From 70ad44adfd7110d7627949e4be29230aff784737 Mon Sep 17 00:00:00 2001
From: Markus Triska <triska@metalevel.at>
Date: Mon, 18 May 2020 11:12:59 +0200
Subject: [PATCH] type check for length argument in crypto_data_hkdf/4

Reported by @notoria in #527.
---
 src/prolog/lib/crypto.pl | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/src/prolog/lib/crypto.pl b/src/prolog/lib/crypto.pl
index 7a246432..419c3d4c 100644
--- a/src/prolog/lib/crypto.pl
+++ b/src/prolog/lib/crypto.pl
@@ -250,6 +250,8 @@ hash_algorithm(sha512_256).
 
 crypto_data_hkdf(Data0, L, Bytes, Options0) :-
         functor_hash_options(algorithm, Algorithm, Options0, Options),
+        must_be(integer, L),
+        L >= 0,
         option(encoding(Encoding), Options, utf8),
         encoding_bytes(Encoding, Data0, Data),
         option(salt(SaltBytes), Options, []),
-- 
2.54.0