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>hifive-unleashed-5.1
Joe Stringer
Daniel Borkmann
parent
29cd77f416
commit
de375f4e91
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@ -36,7 +36,7 @@ TEST_GEN_FILES = test_pkt_access.o test_xdp.o test_l4lb.o test_tcp_estats.o test
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test_get_stack_rawtp.o test_sockmap_kern.o test_sockhash_kern.o \
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test_lwt_seg6local.o sendmsg4_prog.o sendmsg6_prog.o test_lirc_mode2_kern.o \
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get_cgroup_id_kern.o socket_cookie_prog.o test_select_reuseport_kern.o \
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test_skb_cgroup_id_kern.o bpf_flow.o netcnt_prog.o
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test_skb_cgroup_id_kern.o bpf_flow.o netcnt_prog.o test_sk_lookup_kern.o
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# Order correspond to 'make run_tests' order
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TEST_PROGS := test_kmod.sh \
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@ -1698,6 +1698,43 @@ static void test_task_fd_query_tp(void)
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"sys_enter_read");
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}
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static void test_reference_tracking()
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{
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const char *file = "./test_sk_lookup_kern.o";
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struct bpf_object *obj;
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struct bpf_program *prog;
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__u32 duration;
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int err = 0;
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obj = bpf_object__open(file);
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if (IS_ERR(obj)) {
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error_cnt++;
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return;
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}
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bpf_object__for_each_program(prog, obj) {
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const char *title;
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/* Ignore .text sections */
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title = bpf_program__title(prog, false);
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if (strstr(title, ".text") != NULL)
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continue;
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bpf_program__set_type(prog, BPF_PROG_TYPE_SCHED_CLS);
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/* Expect verifier failure if test name has 'fail' */
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if (strstr(title, "fail") != NULL) {
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libbpf_set_print(NULL, NULL, NULL);
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err = !bpf_program__load(prog, "GPL", 0);
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libbpf_set_print(printf, printf, NULL);
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} else {
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err = bpf_program__load(prog, "GPL", 0);
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}
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CHECK(err, title, "\n");
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}
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bpf_object__close(obj);
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}
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int main(void)
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{
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jit_enabled = is_jit_enabled();
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@ -1719,6 +1756,7 @@ int main(void)
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test_get_stack_raw_tp();
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test_task_fd_query_rawtp();
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test_task_fd_query_tp();
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test_reference_tracking();
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printf("Summary: %d PASSED, %d FAILED\n", pass_cnt, error_cnt);
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return error_cnt ? EXIT_FAILURE : EXIT_SUCCESS;
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@ -0,0 +1,180 @@
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/* SPDX-License-Identifier: GPL-2.0 */
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// Copyright (c) 2018 Covalent IO, Inc. http://covalent.io
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#include <stddef.h>
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#include <stdbool.h>
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#include <string.h>
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#include <linux/bpf.h>
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#include <linux/if_ether.h>
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#include <linux/in.h>
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#include <linux/ip.h>
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#include <linux/ipv6.h>
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#include <linux/pkt_cls.h>
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#include <linux/tcp.h>
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#include <sys/socket.h>
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#include "bpf_helpers.h"
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#include "bpf_endian.h"
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int _version SEC("version") = 1;
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char _license[] SEC("license") = "GPL";
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/* Fill 'tuple' with L3 info, and attempt to find L4. On fail, return NULL. */
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static struct bpf_sock_tuple *get_tuple(void *data, __u64 nh_off,
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void *data_end, __u16 eth_proto,
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bool *ipv4)
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{
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struct bpf_sock_tuple *result;
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__u8 proto = 0;
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__u64 ihl_len;
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if (eth_proto == bpf_htons(ETH_P_IP)) {
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struct iphdr *iph = (struct iphdr *)(data + nh_off);
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if (iph + 1 > data_end)
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return NULL;
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ihl_len = iph->ihl * 4;
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proto = iph->protocol;
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*ipv4 = true;
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result = (struct bpf_sock_tuple *)&iph->saddr;
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} else if (eth_proto == bpf_htons(ETH_P_IPV6)) {
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struct ipv6hdr *ip6h = (struct ipv6hdr *)(data + nh_off);
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if (ip6h + 1 > data_end)
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return NULL;
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ihl_len = sizeof(*ip6h);
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proto = ip6h->nexthdr;
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*ipv4 = true;
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result = (struct bpf_sock_tuple *)&ip6h->saddr;
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}
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if (data + nh_off + ihl_len > data_end || proto != IPPROTO_TCP)
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return NULL;
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return result;
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}
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SEC("sk_lookup_success")
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int bpf_sk_lookup_test0(struct __sk_buff *skb)
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{
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void *data_end = (void *)(long)skb->data_end;
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void *data = (void *)(long)skb->data;
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struct ethhdr *eth = (struct ethhdr *)(data);
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struct bpf_sock_tuple *tuple;
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struct bpf_sock *sk;
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size_t tuple_len;
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bool ipv4;
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if (eth + 1 > data_end)
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return TC_ACT_SHOT;
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tuple = get_tuple(data, sizeof(*eth), data_end, eth->h_proto, &ipv4);
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if (!tuple || tuple + sizeof *tuple > data_end)
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return TC_ACT_SHOT;
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tuple_len = ipv4 ? sizeof(tuple->ipv4) : sizeof(tuple->ipv6);
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sk = bpf_sk_lookup_tcp(skb, tuple, tuple_len, 0, 0);
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if (sk)
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bpf_sk_release(sk);
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return sk ? TC_ACT_OK : TC_ACT_UNSPEC;
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}
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SEC("sk_lookup_success_simple")
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int bpf_sk_lookup_test1(struct __sk_buff *skb)
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{
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struct bpf_sock_tuple tuple = {};
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struct bpf_sock *sk;
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sk = bpf_sk_lookup_tcp(skb, &tuple, sizeof(tuple), 0, 0);
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if (sk)
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bpf_sk_release(sk);
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return 0;
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}
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SEC("fail_use_after_free")
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int bpf_sk_lookup_uaf(struct __sk_buff *skb)
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{
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struct bpf_sock_tuple tuple = {};
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struct bpf_sock *sk;
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__u32 family = 0;
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sk = bpf_sk_lookup_tcp(skb, &tuple, sizeof(tuple), 0, 0);
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if (sk) {
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bpf_sk_release(sk);
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family = sk->family;
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}
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return family;
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}
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SEC("fail_modify_sk_pointer")
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int bpf_sk_lookup_modptr(struct __sk_buff *skb)
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{
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struct bpf_sock_tuple tuple = {};
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struct bpf_sock *sk;
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__u32 family;
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sk = bpf_sk_lookup_tcp(skb, &tuple, sizeof(tuple), 0, 0);
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if (sk) {
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sk += 1;
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bpf_sk_release(sk);
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}
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return 0;
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}
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SEC("fail_modify_sk_or_null_pointer")
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int bpf_sk_lookup_modptr_or_null(struct __sk_buff *skb)
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{
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struct bpf_sock_tuple tuple = {};
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struct bpf_sock *sk;
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__u32 family;
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sk = bpf_sk_lookup_tcp(skb, &tuple, sizeof(tuple), 0, 0);
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sk += 1;
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if (sk)
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bpf_sk_release(sk);
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return 0;
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}
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SEC("fail_no_release")
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int bpf_sk_lookup_test2(struct __sk_buff *skb)
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{
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struct bpf_sock_tuple tuple = {};
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bpf_sk_lookup_tcp(skb, &tuple, sizeof(tuple), 0, 0);
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return 0;
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}
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SEC("fail_release_twice")
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int bpf_sk_lookup_test3(struct __sk_buff *skb)
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{
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struct bpf_sock_tuple tuple = {};
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struct bpf_sock *sk;
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sk = bpf_sk_lookup_tcp(skb, &tuple, sizeof(tuple), 0, 0);
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bpf_sk_release(sk);
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bpf_sk_release(sk);
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return 0;
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}
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SEC("fail_release_unchecked")
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int bpf_sk_lookup_test4(struct __sk_buff *skb)
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{
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struct bpf_sock_tuple tuple = {};
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struct bpf_sock *sk;
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sk = bpf_sk_lookup_tcp(skb, &tuple, sizeof(tuple), 0, 0);
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bpf_sk_release(sk);
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return 0;
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}
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void lookup_no_release(struct __sk_buff *skb)
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{
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struct bpf_sock_tuple tuple = {};
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bpf_sk_lookup_tcp(skb, &tuple, sizeof(tuple), 0, 0);
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}
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SEC("fail_no_release_subcall")
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int bpf_sk_lookup_test5(struct __sk_buff *skb)
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{
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lookup_no_release(skb);
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return 0;
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}
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