selftests/bpf: Add C tests for reference tracking

Add some tests that demonstrate and test the balanced lookup/free
nature of socket lookup. Section names that start with "fail" represent
programs that are expected to fail verification; all others should
succeed.

Signed-off-by: Joe Stringer <joe@wand.net.nz>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
This commit is contained in:
Joe Stringer 2018-10-02 13:35:40 -07:00 коммит произвёл Daniel Borkmann
Родитель 29cd77f416
Коммит de375f4e91
3 изменённых файлов: 219 добавлений и 1 удалений

Просмотреть файл

@ -36,7 +36,7 @@ TEST_GEN_FILES = test_pkt_access.o test_xdp.o test_l4lb.o test_tcp_estats.o test
test_get_stack_rawtp.o test_sockmap_kern.o test_sockhash_kern.o \
test_lwt_seg6local.o sendmsg4_prog.o sendmsg6_prog.o test_lirc_mode2_kern.o \
get_cgroup_id_kern.o socket_cookie_prog.o test_select_reuseport_kern.o \
test_skb_cgroup_id_kern.o bpf_flow.o netcnt_prog.o
test_skb_cgroup_id_kern.o bpf_flow.o netcnt_prog.o test_sk_lookup_kern.o
# Order correspond to 'make run_tests' order
TEST_PROGS := test_kmod.sh \

Просмотреть файл

@ -1698,6 +1698,43 @@ static void test_task_fd_query_tp(void)
"sys_enter_read");
}
static void test_reference_tracking()
{
const char *file = "./test_sk_lookup_kern.o";
struct bpf_object *obj;
struct bpf_program *prog;
__u32 duration;
int err = 0;
obj = bpf_object__open(file);
if (IS_ERR(obj)) {
error_cnt++;
return;
}
bpf_object__for_each_program(prog, obj) {
const char *title;
/* Ignore .text sections */
title = bpf_program__title(prog, false);
if (strstr(title, ".text") != NULL)
continue;
bpf_program__set_type(prog, BPF_PROG_TYPE_SCHED_CLS);
/* Expect verifier failure if test name has 'fail' */
if (strstr(title, "fail") != NULL) {
libbpf_set_print(NULL, NULL, NULL);
err = !bpf_program__load(prog, "GPL", 0);
libbpf_set_print(printf, printf, NULL);
} else {
err = bpf_program__load(prog, "GPL", 0);
}
CHECK(err, title, "\n");
}
bpf_object__close(obj);
}
int main(void)
{
jit_enabled = is_jit_enabled();
@ -1719,6 +1756,7 @@ int main(void)
test_get_stack_raw_tp();
test_task_fd_query_rawtp();
test_task_fd_query_tp();
test_reference_tracking();
printf("Summary: %d PASSED, %d FAILED\n", pass_cnt, error_cnt);
return error_cnt ? EXIT_FAILURE : EXIT_SUCCESS;

Просмотреть файл

@ -0,0 +1,180 @@
/* SPDX-License-Identifier: GPL-2.0 */
// Copyright (c) 2018 Covalent IO, Inc. http://covalent.io
#include <stddef.h>
#include <stdbool.h>
#include <string.h>
#include <linux/bpf.h>
#include <linux/if_ether.h>
#include <linux/in.h>
#include <linux/ip.h>
#include <linux/ipv6.h>
#include <linux/pkt_cls.h>
#include <linux/tcp.h>
#include <sys/socket.h>
#include "bpf_helpers.h"
#include "bpf_endian.h"
int _version SEC("version") = 1;
char _license[] SEC("license") = "GPL";
/* Fill 'tuple' with L3 info, and attempt to find L4. On fail, return NULL. */
static struct bpf_sock_tuple *get_tuple(void *data, __u64 nh_off,
void *data_end, __u16 eth_proto,
bool *ipv4)
{
struct bpf_sock_tuple *result;
__u8 proto = 0;
__u64 ihl_len;
if (eth_proto == bpf_htons(ETH_P_IP)) {
struct iphdr *iph = (struct iphdr *)(data + nh_off);
if (iph + 1 > data_end)
return NULL;
ihl_len = iph->ihl * 4;
proto = iph->protocol;
*ipv4 = true;
result = (struct bpf_sock_tuple *)&iph->saddr;
} else if (eth_proto == bpf_htons(ETH_P_IPV6)) {
struct ipv6hdr *ip6h = (struct ipv6hdr *)(data + nh_off);
if (ip6h + 1 > data_end)
return NULL;
ihl_len = sizeof(*ip6h);
proto = ip6h->nexthdr;
*ipv4 = true;
result = (struct bpf_sock_tuple *)&ip6h->saddr;
}
if (data + nh_off + ihl_len > data_end || proto != IPPROTO_TCP)
return NULL;
return result;
}
SEC("sk_lookup_success")
int bpf_sk_lookup_test0(struct __sk_buff *skb)
{
void *data_end = (void *)(long)skb->data_end;
void *data = (void *)(long)skb->data;
struct ethhdr *eth = (struct ethhdr *)(data);
struct bpf_sock_tuple *tuple;
struct bpf_sock *sk;
size_t tuple_len;
bool ipv4;
if (eth + 1 > data_end)
return TC_ACT_SHOT;
tuple = get_tuple(data, sizeof(*eth), data_end, eth->h_proto, &ipv4);
if (!tuple || tuple + sizeof *tuple > data_end)
return TC_ACT_SHOT;
tuple_len = ipv4 ? sizeof(tuple->ipv4) : sizeof(tuple->ipv6);
sk = bpf_sk_lookup_tcp(skb, tuple, tuple_len, 0, 0);
if (sk)
bpf_sk_release(sk);
return sk ? TC_ACT_OK : TC_ACT_UNSPEC;
}
SEC("sk_lookup_success_simple")
int bpf_sk_lookup_test1(struct __sk_buff *skb)
{
struct bpf_sock_tuple tuple = {};
struct bpf_sock *sk;
sk = bpf_sk_lookup_tcp(skb, &tuple, sizeof(tuple), 0, 0);
if (sk)
bpf_sk_release(sk);
return 0;
}
SEC("fail_use_after_free")
int bpf_sk_lookup_uaf(struct __sk_buff *skb)
{
struct bpf_sock_tuple tuple = {};
struct bpf_sock *sk;
__u32 family = 0;
sk = bpf_sk_lookup_tcp(skb, &tuple, sizeof(tuple), 0, 0);
if (sk) {
bpf_sk_release(sk);
family = sk->family;
}
return family;
}
SEC("fail_modify_sk_pointer")
int bpf_sk_lookup_modptr(struct __sk_buff *skb)
{
struct bpf_sock_tuple tuple = {};
struct bpf_sock *sk;
__u32 family;
sk = bpf_sk_lookup_tcp(skb, &tuple, sizeof(tuple), 0, 0);
if (sk) {
sk += 1;
bpf_sk_release(sk);
}
return 0;
}
SEC("fail_modify_sk_or_null_pointer")
int bpf_sk_lookup_modptr_or_null(struct __sk_buff *skb)
{
struct bpf_sock_tuple tuple = {};
struct bpf_sock *sk;
__u32 family;
sk = bpf_sk_lookup_tcp(skb, &tuple, sizeof(tuple), 0, 0);
sk += 1;
if (sk)
bpf_sk_release(sk);
return 0;
}
SEC("fail_no_release")
int bpf_sk_lookup_test2(struct __sk_buff *skb)
{
struct bpf_sock_tuple tuple = {};
bpf_sk_lookup_tcp(skb, &tuple, sizeof(tuple), 0, 0);
return 0;
}
SEC("fail_release_twice")
int bpf_sk_lookup_test3(struct __sk_buff *skb)
{
struct bpf_sock_tuple tuple = {};
struct bpf_sock *sk;
sk = bpf_sk_lookup_tcp(skb, &tuple, sizeof(tuple), 0, 0);
bpf_sk_release(sk);
bpf_sk_release(sk);
return 0;
}
SEC("fail_release_unchecked")
int bpf_sk_lookup_test4(struct __sk_buff *skb)
{
struct bpf_sock_tuple tuple = {};
struct bpf_sock *sk;
sk = bpf_sk_lookup_tcp(skb, &tuple, sizeof(tuple), 0, 0);
bpf_sk_release(sk);
return 0;
}
void lookup_no_release(struct __sk_buff *skb)
{
struct bpf_sock_tuple tuple = {};
bpf_sk_lookup_tcp(skb, &tuple, sizeof(tuple), 0, 0);
}
SEC("fail_no_release_subcall")
int bpf_sk_lookup_test5(struct __sk_buff *skb)
{
lookup_no_release(skb);
return 0;
}