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From:   Eric Dumazet <edumazet@google.com>
Date:   Wed, 14 Mar 2018 07:11:43 -0700
Message-ID: <CANn89iL8gWYReSPRfhHdyYT1+TC+GwxTD45SG+zjCMBEYjY3KQ@mail.gmail.com>
Subject: Re: [PATCH] netlink: make sure nladdr has correct size in netlink_connect()
To:     Alexander Potapenko <glider@google.com>
Cc:     Dmitry Vyukov <dvyukov@google.com>,
        David Miller <davem@davemloft.net>,
        netdev <netdev@vger.kernel.org>,
        LKML <linux-kernel@vger.kernel.org>
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On Wed, Mar 14, 2018 at 7:03 AM, Alexander Potapenko <glider@google.com> wrote:
> KMSAN reports use of uninitialized memory in the case when |alen| is
> smaller than sizeof(struct netlink_sock), and therefore |nladdr| isn't
> fully copied from the userspace.
>
> Signed-off-by: Alexander Potapenko <glider@google.com>
> Fixes: 1da177e4c3f41524 ("Linux-2.6.12-rc2")
> ---
>  net/netlink/af_netlink.c | 3 +++
>  1 file changed, 3 insertions(+)
>
> diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c
> index 07e8478068f0..5d49b39e81c3 100644
> --- a/net/netlink/af_netlink.c
> +++ b/net/netlink/af_netlink.c
> @@ -1085,6 +1085,9 @@ static int netlink_connect(struct socket *sock, struct sockaddr *addr,
>         if (addr->sa_family != AF_NETLINK)
>                 return -EINVAL;
>
> +       if (alen < sizeof(struct netlink_sock))
> +               return -EINVAL;
> +
>

Hmmm. How was this patch tested exactly ?

Thanks.