linux/tools/testing/selftests/bpf/progs/test_lookup_key.c
Roberto Sassu ecce368d6e selftests/bpf: Add additional tests for bpf_lookup_*_key()
Add a test to ensure that bpf_lookup_user_key() creates a referenced
special keyring when the KEY_LOOKUP_CREATE flag is passed to this function.

Ensure that the kfunc rejects invalid flags.

Ensure that a keyring can be obtained from bpf_lookup_system_key() when one
of the pre-determined keyring IDs is provided.

The test is currently blacklisted for s390x (JIT does not support calling
kernel function).

Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
Link: https://lore.kernel.org/r/20220920075951.929132-12-roberto.sassu@huaweicloud.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2022-09-21 17:33:42 -07:00

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C

// 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>
char _license[] SEC("license") = "GPL";
__u32 monitored_pid;
__u32 key_serial;
__u32 key_id;
__u64 flags;
extern struct bpf_key *bpf_lookup_user_key(__u32 serial, __u64 flags) __ksym;
extern struct bpf_key *bpf_lookup_system_key(__u64 id) __ksym;
extern void bpf_key_put(struct bpf_key *key) __ksym;
SEC("lsm.s/bpf")
int BPF_PROG(bpf, int cmd, union bpf_attr *attr, unsigned int size)
{
struct bpf_key *bkey;
__u32 pid;
pid = bpf_get_current_pid_tgid() >> 32;
if (pid != monitored_pid)
return 0;
if (key_serial)
bkey = bpf_lookup_user_key(key_serial, flags);
else
bkey = bpf_lookup_system_key(key_id);
if (!bkey)
return -ENOENT;
bpf_key_put(bkey);
return 0;
}