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// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (C) 2022 Huawei Technologies Duesseldorf GmbH
*
* Author: Roberto Sassu <roberto.sassu@huawei.com>
*/
#include "vmlinux.h"
#include <errno.h>
#include <bpf/bpf_helpers.h>
#include <bpf/bpf_tracing.h>
/* From include/linux/mm.h. */
#define FMODE_WRITE 0x2
struct {
__uint(type, BPF_MAP_TYPE_ARRAY);
__uint(max_entries, 1);
__type(key, __u32);
__type(value, __u32);
} data_input SEC(".maps");
char _license[] SEC("license") = "GPL";
SEC("lsm/bpf_map")
int BPF_PROG(check_access, struct bpf_map *map, fmode_t fmode)
{
if (map != (struct bpf_map *)&data_input)
return 0;
if (fmode & FMODE_WRITE)
return -EACCES;
return 0;
}
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