache inhibit if (!info) MacOSError::check(SecCodeCopySigningInformation(code, kSecCSSigningInformation, &info.aref())); if (SecTrustRef trust = SecTrustRef(CFDictionaryGetValue(info, kSecCodeInfoTrust))) { CFRef<CFDictionaryRef> xinfo; MacOSError::check(SecTrustCopyExtendedResult(trust, &xinfo.aref())); if (CFDateRef limit = CFDateRef(CFDictionaryGetValue(xinfo, kSecTrustExpirationDate))) { this->recordOutcome(code, allow, type, min(expires, dateToJulian(limit)), id); } } } if (allow) { if (SYSPOLICY_ASSESS_OUTCOME_ACCEPT_ENABLED()) { if (!info) MacOSError::check(SecCodeCopySigningInformation(code, kSecCSSigningInformation, &info.aref())); CFDataRef cdhash = CFDataRef(CFDictionaryGetValue(info, kSecCodeInfoUnique)); SYSPOLICY_ASSESS_OUTCOME_ACCEPT(cfString(path).c_str(), type, label, cdhash ? CFDataGetBytePtr(cdhash) : NULL); } } else { if (SYSPOLICY_ASSESS_OUTCOME_DENY_ENABLED() || SYSPOLICY_RECORDER_MODE_ENABLED()) { if (!info) MacOSError::check(SecCodeCopySigningInformation(code, kSecCSSigningInformation, &info.aref())); CFDataRef cdhash = CFDataRef(CFDictionaryGetValue(info, kSecCodeInfoUnique)); std::string cpath = cfString(path); const void *hashp = cdhash ? CFDataGetBytePtr(cdhash) : NULL; SYSPOLICY_ASSESS_OUTCOME_DENY(cpath.c_str(), type, label, hashp); SYSPOLICY_RECORDER_MODE(cpath.c_str(), type, label, hashp, recorder_code_untrusted); } } cfadd(result, "{%O=%B}", kSecAssessmentAssessmentVerdict, allow); addAuthority(flags, result, label, id); return; } // no applicable authority (but signed, perhaps temporarily). Deny by default CFRef<CFDictionaryRef> info; MacOSError::check(SecCodeCopySigningInformation(code, kSecCSSigningInformation, &info.aref())); if (flags & kSecAssessmentFlagRequestOrigin) { if (CFArrayRef chain = CFArrayRef(CFDictionaryGetValue(info, kSecCodeInfoCertificates))) setOrigin(chain, result); } if (SYSPOLICY_ASSESS_OUTCOME_DEFAULT_ENABLED() || SYSPOLICY_RECORDER_MODE_ENABLED()) { CFDataRef cdhash = CFDataRef(CFDictionaryGetValue(info, kSecCodeInfoUnique)); const void *hashp = cdhash ? CFDataGetBytePtr(cdhash) : NULL; std::string cpath = cfString(path); SYSPOLICY_ASSESS_OUTCOME_DEFAULT(cpath.c_str(), type, latentLabel.c_str(), hashp); SYSPOLICY_RECORDER_MODE(cpath.c_str(), type, latentLabel.c_str(), hashp, 0); } if (!(flags & kSecAssessmentFlagNoCache)) this->recordOutcome(code, false, type, this->julianNow() + NEGATIVE_HOLD, latentID); cfadd(result, "{%O=%B}", kSecAssessmentAssessmentVerdict, false); addAuthority(flags, result, latentLabel.c_str(), latentID); }