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Commit 101a6e83 authored by David S. Miller's avatar David S. Miller
Browse files

Merge branch 'bpf-socket-cookie-uid' 



Chenbo Feng says:

====================
net: core: Two Helper function about socket information

Introduce two eBpf helper function to get the socket cookie and
socket uid for each packet. The helper function is useful when
the *sk field inside sk_buff is not empty. These helper functions
can be used on socket and uid based traffic monitoring programs.

Change since V7:
* change the user namespace of uid helper function to sock_net(sk)->user_ns

Change since V6:
* change the user namespace of uid helper function back to init_user_ns
  since in some situation, for example, pinned bpf object, the current
  user namespace is not always applicable.

Change since V5:
* Delete unnecessary blank lines in sample program.
* Refine the variable orders in get_uid helper function.

Change since V4:
* Using current user namespace to get uid instead of using init_ns.
* Add compiling setup of example program in to Makefile.
* Change the name style of the example program binaries.

Change since V3:
* Fixed some typos and incorrect comments in sample program
* replaced raw insns with BPF_STX_XADD and add it to libbpf.h
* Use a temp dir as mount point instead and added a check for
  the user input string.
* Make the get uid helper function returns the user namespace uid
  instead of kuid.
* Return a overflowuid instead of 0 when no uid information is found.

Change since V2:
* Add a sample program to demostrate the usage of the helper function.
* Moved the helper function proto invoking place.
* Add function header into tools/include
* Apply sk_to_full_sk() before getting uid.

Change since V1:
* Removed the unnecessary declarations and export command
* resolved conflict with master branch.
* Examine if the socket is a full socket before getting the uid.
====================

Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parents 16ae1f22 51570a5a

include/linux/sock_diag.h

+1 −0
Original line number Diff line number Diff line
@@ -24,6 +24,7 @@ void sock_diag_unregister(const struct sock_diag_handler *h); 
void sock_diag_register_inet_compat(int (*fn)(struct sk_buff *skb, struct nlmsghdr *nlh));

void sock_diag_unregister_inet_compat(int (*fn)(struct sk_buff *skb, struct nlmsghdr *nlh));



u64 sock_gen_cookie(struct sock *sk);

int sock_diag_check_cookie(struct sock *sk, const __u32 *cookie);

void sock_diag_save_cookie(struct sock *sk, __u32 *cookie);

include/uapi/linux/bpf.h

+15 −1
Original line number Diff line number Diff line
@@ -459,6 +459,18 @@ union bpf_attr { 
 *     Return:

 *       > 0 length of the string including the trailing NUL on success

 *       < 0 error

 *

 * u64 bpf_bpf_get_socket_cookie(skb)

 *     Get the cookie for the socket stored inside sk_buff.

 *     @skb: pointer to skb

 *     Return: 8 Bytes non-decreasing number on success or 0 if the socket

 *     field is missing inside sk_buff

 *

 * 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

 */

#define __BPF_FUNC_MAPPER(FN)		\

	FN(unspec),			\
@@ -506,7 +518,9 @@ union bpf_attr { 
	FN(get_numa_node_id),		\

	FN(skb_change_head),		\

	FN(xdp_adjust_head),		\

	FN(probe_read_str),

	FN(probe_read_str),		\

	FN(get_socket_cookie),		\

	FN(get_socket_uid),



/* integer value in 'imm' field of BPF_CALL instruction selects which helper

 * function eBPF program intends to call

net/core/filter.c

+39 −0
Original line number Diff line number Diff line
@@ -26,6 +26,7 @@ 
#include <linux/mm.h>

#include <linux/fcntl.h>

#include <linux/socket.h>

#include <linux/sock_diag.h>

#include <linux/in.h>

#include <linux/inet.h>

#include <linux/netdevice.h>
@@ -2606,6 +2607,36 @@ static const struct bpf_func_proto bpf_xdp_event_output_proto = { 
	.arg5_type	= ARG_CONST_SIZE,

};



BPF_CALL_1(bpf_get_socket_cookie, struct sk_buff *, skb)

{

	return skb->sk ? sock_gen_cookie(skb->sk) : 0;

}



static const struct bpf_func_proto bpf_get_socket_cookie_proto = {

	.func           = bpf_get_socket_cookie,

	.gpl_only       = false,

	.ret_type       = RET_INTEGER,

	.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 *

bpf_base_func_proto(enum bpf_func_id func_id)

{
@@ -2640,6 +2671,10 @@ sk_filter_func_proto(enum bpf_func_id func_id) 
	switch (func_id) {

	case BPF_FUNC_skb_load_bytes:

		return &bpf_skb_load_bytes_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 bpf_base_func_proto(func_id);

	}
@@ -2699,6 +2734,10 @@ tc_cls_act_func_proto(enum bpf_func_id func_id) 
		return &bpf_get_smp_processor_id_proto;

	case BPF_FUNC_skb_under_cgroup:

		return &bpf_skb_under_cgroup_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 bpf_base_func_proto(func_id);

	}

net/core/sock_diag.c

+1 −1
Original line number Diff line number Diff line
@@ -19,7 +19,7 @@ static int (*inet_rcv_compat)(struct sk_buff *skb, struct nlmsghdr *nlh); 
static DEFINE_MUTEX(sock_diag_table_mutex);

static struct workqueue_struct *broadcast_wq;



static u64 sock_gen_cookie(struct sock *sk)

u64 sock_gen_cookie(struct sock *sk)

{

	while (1) {

		u64 res = atomic64_read(&sk->sk_cookie);

samples/bpf/Makefile

+3 −0
Original line number Diff line number Diff line
@@ -35,6 +35,7 @@ hostprogs-y += tc_l2_redirect 
hostprogs-y += lwt_len_hist

hostprogs-y += xdp_tx_iptunnel

hostprogs-y += test_map_in_map

hostprogs-y += per_socket_stats_example



# Libbpf dependencies

LIBBPF := ../../tools/lib/bpf/bpf.o
@@ -74,6 +75,7 @@ tc_l2_redirect-objs := bpf_load.o $(LIBBPF) tc_l2_redirect_user.o 
lwt_len_hist-objs := bpf_load.o $(LIBBPF) lwt_len_hist_user.o

xdp_tx_iptunnel-objs := bpf_load.o $(LIBBPF) xdp_tx_iptunnel_user.o

test_map_in_map-objs := bpf_load.o $(LIBBPF) test_map_in_map_user.o

per_socket_stats_example-objs := $(LIBBPF) cookie_uid_helper_example.o



# Tell kbuild to always build the programs

always := $(hostprogs-y)
@@ -108,6 +110,7 @@ always += sampleip_kern.o 
always += lwt_len_hist_kern.o

always += xdp_tx_iptunnel_kern.o

always += test_map_in_map_kern.o

always += cookie_uid_helper_example.o



HOSTCFLAGS += -I$(objtree)/usr/include

HOSTCFLAGS += -I$(srctree)/tools/lib/