1// SPDX-License-Identifier: GPL-2.0
2/* Copyright (c) 2023 Meta Platforms, Inc. and affiliates. */
3
4#include "vmlinux.h"
5
6#include <string.h>
7#include <bpf/bpf_helpers.h>
8#include <bpf/bpf_core_read.h>
9#include "bpf_kfuncs.h"
10
11__u8 SERVUN_REWRITE_ADDRESS[] = "\0bpf_cgroup_unix_test_rewrite";
12
13SEC("cgroup/getsockname_unix")
14int getsockname_unix_prog(struct bpf_sock_addr *ctx)
15{
16	struct bpf_sock_addr_kern *sa_kern = bpf_cast_to_kern_ctx(ctx);
17	struct sockaddr_un *sa_kern_unaddr;
18	__u32 unaddrlen = offsetof(struct sockaddr_un, sun_path) +
19			  sizeof(SERVUN_REWRITE_ADDRESS) - 1;
20	int ret;
21
22	ret = bpf_sock_addr_set_sun_path(sa_kern, SERVUN_REWRITE_ADDRESS,
23					 sizeof(SERVUN_REWRITE_ADDRESS) - 1);
24	if (ret)
25		return 1;
26
27	if (sa_kern->uaddrlen != unaddrlen)
28		return 1;
29
30	sa_kern_unaddr = bpf_core_cast(sa_kern->uaddr, struct sockaddr_un);
31	if (memcmp(sa_kern_unaddr->sun_path, SERVUN_REWRITE_ADDRESS,
32			sizeof(SERVUN_REWRITE_ADDRESS) - 1) != 0)
33		return 1;
34
35	return 1;
36}
37
38char _license[] SEC("license") = "GPL";
39