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SubjectRe: [PATCH] can: check for null sk before deferencing it via the call to sock_net
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On 09/08/2017 05:02 PM, Colin King wrote:
> From: Colin Ian King <colin.king@canonical.com>
>
> The assignment of net via call sock_net will dereference sk. This
> is performed before a sanity null check on sk, so there could be
> a potential null dereference on the sock_net call if sk is null.
> Fix this by assigning net after the sk null check. Also replace
> the sk == NULL with the more usual !sk idiom.
>
> Detected by CoverityScan CID#1431862 ("Dereference before null check")
>
> Fixes: 384317ef4187 ("can: network namespace support for CAN_BCM protocol")
> Signed-off-by: Colin Ian King <colin.king@canonical.com>

Acked-by: Oliver Hartkopp <socketcan@hartkopp.net>


Thanks Collin!

> ---
> net/can/bcm.c | 5 +++--
> 1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/net/can/bcm.c b/net/can/bcm.c
> index 47a8748d953a..a3791674b8ce 100644
> --- a/net/can/bcm.c
> +++ b/net/can/bcm.c
> @@ -1493,13 +1493,14 @@ static int bcm_init(struct sock *sk)
> static int bcm_release(struct socket *sock)
> {
> struct sock *sk = sock->sk;
> - struct net *net = sock_net(sk);
> + struct net *net;
> struct bcm_sock *bo;
> struct bcm_op *op, *next;
>
> - if (sk == NULL)
> + if (!sk)
> return 0;
>
> + net = sock_net(sk);
> bo = bcm_sk(sk);
>
> /* remove bcm_ops, timer, rx_unregister(), etc. */
>

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