selftests/bpf: add a test for device cgroup controller (37f1ba09) · Commits · 戴 / test

tools/testing/selftests/bpf/Makefile

+2 −2

Original line number	Diff line number	Diff line
		@@ -13,11 +13,11 @@ CFLAGS += -Wall -O2 -I$(APIDIR) -I$(LIBDIR) -I$(GENDIR) $(GENFLAGS) -I../../../i
		LDLIBS += -lcap -lelf

		TEST_GEN_PROGS = test_verifier test_tag test_maps test_lru_map test_lpm_map test_progs \
		test_align test_verifier_log
		test_align test_verifier_log test_dev_cgroup

		TEST_GEN_FILES = test_pkt_access.o test_xdp.o test_l4lb.o test_tcp_estats.o test_obj_id.o \
		test_pkt_md_access.o test_xdp_redirect.o test_xdp_meta.o sockmap_parse_prog.o \
		sockmap_verdict_prog.o
		sockmap_verdict_prog.o dev_cgroup.o

		TEST_PROGS := test_kmod.sh test_xdp_redirect.sh test_xdp_meta.sh

tools/testing/selftests/bpf/dev_cgroup.c

0 → 100644

+60 −0

Original line number	Diff line number	Diff line
		/* Copyright (c) 2017 Facebook
		*
		* This program is free software; you can redistribute it and/or
		* modify it under the terms of version 2 of the GNU General Public
		* License as published by the Free Software Foundation.
		*/

		#include <linux/bpf.h>
		#include <linux/version.h>
		#include "bpf_helpers.h"

		SEC("cgroup/dev")
		int bpf_prog1(struct bpf_cgroup_dev_ctx *ctx)
		{
		short type = ctx->access_type & 0xFFFF;
		#ifdef DEBUG
		short access = ctx->access_type >> 16;
		char fmt[] = " %d:%d \n";

		switch (type) {
		case BPF_DEVCG_DEV_BLOCK:
		fmt[0] = 'b';
		break;
		case BPF_DEVCG_DEV_CHAR:
		fmt[0] = 'c';
		break;
		default:
		fmt[0] = '?';
		break;
		}

		if (access & BPF_DEVCG_ACC_READ)
		fmt[8] = 'r';

		if (access & BPF_DEVCG_ACC_WRITE)
		fmt[9] = 'w';

		if (access & BPF_DEVCG_ACC_MKNOD)
		fmt[10] = 'm';

		bpf_trace_printk(fmt, sizeof(fmt), ctx->major, ctx->minor);
		#endif

		/* Allow access to /dev/zero and /dev/random.
		* Forbid everything else.
		*/
		if (ctx->major != 1 \|\| type != BPF_DEVCG_DEV_CHAR)
		return 0;

		switch (ctx->minor) {
		case 5: /* 1:5 /dev/zero */
		case 9: /* 1:9 /dev/urandom */
		return 1;
		}

		return 0;
		}

		char _license[] SEC("license") = "GPL";
		__u32 _version SEC("version") = LINUX_VERSION_CODE;

tools/testing/selftests/bpf/test_dev_cgroup.c

0 → 100644

+93 −0

Original line number	Diff line number	Diff line
		/* Copyright (c) 2017 Facebook
		*
		* This program is free software; you can redistribute it and/or
		* modify it under the terms of version 2 of the GNU General Public
		* License as published by the Free Software Foundation.
		*/

		#include <stdio.h>
		#include <stdlib.h>
		#include <string.h>
		#include <errno.h>
		#include <assert.h>

		#include <linux/bpf.h>
		#include <bpf/bpf.h>
		#include <bpf/libbpf.h>

		#include "cgroup_helpers.h"

		#define DEV_CGROUP_PROG "./dev_cgroup.o"

		#define TEST_CGROUP "test-bpf-based-device-cgroup/"

		int main(int argc, char **argv)
		{
		struct bpf_object *obj;
		int error = EXIT_FAILURE;
		int prog_fd, cgroup_fd;
		__u32 prog_cnt;

		if (bpf_prog_load(DEV_CGROUP_PROG, BPF_PROG_TYPE_CGROUP_DEVICE,
		&obj, &prog_fd)) {
		printf("Failed to load DEV_CGROUP program\n");
		goto err;
		}

		if (setup_cgroup_environment()) {
		printf("Failed to load DEV_CGROUP program\n");
		goto err;
		}

		/* Create a cgroup, get fd, and join it */
		cgroup_fd = create_and_get_cgroup(TEST_CGROUP);
		if (!cgroup_fd) {
		printf("Failed to create test cgroup\n");
		goto err;
		}

		if (join_cgroup(TEST_CGROUP)) {
		printf("Failed to join cgroup\n");
		goto err;
		}

		/* Attach bpf program */
		if (bpf_prog_attach(prog_fd, cgroup_fd, BPF_CGROUP_DEVICE, 0)) {
		printf("Failed to attach DEV_CGROUP program");
		goto err;
		}

		if (bpf_prog_query(cgroup_fd, BPF_CGROUP_DEVICE, 0, NULL, NULL,
		&prog_cnt)) {
		printf("Failed to query attached programs");
		goto err;
		}

		/* All operations with /dev/zero and and /dev/urandom are allowed,
		* everything else is forbidden.
		*/
		assert(system("rm -f /tmp/test_dev_cgroup_null") == 0);
		assert(system("mknod /tmp/test_dev_cgroup_null c 1 3"));
		assert(system("rm -f /tmp/test_dev_cgroup_null") == 0);

		/* /dev/zero is whitelisted */
		assert(system("rm -f /tmp/test_dev_cgroup_zero") == 0);
		assert(system("mknod /tmp/test_dev_cgroup_zero c 1 5") == 0);
		assert(system("rm -f /tmp/test_dev_cgroup_zero") == 0);

		assert(system("dd if=/dev/urandom of=/dev/zero count=64") == 0);

		/* src is allowed, target is forbidden */
		assert(system("dd if=/dev/urandom of=/dev/full count=64"));

		/* src is forbidden, target is allowed */
		assert(system("dd if=/dev/random of=/dev/zero count=64"));

		error = 0;
		printf("test_dev_cgroup:PASS\n");

		err:
		cleanup_cgroup_environment();

		return error;
		}

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