packer-cn/builder/azure/common/client/config.go

311 lines
9.8 KiB
Go

//go:generate struct-markdown
package client
import (
"fmt"
"os"
"strings"
"time"
"github.com/Azure/go-autorest/autorest/adal"
"github.com/Azure/go-autorest/autorest/azure"
jwt "github.com/dgrijalva/jwt-go"
"github.com/hashicorp/packer/packer"
)
// Config allows for various ways to authenticate Azure clients.
// When `client_id` and `subscription_id` are specified, Packer will use the
// specified Azure Active Directory (AAD) Service Principal (SP).
// If only `subscription_id` is specified, Packer will try to interactively
// log on the current user (tokens will be cached).
// If none of these options are specified, Packer will attempt to use the
// Managed Identity and subscription of the VM that Packer is running on.
// This will only work if Packer is running on an Azure VM.
type Config struct {
// One of Public, China, Germany, or
// USGovernment. Defaults to Public. Long forms such as
// USGovernmentCloud and AzureUSGovernmentCloud are also supported.
CloudEnvironmentName string `mapstructure:"cloud_environment_name" required:"false"`
cloudEnvironment *azure.Environment
// Authentication fields
// The application ID of the AAD Service Principal.
// Requires either `client_secret`, `client_cert_path` or `client_jwt` to be set as well.
ClientID string `mapstructure:"client_id"`
// A password/secret registered for the AAD SP.
ClientSecret string `mapstructure:"client_secret"`
// The path to a pem-encoded certificate that will be used to authenticate
// as the specified AAD SP.
ClientCertPath string `mapstructure:"client_cert_path"`
// A JWT bearer token for client auth (RFC 7523, Sec. 2.2) that will be used
// to authenticate the AAD SP. Provides more control over token the expiration
// when using certificate authentication than when using `client_cert_path`.
ClientJWT string `mapstructure:"client_jwt"`
// The object ID for the AAD SP. Optional, will be derived from the oAuth token if left empty.
ObjectID string `mapstructure:"object_id"`
// The Active Directory tenant identifier with which your `client_id` and
// `subscription_id` are associated. If not specified, `tenant_id` will be
// looked up using `subscription_id`.
TenantID string `mapstructure:"tenant_id" required:"false"`
// The subscription to use.
SubscriptionID string `mapstructure:"subscription_id"`
authType string
}
const (
authTypeDeviceLogin = "DeviceLogin"
authTypeMSI = "ManagedIdentity"
authTypeClientSecret = "ClientSecret"
authTypeClientCert = "ClientCertificate"
authTypeClientBearerJWT = "ClientBearerJWT"
)
const DefaultCloudEnvironmentName = "Public"
func (c *Config) SetDefaultValues() error {
if c.CloudEnvironmentName == "" {
c.CloudEnvironmentName = DefaultCloudEnvironmentName
}
return c.setCloudEnvironment()
}
func (c *Config) CloudEnvironment() *azure.Environment {
return c.cloudEnvironment
}
func (c *Config) setCloudEnvironment() error {
lookup := map[string]string{
"CHINA": "AzureChinaCloud",
"CHINACLOUD": "AzureChinaCloud",
"AZURECHINACLOUD": "AzureChinaCloud",
"GERMAN": "AzureGermanCloud",
"GERMANCLOUD": "AzureGermanCloud",
"AZUREGERMANCLOUD": "AzureGermanCloud",
"GERMANY": "AzureGermanCloud",
"GERMANYCLOUD": "AzureGermanCloud",
"AZUREGERMANYCLOUD": "AzureGermanCloud",
"PUBLIC": "AzurePublicCloud",
"PUBLICCLOUD": "AzurePublicCloud",
"AZUREPUBLICCLOUD": "AzurePublicCloud",
"USGOVERNMENT": "AzureUSGovernmentCloud",
"USGOVERNMENTCLOUD": "AzureUSGovernmentCloud",
"AZUREUSGOVERNMENTCLOUD": "AzureUSGovernmentCloud",
}
name := strings.ToUpper(c.CloudEnvironmentName)
envName, ok := lookup[name]
if !ok {
return fmt.Errorf("There is no cloud environment matching the name '%s'!", c.CloudEnvironmentName)
}
env, err := azure.EnvironmentFromName(envName)
c.cloudEnvironment = &env
return err
}
func (c Config) Validate(errs *packer.MultiError) {
/////////////////////////////////////////////
// Authentication via OAUTH
// Check if device login is being asked for, and is allowed.
//
// Device login is enabled if the user only defines SubscriptionID and not
// ClientID, ClientSecret, and TenantID.
//
// Device login is not enabled for Windows because the WinRM certificate is
// readable by the ObjectID of the App. There may be another way to handle
// this case, but I am not currently aware of it - send feedback.
if c.UseMSI() {
return
}
if c.useDeviceLogin() {
return
}
if c.SubscriptionID != "" && c.ClientID != "" &&
c.ClientSecret != "" &&
c.ClientCertPath == "" &&
c.ClientJWT == "" {
// Service principal using secret
return
}
if c.SubscriptionID != "" && c.ClientID != "" &&
c.ClientSecret == "" &&
c.ClientCertPath != "" &&
c.ClientJWT == "" {
// Service principal using certificate
if _, err := os.Stat(c.ClientCertPath); err != nil {
errs = packer.MultiErrorAppend(errs, fmt.Errorf("client_cert_path is not an accessible file: %v", err))
}
return
}
if c.SubscriptionID != "" && c.ClientID != "" &&
c.ClientSecret == "" &&
c.ClientCertPath == "" &&
c.ClientJWT != "" {
// Service principal using JWT
// Check that JWT is valid for at least 5 more minutes
p := jwt.Parser{}
claims := jwt.StandardClaims{}
token, _, err := p.ParseUnverified(c.ClientJWT, &claims)
if err != nil {
errs = packer.MultiErrorAppend(errs, fmt.Errorf("client_jwt is not a JWT: %v", err))
} else {
if claims.ExpiresAt < time.Now().Add(5*time.Minute).Unix() {
errs = packer.MultiErrorAppend(errs, fmt.Errorf("client_jwt will expire within 5 minutes, please use a JWT that is valid for at least 5 minutes"))
}
if t, ok := token.Header["x5t"]; !ok || t == "" {
errs = packer.MultiErrorAppend(errs, fmt.Errorf("client_jwt is missing the x5t header value, which is required for bearer JWT client authentication to Azure"))
}
}
return
}
errs = packer.MultiErrorAppend(errs, fmt.Errorf("No valid set of authentication values specified:\n"+
" to use the Managed Identity of the current machine, do not specify any of the fields below\n"+
" to use interactive user authentication, specify only subscription_id\n"+
" to use an Azure Active Directory service principal, specify either:\n"+
" - subscription_id, client_id and client_secret\n"+
" - subscription_id, client_id and client_cert_path\n"+
" - subscription_id, client_id and client_jwt."))
}
func (c Config) useDeviceLogin() bool {
return c.SubscriptionID != "" &&
c.ClientID == "" &&
c.ClientSecret == "" &&
c.ClientJWT == "" &&
c.ClientCertPath == ""
}
func (c Config) UseMSI() bool {
return c.SubscriptionID == "" &&
c.ClientID == "" &&
c.ClientSecret == "" &&
c.ClientJWT == "" &&
c.ClientCertPath == "" &&
c.TenantID == ""
}
func (c Config) GetServicePrincipalTokens(say func(string)) (
servicePrincipalToken *adal.ServicePrincipalToken,
servicePrincipalTokenVault *adal.ServicePrincipalToken,
err error) {
servicePrincipalToken, err = c.GetServicePrincipalToken(say,
c.CloudEnvironment().ResourceManagerEndpoint)
if err != nil {
return nil, nil, err
}
servicePrincipalTokenVault, err = c.GetServicePrincipalToken(say,
strings.TrimRight(c.CloudEnvironment().KeyVaultEndpoint, "/"))
if err != nil {
return nil, nil, err
}
return servicePrincipalToken, servicePrincipalTokenVault, nil
}
func (c Config) GetServicePrincipalToken(
say func(string), forResource string) (
servicePrincipalToken *adal.ServicePrincipalToken,
err error) {
var auth oAuthTokenProvider
switch c.authType {
case authTypeDeviceLogin:
say("Getting tokens using device flow")
auth = NewDeviceFlowOAuthTokenProvider(*c.cloudEnvironment, say, c.TenantID)
case authTypeMSI:
say("Getting tokens using Managed Identity for Azure")
auth = NewMSIOAuthTokenProvider(*c.cloudEnvironment)
case authTypeClientSecret:
say("Getting tokens using client secret")
auth = NewSecretOAuthTokenProvider(*c.cloudEnvironment, c.ClientID, c.ClientSecret, c.TenantID)
case authTypeClientCert:
say("Getting tokens using client certificate")
auth, err = NewCertOAuthTokenProvider(*c.cloudEnvironment, c.ClientID, c.ClientCertPath, c.TenantID)
if err != nil {
return nil, err
}
case authTypeClientBearerJWT:
say("Getting tokens using client bearer JWT")
auth = NewJWTOAuthTokenProvider(*c.cloudEnvironment, c.ClientID, c.ClientJWT, c.TenantID)
default:
panic("authType not set, call FillParameters, or set explicitly")
}
servicePrincipalToken, err = auth.getServicePrincipalTokenWithResource(forResource)
if err != nil {
return nil, err
}
err = servicePrincipalToken.EnsureFresh()
if err != nil {
return nil, err
}
return servicePrincipalToken, nil
}
// FillParameters capture the user intent from the supplied parameter set in authType, retrieves the TenantID and CloudEnvironment if not specified.
// The SubscriptionID is also retrieved in case MSI auth is requested.
func (c *Config) FillParameters() error {
if c.authType == "" {
if c.useDeviceLogin() {
c.authType = authTypeDeviceLogin
} else if c.UseMSI() {
c.authType = authTypeMSI
} else if c.ClientSecret != "" {
c.authType = authTypeClientSecret
} else if c.ClientCertPath != "" {
c.authType = authTypeClientCert
} else {
c.authType = authTypeClientBearerJWT
}
}
if c.authType == authTypeMSI && c.SubscriptionID == "" {
subscriptionID, err := getSubscriptionFromIMDS()
if err != nil {
return fmt.Errorf("error fetching subscriptionID from VM metadata service for Managed Identity authentication: %v", err)
}
c.SubscriptionID = subscriptionID
}
if c.cloudEnvironment == nil {
err := c.setCloudEnvironment()
if err != nil {
return err
}
}
if c.TenantID == "" {
tenantID, err := findTenantID(*c.cloudEnvironment, c.SubscriptionID)
if err != nil {
return err
}
c.TenantID = tenantID
}
return nil
}
// allow override for unit tests
var findTenantID = FindTenantID