From mboxrd@z Thu Jan 1 00:00:00 1970 From: Joe Perches Date: Mon, 13 Apr 2020 21:31:32 +0000 Subject: Re: [PATCH 2/2] crypto: Remove unnecessary memzero_explicit() Message-Id: List-Id: References: <20200413211550.8307-1-longman@redhat.com> <20200413211550.8307-3-longman@redhat.com> In-Reply-To: <20200413211550.8307-3-longman@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Waiman Long , Andrew Morton , David Howells , Jarkko Sakkinen , James Morris , "Serge E. Hallyn" , Linus Torvalds , Matthew Wilcox , David Rientjes Cc: samba-technical@lists.samba.org, virtualization@lists.linux-foundation.org, linux-mm@kvack.org, linux-sctp@vger.kernel.org, target-devel@vger.kernel.org, linux-stm32@st-md-mailman.stormreply.com, devel@driverdev.osuosl.org, linux-s390@vger.kernel.org, linux-scsi@vger.kernel.org, x86@kernel.org, kasan-dev@googlegroups.com, cocci@systeme.lip6.fr, linux-wpan@vger.kernel.org, intel-wired-lan@lists.osuosl.org, linux-crypto@vger.kernel.org, linux-pm@vger.kernel.org, ecryptfs@vger.kernel.org, linux-nfs@vger.kernel.org, linux-fscrypt@vger.kernel.org, linux-mediatek@lists.infradead.org, linux-amlogic@lists.infradead.org, linux-arm-kernel@lists.infradead.org, linux-cifs@vger.kernel.org, netdev@vger.kernel.org, linux-wireless@vger.kernel.org, linux-kernel@vger.kernel.org, linux-bluetooth@vger.kernel.org, linux-security-module@vger.kernel.org, keyrings@vger.kernel.org, tipc-discussion@lists.sourceforge.net, wireguard@lists.zx2c4.com, linux-ppp@vger.kernel.org, linux-integrity@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-btrfs@vger.kernel.org On Mon, 2020-04-13 at 17:15 -0400, Waiman Long wrote: > Since kfree_sensitive() will do an implicit memzero_explicit(), there > is no need to call memzero_explicit() before it. Eliminate those > memzero_explicit() and simplify the call sites. 2 bits of trivia: > diff --git a/drivers/crypto/allwinner/sun8i-ce/sun8i-ce-cipher.c b/drivers/crypto/allwinner/sun8i-ce/sun8i-ce-cipher.c [] > @@ -391,10 +388,7 @@ int sun8i_ce_aes_setkey(struct crypto_skcipher *tfm, const u8 *key, > dev_dbg(ce->dev, "ERROR: Invalid keylen %u\n", keylen); > return -EINVAL; > } > - if (op->key) { > - memzero_explicit(op->key, op->keylen); > - kfree(op->key); > - } > + kfree_sensitive(op->key); > op->keylen = keylen; > op->key = kmemdup(key, keylen, GFP_KERNEL | GFP_DMA); > if (!op->key) It might be a defect to set op->keylen before the kmemdup succeeds. > @@ -416,10 +410,7 @@ int sun8i_ce_des3_setkey(struct crypto_skcipher *tfm, const u8 *key, > if (err) > return err; > > - if (op->key) { > - memzero_explicit(op->key, op->keylen); > - kfree(op->key); > - } > + free_sensitive(op->key, op->keylen); Why not kfree_sensitive(op->key) ?