94 lines
2.9 KiB
Go
94 lines
2.9 KiB
Go
package ca
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import (
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"bytes"
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"crypto/x509"
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"fmt"
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"github.com/hashicorp/consul/agent/connect"
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)
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func validateSetIntermediate(intermediatePEM, rootPEM string, spiffeID *connect.SpiffeIDSigning) error {
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// Get the key from the incoming intermediate cert so we can compare it
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// to the currently stored key.
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intermediate, err := connect.ParseCert(intermediatePEM)
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if err != nil {
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return fmt.Errorf("error parsing intermediate PEM: %v", err)
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}
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// Validate the remaining fields and make sure the intermediate validates against
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// the given root cert.
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if !intermediate.IsCA {
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return fmt.Errorf("intermediate is not a CA certificate")
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}
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if uriCount := len(intermediate.URIs); uriCount != 1 {
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return fmt.Errorf("incoming intermediate cert has unexpected number of URIs: %d", uriCount)
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}
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if got, want := intermediate.URIs[0].String(), spiffeID.URI().String(); got != want {
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return fmt.Errorf("incoming cert URI %q does not match current URI: %q", got, want)
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}
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pool := x509.NewCertPool()
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pool.AppendCertsFromPEM([]byte(rootPEM))
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_, err = intermediate.Verify(x509.VerifyOptions{
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Roots: pool,
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})
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if err != nil {
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return fmt.Errorf("could not verify intermediate cert against root: %v", err)
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}
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return nil
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}
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func validateIntermediateSignedByPrivateKey(intermediatePEM string, privateKey string) error {
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intermediate, err := connect.ParseCert(intermediatePEM)
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if err != nil {
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return fmt.Errorf("error parsing intermediate PEM: %v", err)
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}
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privKey, err := connect.ParseSigner(privateKey)
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if err != nil {
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return err
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}
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// Compare the two keys to make sure they match.
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b1, err := x509.MarshalPKIXPublicKey(intermediate.PublicKey)
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if err != nil {
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return err
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}
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b2, err := x509.MarshalPKIXPublicKey(privKey.Public())
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if err != nil {
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return err
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}
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if !bytes.Equal(b1, b2) {
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return fmt.Errorf("intermediate cert is for a different private key")
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}
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return nil
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}
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func validateSignIntermediate(csr *x509.CertificateRequest, spiffeID *connect.SpiffeIDSigning) error {
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// We explicitly _don't_ require that the CSR has a valid SPIFFE signing URI
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// SAN because AWS PCA doesn't let us set one :(. We need to relax it here
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// otherwise it would be impossible to migrate from built-in provider to AWS
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// in multiple DCs without downtime. Nothing in Connect actually checks that
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// currently so this is OK for now but it's sad we have to break the SPIFFE
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// spec for AWS sake. Hopefully they'll add that ability soon.
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uriCount := len(csr.URIs)
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if uriCount > 0 {
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if uriCount != 1 {
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return fmt.Errorf("incoming CSR has unexpected number of URIs: %d", uriCount)
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}
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certURI, err := connect.ParseCertURI(csr.URIs[0])
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if err != nil {
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return err
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}
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// Verify that the trust domain is valid.
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if !spiffeID.CanSign(certURI) {
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return fmt.Errorf("incoming CSR domain %q is not valid for our domain %q",
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certURI.URI().String(), spiffeID.URI().String())
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}
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}
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return nil
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}
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