openpgp: Improve error handling.

  - Return an Error::InvalidArgument when trying to parse a ciphertext
    with a signature algorithm specifier, or a signature with an
    encryption one.

1 files changed, 4 insertions, 6 deletions

diff --git a/openpgp/src/parse/mpis.rs b/openpgp/src/parse/mpis.rs
index 99311dc7..ac17525d 100644
--- a/openpgp/src/parse/mpis.rs
+++ b/openpgp/src/parse/mpis.rs
@@ -339,9 +339,8 @@ impl MPIs {
                 })
             }
 
-            RSASign | DSA | EdDSA | ECDSA => {
-                Err(Error::UnknownPublicKeyAlgorithm(algo).into())
-            }
+            RSASign | DSA | EdDSA | ECDSA => Err(Error::InvalidArgument(
+                format!("not an encryption algorithm: {:?}", algo)).into()),
         }
     }
 
@@ -438,9 +437,8 @@ impl MPIs {
                 })
             }
 
-            RSAEncrypt | ElgamalEncrypt | ECDH => {
-                Err(Error::UnknownPublicKeyAlgorithm(algo).into())
-            }
+            RSAEncrypt | ElgamalEncrypt | ECDH => Err(Error::InvalidArgument(
+                format!("not a signature algorithm: {:?}", algo)).into()),
         }
     }
 }