1f87dcf116
Task local storage is enabled for tracing programs. Add two tests for task local storage without CONFIG_BPF_LSM. The first test stores a value in sys_enter and read it back in sys_exit. The second test checks whether the kernel allows allocating task local storage in exit_creds() (which it should not). Signed-off-by: Song Liu <songliubraving@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20210225234319.336131-4-songliubraving@fb.com
65 lines
1.3 KiB
C
65 lines
1.3 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/* Copyright (c) 2021 Facebook */
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#include "vmlinux.h"
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#include <bpf/bpf_helpers.h>
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#include <bpf/bpf_tracing.h>
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char _license[] SEC("license") = "GPL";
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struct {
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__uint(type, BPF_MAP_TYPE_TASK_STORAGE);
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__uint(map_flags, BPF_F_NO_PREALLOC);
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__type(key, int);
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__type(value, long);
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} enter_id SEC(".maps");
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#define MAGIC_VALUE 0xabcd1234
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pid_t target_pid = 0;
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int mismatch_cnt = 0;
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int enter_cnt = 0;
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int exit_cnt = 0;
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SEC("tp_btf/sys_enter")
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int BPF_PROG(on_enter, struct pt_regs *regs, long id)
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{
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struct task_struct *task;
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long *ptr;
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task = bpf_get_current_task_btf();
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if (task->pid != target_pid)
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return 0;
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ptr = bpf_task_storage_get(&enter_id, task, 0,
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BPF_LOCAL_STORAGE_GET_F_CREATE);
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if (!ptr)
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return 0;
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__sync_fetch_and_add(&enter_cnt, 1);
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*ptr = MAGIC_VALUE + enter_cnt;
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return 0;
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}
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SEC("tp_btf/sys_exit")
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int BPF_PROG(on_exit, struct pt_regs *regs, long id)
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{
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struct task_struct *task;
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long *ptr;
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task = bpf_get_current_task_btf();
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if (task->pid != target_pid)
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return 0;
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ptr = bpf_task_storage_get(&enter_id, task, 0,
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BPF_LOCAL_STORAGE_GET_F_CREATE);
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if (!ptr)
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return 0;
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__sync_fetch_and_add(&exit_cnt, 1);
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if (*ptr != MAGIC_VALUE + exit_cnt)
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__sync_fetch_and_add(&mismatch_cnt, 1);
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return 0;
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}
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