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1// SPDX-License-Identifier: GPL-2.02 3/*4 * Copyright (C) 2022 Huawei Technologies Duesseldorf GmbH5 *6 * Author: Roberto Sassu <roberto.sassu@huawei.com>7 */8 9#include "vmlinux.h"10#include <errno.h>11#include <bpf/bpf_helpers.h>12#include <bpf/bpf_tracing.h>13 14char _license[] SEC("license") = "GPL";15 16__u32 monitored_pid;17__u32 key_serial;18__u32 key_id;19__u64 flags;20 21extern struct bpf_key *bpf_lookup_user_key(__u32 serial, __u64 flags) __ksym;22extern struct bpf_key *bpf_lookup_system_key(__u64 id) __ksym;23extern void bpf_key_put(struct bpf_key *key) __ksym;24 25SEC("lsm.s/bpf")26int BPF_PROG(bpf, int cmd, union bpf_attr *attr, unsigned int size)27{28 struct bpf_key *bkey;29 __u32 pid;30 31 pid = bpf_get_current_pid_tgid() >> 32;32 if (pid != monitored_pid)33 return 0;34 35 if (key_serial)36 bkey = bpf_lookup_user_key(key_serial, flags);37 else38 bkey = bpf_lookup_system_key(key_id);39 40 if (!bkey)41 return -ENOENT;42 43 bpf_key_put(bkey);44 45 return 0;46}47