1 // SPDX-License-Identifier: GPL-2.0 2 /* Copyright (c) 2026 Christian Brauner */ 3 4 #include <vmlinux.h> 5 #include <bpf/bpf_tracing.h> 6 #include <bpf/bpf_helpers.h> 7 #include <bpf/bpf_core_read.h> 8 #include "bpf_experimental.h" 9 #include "bpf_misc.h" 10 11 char _license[] SEC("license") = "GPL"; 12 13 char value[16]; 14 int read_ret = -1; 15 __u32 monitored_pid = 0; 16 17 static __always_inline void read_xattr(struct socket *sock) 18 { 19 struct bpf_dynptr value_ptr; 20 21 bpf_dynptr_from_mem(value, sizeof(value), 0, &value_ptr); 22 bpf_sock_read_xattr(sock, "user.bpf_test", &value_ptr); 23 } 24 25 SEC("lsm.s/socket_connect") 26 __success 27 int BPF_PROG(trusted_sock_ptr_sleepable, struct socket *sock) 28 { 29 read_xattr(sock); 30 return 0; 31 } 32 33 SEC("lsm/socket_connect") 34 __success 35 int BPF_PROG(trusted_sock_ptr_non_sleepable, struct socket *sock) 36 { 37 read_xattr(sock); 38 return 0; 39 } 40 41 SEC("lsm.s/socket_connect") 42 __success 43 int BPF_PROG(read_sock_xattr, struct socket *sock) 44 { 45 struct bpf_dynptr value_ptr; 46 __u32 pid = bpf_get_current_pid_tgid() >> 32; 47 48 if (pid != monitored_pid) 49 return 0; 50 51 bpf_dynptr_from_mem(value, sizeof(value), 0, &value_ptr); 52 read_ret = bpf_sock_read_xattr(sock, "user.bpf_test", &value_ptr); 53 return 0; 54 } 55