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1// SPDX-License-Identifier: GPL-2.02/* Copyright (c) 2023 Meta Platforms, Inc. and affiliates. */3 4#include "vmlinux.h"5#include <errno.h>6#include <bpf/bpf_helpers.h>7#include <bpf/bpf_tracing.h>8#include "bpf_kfuncs.h"9 10char _license[] SEC("license") = "GPL";11 12__u32 monitored_pid;13__u32 found_xattr_from_file;14__u32 found_xattr_from_dentry;15 16static const char expected_value[] = "hello";17char value1[32];18char value2[32];19 20SEC("lsm.s/file_open")21int BPF_PROG(test_file_open, struct file *f)22{23 struct bpf_dynptr value_ptr;24 __u32 pid;25 int ret;26 27 pid = bpf_get_current_pid_tgid() >> 32;28 if (pid != monitored_pid)29 return 0;30 31 bpf_dynptr_from_mem(value1, sizeof(value1), 0, &value_ptr);32 33 ret = bpf_get_file_xattr(f, "user.kfuncs", &value_ptr);34 if (ret != sizeof(expected_value))35 return 0;36 if (bpf_strncmp(value1, ret, expected_value))37 return 0;38 found_xattr_from_file = 1;39 return 0;40}41 42SEC("lsm.s/inode_getxattr")43int BPF_PROG(test_inode_getxattr, struct dentry *dentry, char *name)44{45 struct bpf_dynptr value_ptr;46 __u32 pid;47 int ret;48 49 pid = bpf_get_current_pid_tgid() >> 32;50 if (pid != monitored_pid)51 return 0;52 53 bpf_dynptr_from_mem(value2, sizeof(value2), 0, &value_ptr);54 55 ret = bpf_get_dentry_xattr(dentry, "user.kfuncs", &value_ptr);56 if (ret != sizeof(expected_value))57 return 0;58 if (bpf_strncmp(value2, ret, expected_value))59 return 0;60 found_xattr_from_dentry = 1;61 62 /* return non-zero to fail getxattr from user space */63 return -EINVAL;64}65