package ca import ( "bytes" "context" "crypto/x509" "encoding/pem" "fmt" "io/ioutil" "net/http" "os" "strings" "time" "github.com/hashicorp/go-hclog" vaultapi "github.com/hashicorp/vault/api" "github.com/mitchellh/mapstructure" "github.com/hashicorp/consul/agent/connect" "github.com/hashicorp/consul/agent/structs" "github.com/hashicorp/consul/lib/decode" ) const ( VaultCALeafCertRole = "leaf-cert" VaultAuthMethodTypeAliCloud = "alicloud" VaultAuthMethodTypeAppRole = "approle" VaultAuthMethodTypeAWS = "aws" VaultAuthMethodTypeAzure = "azure" VaultAuthMethodTypeCloudFoundry = "cf" VaultAuthMethodTypeGitHub = "github" VaultAuthMethodTypeGCP = "gcp" VaultAuthMethodTypeJWT = "jwt" VaultAuthMethodTypeKerberos = "kerberos" VaultAuthMethodTypeKubernetes = "kubernetes" VaultAuthMethodTypeLDAP = "ldap" VaultAuthMethodTypeOCI = "oci" VaultAuthMethodTypeOkta = "okta" VaultAuthMethodTypeRadius = "radius" VaultAuthMethodTypeTLS = "cert" VaultAuthMethodTypeToken = "token" VaultAuthMethodTypeUserpass = "userpass" defaultK8SServiceAccountTokenPath = "/var/run/secrets/kubernetes.io/serviceaccount/token" ) var ErrBackendNotMounted = fmt.Errorf("backend not mounted") var ErrBackendNotInitialized = fmt.Errorf("backend not initialized") type VaultProvider struct { config *structs.VaultCAProviderConfig client *vaultapi.Client shutdown func() isPrimary bool clusterID string spiffeID *connect.SpiffeIDSigning setupIntermediatePKIPathDone bool logger hclog.Logger } func NewVaultProvider(logger hclog.Logger) *VaultProvider { return &VaultProvider{ shutdown: func() {}, logger: logger, } } func vaultTLSConfig(config *structs.VaultCAProviderConfig) *vaultapi.TLSConfig { return &vaultapi.TLSConfig{ CACert: config.CAFile, CAPath: config.CAPath, ClientCert: config.CertFile, ClientKey: config.KeyFile, Insecure: config.TLSSkipVerify, TLSServerName: config.TLSServerName, } } // Configure sets up the provider using the given configuration. func (v *VaultProvider) Configure(cfg ProviderConfig) error { config, err := ParseVaultCAConfig(cfg.RawConfig) if err != nil { return err } clientConf := &vaultapi.Config{ Address: config.Address, } err = clientConf.ConfigureTLS(vaultTLSConfig(config)) if err != nil { return err } client, err := vaultapi.NewClient(clientConf) if err != nil { return err } if config.AuthMethod != nil { loginResp, err := vaultLogin(client, config.AuthMethod) if err != nil { return err } config.Token = loginResp.Auth.ClientToken } client.SetToken(config.Token) // We don't want to set the namespace if it's empty to prevent potential // unknown behavior (what does Vault do with an empty namespace). The Vault // client also makes sure the inputs are not empty strings so let's do the // same. if config.Namespace != "" { client.SetNamespace(config.Namespace) } v.config = config v.client = client v.isPrimary = cfg.IsPrimary v.clusterID = cfg.ClusterID v.spiffeID = connect.SpiffeIDSigningForCluster(v.clusterID) // Look up the token to see if we can auto-renew its lease. secret, err := client.Auth().Token().LookupSelf() if err != nil { return err } else if secret == nil { return fmt.Errorf("could not look up Vault provider token: not found") } var token struct { Renewable bool TTL int } if err := mapstructure.Decode(secret.Data, &token); err != nil { return err } // Set up a renewer to renew the token automatically, if supported. if token.Renewable || config.AuthMethod != nil { lifetimeWatcher, err := client.NewLifetimeWatcher(&vaultapi.LifetimeWatcherInput{ Secret: &vaultapi.Secret{ Auth: &vaultapi.SecretAuth{ ClientToken: config.Token, Renewable: token.Renewable, LeaseDuration: secret.LeaseDuration, }, }, Increment: token.TTL, RenewBehavior: vaultapi.RenewBehaviorIgnoreErrors, }) if err != nil { return fmt.Errorf("error beginning Vault provider token renewal: %v", err) } ctx, cancel := context.WithCancel(context.Background()) v.shutdown = cancel go v.renewToken(ctx, lifetimeWatcher) } return nil } func (v *VaultProvider) ValidateConfigUpdate(prevRaw, nextRaw map[string]interface{}) error { prev, err := ParseVaultCAConfig(prevRaw) if err != nil { return fmt.Errorf("failed to parse existing CA config: %w", err) } next, err := ParseVaultCAConfig(nextRaw) if err != nil { return fmt.Errorf("failed to parse new CA config: %w", err) } if prev.RootPKIPath != next.RootPKIPath { return nil } if prev.PrivateKeyType != "" && prev.PrivateKeyType != connect.DefaultPrivateKeyType { if prev.PrivateKeyType != next.PrivateKeyType { return fmt.Errorf("cannot update the PrivateKeyType field without changing RootPKIPath") } } if prev.PrivateKeyBits != 0 && prev.PrivateKeyBits != connect.DefaultPrivateKeyBits { if prev.PrivateKeyBits != next.PrivateKeyBits { return fmt.Errorf("cannot update the PrivateKeyBits field without changing RootPKIPath") } } return nil } // renewToken uses a vaultapi.LifetimeWatcher to repeatedly renew our token's lease. // If the token can no longer be renewed and auth method is set, // it will re-authenticate to Vault using the auth method and restart the renewer with the new token. func (v *VaultProvider) renewToken(ctx context.Context, watcher *vaultapi.LifetimeWatcher) { go watcher.Start() defer watcher.Stop() for { select { case <-ctx.Done(): return case err := <-watcher.DoneCh(): if err != nil { v.logger.Error("Error renewing token for Vault provider", "error", err) } // If the watcher has exited and auth method is enabled, // re-authenticate using the auth method and set up a new watcher. if v.config.AuthMethod != nil { // Login to Vault using the auth method. loginResp, err := vaultLogin(v.client, v.config.AuthMethod) if err != nil { v.logger.Error("Error login in to Vault with %q auth method", v.config.AuthMethod.Type) // Restart the watcher. go watcher.Start() continue } // Set the new token for the vault client. v.client.SetToken(loginResp.Auth.ClientToken) v.logger.Info("Successfully re-authenticated with Vault using auth method") // Start the new watcher for the new token. watcher, err = v.client.NewLifetimeWatcher(&vaultapi.LifetimeWatcherInput{ Secret: loginResp, RenewBehavior: vaultapi.RenewBehaviorIgnoreErrors, }) if err != nil { v.logger.Error("Error starting token renewal process") go watcher.Start() continue } } // Restart the watcher. go watcher.Start() case <-watcher.RenewCh(): v.logger.Info("Successfully renewed token for Vault provider") } } } // State implements Provider. Vault provider needs no state other than the // user-provided config currently. func (v *VaultProvider) State() (map[string]string, error) { return nil, nil } // GenerateRoot mounts and initializes a new root PKI backend if needed. func (v *VaultProvider) GenerateRoot() (RootResult, error) { if !v.isPrimary { return RootResult{}, fmt.Errorf("provider is not the root certificate authority") } // Set up the root PKI backend if necessary. rootPEM, err := v.getCA(v.config.RootPKIPath) switch err { case ErrBackendNotMounted: err := v.client.Sys().Mount(v.config.RootPKIPath, &vaultapi.MountInput{ Type: "pki", Description: "root CA backend for Consul Connect", Config: vaultapi.MountConfigInput{ // the max lease ttl denotes the maximum ttl that secrets are created from the engine // the default lease ttl is the kind of ttl that will *reliably* set the ttl to v.config.RootCertTTL // https://www.vaultproject.io/docs/secrets/pki#configure-a-ca-certificate MaxLeaseTTL: v.config.RootCertTTL.String(), DefaultLeaseTTL: v.config.RootCertTTL.String(), }, }) if err != nil { return RootResult{}, err } fallthrough case ErrBackendNotInitialized: uid, err := connect.CompactUID() if err != nil { return RootResult{}, err } _, err = v.client.Logical().Write(v.config.RootPKIPath+"root/generate/internal", map[string]interface{}{ "common_name": connect.CACN("vault", uid, v.clusterID, v.isPrimary), "uri_sans": v.spiffeID.URI().String(), "key_type": v.config.PrivateKeyType, "key_bits": v.config.PrivateKeyBits, }) if err != nil { return RootResult{}, err } // retrieve the newly generated cert so that we can return it // TODO: is this already available from the Local().Write() above? rootPEM, err = v.getCA(v.config.RootPKIPath) if err != nil { return RootResult{}, err } default: if err != nil { return RootResult{}, err } } return RootResult{PEM: rootPEM}, nil } // GenerateIntermediateCSR creates a private key and generates a CSR // for another datacenter's root to sign, overwriting the intermediate backend // in the process. func (v *VaultProvider) GenerateIntermediateCSR() (string, error) { if v.isPrimary { return "", fmt.Errorf("provider is the root certificate authority, " + "cannot generate an intermediate CSR") } return v.generateIntermediateCSR() } func (v *VaultProvider) setupIntermediatePKIPath() error { if v.setupIntermediatePKIPathDone { return nil } mounts, err := v.client.Sys().ListMounts() if err != nil { return err } // Mount the backend if it isn't mounted already. if _, ok := mounts[v.config.IntermediatePKIPath]; !ok { err := v.client.Sys().Mount(v.config.IntermediatePKIPath, &vaultapi.MountInput{ Type: "pki", Description: "intermediate CA backend for Consul Connect", Config: vaultapi.MountConfigInput{ MaxLeaseTTL: v.config.IntermediateCertTTL.String(), }, }) if err != nil { return err } } // Create the role for issuing leaf certs if it doesn't exist yet rolePath := v.config.IntermediatePKIPath + "roles/" + VaultCALeafCertRole role, err := v.client.Logical().Read(rolePath) if err != nil { return err } if role == nil { _, err := v.client.Logical().Write(rolePath, map[string]interface{}{ "allow_any_name": true, "allowed_uri_sans": "spiffe://*", "key_type": "any", "max_ttl": v.config.LeafCertTTL.String(), "no_store": true, "require_cn": false, }) if err != nil { return err } } v.setupIntermediatePKIPathDone = true return nil } func (v *VaultProvider) generateIntermediateCSR() (string, error) { err := v.setupIntermediatePKIPath() if err != nil { return "", err } // Generate a new intermediate CSR for the root to sign. uid, err := connect.CompactUID() if err != nil { return "", err } data, err := v.client.Logical().Write(v.config.IntermediatePKIPath+"intermediate/generate/internal", map[string]interface{}{ "common_name": connect.CACN("vault", uid, v.clusterID, v.isPrimary), "key_type": v.config.PrivateKeyType, "key_bits": v.config.PrivateKeyBits, "uri_sans": v.spiffeID.URI().String(), }) if err != nil { return "", err } if data == nil || data.Data["csr"] == "" { return "", fmt.Errorf("got empty value when generating intermediate CSR") } csr, ok := data.Data["csr"].(string) if !ok { return "", fmt.Errorf("csr result is not a string") } return csr, nil } // SetIntermediate writes the incoming intermediate and root certificates to the // intermediate backend (as a chain). func (v *VaultProvider) SetIntermediate(intermediatePEM, rootPEM string) error { if v.isPrimary { return fmt.Errorf("cannot set an intermediate using another root in the primary datacenter") } err := validateSetIntermediate(intermediatePEM, rootPEM, v.spiffeID) if err != nil { return err } _, err = v.client.Logical().Write(v.config.IntermediatePKIPath+"intermediate/set-signed", map[string]interface{}{ "certificate": intermediatePEM, }) if err != nil { return err } return nil } // ActiveIntermediate returns the current intermediate certificate. func (v *VaultProvider) ActiveIntermediate() (string, error) { if err := v.setupIntermediatePKIPath(); err != nil { return "", err } cert, err := v.getCA(v.config.IntermediatePKIPath) // This error is expected when calling initializeSecondaryCA for the // first time. It means that the backend is mounted and ready, but // there is no intermediate. // This error is swallowed because there is nothing the caller can do // about it. The caller needs to handle the empty cert though and // create an intermediate CA. if err == ErrBackendNotInitialized { return "", nil } return cert, err } // getCA returns the raw CA cert for the given endpoint if there is one. // We have to use the raw NewRequest call here instead of Logical().Read // because the endpoint only returns the raw PEM contents of the CA cert // and not the typical format of the secrets endpoints. func (v *VaultProvider) getCA(path string) (string, error) { req := v.client.NewRequest("GET", "/v1/"+path+"/ca/pem") resp, err := v.client.RawRequest(req) if resp != nil { defer resp.Body.Close() } if resp != nil && resp.StatusCode == http.StatusNotFound { return "", ErrBackendNotMounted } if err != nil { return "", err } bytes, err := ioutil.ReadAll(resp.Body) if err != nil { return "", err } root := EnsureTrailingNewline(string(bytes)) if root == "" { return "", ErrBackendNotInitialized } return root, nil } // GenerateIntermediate mounts the configured intermediate PKI backend if // necessary, then generates and signs a new CA CSR using the root PKI backend // and updates the intermediate backend to use that new certificate. func (v *VaultProvider) GenerateIntermediate() (string, error) { csr, err := v.generateIntermediateCSR() if err != nil { return "", err } // Sign the CSR with the root backend. intermediate, err := v.client.Logical().Write(v.config.RootPKIPath+"root/sign-intermediate", map[string]interface{}{ "csr": csr, "use_csr_values": true, "format": "pem_bundle", "ttl": v.config.IntermediateCertTTL.String(), }) if err != nil { return "", err } if intermediate == nil || intermediate.Data["certificate"] == "" { return "", fmt.Errorf("got empty value when generating intermediate certificate") } // Set the intermediate backend to use the new certificate. _, err = v.client.Logical().Write(v.config.IntermediatePKIPath+"intermediate/set-signed", map[string]interface{}{ "certificate": intermediate.Data["certificate"], }) if err != nil { return "", err } return v.ActiveIntermediate() } // Sign calls the configured role in the intermediate PKI backend to issue // a new leaf certificate based on the provided CSR, with the issuing // intermediate CA cert attached. func (v *VaultProvider) Sign(csr *x509.CertificateRequest) (string, error) { connect.HackSANExtensionForCSR(csr) var pemBuf bytes.Buffer if err := pem.Encode(&pemBuf, &pem.Block{Type: "CERTIFICATE REQUEST", Bytes: csr.Raw}); err != nil { return "", err } // Use the leaf cert role to sign a new cert for this CSR. response, err := v.client.Logical().Write(v.config.IntermediatePKIPath+"sign/"+VaultCALeafCertRole, map[string]interface{}{ "csr": pemBuf.String(), "ttl": v.config.LeafCertTTL.String(), }) if err != nil { return "", fmt.Errorf("error issuing cert: %v", err) } if response == nil || response.Data["certificate"] == "" || response.Data["issuing_ca"] == "" { return "", fmt.Errorf("certificate info returned from Vault was blank") } cert, ok := response.Data["certificate"].(string) if !ok { return "", fmt.Errorf("certificate was not a string") } return EnsureTrailingNewline(cert), nil } // SignIntermediate returns a signed CA certificate with a path length constraint // of 0 to ensure that the certificate cannot be used to generate further CA certs. func (v *VaultProvider) SignIntermediate(csr *x509.CertificateRequest) (string, error) { err := validateSignIntermediate(csr, v.spiffeID) if err != nil { return "", err } var pemBuf bytes.Buffer err = pem.Encode(&pemBuf, &pem.Block{Type: "CERTIFICATE REQUEST", Bytes: csr.Raw}) if err != nil { return "", err } // Sign the CSR with the root backend. data, err := v.client.Logical().Write(v.config.RootPKIPath+"root/sign-intermediate", map[string]interface{}{ "csr": pemBuf.String(), "use_csr_values": true, "format": "pem_bundle", "max_path_length": 0, "ttl": v.config.IntermediateCertTTL.String(), }) if err != nil { return "", err } if data == nil || data.Data["certificate"] == "" { return "", fmt.Errorf("got empty value when generating intermediate certificate") } intermediate, ok := data.Data["certificate"].(string) if !ok { return "", fmt.Errorf("signed intermediate result is not a string") } return EnsureTrailingNewline(intermediate), nil } // CrossSignCA takes a CA certificate and cross-signs it to form a trust chain // back to our active root. func (v *VaultProvider) CrossSignCA(cert *x509.Certificate) (string, error) { rootPEM, err := v.getCA(v.config.RootPKIPath) if err != nil { return "", err } rootCert, err := connect.ParseCert(rootPEM) if err != nil { return "", fmt.Errorf("error parsing root cert: %v", err) } if rootCert.NotAfter.Before(time.Now()) { return "", fmt.Errorf("root certificate is expired") } var pemBuf bytes.Buffer err = pem.Encode(&pemBuf, &pem.Block{Type: "CERTIFICATE", Bytes: cert.Raw}) if err != nil { return "", err } // Have the root PKI backend sign this cert. response, err := v.client.Logical().Write(v.config.RootPKIPath+"root/sign-self-issued", map[string]interface{}{ "certificate": pemBuf.String(), }) if err != nil { return "", fmt.Errorf("error having Vault cross-sign cert: %v", err) } if response == nil || response.Data["certificate"] == "" { return "", fmt.Errorf("certificate info returned from Vault was blank") } xcCert, ok := response.Data["certificate"].(string) if !ok { return "", fmt.Errorf("certificate was not a string") } return EnsureTrailingNewline(xcCert), nil } // SupportsCrossSigning implements Provider func (v *VaultProvider) SupportsCrossSigning() (bool, error) { return true, nil } // Cleanup unmounts the configured intermediate PKI backend. It's fine to tear // this down and recreate it on small config changes because the intermediate // certs get bundled with the leaf certs, so there's no cost to the CA changing. func (v *VaultProvider) Cleanup(providerTypeChange bool, otherConfig map[string]interface{}) error { v.Stop() if !providerTypeChange { newConfig, err := ParseVaultCAConfig(otherConfig) if err != nil { return err } // if the intermeidate PKI path isn't changing we don't want to delete it as // Cleanup is called after initializing the new provider if newConfig.IntermediatePKIPath == v.config.IntermediatePKIPath { return nil } } err := v.client.Sys().Unmount(v.config.IntermediatePKIPath) switch err { case ErrBackendNotMounted, ErrBackendNotInitialized: // suppress these errors if we didn't finish initialization before return nil default: return err } } // Stop shuts down the token renew goroutine. func (v *VaultProvider) Stop() { v.shutdown() } func (v *VaultProvider) PrimaryUsesIntermediate() {} func ParseVaultCAConfig(raw map[string]interface{}) (*structs.VaultCAProviderConfig, error) { config := structs.VaultCAProviderConfig{ CommonCAProviderConfig: defaultCommonConfig(), } decodeConf := &mapstructure.DecoderConfig{ DecodeHook: mapstructure.ComposeDecodeHookFunc( structs.ParseDurationFunc(), decode.HookTranslateKeys, ), Result: &config, WeaklyTypedInput: true, } decoder, err := mapstructure.NewDecoder(decodeConf) if err != nil { return nil, err } if err := decoder.Decode(raw); err != nil { return nil, fmt.Errorf("error decoding config: %s", err) } if config.Token == "" && config.AuthMethod == nil { return nil, fmt.Errorf("must provide a Vault token or configure a Vault auth method") } if config.Token != "" && config.AuthMethod != nil { return nil, fmt.Errorf("only one of Vault token or Vault auth method can be provided, but not both") } if config.RootPKIPath == "" { return nil, fmt.Errorf("must provide a valid path to a root PKI backend") } if !strings.HasSuffix(config.RootPKIPath, "/") { config.RootPKIPath += "/" } if config.IntermediatePKIPath == "" { return nil, fmt.Errorf("must provide a valid path for the intermediate PKI backend") } if !strings.HasSuffix(config.IntermediatePKIPath, "/") { config.IntermediatePKIPath += "/" } if err := config.CommonCAProviderConfig.Validate(); err != nil { return nil, err } return &config, nil } func vaultLogin(client *vaultapi.Client, authMethod *structs.VaultAuthMethod) (*vaultapi.Secret, error) { // Adapted from https://www.vaultproject.io/docs/auth/kubernetes#code-example loginPath, err := configureVaultAuthMethod(authMethod) if err != nil { return nil, err } resp, err := client.Logical().Write(loginPath, authMethod.Params) if err != nil { return nil, err } if resp == nil || resp.Auth == nil || resp.Auth.ClientToken == "" { return nil, fmt.Errorf("login response did not return client token") } return resp, nil } func configureVaultAuthMethod(authMethod *structs.VaultAuthMethod) (loginPath string, err error) { if authMethod.MountPath == "" { authMethod.MountPath = authMethod.Type } switch authMethod.Type { case VaultAuthMethodTypeKubernetes: // For the Kubernetes Auth method, we will try to read the JWT token // from the default service account file location if jwt was not provided. if jwt, ok := authMethod.Params["jwt"]; !ok || jwt == "" { serviceAccountToken, err := os.ReadFile(defaultK8SServiceAccountTokenPath) if err != nil { return "", err } authMethod.Params["jwt"] = string(serviceAccountToken) } loginPath = fmt.Sprintf("auth/%s/login", authMethod.MountPath) // These auth methods require a username for the login API path. case VaultAuthMethodTypeLDAP, VaultAuthMethodTypeUserpass, VaultAuthMethodTypeOkta, VaultAuthMethodTypeRadius: // Get username from the params. if username, ok := authMethod.Params["username"]; ok { loginPath = fmt.Sprintf("auth/%s/login/%s", authMethod.MountPath, username) } else { return "", fmt.Errorf("failed to get 'username' from auth method params") } // This auth method requires a role for the login API path. case VaultAuthMethodTypeOCI: if role, ok := authMethod.Params["role"]; ok { loginPath = fmt.Sprintf("auth/%s/login/%s", authMethod.MountPath, role) } else { return "", fmt.Errorf("failed to get 'role' from auth method params") } case VaultAuthMethodTypeToken: return "", fmt.Errorf("'token' auth method is not supported via auth method configuration; " + "please provide the token with the 'token' parameter in the CA configuration") // The rest of the auth methods use auth/ login API path. case VaultAuthMethodTypeAliCloud, VaultAuthMethodTypeAppRole, VaultAuthMethodTypeAWS, VaultAuthMethodTypeAzure, VaultAuthMethodTypeCloudFoundry, VaultAuthMethodTypeGitHub, VaultAuthMethodTypeGCP, VaultAuthMethodTypeJWT, VaultAuthMethodTypeKerberos, VaultAuthMethodTypeTLS: loginPath = fmt.Sprintf("auth/%s/login", authMethod.MountPath) default: return "", fmt.Errorf("auth method %q is not supported", authMethod.Type) } return }