From 31d5c3897686a2e2055a2f14acb76fec1f5c6305 Mon Sep 17 00:00:00 2001
From: Jeffrey Altman <jaltman@secure-endpoints.com>
Date: Mon, 24 Jan 2022 10:14:17 -0500
Subject: [PATCH] lib/hcrypto: mpz2BN return NULL if mp_ubin_size(s) returns
 zero

If mp_ubin_size(s) returns zero then mp_to_ubin() will fail and
not return MP_OKAY.  If MP_OKAY is not returned, NULL is returned
to the caller of mpz2BN().

This change avoids the unnecessary memory allocation and function
calls.  It also removes a dereference after null warning from
coverity.

Change-Id: I52ff2c166964e41cb4eef1dac637904bf2bf13bf
---
 lib/hcrypto/rsa-ltm.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/lib/hcrypto/rsa-ltm.c b/lib/hcrypto/rsa-ltm.c
index 28515195d..1d5b73e60 100644
--- a/lib/hcrypto/rsa-ltm.c
+++ b/lib/hcrypto/rsa-ltm.c
@@ -456,8 +456,11 @@ mpz2BN(mp_int *s)
     void *p;
 
     size = mp_ubin_size(s);
+    if (size == 0)
+	return NULL;
+
     p = malloc(size);
-    if (p == NULL && size != 0)
+    if (p == NULL)
 	return NULL;
 
     ret = mp_to_ubin(s, p, SIZE_MAX, NULL);
-- 
2.11.4.GIT