From 55a8161c3f5238df522447499a38bf2e9497b074 Mon Sep 17 00:00:00 2001
From: Dylan Gray <35609490+Dylan-MSFT@users.noreply.github.com>
Date: Fri, 13 Jul 2018 15:09:01 -0700
Subject: [PATCH] Zap copy of secret in RC4 string-to-key

Commit b8814745049b5f401e3ae39a81dc1e14598ae48c (ticket 8576) added a
zero-terminated copy of the input string in
krb5int_arcfour_string_to_key().  This copy should be zeroed when
freed as the input string typically contains a password.

[ghudson@mit.edu: rewrote commit message]

ticket: 8713 (new)
---
 src/lib/crypto/krb/s2k_rc4.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/lib/crypto/krb/s2k_rc4.c b/src/lib/crypto/krb/s2k_rc4.c
index 081a91217..f7e699d60 100644
--- a/src/lib/crypto/krb/s2k_rc4.c
+++ b/src/lib/crypto/krb/s2k_rc4.c
@@ -25,7 +25,7 @@ krb5int_arcfour_string_to_key(const struct krb5_keytypes *ktp,
     if (utf8 == NULL)
         return err;
     err = k5_utf8_to_utf16le(utf8, &copystr, &copystrlen);
-    free(utf8);
+    zapfree(utf8, string->length);
     if (err)
         return err;