From 16c0196b1d3a97abd00e6b52615a78b7ac0ad11c Mon Sep 17 00:00:00 2001
From: Julien Cretin <cretin@google.com>
Date: Fri, 4 Dec 2020 14:42:16 +0100
Subject: [PATCH] Check global counter length

---
 src/ctap/storage.rs | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/src/ctap/storage.rs b/src/ctap/storage.rs
index 0f1c73f..a10f2eb 100644
--- a/src/ctap/storage.rs
+++ b/src/ctap/storage.rs
@@ -294,10 +294,11 @@ impl PersistentStore {
 
     /// Returns the global signature counter.
     pub fn global_signature_counter(&self) -> Result<u32, Ctap2StatusCode> {
-        Ok(match self.store.find(key::GLOBAL_SIGNATURE_COUNTER)? {
-            None => 0,
-            Some(value) => u32::from_ne_bytes(*array_ref!(&value, 0, 4)),
-        })
+        match self.store.find(key::GLOBAL_SIGNATURE_COUNTER)? {
+            None => Ok(0),
+            Some(value) if value.len() == 4 => Ok(u32::from_ne_bytes(*array_ref!(&value, 0, 4))),
+            Some(_) => Err(Ctap2StatusCode::CTAP2_ERR_VENDOR_INVALID_PERSISTENT_STORAGE),
+        }
     }
 
     /// Increments the global signature counter.