Am 19.06.2016 um 12:36 schrieb Shanker Wang: > >> 在 2016年6月19日，12:13，Richard Weinberger <rich...@nod.at> 写道： >> >> Am 19.06.2016 um 07:21 schrieb Shanker Wang: >>> This patch removes the check for CAP_NET_ADMIN in the initial namespace >>> when opening /dev/open. Instead, CAP_NET_ADMIN is checked in the user >>> namespace the net namespace was created so that /dev/ppp cat get opened >>> in a unprivileged container. >>> >>> Cc: Hannes Frederic Sowa <han...@stressinduktion.org> >>> Cc: Richard Weinberger <richard.weinber...@gmail.com> >>> Cc: Guillaume Nault <g.na...@alphalink.fr> >>> Cc: Miao Wang <shankerwangm...@gmail.com> >>> Signed-off-by: Miao Wang <miao.w...@tuna.tsinghua.edu.cn> >>> --- >>> drivers/net/ppp/ppp_generic.c | 2 +- >>> 1 file changed, 1 insertion(+), 1 deletion(-) >>> >>> diff --git a/drivers/net/ppp/ppp_generic.c b/drivers/net/ppp/ppp_generic.c >>> index f572b31..4b3b2b5 100644 >>> --- a/drivers/net/ppp/ppp_generic.c >>> +++ b/drivers/net/ppp/ppp_generic.c >>> @@ -380,7 +380,7 @@ static int ppp_open(struct inode *inode, struct file >>> *file) >>> /* >>> * This could (should?) be enforced by the permissions on /dev/ppp. >>> */ >>> - if (!capable(CAP_NET_ADMIN)) >>> + if (!ns_capable(current->nsproxy->net_ns->user_ns, CAP_NET_ADMIN)) >>> return -EPERM; >> >> Shouldn't this be a ns_capable(net->user_ns, …? >> Otherwise an user can create a new user_ns followed by a new net_ns and has >> CAP_NET_ADMIN. We need to check whether he is allowed in the user_ns of the >> net_ns which belongs to the ppp net device which you want to open. > You are totally right. However, I wonder how can i get the “net” struct when > opening /dev/ppp
I'm sure you can get it somehow via file->private_data. Thanks, //richard
