7121: Add collisionOrCorrupt->DiskHashError test cases where the mismatched data...

[arvados.git] / services / keepstore / perms.go

diff --git a/services/keepstore/perms.go b/services/keepstore/perms.go
index 1048f53130315525da0a80c1214207a9eb101cd5..65160b1868913638e8315a266e0b3736ecfbe14c 100644 (file)
--- a/services/keepstore/perms.go
+++ b/services/keepstore/perms.go
@@ -82,22 +82,29 @@ func SignLocator(blob_locator string, api_token string, expiry time.Time) string
 
 var signedLocatorRe = regexp.MustCompile(`^([[:xdigit:]]{32}).*\+A([[:xdigit:]]{40})@([[:xdigit:]]{8})`)
 
-// VerifySignature returns true if the signature on the signed_locator
-// can be verified using the given api_token.
-func VerifySignature(signed_locator string, api_token string) bool {
+// VerifySignature returns nil if the signature on the signed_locator
+// can be verified using the given api_token. Otherwise it returns
+// either ExpiredError (if the timestamp has expired, which is
+// something the client could have figured out independently) or
+// PermissionError.
+func VerifySignature(signed_locator string, api_token string) error {
        matches := signedLocatorRe.FindStringSubmatch(signed_locator)
        if matches == nil {
                // Could not find a permission signature at all
-               return false
+               return PermissionError
        }
        blob_hash := matches[1]
        sig_hex := matches[2]
        exp_hex := matches[3]
-       if exp_time, err := ParseHexTimestamp(exp_hex); err != nil || exp_time.Before(time.Now()) {
-               // Signature is expired, or timestamp is unparseable
-               return false
+       if exp_time, err := ParseHexTimestamp(exp_hex); err != nil {
+               return PermissionError
+       } else if exp_time.Before(time.Now()) {
+               return ExpiredError
        }
-       return sig_hex == MakePermSignature(blob_hash, api_token, exp_hex)
+       if sig_hex != MakePermSignature(blob_hash, api_token, exp_hex) {
+               return PermissionError
+       }
+       return nil
 }
 
 func ParseHexTimestamp(timestamp_hex string) (ts time.Time, err error) {