archive mirror
 help / color / mirror / Atom feed
From: "Gustavo A. R. Silva" <>
To: Oliver Hartkopp <>,
	Marc Kleine-Budde <>,
	"David S. Miller" <>
	"Gustavo A. R. Silva" <>
Subject: [PATCH] can: af_can: Fix Spectre v1 vulnerability
Date: Fri, 21 Dec 2018 15:22:29 -0600	[thread overview]
Message-ID: <20181221212229.GA32635@embeddedor> (raw)

protocol is indirectly controlled by user-space, hence leading to
a potential exploitation of the Spectre variant 1 vulnerability.

This issue was detected with the help of Smatch:

net/can/af_can.c:115 can_get_proto() warn: potential spectre issue 'proto_tab' [w]

Fix this by sanitizing protocol before using it to index proto_tab.

Notice that given that speculation windows are large, the policy is
to kill the speculation on the first load and not worry if it can be
completed with a dependent load/store [1].


Signed-off-by: Gustavo A. R. Silva <>
 net/can/af_can.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/net/can/af_can.c b/net/can/af_can.c
index 1684ba5b51eb..cade7250c6d4 100644
--- a/net/can/af_can.c
+++ b/net/can/af_can.c
@@ -59,6 +59,7 @@
 #include <linux/can/core.h>
 #include <linux/can/skb.h>
 #include <linux/ratelimit.h>
+#include <linux/nospec.h>
 #include <net/net_namespace.h>
 #include <net/sock.h>
@@ -136,6 +137,7 @@ static int can_create(struct net *net, struct socket *sock, int protocol,
 	if (protocol < 0 || protocol >= CAN_NPROTO)
 		return -EINVAL;
+	protocol = array_index_nospec(protocol, CAN_NPROTO);
 	cp = can_get_proto(protocol);

             reply	other threads:[~2018-12-21 21:47 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-12-21 21:22 Gustavo A. R. Silva [this message]
2018-12-23 19:02 ` [PATCH] can: af_can: Fix Spectre v1 vulnerability Oliver Hartkopp

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20181221212229.GA32635@embeddedor \ \ \ \ \ \ \ \

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).