From a61cc44812ff94793987bf43b70a3d9bc64a6820 Mon Sep 17 00:00:00 2001
From: Jesper Juhl <juhl-lkml@dif.dk>
Date: Wed, 6 Jul 2005 13:54:31 -0700
Subject: [PATCH] [CRYPTO] Add null short circuit to crypto_free_tfm
As far as I'm aware there's a general concensus that functions that are
responsible for freeing resources should be able to cope with being passed
a NULL pointer. This makes sense as it removes the need for all callers to
check for NULL, thus elliminating the bugs that happen when some forget
(safer to just check centrally in the freeing function) and it also makes
for smaller code all over due to the lack of all those NULL checks.
This patch makes it safe to pass the crypto_free_tfm() function a NULL
pointer. Once this patch is applied we can start removing the NULL checks
from the callers.
Signed-off-by: Jesper Juhl <juhl-lkml@dif.dk>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
crypto/api.c | 12 ++++++++++--
1 file changed, 10 insertions(+), 2 deletions(-)
diff --git a/crypto/api.c b/crypto/api.c
index 2d8d828c0ca2..b4728811ce3b 100644
--- a/crypto/api.c
+++ b/crypto/api.c
@@ -13,6 +13,8 @@
* any later version.
*
*/
+
+#include <linux/compiler.h>
#include <linux/init.h>
#include <linux/crypto.h>
#include <linux/errno.h>
@@ -189,8 +191,14 @@ out:
void crypto_free_tfm(struct crypto_tfm *tfm)
{
- struct crypto_alg *alg = tfm->__crt_alg;
- int size = sizeof(*tfm) + alg->cra_ctxsize;
+ struct crypto_alg *alg;
+ int size;
+
+ if (unlikely(!tfm))
+ return;
+
+ alg = tfm->__crt_alg;
+ size = sizeof(*tfm) + alg->cra_ctxsize;
crypto_exit_ops(tfm);
crypto_alg_put(alg);
--
GitLab