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// SPDX-License-Identifier: GPL-2.0
/* Copyright (c) 2023 Meta Platforms, Inc. and affiliates. */
#include "vmlinux.h"
#include <errno.h>
#include <bpf/bpf_helpers.h>
#include <bpf/bpf_tracing.h>
#include "bpf_kfuncs.h"
char _license[] SEC("license") = "GPL";
__u32 monitored_pid;
__u32 found_xattr_from_file;
__u32 found_xattr_from_dentry;
static const char expected_value[] = "hello";
char value1[32];
char value2[32];
SEC("lsm.s/file_open")
int BPF_PROG(test_file_open, struct file *f)
{
struct bpf_dynptr value_ptr;
__u32 pid;
int ret;
pid = bpf_get_current_pid_tgid() >> 32;
if (pid != monitored_pid)
return 0;
bpf_dynptr_from_mem(value1, sizeof(value1), 0, &value_ptr);
ret = bpf_get_file_xattr(f, "user.kfuncs", &value_ptr);
if (ret != sizeof(expected_value))
return 0;
if (bpf_strncmp(value1, ret, expected_value))
return 0;
found_xattr_from_file = 1;
return 0;
}
SEC("lsm.s/inode_getxattr")
int BPF_PROG(test_inode_getxattr, struct dentry *dentry, char *name)
{
struct bpf_dynptr value_ptr;
__u32 pid;
int ret;
pid = bpf_get_current_pid_tgid() >> 32;
if (pid != monitored_pid)
return 0;
bpf_dynptr_from_mem(value2, sizeof(value2), 0, &value_ptr);
ret = bpf_get_dentry_xattr(dentry, "user.kfuncs", &value_ptr);
if (ret != sizeof(expected_value))
return 0;
if (bpf_strncmp(value2, ret, expected_value))
return 0;
found_xattr_from_dentry = 1;
/* return non-zero to fail getxattr from user space */
return -EINVAL;
}
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