[v2,38/63] xfrm: Use memset_after() to clear padding

Message ID	20210818060533.3569517-39-keescook@chromium.org
State	New
Headers	show Return-Path: <linux-wireless-owner@kernel.org> From: Kees Cook <keescook@chromium.org> To: linux-kernel@vger.kernel.org Cc: Kees Cook <keescook@chromium.org>, Steffen Klassert <steffen.klassert@secunet.com>, Herbert Xu <herbert@gondor.apana.org.au>, "David S. Miller" <davem@davemloft.net>, Jakub Kicinski <kuba@kernel.org>, netdev@vger.kernel.org, "Gustavo A. R. Silva" <gustavoars@kernel.org>, Greg Kroah-Hartman <gregkh@linuxfoundation.org>, Andrew Morton <akpm@linux-foundation.org>, linux-wireless@vger.kernel.org, dri-devel@lists.freedesktop.org, linux-staging@lists.linux.dev, linux-block@vger.kernel.org, linux-kbuild@vger.kernel.org, clang-built-linux@googlegroups.com, Rasmus Villemoes <linux@rasmusvillemoes.dk>, linux-hardening@vger.kernel.org Subject: [PATCH v2 38/63] xfrm: Use memset_after() to clear padding Date: Tue, 17 Aug 2021 23:05:08 -0700 Message-Id: <20210818060533.3569517-39-keescook@chromium.org> In-Reply-To: <20210818060533.3569517-1-keescook@chromium.org> References: <20210818060533.3569517-1-keescook@chromium.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk
Series	Introduce strict memcpy() bounds checking \| expand [v2,00/63] Introduce strict memcpy() bounds checking [v2,04/63] pcmcia: ray_cs: Split memcpy() to avoid bounds check warning [v2,05/63] stddef: Introduce struct_group() helper macro [v2,07/63] skbuff: Switch structure bounds to struct_group() [v2,08/63] bnxt_en: Use struct_group_attr() for memcpy() region [v2,12/63] thermal: intel: int340x_thermal: Use struct_group() for memcpy() region [v2,13/63] iommu/amd: Use struct_group() for memcpy() region [v2,15/63] intersil: Use struct_group() for memcpy() region [v2,17/63] bnx2x: Use struct_group() for memcpy() region [v2,18/63] drm/amd/pm: Use struct_group() for memcpy() region [v2,21/63] net/mlx5e: Use struct_group() for memcpy() region [v2,23/63] media: omap3isp: Use struct_group() for memcpy() region [v2,26/63] lib/string: Move helper functions out of string.c [v2,27/63] fortify: Move remaining fortify helpers into fortify-string.h [v2,28/63] fortify: Explicitly disable Clang support [v2,31/63] fortify: Allow strlen() and strnlen() to pass compile-time known lengths [v2,34/63] fortify: Detect struct member overflows in memcpy() at compile-time [v2,37/63] string.h: Introduce memset_after() for wiping trailing members/padding [v2,38/63] xfrm: Use memset_after() to clear padding [v2,40/63] netfilter: conntrack: Use memset_startat() to zero struct nf_conn [v2,41/63] net: 802: Use memset_startat() to clear struct fields [v2,42/63] net: dccp: Use memset_startat() for TP zeroing [v2,44/63] mac80211: Use memset_after() to clear tx status [v2,45/63] ath11k: Use memset_startat() for clearing queue descriptors [v2,47/63] intel_th: msu: Use memset_startat() for clearing hw header [v2,48/63] IB/mthca: Use memset_startat() for clearing mpt_entry [v2,49/63] btrfs: Use memset_startat() to clear end of struct [v2,52/63] cm4000_cs: Use struct_group() to zero struct cm4000_dev region [v2,55/63] HID: roccat: Use struct_group() to zero kone_mouse_event [v2,58/63] ethtool: stats: Use struct_group() to clear all stats at once [v2,60/63] net/af_iucv: Use struct_group() to zero struct iucv_sock region [v2,61/63] powerpc: Split memset() to avoid multi-field overflow

Message ID

20210818060533.3569517-39-keescook@chromium.org

State

New

Headers

From: Kees Cook <keescook@chromium.org>
To: linux-kernel@vger.kernel.org
Cc: Kees Cook <keescook@chromium.org>,
	Steffen Klassert <steffen.klassert@secunet.com>,
	Herbert Xu <herbert@gondor.apana.org.au>,
	"David S. Miller" <davem@davemloft.net>,
	Jakub Kicinski <kuba@kernel.org>, netdev@vger.kernel.org,
	"Gustavo A. R. Silva" <gustavoars@kernel.org>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	linux-wireless@vger.kernel.org, dri-devel@lists.freedesktop.org,
	linux-staging@lists.linux.dev, linux-block@vger.kernel.org,
	linux-kbuild@vger.kernel.org, clang-built-linux@googlegroups.com,
	Rasmus Villemoes <linux@rasmusvillemoes.dk>,
	linux-hardening@vger.kernel.org
Subject: [PATCH v2 38/63] xfrm: Use memset_after() to clear padding
Date: Tue, 17 Aug 2021 23:05:08 -0700
Message-Id: <20210818060533.3569517-39-keescook@chromium.org>
In-Reply-To: <20210818060533.3569517-1-keescook@chromium.org>
References: <20210818060533.3569517-1-keescook@chromium.org>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

Series

Introduce strict memcpy() bounds checking | expand

Commit Message

Kees Cook Aug. 18, 2021, 6:05 a.m. UTC

In preparation for FORTIFY_SOURCE performing compile-time and run-time
field bounds checking for memset(), avoid intentionally writing across
neighboring fields.

Clear trailing padding bytes using the new helper so that memset()
doesn't get confused about writing "past the end" of the last struct
member. There is no change to the resulting machine code.

Cc: Steffen Klassert <steffen.klassert@secunet.com>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: netdev@vger.kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>
---
 net/xfrm/xfrm_policy.c | 4 +---
 net/xfrm/xfrm_user.c   | 2 +-
 2 files changed, 2 insertions(+), 4 deletions(-)

diff --git a/net/xfrm/xfrm_policy.c b/net/xfrm/xfrm_policy.c
index 37d17a79617c..1a06585022ab 100644
--- a/net/xfrm/xfrm_policy.c
+++ b/net/xfrm/xfrm_policy.c
@@ -2486,9 +2486,7 @@  static inline struct xfrm_dst *xfrm_alloc_dst(struct net *net, int family)
 	xdst = dst_alloc(dst_ops, NULL, 1, DST_OBSOLETE_NONE, 0);
 
 	if (likely(xdst)) {
-		struct dst_entry *dst = &xdst->u.dst;
-
-		memset(dst + 1, 0, sizeof(*xdst) - sizeof(*dst));
+		memset_after(xdst, 0, u.dst);
 	} else
 		xdst = ERR_PTR(-ENOBUFS);
 
diff --git a/net/xfrm/xfrm_user.c b/net/xfrm/xfrm_user.c
index 03b66d154b2b..b7b986520dc7 100644
--- a/net/xfrm/xfrm_user.c
+++ b/net/xfrm/xfrm_user.c
@@ -2912,7 +2912,7 @@  static int build_expire(struct sk_buff *skb, struct xfrm_state *x, const struct
 	copy_to_user_state(x, &ue->state);
 	ue->hard = (c->data.hard != 0) ? 1 : 0;
 	/* clear the padding bytes */
-	memset(&ue->hard + 1, 0, sizeof(*ue) - offsetofend(typeof(*ue), hard));
+	memset_after(ue, 0, hard);
 
 	err = xfrm_mark_put(skb, &x->mark);
 	if (err)

[v2,38/63] xfrm: Use memset_after() to clear padding

Commit Message

Patch