mirror of
https://github.com/letic/terraform-provider-google.git
synced 2024-09-07 09:36:44 +00:00
361 lines
9.3 KiB
Go
361 lines
9.3 KiB
Go
package google
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import (
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"bytes"
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"crypto"
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"crypto/rand"
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"crypto/rsa"
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"crypto/sha256"
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"crypto/x509"
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"encoding/base64"
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"encoding/pem"
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"errors"
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"fmt"
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"log"
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"net/url"
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"os"
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"strconv"
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"strings"
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"time"
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"sort"
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"github.com/hashicorp/errwrap"
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"github.com/hashicorp/terraform/helper/pathorcontents"
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"github.com/hashicorp/terraform/helper/schema"
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"github.com/hashicorp/terraform/helper/validation"
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"golang.org/x/oauth2/google"
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"golang.org/x/oauth2/jwt"
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)
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const gcsBaseUrl = "https://storage.googleapis.com"
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const googleCredentialsEnvVar = "GOOGLE_APPLICATION_CREDENTIALS"
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func dataSourceGoogleSignedUrl() *schema.Resource {
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return &schema.Resource{
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Read: dataSourceGoogleSignedUrlRead,
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Schema: map[string]*schema.Schema{
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"bucket": &schema.Schema{
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Type: schema.TypeString,
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Required: true,
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},
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"content_md5": &schema.Schema{
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Type: schema.TypeString,
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Optional: true,
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Default: "",
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},
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"content_type": &schema.Schema{
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Type: schema.TypeString,
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Optional: true,
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Default: "",
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},
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"credentials": &schema.Schema{
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Type: schema.TypeString,
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Optional: true,
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},
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"duration": &schema.Schema{
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Type: schema.TypeString,
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Optional: true,
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Default: "1h",
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},
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"extension_headers": &schema.Schema{
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Type: schema.TypeMap,
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Optional: true,
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Elem: schema.TypeString,
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ValidateFunc: validateExtensionHeaders,
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},
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"http_method": &schema.Schema{
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Type: schema.TypeString,
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Optional: true,
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Default: "GET",
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ValidateFunc: validation.StringInSlice([]string{"GET", "HEAD", "PUT", "DELETE"}, true),
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},
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"path": &schema.Schema{
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Type: schema.TypeString,
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Required: true,
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},
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"signed_url": &schema.Schema{
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Type: schema.TypeString,
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Computed: true,
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},
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},
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}
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}
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func validateExtensionHeaders(v interface{}, k string) (ws []string, errors []error) {
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hdrMap := v.(map[string]interface{})
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for k, _ := range hdrMap {
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if !strings.HasPrefix(strings.ToLower(k), "x-goog-") {
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errors = append(errors, fmt.Errorf(
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"extension_header (%s) not valid, header name must begin with 'x-goog-'", k))
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}
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}
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return
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}
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func dataSourceGoogleSignedUrlRead(d *schema.ResourceData, meta interface{}) error {
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config := meta.(*Config)
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// Build UrlData object from data source attributes
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urlData := &UrlData{}
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// HTTP Method
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if method, ok := d.GetOk("http_method"); ok {
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urlData.HttpMethod = method.(string)
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}
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// convert duration to an expiration datetime (unix time in seconds)
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durationString := "1h"
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if v, ok := d.GetOk("duration"); ok {
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durationString = v.(string)
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}
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duration, err := time.ParseDuration(durationString)
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if err != nil {
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return errwrap.Wrapf("could not parse duration: {{err}}", err)
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}
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expires := time.Now().Unix() + int64(duration.Seconds())
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urlData.Expires = int(expires)
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// content_md5 is optional
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if v, ok := d.GetOk("content_md5"); ok {
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urlData.ContentMd5 = v.(string)
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}
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// content_type is optional
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if v, ok := d.GetOk("content_type"); ok {
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urlData.ContentType = v.(string)
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}
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// extension_headers (x-goog-* HTTP headers) are optional
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if v, ok := d.GetOk("extension_headers"); ok {
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hdrMap := v.(map[string]interface{})
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if len(hdrMap) > 0 {
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urlData.HttpHeaders = make(map[string]string, len(hdrMap))
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for k, v := range hdrMap {
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urlData.HttpHeaders[k] = v.(string)
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}
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}
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}
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urlData.Path = fmt.Sprintf("/%s/%s", d.Get("bucket").(string), d.Get("path").(string))
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// Load JWT Config from Google Credentials
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jwtConfig, err := loadJwtConfig(d, config)
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if err != nil {
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return err
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}
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urlData.JwtConfig = jwtConfig
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// Construct URL
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signedUrl, err := urlData.SignedUrl()
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if err != nil {
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return err
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}
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// Success
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d.Set("signed_url", signedUrl)
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encodedSig, err := urlData.EncodedSignature()
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if err != nil {
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return err
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}
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d.SetId(encodedSig)
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return nil
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}
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// loadJwtConfig looks for credentials json in the following places,
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// in order of preference:
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// 1. `credentials` attribute of the datasource
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// 2. `credentials` attribute in the provider definition.
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// 3. A JSON file whose path is specified by the
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// GOOGLE_APPLICATION_CREDENTIALS environment variable.
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func loadJwtConfig(d *schema.ResourceData, meta interface{}) (*jwt.Config, error) {
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config := meta.(*Config)
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credentials := ""
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if v, ok := d.GetOk("credentials"); ok {
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log.Println("[DEBUG] using data source credentials to sign URL")
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credentials = v.(string)
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} else if config.Credentials != "" {
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log.Println("[DEBUG] using provider credentials to sign URL")
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credentials = config.Credentials
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} else if filename := os.Getenv(googleCredentialsEnvVar); filename != "" {
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log.Println("[DEBUG] using env GOOGLE_APPLICATION_CREDENTIALS credentials to sign URL")
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credentials = filename
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}
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if strings.TrimSpace(credentials) != "" {
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contents, _, err := pathorcontents.Read(credentials)
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if err != nil {
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return nil, errwrap.Wrapf("Error loading credentials: {{err}}", err)
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}
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cfg, err := google.JWTConfigFromJSON([]byte(contents), "")
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if err != nil {
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return nil, errwrap.Wrapf("Error parsing credentials: {{err}}", err)
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}
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return cfg, nil
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}
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return nil, errors.New("Credentials not found in datasource, provider configuration or GOOGLE_APPLICATION_CREDENTIALS environment variable.")
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}
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// parsePrivateKey converts the binary contents of a private key file
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// to an *rsa.PrivateKey. It detects whether the private key is in a
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// PEM container or not. If so, it extracts the the private key
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// from PEM container before conversion. It only supports PEM
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// containers with no passphrase.
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// copied from golang.org/x/oauth2/internal
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func parsePrivateKey(key []byte) (*rsa.PrivateKey, error) {
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block, _ := pem.Decode(key)
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if block != nil {
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key = block.Bytes
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}
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parsedKey, err := x509.ParsePKCS8PrivateKey(key)
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if err != nil {
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parsedKey, err = x509.ParsePKCS1PrivateKey(key)
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if err != nil {
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return nil, errwrap.Wrapf("private key should be a PEM or plain PKSC1 or PKCS8; parse error: {{err}}", err)
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}
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}
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parsed, ok := parsedKey.(*rsa.PrivateKey)
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if !ok {
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return nil, errors.New("private key is invalid")
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}
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return parsed, nil
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}
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// UrlData stores the values required to create a Signed Url
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type UrlData struct {
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JwtConfig *jwt.Config
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ContentMd5 string
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ContentType string
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HttpMethod string
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Expires int
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HttpHeaders map[string]string
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Path string
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}
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// SigningString creates a string representation of the UrlData in a form ready for signing:
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// see https://cloud.google.com/storage/docs/access-control/create-signed-urls-program
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// Example output:
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// -------------------
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// GET
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//
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//
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// 1388534400
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// bucket/objectname
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// -------------------
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func (u *UrlData) SigningString() []byte {
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var buf bytes.Buffer
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// HTTP Verb
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buf.WriteString(u.HttpMethod)
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buf.WriteString("\n")
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// Content MD5 (optional, always add new line)
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buf.WriteString(u.ContentMd5)
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buf.WriteString("\n")
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// Content Type (optional, always add new line)
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buf.WriteString(u.ContentType)
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buf.WriteString("\n")
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// Expiration
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buf.WriteString(strconv.Itoa(u.Expires))
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buf.WriteString("\n")
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// Extra HTTP headers (optional)
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// Must be sorted in lexigraphical order
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var keys []string
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for k := range u.HttpHeaders {
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keys = append(keys, strings.ToLower(k))
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}
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sort.Strings(keys)
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// Write sorted headers to signing string buffer
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for _, k := range keys {
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buf.WriteString(fmt.Sprintf("%s:%s\n", k, u.HttpHeaders[k]))
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}
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// Storate Object path (includes bucketname)
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buf.WriteString(u.Path)
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return buf.Bytes()
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}
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func (u *UrlData) Signature() ([]byte, error) {
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// Sign url data
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signature, err := SignString(u.SigningString(), u.JwtConfig)
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if err != nil {
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return nil, err
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}
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return signature, nil
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}
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// EncodedSignature returns the Signature() after base64 encoding and url escaping
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func (u *UrlData) EncodedSignature() (string, error) {
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signature, err := u.Signature()
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if err != nil {
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return "", err
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}
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// base64 encode signature
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encoded := base64.StdEncoding.EncodeToString(signature)
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// encoded signature may include /, = characters that need escaping
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encoded = url.QueryEscape(encoded)
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return encoded, nil
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}
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// SignedUrl constructs the final signed URL a client can use to retrieve storage object
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func (u *UrlData) SignedUrl() (string, error) {
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encodedSig, err := u.EncodedSignature()
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if err != nil {
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return "", err
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}
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// build url
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// https://cloud.google.com/storage/docs/access-control/create-signed-urls-program
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var urlBuffer bytes.Buffer
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urlBuffer.WriteString(gcsBaseUrl)
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urlBuffer.WriteString(u.Path)
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urlBuffer.WriteString("?GoogleAccessId=")
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urlBuffer.WriteString(u.JwtConfig.Email)
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urlBuffer.WriteString("&Expires=")
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urlBuffer.WriteString(strconv.Itoa(u.Expires))
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urlBuffer.WriteString("&Signature=")
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urlBuffer.WriteString(encodedSig)
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return urlBuffer.String(), nil
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}
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// SignString calculates the SHA256 signature of the input string
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func SignString(toSign []byte, cfg *jwt.Config) ([]byte, error) {
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// Parse private key
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pk, err := parsePrivateKey(cfg.PrivateKey)
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if err != nil {
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return nil, errwrap.Wrapf("failed to sign string, could not parse key: {{err}}", err)
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}
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// Hash string
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hasher := sha256.New()
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hasher.Write(toSign)
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// Sign string
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signed, err := rsa.SignPKCS1v15(rand.Reader, pk, crypto.SHA256, hasher.Sum(nil))
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if err != nil {
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return nil, errwrap.Wrapf("failed to sign string, an error occurred: {{err}}", err)
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}
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return signed, nil
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}
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