From: Matt Caswell <matt@openssl.org>
Date: Wed, 16 Sep 2015 09:47:15 +0000 (+0100)
Subject: Make sure OPENSSL_cleanse checks for NULL
X-Git-Tag: OpenSSL_1_1_0-pre1~603
X-Git-Url: https://git.openssl.org/gitweb/?p=openssl.git;a=commitdiff_plain;h=020d8fc83fe1a94232db1ee1166309e2458a8a18;hp=b785504a10310cb2872270eb409b70971be5e76e

Make sure OPENSSL_cleanse checks for NULL

In master we have the function OPENSSL_clear_free(x,y), which immediately
returns if x == NULL. In <=1.0.2 this function does not exist so we have to
do:
OPENSSL_cleanse(x, y);
OPENSSL_free(x);

However, previously, OPENSSL_cleanse did not check that if x == NULL, so
the real equivalent check would have to be:
if (x != NULL)
    OPENSSL_cleanse(x, y);
OPENSSL_free(x);

It would be easy to get this wrong during cherry-picking to other branches
and therefore, for safety, it is best to just ensure OPENSSL_cleanse also
checks for NULL.

Reviewed-by: Rich Salz <rsalz@openssl.org>
---

diff --git a/crypto/mem_clr.c b/crypto/mem_clr.c
index 3df1f3928d..1a06636d0c 100644
--- a/crypto/mem_clr.c
+++ b/crypto/mem_clr.c
@@ -66,6 +66,10 @@ void OPENSSL_cleanse(void *ptr, size_t len)
 {
     unsigned char *p = ptr;
     size_t loop = len, ctr = cleanse_ctr;
+
+    if (ptr == NULL)
+        return;
+
     while (loop--) {
         *(p++) = (unsigned char)ctr;
         ctr += (17 + ((size_t)p & 0xF));