7167: Tidy up errors. Remove extra comment copy.

diff --git a/sdk/go/keepclient/perms.go b/sdk/go/keepclient/perms.go
index 5b792a834946b69681cefc5a0f114a13183e359b..0797b070b8fcb8d0ab657f40a73df3dd60382987 100644 (file)
--- a/sdk/go/keepclient/perms.go
+++ b/sdk/go/keepclient/perms.go
@@ -38,6 +38,7 @@ package keepclient
 import (
        "crypto/hmac"
        "crypto/sha1"
+       "errors"
        "fmt"
        "regexp"
        "strconv"
@@ -45,22 +46,13 @@ import (
        "time"
 )
 
-// KeepError types.
-//
-type KeepError struct {
-       HTTPCode int
-       ErrMsg   string
-}
-
 var (
-       PermissionError = &KeepError{403, "Forbidden"}
-       ExpiredError    = &KeepError{401, "Expired permission signature"}
+       ErrSignatureExpired   = errors.New("Signature expired")
+       ErrSignatureInvalid   = errors.New("Invalid signature")
+       ErrSignatureMalformed = errors.New("Malformed signature")
+       ErrSignatureMissing   = errors.New("Missing signature")
 )
 
-func (e *KeepError) Error() string {
-       return e.ErrMsg
-}
-
 // makePermSignature returns a string representing the signed permission
 // hint for the blob identified by blobHash, apiToken, expiration timestamp, and permission secret.
 //
@@ -105,18 +97,18 @@ func VerifySignature(signedLocator string, apiToken string, permissionSecret []b
        matches := signedLocatorRe.FindStringSubmatch(signedLocator)
        if matches == nil {
                // Could not find a permission signature at all
-               return PermissionError
+               return ErrSignatureMissing
        }
        blobHash := matches[1]
        sigHex := matches[2]
        expHex := matches[3]
        if expTime, err := parseHexTimestamp(expHex); err != nil {
-               return PermissionError
+               return ErrSignatureMalformed
        } else if expTime.Before(time.Now()) {
-               return ExpiredError
+               return ErrSignatureExpired
        }
        if sigHex != makePermSignature(blobHash, apiToken, expHex, permissionSecret) {
-               return PermissionError
+               return ErrSignatureInvalid
        }
        return nil
 }

diff --git a/services/keepstore/perms.go b/services/keepstore/perms.go
index 494e6b7f58340738eb46ef547b1f55761266016c..6168a321c27e464fff5d0555ed363b2636331c76 100644 (file)
--- a/services/keepstore/perms.go
+++ b/services/keepstore/perms.go
@@ -1,38 +1,3 @@
-/*
-Permissions management on Arvados locator hashes.
-
-The permissions structure for Arvados is as follows (from
-https://arvados.org/issues/2328)
-
-A Keep locator string has the following format:
-
-    [hash]+[size]+A[signature]@[timestamp]
-
-The "signature" string here is a cryptographic hash, expressed as a
-string of hexadecimal digits, and timestamp is a 32-bit Unix timestamp
-expressed as a hexadecimal number.  e.g.:
-
-    acbd18db4cc2f85cedef654fccc4a4d8+3+A257f3f5f5f0a4e4626a18fc74bd42ec34dcb228a@7fffffff
-
-The signature represents a guarantee that this locator was generated
-by either Keep or the API server for use with the supplied API token.
-If a request to Keep includes a locator with a valid signature and is
-accompanied by the proper API token, the user has permission to GET
-that object.
-
-The signature may be generated either by Keep (after the user writes a
-block) or by the API server (if the user has can_read permission on
-the specified object). Keep and API server share a secret that is used
-to generate signatures.
-
-To verify a permission hint, Keep generates a new hint for the
-requested object (using the locator string, the timestamp, the
-permission secret and the user's API token, which must appear in the
-request headers) and compares it against the hint included in the
-request. If the permissions do not match, or if the API token is not
-present, Keep returns a 401 error.
-*/
-
 package main
 
 import (
@@ -47,7 +12,7 @@ var PermissionSecret []byte
 
 // SignLocator takes a blobLocator, an apiToken and an expiry time, and
 // returns a signed locator string.
-func SignLocator(blobLocator string, apiToken string, expiry time.Time) string {
+func SignLocator(blobLocator, apiToken string, expiry time.Time) string {
        return keepclient.SignLocator(blobLocator, apiToken, expiry, PermissionSecret)
 }
 
@@ -56,14 +21,12 @@ func SignLocator(blobLocator string, apiToken string, expiry time.Time) string {
 // either ExpiredError (if the timestamp has expired, which is
 // something the client could have figured out independently) or
 // PermissionError.
-func VerifySignature(signedLocator string, apiToken string) error {
+func VerifySignature(signedLocator, apiToken string) error {
        err := keepclient.VerifySignature(signedLocator, apiToken, PermissionSecret)
-       if err != nil {
-               if err == keepclient.PermissionError {
-                       return PermissionError
-               } else if err == keepclient.ExpiredError {
-                       return ExpiredError
-               }
+       if err == keepclient.ErrSignatureExpired {
+               return ExpiredError
+       } else if err != nil {
+               return PermissionError
        }
-       return err
+       return nil
 }