// Creates a new *syscall.CertContext representing the leaf certificate in an in-memory
// certificate store containing itself and all of the intermediate certificates specified
// in the opts.Intermediates CertPool.
//
// A pointer to the in-memory store is available in the returned CertContext's Store field.
// The store is automatically freed when the CertContext is freed using
// syscall.CertFreeCertificateContext.
func createStoreContext(leaf *Certificate, opts *VerifyOptions) (*syscall.CertContext, error) {
var storeCtx *syscall.CertContext
leafCtx, err := syscall.CertCreateCertificateContext(syscall.X509_ASN_ENCODING|syscall.PKCS_7_ASN_ENCODING, &leaf.Raw[0], uint32(len(leaf.Raw)))
if err != nil {
return nil, err
}
defer syscall.CertFreeCertificateContext(leafCtx)
handle, err := syscall.CertOpenStore(syscall.CERT_STORE_PROV_MEMORY, 0, 0, syscall.CERT_STORE_DEFER_CLOSE_UNTIL_LAST_FREE_FLAG, 0)
if err != nil {
return nil, err
}
defer syscall.CertCloseStore(handle, 0)
err = syscall.CertAddCertificateContextToStore(handle, leafCtx, syscall.CERT_STORE_ADD_ALWAYS, &storeCtx)
if err != nil {
return nil, err
}
if opts.Intermediates != nil {
for _, intermediate := range opts.Intermediates.certs {
ctx, err := syscall.CertCreateCertificateContext(syscall.X509_ASN_ENCODING|syscall.PKCS_7_ASN_ENCODING, &intermediate.Raw[0], uint32(len(intermediate.Raw)))
if err != nil {
return nil, err
}
err = syscall.CertAddCertificateContextToStore(handle, ctx, syscall.CERT_STORE_ADD_ALWAYS, nil)
syscall.CertFreeCertificateContext(ctx)
if err != nil {
return nil, err
}
}
}
return storeCtx, nil
}
// systemVerify is like Verify, except that it uses CryptoAPI calls
// to build certificate chains and verify them.
func (c *Certificate) systemVerify(opts *VerifyOptions) (chains [][]*Certificate, err error) {
hasDNSName := opts != nil && len(opts.DNSName) > 0
storeCtx, err := createStoreContext(c, opts)
if err != nil {
return nil, err
}
defer syscall.CertFreeCertificateContext(storeCtx)
para := new(syscall.CertChainPara)
para.Size = uint32(unsafe.Sizeof(*para))
// If there's a DNSName set in opts, assume we're verifying
// a certificate from a TLS server.
if hasDNSName {
oids := []*byte{
&syscall.OID_PKIX_KP_SERVER_AUTH[0],
// Both IE and Chrome allow certificates with
// Server Gated Crypto as well. Some certificates
// in the wild require them.
&syscall.OID_SERVER_GATED_CRYPTO[0],
&syscall.OID_SGC_NETSCAPE[0],
}
para.RequestedUsage.Type = syscall.USAGE_MATCH_TYPE_OR
para.RequestedUsage.Usage.Length = uint32(len(oids))
para.RequestedUsage.Usage.UsageIdentifiers = &oids[0]
} else {
para.RequestedUsage.Type = syscall.USAGE_MATCH_TYPE_AND
para.RequestedUsage.Usage.Length = 0
para.RequestedUsage.Usage.UsageIdentifiers = nil
}
var verifyTime *syscall.Filetime
if opts != nil && !opts.CurrentTime.IsZero() {
ft := syscall.NsecToFiletime(opts.CurrentTime.UnixNano())
verifyTime = &ft
}
// CertGetCertificateChain will traverse Windows's root stores
// in an attempt to build a verified certificate chain. Once
// it has found a verified chain, it stops. MSDN docs on
// CERT_CHAIN_CONTEXT:
//
// When a CERT_CHAIN_CONTEXT is built, the first simple chain
// begins with an end certificate and ends with a self-signed
// certificate. If that self-signed certificate is not a root
// or otherwise trusted certificate, an attempt is made to
// build a new chain. CTLs are used to create the new chain
// beginning with the self-signed certificate from the original
// chain as the end certificate of the new chain. This process
// continues building additional simple chains until the first
// self-signed certificate is a trusted certificate or until
// an additional simple chain cannot be built.
//
// The result is that we'll only get a single trusted chain to
// return to our caller.
var chainCtx *syscall.CertChainContext
err = syscall.CertGetCertificateChain(syscall.Handle(0), storeCtx, verifyTime, storeCtx.Store, para, 0, 0, &chainCtx)
if err != nil {
return nil, err
}
defer syscall.CertFreeCertificateChain(chainCtx)
err = checkChainTrustStatus(c, chainCtx)
if err != nil {
return nil, err
}
if hasDNSName {
err = checkChainSSLServerPolicy(c, chainCtx, opts)
if err != nil {
return nil, err
}
}
chain, err := extractSimpleChain(chainCtx.Chains, int(chainCtx.ChainCount))
if err != nil {
return nil, err
}
chains = append(chains, chain)
return chains, nil
}