lkml.org 
[lkml]   [2018]   [Dec]   [23]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [PATCH] can: af_can: Fix Spectre v1 vulnerability
From
Date
After *trying* to follow the discussion on ...

https://marc.info/?l=linux-kernel&m=154554485324143&w=2
[PATCH] net: core: Fix Spectre v1 vulnerability

... I'm still not sure whether af_can.c needs this enhancement or not.

Just waiting for the end of the discussion :-)

Thanks to the experts!

Oliver

On 12/21/18 10:22 PM, Gustavo A. R. Silva wrote:
> 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].
>
> [1] https://marc.info/?l=linux-kernel&m=152449131114778&w=2
>
> Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
> ---
> 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);
>
>

\
 
 \ /
  Last update: 2018-12-23 20:15    [W:0.033 / U:0.484 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site