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1// SPDX-License-Identifier: GPL-2.02/* Copyright (C) 2021. Huawei Technologies Co., Ltd */3#include <stdbool.h>4#include <linux/types.h>5#include <linux/bpf.h>6#include <bpf/bpf_helpers.h>7#include <bpf/bpf_tracing.h>8 9#define STRNCMP_STR_SZ 810 11const char target[STRNCMP_STR_SZ] = "EEEEEEE";12char str[STRNCMP_STR_SZ];13int cmp_ret = 0;14int target_pid = 0;15 16const char no_str_target[STRNCMP_STR_SZ] = "12345678";17char writable_target[STRNCMP_STR_SZ];18unsigned int no_const_str_size = STRNCMP_STR_SZ;19 20char _license[] SEC("license") = "GPL";21 22SEC("?tp/syscalls/sys_enter_nanosleep")23int do_strncmp(void *ctx)24{25 if ((bpf_get_current_pid_tgid() >> 32) != target_pid)26 return 0;27 28 cmp_ret = bpf_strncmp(str, STRNCMP_STR_SZ, target);29 return 0;30}31 32SEC("?tp/syscalls/sys_enter_nanosleep")33int strncmp_bad_not_const_str_size(void *ctx)34{35 /* The value of string size is not const, so will fail */36 cmp_ret = bpf_strncmp(str, no_const_str_size, target);37 return 0;38}39 40SEC("?tp/syscalls/sys_enter_nanosleep")41int strncmp_bad_writable_target(void *ctx)42{43 /* Compared target is not read-only, so will fail */44 cmp_ret = bpf_strncmp(str, STRNCMP_STR_SZ, writable_target);45 return 0;46}47 48SEC("?tp/syscalls/sys_enter_nanosleep")49int strncmp_bad_not_null_term_target(void *ctx)50{51 /* Compared target is not null-terminated, so will fail */52 cmp_ret = bpf_strncmp(str, STRNCMP_STR_SZ, no_str_target);53 return 0;54}55