selftests/bpf: Add selftest for PTR_UNTRUSTED

Add a new selftest to check the PTR_UNTRUSTED condition. Below is the
result,

 #160     ptr_untrusted:OK

Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
Link: https://lore.kernel.org/r/20230713025642.27477-5-laoar.shao@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This commit is contained in:
Yafang Shao 2023-07-13 02:56:42 +00:00 committed by Alexei Starovoitov
parent 33937607ef
commit 1cd0e7715c
2 changed files with 65 additions and 0 deletions

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// SPDX-License-Identifier: GPL-2.0
/* Copyright (C) 2023 Yafang Shao <laoar.shao@gmail.com> */
#include <string.h>
#include <linux/bpf.h>
#include <test_progs.h>
#include "test_ptr_untrusted.skel.h"
#define TP_NAME "sched_switch"
void serial_test_ptr_untrusted(void)
{
struct test_ptr_untrusted *skel;
int err;
skel = test_ptr_untrusted__open_and_load();
if (!ASSERT_OK_PTR(skel, "skel_open"))
goto cleanup;
/* First, attach lsm prog */
skel->links.lsm_run = bpf_program__attach_lsm(skel->progs.lsm_run);
if (!ASSERT_OK_PTR(skel->links.lsm_run, "lsm_attach"))
goto cleanup;
/* Second, attach raw_tp prog. The lsm prog will be triggered. */
skel->links.raw_tp_run = bpf_program__attach_raw_tracepoint(skel->progs.raw_tp_run,
TP_NAME);
if (!ASSERT_OK_PTR(skel->links.raw_tp_run, "raw_tp_attach"))
goto cleanup;
err = strncmp(skel->bss->tp_name, TP_NAME, strlen(TP_NAME));
ASSERT_EQ(err, 0, "cmp_tp_name");
cleanup:
test_ptr_untrusted__destroy(skel);
}

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// SPDX-License-Identifier: GPL-2.0
/* Copyright (C) 2023 Yafang Shao <laoar.shao@gmail.com> */
#include "vmlinux.h"
#include <bpf/bpf_tracing.h>
char tp_name[128];
SEC("lsm/bpf")
int BPF_PROG(lsm_run, int cmd, union bpf_attr *attr, unsigned int size)
{
switch (cmd) {
case BPF_RAW_TRACEPOINT_OPEN:
bpf_probe_read_user_str(tp_name, sizeof(tp_name) - 1,
(void *)attr->raw_tracepoint.name);
break;
default:
break;
}
return 0;
}
SEC("raw_tracepoint")
int BPF_PROG(raw_tp_run)
{
return 0;
}
char _license[] SEC("license") = "GPL";