session: Truncate returned buffer from operation

All these operations follow Section 5.2 semantics, which allow the size
query to return larger buffer and adjust the returned length to the real
length during the operation.

Previously, the `resize()` was used, but it was discussed several times
that it can not extend the buffer (unless the pkcs11 module misbehaves)
so changing all the places to `truncate()` instead.

Signed-off-by: Jakub Jelen <jjelen@redhat.com>

Author: Jakuje

cryptoki/src/session/decryption.rs

@@ -56,7 +56,7 @@ impl Session {
             .into_result(Function::Decrypt)?;
         }
 
-        data.resize(data_len.try_into()?, 0);
+        data.truncate(data_len.try_into()?);
 
         Ok(data)
     }
@@ -136,7 +136,7 @@ impl Session {
             .into_result(Function::DecryptFinal)?;
         }
 
-        data.resize(data_len.try_into()?, 0);
+        data.truncate(data_len.try_into()?);
 
         Ok(data)
     }

cryptoki/src/session/digesting.rs

@@ -49,7 +49,7 @@ impl Session {
             .into_result(Function::Digest)?;
         }
 
-        digest.resize(digest_len.try_into()?, 0);
+        digest.truncate(digest_len.try_into()?);
 
         Ok(digest)
     }
@@ -124,7 +124,7 @@ impl Session {
             .into_result(Function::DigestFinal)?;
         }
 
-        digest.resize(digest_len.try_into()?, 0);
+        digest.truncate(digest_len.try_into()?);
 
         Ok(digest)
     }

cryptoki/src/session/encapsulation.rs

@@ -54,7 +54,7 @@ impl Session {
             .into_result(Function::EncapsulateKey)?;
         }
 
-        encapsulated.resize(encapsulated_len.try_into()?, 0);
+        encapsulated.truncate(encapsulated_len.try_into()?);
 
         Ok((encapsulated, ObjectHandle::new(handle)))
     }

cryptoki/src/session/encryption.rs

@@ -55,7 +55,7 @@ impl Session {
             .into_result(Function::Encrypt)?;
         }
 
-        encrypted_data.resize(encrypted_data_len.try_into()?, 0);
+        encrypted_data.truncate(encrypted_data_len.try_into()?);
 
         Ok(encrypted_data)
     }
@@ -135,7 +135,7 @@ impl Session {
             .into_result(Function::EncryptFinal)?;
         }
 
-        encrypted_data.resize(encrypted_data_len.try_into()?, 0);
+        encrypted_data.truncate(encrypted_data_len.try_into()?);
 
         Ok(encrypted_data)
     }

cryptoki/src/session/message_decryption.rs

@@ -68,7 +68,7 @@ impl Session {
             .into_result(Function::DecryptMessage)?;
         }
 
-        data.resize(data_len.try_into()?, 0);
+        data.truncate(data_len.try_into()?);
 
         Ok(data)
     }
@@ -123,7 +123,7 @@ impl Session {
             ))
             .into_result(Function::DecryptMessageNext)?;
         }
-        data.resize(data_len.try_into()?, 0);
+        data.truncate(data_len.try_into()?);
 
         Ok(data)
     }

cryptoki/src/session/message_encryption.rs

@@ -68,7 +68,7 @@ impl Session {
             .into_result(Function::EncryptMessage)?;
         }
 
-        encrypted_data.resize(encrypted_data_len.try_into()?, 0);
+        encrypted_data.truncate(encrypted_data_len.try_into()?);
 
         Ok(encrypted_data)
     }
@@ -123,7 +123,7 @@ impl Session {
             ))
             .into_result(Function::EncryptMessageNext)?;
         }
-        encrypted_data.resize(encrypted_data_len.try_into()?, 0);
+        encrypted_data.truncate(encrypted_data_len.try_into()?);
 
         Ok(encrypted_data)
     }

cryptoki/src/session/signing_macing.rs

@@ -51,7 +51,7 @@ impl Session {
             .into_result(Function::Sign)?;
         }
 
-        signature.resize(signature_len.try_into()?, 0);
+        signature.truncate(signature_len.try_into()?);
 
         Ok(signature)
     }
@@ -113,7 +113,7 @@ impl Session {
             .into_result(Function::SignFinal)?;
         }
 
-        signature.resize(signature_len.try_into()?, 0);
+        signature.truncate(signature_len.try_into()?);
 
         Ok(signature)
     }