Re: [PATCH net] net: sit: require CAP_NET_ADMIN in the device netns for changelink

[Nicolas Dichtel]

Le 18/06/2026 à 09:08, Maoyi Xie a écrit :
> ipip6_changelink() operates on at most two netns, dev_net(dev) and the
> tunnel link netns t->net. They differ once the device is created in or
> moved to a netns other than the one the request runs in. The rtnl
> changelink path checks CAP_NET_ADMIN only against dev_net(dev), so a
> caller privileged there but not in t->net can rewrite a tunnel that
> lives in t->net.
> 
> Gate ipip6_changelink() on rtnl_dev_link_net_capable() at its top,
> before any attribute is parsed. sit was the one tunnel type not covered
> by the recent series that added this check to the other changelink()
> handlers.
> 
> Fixes: 5e6700b3bf98 ("sit: add support of x-netns")
> Link: https://lore.kernel.org/netdev/20260612085941.3158249-1-maoyixie.tju@xxxxxxxxx/
> Cc: stable@xxxxxxxxxxxxxxx
> Signed-off-by: Maoyi Xie <maoyixie.tju@xxxxxxxxx>

Reviewed-by: Nicolas Dichtel <nicolas.dichtel@xxxxxxxxx>