fix: handle invalid input length when parsing a node id (#3155)

This avoids a panic when calling `decode_mut` with an invalid input
length.

Closes #3153

iroh-base/src/key.rs

@@ -330,7 +330,12 @@ fn decode_base32_hex(s: &str) -> Result<[u8; 32], KeyParsingError> {
         // hex
         data_encoding::HEXLOWER.decode_mut(s.as_bytes(), &mut bytes)
     } else {
-        data_encoding::BASE32_NOPAD.decode_mut(s.to_ascii_uppercase().as_bytes(), &mut bytes)
+        let input = s.to_ascii_uppercase();
+        let input = input.as_bytes();
+        if data_encoding::BASE32_NOPAD.decode_len(input.len())? != bytes.len() {
+            return Err(KeyParsingError::DecodeInvalidLength);
+        }
+        data_encoding::BASE32_NOPAD.decode_mut(input, &mut bytes)
     };
     match res {
         Ok(len) => {
@@ -390,4 +395,10 @@ mod tests {
             key.public()
         );
     }
+
+    #[test]
+    fn test_regression_parse_node_id_panic() {
+        let not_a_node_id = "foobarbaz";
+        assert!(PublicKey::from_str(not_a_node_id).is_err());
+    }
 }