From dbe9a4173ea53b72b2c35d19f676a85b69f1c9fe Mon Sep 17 00:00:00 2001 From: "Eric W. Biederman" Date: Thu, 6 Sep 2012 18:20:01 +0000 Subject: scm: Don't use struct ucred in NETLINK_CB and struct scm_cookie. Passing uids and gids on NETLINK_CB from a process in one user namespace to a process in another user namespace can result in the wrong uid or gid being presented to userspace. Avoid that problem by passing kuids and kgids instead. - define struct scm_creds for use in scm_cookie and netlink_skb_parms that holds uid and gid information in kuid_t and kgid_t. - Modify scm_set_cred to fill out scm_creds by heand instead of using cred_to_ucred to fill out struct ucred. This conversion ensures userspace does not get incorrect uid or gid values to look at. - Modify scm_recv to convert from struct scm_creds to struct ucred before copying credential values to userspace. - Modify __scm_send to populate struct scm_creds on in the scm_cookie, instead of just copying struct ucred from userspace. - Modify netlink_sendmsg to copy scm_creds instead of struct ucred into the NETLINK_CB. Signed-off-by: "Eric W. Biederman" Signed-off-by: David S. Miller --- net/netlink/af_netlink.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'net/netlink') diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c index 38211991716..f530b1ca177 100644 --- a/net/netlink/af_netlink.c +++ b/net/netlink/af_netlink.c @@ -1399,7 +1399,7 @@ static int netlink_sendmsg(struct kiocb *kiocb, struct socket *sock, NETLINK_CB(skb).pid = nlk->pid; NETLINK_CB(skb).dst_group = dst_group; - memcpy(NETLINK_CREDS(skb), &siocb->scm->creds, sizeof(struct ucred)); + NETLINK_CB(skb).creds = siocb->scm->creds; err = -EFAULT; if (memcpy_fromiovec(skb_put(skb, len), msg->msg_iov, len)) { -- cgit v1.2.3-18-g5258