/*
* Verify a chain of DER-encoded certs.
*/
static OSStatus sslVerifyCertChain(
SSLContext *ctx)
{
OSStatus status;
SecTrustRef trust = NULL;
/* renegotiate - start with a new SecTrustRef */
CFReleaseNull(ctx->peerSecTrust);
/* on failure, we always return trust==NULL, so we don't check the returned status here */
sslCreateSecTrust(ctx, &trust);
if(trust==NULL) {
if(ctx->protocolSide == kSSLClientSide) {
/* No cert chain is always a trust failure on the server side */
status = errSSLXCertChainInvalid;
sslErrorLog("***Error: NULL server cert chain\n");
} else {
/* No cert chain on the client side is ok unless using kAlwaysAuthenticate */
if(ctx->clientAuth == kAlwaysAuthenticate) {
sslErrorLog("***Error: NULL client cert chain\n");
status = errSSLXCertChainInvalid;
} else {
status = noErr;
}
}
goto errOut;
}
if (!ctx->enableCertVerify) {
/* trivial case, this is caller's responsibility */
status = errSecSuccess;
goto errOut;
}
SecTrustResultType secTrustResult;
require_noerr(status = SecTrustEvaluate(trust, &secTrustResult), errOut);
switch (secTrustResult) {
case kSecTrustResultUnspecified:
/* cert chain valid, no special UserTrust assignments */
case kSecTrustResultProceed:
/* cert chain valid AND user explicitly trusts this */
status = errSecSuccess;
break;
case kSecTrustResultDeny:
case kSecTrustResultConfirm:
case kSecTrustResultRecoverableTrustFailure:
default:
if(ctx->allowAnyRoot) {
sslErrorLog("***Warning: accepting unverified cert chain\n");
status = errSecSuccess;
}
else {
#if !TARGET_OS_IPHONE
/*
* If the caller provided a list of trusted leaf certs, check them here
*/
if(ctx->trustedLeafCerts) {
if (sslGetMatchingCertInArray(SecTrustGetCertificateAtIndex(trust, 0),
ctx->trustedLeafCerts)) {
status = errSecSuccess;
goto errOut;
}
}
#endif
status = errSSLXCertChainInvalid;
}
/* Do we really need to return things like:
errSSLNoRootCert
errSSLUnknownRootCert
errSSLCertExpired
errSSLCertNotYetValid
errSSLHostNameMismatch
for our client to see what went wrong, or should we just always
return
errSSLXCertChainInvalid
when something is wrong? */
break;
}
errOut:
ctx->peerSecTrust = trust;
return status;
}
/*
* Verify a chain of DER-encoded certs.
* Last cert in a chain is the leaf; this must also be present
* in ctx->trustedCerts.
*
* If arePeerCerts is true, host name verification is enabled and we
* save the resulting SecTrustRef in ctx->peerSecTrust. Otherwise
* we're just validating our own certs; no host name checking and
* peerSecTrust is transient.
*/
extern OSStatus sslVerifyCertChain(
SSLContext *ctx,
CFArrayRef certChain,
bool arePeerCerts)
{
OSStatus status;
SecTrustRef trust = NULL;
assert(certChain);
if (arePeerCerts) {
/* renegotiate - start with a new SecTrustRef */
CFReleaseNull(ctx->peerSecTrust);
}
status = sslCreateSecTrust(ctx, certChain, arePeerCerts, &trust);
if (!ctx->enableCertVerify) {
/* trivial case, this is caller's responsibility */
status = noErr;
goto errOut;
}
SecTrustResultType secTrustResult;
require_noerr(status = SecTrustEvaluate(trust, &secTrustResult), errOut);
switch (secTrustResult) {
case kSecTrustResultUnspecified:
/* cert chain valid, no special UserTrust assignments */
case kSecTrustResultProceed:
/* cert chain valid AND user explicitly trusts this */
status = noErr;
break;
case kSecTrustResultDeny:
case kSecTrustResultConfirm:
case kSecTrustResultRecoverableTrustFailure:
default:
if(ctx->allowAnyRoot) {
sslErrorLog("***Warning: accepting unverified cert chain\n");
status = noErr;
}
else {
/*
* If the caller provided a list of trusted leaf certs, check them here
*/
if(ctx->trustedLeafCerts) {
if (sslGetMatchingCertInArray((SecCertificateRef)CFArrayGetValueAtIndex(certChain, 0),
ctx->trustedLeafCerts)) {
status = noErr;
goto errOut;
}
}
status = errSSLXCertChainInvalid;
}
/* Do we really need to return things like:
errSSLNoRootCert
errSSLUnknownRootCert
errSSLCertExpired
errSSLCertNotYetValid
errSSLHostNameMismatch
for our client to see what went wrong, or should we just always
return
errSSLXCertChainInvalid
when something is wrong? */
break;
}
errOut:
if (arePeerCerts)
ctx->peerSecTrust = trust;
else
CFReleaseSafe(trust);
return status;
}
