open-consul/agent/connect/ca/provider_vault.go

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2018-06-13 08:40:03 +00:00
package ca
import (
"bytes"
"crypto/x509"
"encoding/pem"
"fmt"
"io/ioutil"
"net/http"
"strings"
"github.com/hashicorp/consul/agent/connect"
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"github.com/hashicorp/consul/agent/structs"
vaultapi "github.com/hashicorp/vault/api"
"github.com/mitchellh/mapstructure"
)
const VaultCALeafCertRole = "leaf-cert"
var ErrBackendNotMounted = fmt.Errorf("backend not mounted")
var ErrBackendNotInitialized = fmt.Errorf("backend not initialized")
type VaultProvider struct {
config *structs.VaultCAProviderConfig
client *vaultapi.Client
clusterId string
}
// NewVaultProvider returns a vault provider with its root and intermediate PKI
// backends mounted and initialized. If the root backend is not set up already,
// it will be mounted/generated as needed, but any existing state will not be
// overwritten.
func NewVaultProvider(rawConfig map[string]interface{}, clusterId string) (*VaultProvider, error) {
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conf, err := ParseVaultCAConfig(rawConfig)
if err != nil {
return nil, err
}
// todo(kyhavlov): figure out the right way to pass the TLS config
clientConf := &vaultapi.Config{
Address: conf.Address,
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}
client, err := vaultapi.NewClient(clientConf)
if err != nil {
return nil, err
}
client.SetToken(conf.Token)
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provider := &VaultProvider{
config: conf,
client: client,
clusterId: clusterId,
}
// Set up the root PKI backend if necessary.
_, err = provider.ActiveRoot()
switch err {
case ErrBackendNotMounted:
err := client.Sys().Mount(conf.RootPKIPath, &vaultapi.MountInput{
Type: "pki",
Description: "root CA backend for Consul Connect",
Config: vaultapi.MountConfigInput{
MaxLeaseTTL: "8760h",
},
})
if err != nil {
return nil, err
}
fallthrough
case ErrBackendNotInitialized:
spiffeID := connect.SpiffeIDSigning{ClusterID: clusterId, Domain: "consul"}
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_, err := client.Logical().Write(conf.RootPKIPath+"root/generate/internal", map[string]interface{}{
"uri_sans": spiffeID.URI().String(),
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})
if err != nil {
return nil, err
}
default:
if err != nil {
return nil, err
}
}
// Set up the intermediate backend.
if _, err := provider.GenerateIntermediate(); err != nil {
return nil, err
}
return provider, nil
}
func (v *VaultProvider) ActiveRoot() (string, error) {
return v.getCA(v.config.RootPKIPath)
}
func (v *VaultProvider) ActiveIntermediate() (string, error) {
return v.getCA(v.config.IntermediatePKIPath)
}
// 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 := 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) {
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: "2160h",
},
})
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
}
spiffeID := connect.SpiffeIDSigning{ClusterID: v.clusterId, Domain: "consul"}
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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": "72h",
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})
if err != nil {
return "", err
}
}
// Generate a new intermediate CSR for the root to sign.
csr, err := v.client.Logical().Write(v.config.IntermediatePKIPath+"intermediate/generate/internal", map[string]interface{}{
"common_name": "Vault CA Intermediate Authority",
"uri_sans": spiffeID.URI().String(),
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})
if err != nil {
return "", err
}
if csr == nil || csr.Data["csr"] == nil {
return "", fmt.Errorf("got empty value when generating intermediate CSR")
}
// Sign the CSR with the root backend.
intermediate, err := v.client.Logical().Write(v.config.RootPKIPath+"root/sign-intermediate", map[string]interface{}{
"csr": csr.Data["csr"],
"format": "pem_bundle",
})
if err != nil {
return "", err
}
if intermediate == nil || intermediate.Data["certificate"] == nil {
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) {
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(),
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})
if err != nil {
return "", fmt.Errorf("error issuing cert: %v", err)
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}
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")
}
ca, ok := response.Data["issuing_ca"].(string)
if !ok {
return "", fmt.Errorf("issuing_ca was not a string")
}
return fmt.Sprintf("%s\n%s", cert, ca), nil
}
// todo(kyhavlov): decide which vault endpoint to use here
func (v *VaultProvider) CrossSignCA(cert *x509.Certificate) (string, error) {
var pemBuf bytes.Buffer
if err := pem.Encode(&pemBuf, &pem.Block{Type: "CERTIFICATE", Bytes: cert.Raw}); err != nil {
return "", err
}
return pemBuf.String(), 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() error {
return v.client.Sys().Unmount(v.config.IntermediatePKIPath)
}
func ParseVaultCAConfig(raw map[string]interface{}) (*structs.VaultCAProviderConfig, error) {
var config structs.VaultCAProviderConfig
if err := mapstructure.Decode(raw, &config); err != nil {
return nil, fmt.Errorf("error decoding config: %s", err)
}
if config.Token == "" {
return nil, fmt.Errorf("must provide a Vault token")
}
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 += "/"
}
return &config, nil
}