objects: Do not attempt to alloc memory for unavailable attributes

Signed-off-by: Jakub Jelen <[email protected]>

Author: Jakuje

cryptoki/src/object.rs

@@ -1378,6 +1378,8 @@ pub enum AttributeInfo {
     Sensitive,
     /// The attribute is available to get from the object and has the specified size in bytes.
     Available(usize),
+    /// The attribute is not available.
+    Unavailable,
 }
 
 #[derive(Debug, Copy, Clone, PartialEq, Eq)]

cryptoki/src/session/object_management.rs

@@ -454,7 +454,11 @@ impl Session {
                 ))
             } {
                 Rv::Ok => {
-                    results.push(AttributeInfo::Available(template[0].ulValueLen.try_into()?))
+                    if template[0].ulValueLen == CK_UNAVAILABLE_INFORMATION {
+                        results.push(AttributeInfo::Unavailable)
+                    } else {
+                        results.push(AttributeInfo::Available(template[0].ulValueLen.try_into()?))
+                    }
                 }
                 Rv::Error(RvError::AttributeSensitive) => results.push(AttributeInfo::Sensitive),
                 Rv::Error(RvError::AttributeTypeInvalid) => {