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/sendmsg_unix") 14 int sendmsg_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 char _license[] SEC("license") = "GPL"; 40