Esempio n. 1
0
void Download::Initialize (CFDataRef ticket,
						   SecureDownloadTrustSetupCallback setup,
						   void* setupContext,
						   SecureDownloadTrustEvaluateCallback evaluate,
						   void* evaluateContext)
{
	// decode the ticket
	SecCmsMessageRef cmsMessage = GetCmsMessageFromData (ticket);
	
	// get a policy
	SecPolicyRef policy = GetPolicy ();

	// parse the CMS message
	int contentLevelCount = SecCmsMessageContentLevelCount (cmsMessage);
	SecCmsSignedDataRef signedData;

	OSStatus result;
	
	int i = 0;
	while (i < contentLevelCount)
	{
		SecCmsContentInfoRef contentInfo = SecCmsMessageContentLevel (cmsMessage, i++);
		SECOidTag contentTypeTag = SecCmsContentInfoGetContentTypeTag (contentInfo);
		
		if (contentTypeTag != SEC_OID_PKCS7_SIGNED_DATA)
		{
			continue;
		}

		signedData = (SecCmsSignedDataRef) SecCmsContentInfoGetContent (contentInfo);
		if (signedData == NULL)
		{
			MacOSError::throwMe (errSecureDownloadInvalidTicket);
		}
		
		// import the certificates found in the cms message
		result = SecCmsSignedDataImportCerts (signedData, NULL, certUsageObjectSigner, true);
		if (result != 0)
		{
			MacOSError::throwMe (errSecureDownloadInvalidTicket);
		}
		
		int numberOfSigners = SecCmsSignedDataSignerInfoCount (signedData);
		int j;
		
		if (numberOfSigners == 0) // no signers?  This is a possible attack
		{
			MacOSError::throwMe (errSecureDownloadInvalidTicket);
		}
		
		for (j = 0; j < numberOfSigners; ++j)
		{
			SecTrustResultType resultType;
			
			// do basic verification of the message
			SecTrustRef trustRef;
			result = SecCmsSignedDataVerifySignerInfo (signedData, j, NULL, policy, &trustRef);
			
			// notify the user of the new trust ref
			if (setup != NULL)
			{
				SecureDownloadTrustCallbackResult tcResult = setup (trustRef, setupContext);
				switch (tcResult)
				{
					case kSecureDownloadDoNotEvaluateSigner:
						continue;
					
					case kSecureDownloadFailEvaluation:
						MacOSError::throwMe (errSecureDownloadInvalidTicket);
					
					case kSecureDownloadEvaluateSigner:
					break;
				}
			}
			
			if (result != 0)
			{
				MacOSError::throwMe (errSecureDownloadInvalidTicket);
			}
			
			result = SecTrustEvaluate (trustRef, &resultType);
			if (result != noErr)
			{
				MacOSError::throwMe (errSecureDownloadInvalidTicket);
			}
			
			if (evaluate != NULL)
			{
				resultType = evaluate (trustRef, resultType, evaluateContext);
			}
			
			GoOrNoGo (resultType);
		}
	}
	
	// extract the message 
	CSSM_DATA_PTR message = SecCmsMessageGetContent (cmsMessage);
	CFDataRef ticketData = CFDataCreateWithBytesNoCopy (NULL, message->Data, message->Length, kCFAllocatorNull);
	CheckCFThingForNULL (ticketData);
	
	ParseTicket (ticketData);

	// setup for hashing
	CC_SHA256_Init (&mSHA256Context);
	
	// clean up
	CFRelease (ticketData);
	SecCmsMessageDestroy (cmsMessage);
}
/*
 * Obtain the status of a CMS message's signature. A CMS message can
 * be signed my multiple signers; this function returns the status
 * associated with signer 'n' as indicated by the signerIndex parameter.
 */
OSStatus CMSDecoderCopySignerStatus(
                                    CMSDecoderRef		cmsDecoder,
                                    size_t				signerIndex,
                                    CFTypeRef			policyOrArray,
                                    Boolean				evaluateSecTrust,
                                    CMSSignerStatus		*signerStatus,			/* optional; RETURNED */
                                    SecTrustRef			*secTrust,				/* optional; RETURNED */
                                    OSStatus			*certVerifyResultCode)	/* optional; RETURNED */
{
	if((cmsDecoder == NULL) || (cmsDecoder->decState != DS_Final)) {
		return errSecParam;
	}
	
	/* initialize return values */
	if(signerStatus) {
		*signerStatus = kCMSSignerUnsigned;
	}
	if(secTrust) {
		*secTrust = NULL;
	}
	if(certVerifyResultCode) {
		*certVerifyResultCode = 0;
	}
	
	if(cmsDecoder->signedData == NULL) {
		*signerStatus = kCMSSignerUnsigned;	/* redundant, I know, but explicit */
		return errSecSuccess;
	}
	ASSERT(cmsDecoder->numSigners > 0);
	if(signerIndex >= cmsDecoder->numSigners) {
		*signerStatus = kCMSSignerInvalidIndex;
		return errSecSuccess;
	}
	if(!SecCmsSignedDataHasDigests(cmsDecoder->signedData)) {
		*signerStatus = kCMSSignerNeedsDetachedContent;
		return errSecSuccess;
	}
	
	/*
	 * OK, we should be able to verify this signerInfo.
	 * I think we have to do the SecCmsSignedDataVerifySignerInfo first
	 * in order get all the cert pieces into place before returning them
	 * to the caller.
	 */
	SecTrustRef theTrust = NULL;
	OSStatus vfyRtn = SecCmsSignedDataVerifySignerInfo(cmsDecoder->signedData,
                                                       (int)signerIndex,
                                                       /*
                                                        * FIXME this cast should not be necessary, but libsecurity_smime
                                                        * declares this argument as a SecKeychainRef
                                                        */
                                                       (SecKeychainRef)cmsDecoder->keychainOrArray,
                                                       policyOrArray,
                                                       &theTrust);
    /* Subsequent errors to errOut: */
    
	/*
	 * NOTE the smime lib did NOT evaluate that SecTrust - it only does
	 * SecTrustEvaluate() if we don't ask for a copy.
	 *
	 * FIXME deal with multitudes of status returns here...for now, proceed with
	 * obtaining components the caller wants and assume that a nonzero vfyRtn
	 * means "bad signature".
	 */
	OSStatus ortn = errSecSuccess;
	SecTrustResultType secTrustResult;
	CSSM_RETURN tpVfyStatus = CSSM_OK;
	OSStatus evalRtn;
	
	if(secTrust != NULL) {
		*secTrust = theTrust;
		/* we'll release our reference at the end */
		if (theTrust)
			CFRetain(theTrust);
	}
	SecCmsSignerInfoRef signerInfo =
    SecCmsSignedDataGetSignerInfo(cmsDecoder->signedData, (int)signerIndex);
	if(signerInfo == NULL) {
		/* should never happen */
		ASSERT(0);
		dprintf("CMSDecoderCopySignerStatus: no signerInfo\n");
		ortn = errSecInternalComponent;
		goto errOut;
	}
    
	/* now do the actual cert verify */
	if(evaluateSecTrust) {
		evalRtn = SecTrustEvaluate(theTrust, &secTrustResult);
		if(evalRtn) {
			/* should never happen */
			CSSM_PERROR("SecTrustEvaluate", evalRtn);
			dprintf("CMSDecoderCopySignerStatus: SecTrustEvaluate error\n");
			ortn = errSecInternalComponent;
			goto errOut;
		}
		switch(secTrustResult) {
			case kSecTrustResultUnspecified:
				/* cert chain valid, no special UserTrust assignments */
			case kSecTrustResultProceed:
				/* cert chain valid AND user explicitly trusts this */
				break;
			case kSecTrustResultDeny:
				tpVfyStatus = CSSMERR_APPLETP_TRUST_SETTING_DENY;
				break;
			case kSecTrustResultConfirm:
				dprintf("SecTrustEvaluate reported confirm\n");
				tpVfyStatus = CSSMERR_TP_NOT_TRUSTED;
				break;
			default:
			{
				/* get low-level TP error */
				OSStatus tpStatus;
				ortn = SecTrustGetCssmResultCode(theTrust, &tpStatus);
				if(ortn) {
					CSSM_PERROR("SecTrustGetCssmResultCode", ortn);
				}
				else {
					tpVfyStatus = tpStatus;
				}
				CSSM_PERROR("TP status after SecTrustEvaluate", tpVfyStatus);
				break;
			}
		} 	/* switch(secTrustResult) */
	}		/* evaluateSecTrust true */
	if(certVerifyResultCode != NULL) {
		*certVerifyResultCode = tpVfyStatus;
	}
	
	/* cook up global status based on vfyRtn and tpVfyStatus */
	if(signerStatus != NULL) {
		if((vfyRtn == errSecSuccess) && (tpVfyStatus == CSSM_OK))  {
			*signerStatus = kCMSSignerValid;
		}
		else if(vfyRtn != errSecSuccess) {
			/* this could mean other things, but for now... */
			*signerStatus = kCMSSignerInvalidSignature;
		}
		else {
			*signerStatus = kCMSSignerInvalidCert;
		}
	}
errOut:
	CFRELEASE(theTrust);
	return ortn;
}