netlink: Make the sending netlink socket availabe in NETLINK_CB (3fbc2905) · Commits · 戴 / test

The sending socket of an skb is already available by it's port id in the NETLINK_CB. If you want to know more like to examine the credentials on the sending socket you have to look up the sending socket by it's port id and all of the needed functions and data structures are static inside of af_netlink.c. So do the simple thing and pass the sending socket to the receivers in the NETLINK_CB. I intend to use this to get the user namespace of the sending socket in inet_diag so that I can report uids in the context of the process who opened the socket, the same way I report uids in the contect of the process who opens files. Acked-by:

David S. Miller <davem@davemloft.net> Acked-by:

Serge Hallyn <serge.hallyn@canonical.com> Signed-off-by:

Eric W. Biederman <ebiederm@xmission.com>

include/linux/netlink.h

+1 −0

Original line number	Diff line number	Diff line
		@@ -165,6 +165,7 @@ struct netlink_skb_parms {
		struct ucred creds; /* Skb credentials */
		__u32 pid;
		__u32 dst_group;
		struct sock *ssk;
		};

		#define NETLINK_CB(skb) ((struct netlink_skb_parms)&((skb)->cb))

net/netlink/af_netlink.c

+4 −2

Original line number	Diff line number	Diff line
		@@ -912,7 +912,8 @@ static void netlink_rcv_wake(struct sock *sk)
		wake_up_interruptible(&nlk->wait);
		}

		static int netlink_unicast_kernel(struct sock sk, struct sk_buff skb)
		static int netlink_unicast_kernel(struct sock sk, struct sk_buff skb,
		struct sock *ssk)
		{
		int ret;
		struct netlink_sock *nlk = nlk_sk(sk);
		@@ -921,6 +922,7 @@ static int netlink_unicast_kernel(struct sock sk, struct sk_buff skb)
		if (nlk->netlink_rcv != NULL) {
		ret = skb->len;
		skb_set_owner_r(skb, sk);
		NETLINK_CB(skb).ssk = ssk;
		nlk->netlink_rcv(skb);
		consume_skb(skb);
		} else {
		@@ -947,7 +949,7 @@ retry:
		return PTR_ERR(sk);
		}
		if (netlink_is_kernel(sk))
		return netlink_unicast_kernel(sk, skb);
		return netlink_unicast_kernel(sk, skb, ssk);

		if (sk_filter(sk, skb)) {
		err = skb->len;

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