strncmp_test.c (1398B)
1// SPDX-License-Identifier: GPL-2.0 2/* 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 8 10 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}