1 // SPDX-License-Identifier: GPL-2.0 2 /* Copyright (c) 2023 Meta Platforms, Inc. and affiliates. */ 3 4 #include "vmlinux.h" 5 #include <bpf/bpf_helpers.h> 6 #include <bpf/bpf_tracing.h> 7 #include "bpf_kfuncs.h" 8 9 char _license[] SEC("license") = "GPL"; 10 11 __u32 monitored_pid; 12 __u32 found_xattr; 13 14 static const char expected_value[] = "hello"; 15 char value[32]; 16 17 SEC("lsm.s/file_open") 18 int BPF_PROG(test_file_open, struct file *f) 19 { 20 struct bpf_dynptr value_ptr; 21 __u32 pid; 22 int ret; 23 24 pid = bpf_get_current_pid_tgid() >> 32; 25 if (pid != monitored_pid) 26 return 0; 27 28 bpf_dynptr_from_mem(value, sizeof(value), 0, &value_ptr); 29 30 ret = bpf_get_file_xattr(f, "user.kfuncs", &value_ptr); 31 if (ret != sizeof(expected_value)) 32 return 0; 33 if (bpf_strncmp(value, ret, expected_value)) 34 return 0; 35 found_xattr = 1; 36 return 0; 37 } 38