lists.openwall.net   lists  /  announce  owl-users  owl-dev  john-users  john-dev  passwdqc-users  yescrypt  popa3d-users  /  oss-security  kernel-hardening  musl  sabotage  tlsify  passwords  /  crypt-dev  xvendor  /  Bugtraq  Full-Disclosure  linux-kernel  linux-netdev  linux-ext4  linux-hardening  PHC 
Open Source and information security mailing list archives
 
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Date:   Tue, 17 Aug 2021 23:05:08 -0700
From:   Kees Cook <keescook@...omium.org>
To:     linux-kernel@...r.kernel.org
Cc:     Kees Cook <keescook@...omium.org>,
        Steffen Klassert <steffen.klassert@...unet.com>,
        Herbert Xu <herbert@...dor.apana.org.au>,
        "David S. Miller" <davem@...emloft.net>,
        Jakub Kicinski <kuba@...nel.org>, netdev@...r.kernel.org,
        "Gustavo A. R. Silva" <gustavoars@...nel.org>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Andrew Morton <akpm@...ux-foundation.org>,
        linux-wireless@...r.kernel.org, dri-devel@...ts.freedesktop.org,
        linux-staging@...ts.linux.dev, linux-block@...r.kernel.org,
        linux-kbuild@...r.kernel.org, clang-built-linux@...glegroups.com,
        Rasmus Villemoes <linux@...musvillemoes.dk>,
        linux-hardening@...r.kernel.org
Subject: [PATCH v2 38/63] xfrm: Use memset_after() to clear padding

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@...unet.com>
Cc: Herbert Xu <herbert@...dor.apana.org.au>
Cc: "David S. Miller" <davem@...emloft.net>
Cc: Jakub Kicinski <kuba@...nel.org>
Cc: netdev@...r.kernel.org
Signed-off-by: Kees Cook <keescook@...omium.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)
-- 
2.30.2

Powered by blists - more mailing lists