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SubjectRe: [PATCH net] tuntap: correctly handle error in tun_set_iff()
On Wed, Sep 11, 2013 at 04:24:05PM +0800, Jason Wang wrote:
> Commit c8d68e6be1c3b242f1c598595830890b65cea64a (tuntap: multiqueue support)
> only call free_netdev() on err in tun_set_iff(). This causes several issues:
>
> - memory of tun security were leaked

Not just tun security - sock reference too (didn't detach)

> - use after free since the flow gc timer was not deleted and the tfile were not
> detached
>
> This patch solves the above issues.
>
> Reported-by: Wannes Rombouts <wannes.rombouts@epitech.eu>
> Cc: Michael S. Tsirkin <mst@redhat.com>
> Signed-off-by: Jason Wang <jasowang@redhat.com>
> ---
> The patch were also needed for stable 3.8+.
> ---
> drivers/net/tun.c | 9 +++++++--
> 1 files changed, 7 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/net/tun.c b/drivers/net/tun.c
> index a639de8..e5fb5d3 100644
> --- a/drivers/net/tun.c
> +++ b/drivers/net/tun.c
> @@ -1641,11 +1641,11 @@ static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr)
> INIT_LIST_HEAD(&tun->disabled);
> err = tun_attach(tun, file, false);
> if (err < 0)
> - goto err_free_dev;
> + goto err_free_flow;
>
> err = register_netdevice(tun->dev);
> if (err < 0)
> - goto err_free_dev;
> + goto err_detach;
>
> if (device_create_file(&tun->dev->dev, &dev_attr_tun_flags) ||
> device_create_file(&tun->dev->dev, &dev_attr_owner) ||
> @@ -1689,6 +1689,11 @@ static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr)
> strcpy(ifr->ifr_name, tun->dev->name);
> return 0;
>
> +err_detach:
> + tun_detach_all(dev);
> +err_free_flow:
> + tun_flow_uninit(tun);
> + security_tun_dev_free_security(tun->security);

This bit looks wrong: if flow_init fails, we
need security_tun_dev_free_security, don't we?
I think we need:
+err_free_sec: security_tun_dev_free_security(tun->security);
and goto here on flow_init failures.

> err_free_dev:

Pls shift this one 1 space left for consistency.

> free_netdev(dev);
> return err;
> --
> 1.7.1


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