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Commit a29c81e9 authored by Chenbo Feng's avatar Chenbo Feng
Browse files

BACKPORT: UPSTREAM: Add a eBPF helper function to retrieve socket uid 



Cherry-pick from commit 6acc5c2910689fc6ee181bf63085c5efff6a42bd

Returns the owner uid of the socket inside a sk_buff. This is useful to
perform per-UID accounting of network traffic or per-UID packet
filtering. The socket need to be a fullsock otherwise overflowuid is
returned.

Signed-off-by: default avatarChenbo Feng <fengc@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
Bug: 30950746
Change-Id: Idc00947ccfdd4e9f2214ffc4178d701cd9ead0ac
parent 09313663

include/uapi/linux/bpf.h

+9 −0
Original line number Diff line number Diff line
@@ -495,6 +495,15 @@ enum bpf_func_id { 
	 */

	BPF_FUNC_get_socket_cookie,



	/**

	 * u32 bpf_get_socket_uid(skb)

	 *     Get the owner uid of the socket stored inside sk_buff.

	 *     @skb: pointer to skb

	 *     Return: uid of the socket owner on success or 0 if the socket pointer

	 *     inside sk_buff is NULL

	 */

	BPF_FUNC_get_socket_uid,



	__BPF_FUNC_MAX_ID,

};

net/core/filter.c

+20 −0
Original line number Diff line number Diff line
@@ -2547,6 +2547,24 @@ static const struct bpf_func_proto bpf_get_socket_cookie_proto = { 
	.arg1_type      = ARG_PTR_TO_CTX,

};



BPF_CALL_1(bpf_get_socket_uid, struct sk_buff *, skb)

{

	struct sock *sk = sk_to_full_sk(skb->sk);

	kuid_t kuid;



	if (!sk || !sk_fullsock(sk))

		return overflowuid;

	kuid = sock_net_uid(sock_net(sk), sk);

	return from_kuid_munged(sock_net(sk)->user_ns, kuid);

}



static const struct bpf_func_proto bpf_get_socket_uid_proto = {

	.func           = bpf_get_socket_uid,

	.gpl_only       = false,

	.ret_type       = RET_INTEGER,

	.arg1_type      = ARG_PTR_TO_CTX,

};



static const struct bpf_func_proto *

sk_filter_func_proto(enum bpf_func_id func_id)

{
@@ -2570,6 +2588,8 @@ sk_filter_func_proto(enum bpf_func_id func_id) 
			return bpf_get_trace_printk_proto();

	case BPF_FUNC_get_socket_cookie:

		return &bpf_get_socket_cookie_proto;

	case BPF_FUNC_get_socket_uid:

		return &bpf_get_socket_uid_proto;

	default:

		return NULL;

	}

tools/include/uapi/linux/bpf.h

+8 −0
Original line number Diff line number Diff line
@@ -466,6 +466,14 @@ enum bpf_func_id { 
	 */

	BPF_FUNC_get_socket_cookie,



	/**

	 * u32 bpf_get_socket_uid(skb)

	 *     Get the owner uid of the socket stored inside sk_buff.

	 *     @skb: pointer to skb

	 *     Return: uid of the socket owner on success or overflowuid if failed.

	 */

	BPF_FUNC_get_socket_uid,



	__BPF_FUNC_MAX_ID,

};