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

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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
isRoot bool
clusterID string
spiffeID *connect.SpiffeIDSigning
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}
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(clusterID string, isRoot bool, rawConfig map[string]interface{}, state map[string]string) error {
config, err := ParseVaultCAConfig(rawConfig)
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if err != nil {
return err
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}
clientConf := &vaultapi.Config{
Address: config.Address,
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}
err = clientConf.ConfigureTLS(vaultTLSConfig(config))
if err != nil {
return err
}
client, err := vaultapi.NewClient(clientConf)
if err != nil {
return err
}
client.SetToken(config.Token)
v.config = config
v.client = client
v.isRoot = isRoot
v.clusterID = clusterID
v.spiffeID = connect.SpiffeIDSigningForCluster(&structs.CAConfiguration{ClusterID: clusterID})
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return nil
}
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// 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
}
// ActiveRoot returns the active root CA certificate.
func (v *VaultProvider) ActiveRoot() (string, error) {
return v.getCA(v.config.RootPKIPath)
}
// GenerateRoot mounts and initializes a new root PKI backend if needed.
func (v *VaultProvider) GenerateRoot() error {
if !v.isRoot {
return fmt.Errorf("provider is not the root certificate authority")
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}
// Set up the root PKI backend if necessary.
_, err := v.ActiveRoot()
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switch err {
case ErrBackendNotMounted:
err := v.client.Sys().Mount(v.config.RootPKIPath, &vaultapi.MountInput{
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Type: "pki",
Description: "root CA backend for Consul Connect",
Config: vaultapi.MountConfigInput{
MaxLeaseTTL: "8760h",
},
})
if err != nil {
return err
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}
fallthrough
case ErrBackendNotInitialized:
uid, err := connect.CompactUID()
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if err != nil {
return err
}
_, err = v.client.Logical().Write(v.config.RootPKIPath+"root/generate/internal", map[string]interface{}{
"common_name": connect.CACN("vault", uid, v.clusterID, v.isRoot),
"uri_sans": v.spiffeID.URI().String(),
"key_type": v.config.PrivateKeyType,
"key_bits": v.config.PrivateKeyBits,
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})
if err != nil {
return err
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}
default:
if err != nil {
return err
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}
}
return nil
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}
// 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.isRoot {
return "", fmt.Errorf("provider is the root certificate authority, " +
"cannot generate an intermediate CSR")
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}
return v.generateIntermediateCSR()
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}
func (v *VaultProvider) generateIntermediateCSR() (string, error) {
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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
}
if role == nil {
_, err := v.client.Logical().Write(rolePath, map[string]interface{}{
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"allow_any_name": true,
"allowed_uri_sans": "spiffe://*",
"key_type": "any",
"max_ttl": v.config.LeafCertTTL.String(),
"no_store": true,
"require_cn": false,
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})
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.isRoot),
"key_type": v.config.PrivateKeyType,
"key_bits": v.config.PrivateKeyBits,
"uri_sans": v.spiffeID.URI().String(),
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})
if err != nil {
return "", err
}
if data == nil || data.Data["csr"] == "" {
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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.isRoot {
return fmt.Errorf("cannot set an intermediate using another root in the primary datacenter")
}
err := validateSetIntermediate(
intermediatePEM, rootPEM,
"", // we don't have access to the private key directly
v.spiffeID,
)
if err != nil {
return err
}
_, err = v.client.Logical().Write(v.config.IntermediatePKIPath+"intermediate/set-signed", map[string]interface{}{
"certificate": fmt.Sprintf("%s\n%s", intermediatePEM, rootPEM),
})
if err != nil {
return err
}
return nil
}
// ActiveIntermediate returns the current intermediate certificate.
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) {
csr, err := v.generateIntermediateCSR()
if err != nil {
return "", err
}
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// 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",
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})
if err != nil {
return "", err
}
if intermediate == nil || intermediate.Data["certificate"] == "" {
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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(),
"ttl": v.config.LeafCertTTL.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
}
// 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) {
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,
})
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 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) {
var pemBuf bytes.Buffer
err := pem.Encode(&pemBuf, &pem.Block{Type: "CERTIFICATE", Bytes: cert.Raw})
if err != nil {
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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 xcCert, nil
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}
// SupportsCrossSigning implements Provider
func (c *VaultProvider) SupportsCrossSigning() (bool, error) {
return true, nil
}
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// 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) {
config := structs.VaultCAProviderConfig{
CommonCAProviderConfig: defaultCommonConfig(),
}
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decodeConf := &mapstructure.DecoderConfig{
Fix CA pruning when CA config uses string durations. (#4669) * Fix CA pruning when CA config uses string durations. The tl;dr here is: - Configuring LeafCertTTL with a string like "72h" is how we do it by default and should be supported - Most of our tests managed to escape this by defining them as time.Duration directly - Out actual default value is a string - Since this is stored in a map[string]interface{} config, when it is written to Raft it goes through a msgpack encode/decode cycle (even though it's written from server not over RPC). - msgpack decode leaves the string as a `[]uint8` - Some of our parsers required string and failed - So after 1 hour, a default configured server would throw an error about pruning old CAs - If a new CA was configured that set LeafCertTTL as a time.Duration, things might be OK after that, but if a new CA was just configured from config file, intialization would cause same issue but always fail still so would never prune the old CA. - Mostly this is just a janky error that got passed tests due to many levels of complicated encoding/decoding. tl;dr of the tl;dr: Yay for type safety. Map[string]interface{} combined with msgpack always goes wrong but we somehow get bitten every time in a new way :D We already fixed this once! The main CA config had the same problem so @kyhavlov already wrote the mapstructure DecodeHook that fixes it. It wasn't used in several places it needed to be and one of those is notw in `structs` which caused a dependency cycle so I've moved them. This adds a whole new test thta explicitly tests the case that broke here. It also adds tests that would have failed in other places before (Consul and Vaul provider parsing functions). I'm not sure if they would ever be affected as it is now as we've not seen things broken with them but it seems better to explicitly test that and support it to not be bitten a third time! * Typo fix * Fix bad Uint8 usage
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DecodeHook: structs.ParseDurationFunc(),
Result: &config,
WeaklyTypedInput: true,
}
decoder, err := mapstructure.NewDecoder(decodeConf)
if err != nil {
return nil, err
}
if err := decoder.Decode(raw); err != nil {
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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 += "/"
}
if err := config.CommonCAProviderConfig.Validate(); err != nil {
return nil, err
}
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return &config, nil
}