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
13 SEC("cgroup/connect_unix")
14 int connect_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 /* Rewrite destination. */
23 ret = bpf_sock_addr_set_sun_path(sa_kern, SERVUN_REWRITE_ADDRESS,
24 sizeof(SERVUN_REWRITE_ADDRESS) - 1);
25 if (ret)
26 return 0;
27
28 if (sa_kern->uaddrlen != unaddrlen)
29 return 0;
30
31 sa_kern_unaddr = bpf_core_cast(sa_kern->uaddr, struct sockaddr_un);
32 if (memcmp(sa_kern_unaddr->sun_path, SERVUN_REWRITE_ADDRESS,
33 sizeof(SERVUN_REWRITE_ADDRESS) - 1) != 0)
34 return 0;
35
36 return 1;
37 }
38
39 SEC("cgroup/connect_unix")
40 int connect_unix_deny_prog(struct bpf_sock_addr *ctx)
41 {
42 return 0;
43 }
44
45 char _license[] SEC("license") = "GPL";
46
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