samples/bpf: add userspace example for prohibiting sockets (554ae6e7) · Commits · e / devices / android_kernel_fairphone_FP4

samples/bpf/Makefile

+4 −0

Original line number	Diff line number	Diff line
		@@ -24,6 +24,7 @@ hostprogs-y += test_overhead
		hostprogs-y += test_cgrp2_array_pin
		hostprogs-y += test_cgrp2_attach
		hostprogs-y += test_cgrp2_sock
		hostprogs-y += test_cgrp2_sock2
		hostprogs-y += xdp1
		hostprogs-y += xdp2
		hostprogs-y += test_current_task_under_cgroup
		@@ -54,6 +55,7 @@ test_overhead-objs := bpf_load.o libbpf.o test_overhead_user.o
		test_cgrp2_array_pin-objs := libbpf.o test_cgrp2_array_pin.o
		test_cgrp2_attach-objs := libbpf.o test_cgrp2_attach.o
		test_cgrp2_sock-objs := libbpf.o test_cgrp2_sock.o
		test_cgrp2_sock2-objs := bpf_load.o libbpf.o test_cgrp2_sock2.o
		xdp1-objs := bpf_load.o libbpf.o xdp1_user.o
		# reuse xdp1 source intentionally
		xdp2-objs := bpf_load.o libbpf.o xdp1_user.o
		@@ -75,6 +77,7 @@ always += tracex3_kern.o
		always += tracex4_kern.o
		always += tracex5_kern.o
		always += tracex6_kern.o
		always += sock_flags_kern.o
		always += test_probe_write_user_kern.o
		always += trace_output_kern.o
		always += tcbpf1_kern.o
		@@ -109,6 +112,7 @@ HOSTLOADLIBES_tracex3 += -lelf
		HOSTLOADLIBES_tracex4 += -lelf -lrt
		HOSTLOADLIBES_tracex5 += -lelf
		HOSTLOADLIBES_tracex6 += -lelf
		HOSTLOADLIBES_test_cgrp2_sock2 += -lelf
		HOSTLOADLIBES_test_probe_write_user += -lelf
		HOSTLOADLIBES_trace_output += -lelf -lrt
		HOSTLOADLIBES_lathist += -lelf

0 → 100644

+44 −0

Original line number	Diff line number	Diff line
		#include <uapi/linux/bpf.h>
		#include <linux/socket.h>
		#include <linux/net.h>
		#include <uapi/linux/in.h>
		#include <uapi/linux/in6.h>
		#include "bpf_helpers.h"

		SEC("cgroup/sock1")
		int bpf_prog1(struct bpf_sock *sk)
		{
		char fmt[] = "socket: family %d type %d protocol %d\n";

		bpf_trace_printk(fmt, sizeof(fmt), sk->family, sk->type, sk->protocol);

		/* block PF_INET6, SOCK_RAW, IPPROTO_ICMPV6 sockets
		* ie., make ping6 fail
		*/
		if (sk->family == PF_INET6 &&
		sk->type == SOCK_RAW &&
		sk->protocol == IPPROTO_ICMPV6)
		return 0;

		return 1;
		}

		SEC("cgroup/sock2")
		int bpf_prog2(struct bpf_sock *sk)
		{
		char fmt[] = "socket: family %d type %d protocol %d\n";

		bpf_trace_printk(fmt, sizeof(fmt), sk->family, sk->type, sk->protocol);

		/* block PF_INET, SOCK_RAW, IPPROTO_ICMP sockets
		* ie., make ping fail
		*/
		if (sk->family == PF_INET &&
		sk->type == SOCK_RAW &&
		sk->protocol == IPPROTO_ICMP)
		return 0;

		return 1;
		}

		char _license[] SEC("license") = "GPL";

0 → 100644

+66 −0

Original line number	Diff line number	Diff line
		/* eBPF example program:
		*
		* - Loads eBPF program
		*
		* The eBPF program loads a filter from file and attaches the
		* program to a cgroup using BPF_PROG_ATTACH
		*/

		#define _GNU_SOURCE

		#include <stdio.h>
		#include <stdlib.h>
		#include <stddef.h>
		#include <string.h>
		#include <unistd.h>
		#include <assert.h>
		#include <errno.h>
		#include <fcntl.h>
		#include <net/if.h>
		#include <linux/bpf.h>

		#include "libbpf.h"
		#include "bpf_load.h"

		static int usage(const char *argv0)
		{
		printf("Usage: %s cg-path filter-path [filter-id]\n", argv0);
		return EXIT_FAILURE;
		}

		int main(int argc, char **argv)
		{
		int cg_fd, ret, filter_id = 0;

		if (argc < 3)
		return usage(argv[0]);

		cg_fd = open(argv[1], O_DIRECTORY \| O_RDONLY);
		if (cg_fd < 0) {
		printf("Failed to open cgroup path: '%s'\n", strerror(errno));
		return EXIT_FAILURE;
		}

		if (load_bpf_file(argv[2]))
		return EXIT_FAILURE;

		printf("Output from kernel verifier:\n%s\n-------\n", bpf_log_buf);

		if (argc > 3)
		filter_id = atoi(argv[3]);

		if (filter_id > prog_cnt) {
		printf("Invalid program id; program not found in file\n");
		return EXIT_FAILURE;
		}

		ret = bpf_prog_attach(prog_fd[filter_id], cg_fd,
		BPF_CGROUP_INET_SOCK_CREATE);
		if (ret < 0) {
		printf("Failed to attach prog to cgroup: '%s'\n",
		strerror(errno));
		return EXIT_FAILURE;
		}

		return EXIT_SUCCESS;
		}

0 → 100755

+81 −0

Original line number	Diff line number	Diff line
		#!/bin/bash

		function config_device {
		ip netns add at_ns0
		ip link add veth0 type veth peer name veth0b
		ip link set veth0b up
		ip link set veth0 netns at_ns0
		ip netns exec at_ns0 ip addr add 172.16.1.100/24 dev veth0
		ip netns exec at_ns0 ip addr add 2401:db00::1/64 dev veth0 nodad
		ip netns exec at_ns0 ip link set dev veth0 up
		ip addr add 172.16.1.101/24 dev veth0b
		ip addr add 2401:db00::2/64 dev veth0b nodad
		}

		function config_cgroup {
		rm -rf /tmp/cgroupv2
		mkdir -p /tmp/cgroupv2
		mount -t cgroup2 none /tmp/cgroupv2
		mkdir -p /tmp/cgroupv2/foo
		echo $$ >> /tmp/cgroupv2/foo/cgroup.procs
		}


		function attach_bpf {
		test_cgrp2_sock2 /tmp/cgroupv2/foo sock_flags_kern.o $1
		[ $? -ne 0 ] && exit 1
		}

		function cleanup {
		ip link del veth0b
		ip netns delete at_ns0
		umount /tmp/cgroupv2
		rm -rf /tmp/cgroupv2
		}

		cleanup 2>/dev/null

		set -e
		config_device
		config_cgroup
		set +e

		#
		# Test 1 - fail ping6
		#
		attach_bpf 0
		ping -c1 -w1 172.16.1.100
		if [ $? -ne 0 ]; then
		echo "ping failed when it should succeed"
		cleanup
		exit 1
		fi

		ping6 -c1 -w1 2401:db00::1
		if [ $? -eq 0 ]; then
		echo "ping6 succeeded when it should not"
		cleanup
		exit 1
		fi

		#
		# Test 2 - fail ping
		#
		attach_bpf 1
		ping6 -c1 -w1 2401:db00::1
		if [ $? -ne 0 ]; then
		echo "ping6 failed when it should succeed"
		cleanup
		exit 1
		fi

		ping -c1 -w1 172.16.1.100
		if [ $? -eq 0 ]; then
		echo "ping succeeded when it should not"
		cleanup
		exit 1
		fi

		cleanup
		echo
		echo "* PASS *"