X-Git-Url: https://git.arvados.org/arvados.git/blobdiff_plain/5b80941723d6be1fd22589026635a43b33e6cf20..72900c01e197d602e79fda8d306b17fd1e32a3ea:/sdk/go/keepclient/perms.go

diff --git a/sdk/go/keepclient/perms.go b/sdk/go/keepclient/perms.go
index 7dc06e20af..d650f0d7ad 100644
--- a/sdk/go/keepclient/perms.go
+++ b/sdk/go/keepclient/perms.go
@@ -16,21 +16,28 @@ import (
 )
 
 var (
-	ErrSignatureExpired   = errors.New("Signature expired")
-	ErrSignatureInvalid   = errors.New("Invalid signature")
-	ErrSignatureMalformed = errors.New("Malformed signature")
-	ErrSignatureMissing   = errors.New("Missing signature")
+	// ErrSignatureExpired - a signature was rejected because the
+	// expiry time has passed.
+	ErrSignatureExpired = errors.New("Signature expired")
+	// ErrSignatureInvalid - a signature was rejected because it
+	// was badly formatted or did not match the given secret key.
+	ErrSignatureInvalid = errors.New("Invalid signature")
+	// ErrSignatureMissing - the given locator does not have a
+	// signature hint.
+	ErrSignatureMissing = errors.New("Missing signature")
 )
 
 // makePermSignature generates a SHA-1 HMAC digest for the given blob,
 // token, expiry, and site secret.
-func makePermSignature(blobHash, apiToken, expiry string, permissionSecret []byte) string {
+func makePermSignature(blobHash, apiToken, expiry, blobSignatureTTL string, permissionSecret []byte) string {
 	hmac := hmac.New(sha1.New, permissionSecret)
 	hmac.Write([]byte(blobHash))
 	hmac.Write([]byte("@"))
 	hmac.Write([]byte(apiToken))
 	hmac.Write([]byte("@"))
 	hmac.Write([]byte(expiry))
+	hmac.Write([]byte("@"))
+	hmac.Write([]byte(blobSignatureTTL))
 	digest := hmac.Sum(nil)
 	return fmt.Sprintf("%x", digest)
 }
@@ -41,15 +48,16 @@ func makePermSignature(blobHash, apiToken, expiry string, permissionSecret []byt
 //
 // This function is intended to be used by system components and admin
 // utilities: userland programs do not know the permissionSecret.
-func SignLocator(blobLocator, apiToken string, expiry time.Time, permissionSecret []byte) string {
+func SignLocator(blobLocator, apiToken string, expiry time.Time, blobSignatureTTL time.Duration, permissionSecret []byte) string {
 	if len(permissionSecret) == 0 || apiToken == "" {
 		return blobLocator
 	}
 	// Strip off all hints: only the hash is used to sign.
 	blobHash := strings.Split(blobLocator, "+")[0]
 	timestampHex := fmt.Sprintf("%08x", expiry.Unix())
+	blobSignatureTTLHex := strconv.FormatInt(int64(blobSignatureTTL.Seconds()), 16)
 	return blobLocator +
-		"+A" + makePermSignature(blobHash, apiToken, timestampHex, permissionSecret) +
+		"+A" + makePermSignature(blobHash, apiToken, timestampHex, blobSignatureTTLHex, permissionSecret) +
 		"@" + timestampHex
 }
 
@@ -57,26 +65,29 @@ var signedLocatorRe = regexp.MustCompile(`^([[:xdigit:]]{32}).*\+A([[:xdigit:]]{
 
 // VerifySignature returns nil if the signature on the signedLocator
 // can be verified using the given apiToken. Otherwise it returns
-// either ExpiredError (if the timestamp has expired, which is
-// something the client could have figured out independently) or
-// PermissionError.
+// ErrSignatureExpired (if the signature's expiry time has passed,
+// which is something the client could have figured out
+// independently), ErrSignatureMissing (if there is no signature hint
+// at all), or ErrSignatureInvalid (if the signature is present but
+// badly formatted or incorrect).
 //
 // This function is intended to be used by system components and admin
 // utilities: userland programs do not know the permissionSecret.
-func VerifySignature(signedLocator, apiToken string, permissionSecret []byte) error {
+func VerifySignature(signedLocator, apiToken string, blobSignatureTTL time.Duration, permissionSecret []byte) error {
 	matches := signedLocatorRe.FindStringSubmatch(signedLocator)
 	if matches == nil {
 		return ErrSignatureMissing
 	}
 	blobHash := matches[1]
-	sigHex := matches[2]
-	expHex := matches[3]
-	if expTime, err := parseHexTimestamp(expHex); err != nil {
-		return ErrSignatureMalformed
-	} else if expTime.Before(time.Now()) {
+	signatureHex := matches[2]
+	expiryHex := matches[3]
+	if expiryTime, err := parseHexTimestamp(expiryHex); err != nil {
+		return ErrSignatureInvalid
+	} else if expiryTime.Before(time.Now()) {
 		return ErrSignatureExpired
 	}
-	if sigHex != makePermSignature(blobHash, apiToken, expHex, permissionSecret) {
+	blobSignatureTTLHex := strconv.FormatInt(int64(blobSignatureTTL.Seconds()), 16)
+	if signatureHex != makePermSignature(blobHash, apiToken, expiryHex, blobSignatureTTLHex, permissionSecret) {
 		return ErrSignatureInvalid
 	}
 	return nil