From 9e185cd611e2f7f245b63dd02fa46bda9cc32875 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ond=C5=99ej=20Sur=C3=BD?= <ondrej@isc.org>
Date: Mon, 9 Jan 2023 16:00:18 +0100
Subject: [PATCH] BN_free() and BN_clear_free() both accept NULL

Remove the extra check in opensslrsa_components_free() as both BN_free()
and BN_clear_free() both accepts NULL as valid argument and do nothing.
---
 lib/dns/opensslrsa_link.c | 39 +++++++++++++++------------------------
 1 file changed, 15 insertions(+), 24 deletions(-)

diff --git a/lib/dns/opensslrsa_link.c b/lib/dns/opensslrsa_link.c
index 221e9e1723..7ee70eebfe 100644
--- a/lib/dns/opensslrsa_link.c
+++ b/lib/dns/opensslrsa_link.c
@@ -144,30 +144,21 @@ opensslrsa_components_free(rsa_components_t *c) {
 	if (!c->bnfree) {
 		return;
 	}
-	if (c->e != NULL) {
-		BN_free((BIGNUM *)c->e);
-	}
-	if (c->n != NULL) {
-		BN_free((BIGNUM *)c->n);
-	}
-	if (c->d != NULL) {
-		BN_clear_free((BIGNUM *)c->d);
-	}
-	if (c->p != NULL) {
-		BN_clear_free((BIGNUM *)c->p);
-	}
-	if (c->q != NULL) {
-		BN_clear_free((BIGNUM *)c->q);
-	}
-	if (c->dmp1 != NULL) {
-		BN_clear_free((BIGNUM *)c->dmp1);
-	}
-	if (c->dmq1 != NULL) {
-		BN_clear_free((BIGNUM *)c->dmq1);
-	}
-	if (c->iqmp != NULL) {
-		BN_clear_free((BIGNUM *)c->iqmp);
-	}
+	/*
+	 * NOTE: BN_free() frees the components of the BIGNUM, and if it was
+	 * created by BN_new(), also the structure itself. BN_clear_free()
+	 * additionally overwrites the data before the memory is returned to the
+	 * system. If a is NULL, nothing is done.
+	 */
+	BN_free((BIGNUM *)c->e);
+	BN_free((BIGNUM *)c->n);
+	BN_clear_free((BIGNUM *)c->d);
+	BN_clear_free((BIGNUM *)c->p);
+	BN_clear_free((BIGNUM *)c->q);
+	BN_clear_free((BIGNUM *)c->dmp1);
+	BN_clear_free((BIGNUM *)c->dmq1);
+	BN_clear_free((BIGNUM *)c->iqmp);
+	c->bnfree = false;
 }
 
 static bool