src/core/protocol/server_responses.rs

@@ -76,6 +76,7 @@ impl OwnerValidationError {
                 indoc! {r#"
                   Invalid {} name prefix: '{}' does not match your username or any of your groups.
                   Are you sure you are allowed to create {} names with this prefix?
+                  The format should be: <prefix>_<{} name>
 
                   Allowed prefixes:
                     - {}
@@ -84,6 +85,7 @@ impl OwnerValidationError {
                 db_or_user.lowercased(),
                 name,
                 db_or_user.lowercased(),
+                db_or_user.lowercased(),
                 user.as_ref()
                     .map(|u| u.username.clone())
                     .unwrap_or("???".to_string()),

src/server/input_sanitization.rs

@@ -45,7 +45,7 @@ pub fn validate_ownership_by_prefixes(
 
     if prefixes
         .iter()
-        .filter(|p| name.starts_with(*p))
+        .filter(|p| name.starts_with(&(p.to_string() + "_")))
         .collect::<Vec<_>>()
         .is_empty()
     {