// SPDX-License-Identifier: GPL-2.0 /* Copyright (C) 2021. Huawei Technologies Co., Ltd */ #include <stdbool.h> #include <linux/types.h> #include <linux/bpf.h> #include <bpf/bpf_helpers.h> #include <bpf/bpf_tracing.h> #define STRNCMP_STR_SZ 8 const char target[STRNCMP_STR_SZ] = "EEEEEEE"; char str[STRNCMP_STR_SZ]; int cmp_ret = 0; int target_pid = 0; const char no_str_target[STRNCMP_STR_SZ] = "12345678"; char writable_target[STRNCMP_STR_SZ]; unsigned int no_const_str_size = STRNCMP_STR_SZ; char _license[] SEC("license") = "GPL"; SEC("?tp/syscalls/sys_enter_nanosleep") int do_strncmp(void *ctx) { if ((bpf_get_current_pid_tgid() >> 32) != target_pid) return 0; cmp_ret = bpf_strncmp(str, STRNCMP_STR_SZ, target); return 0; } SEC("?tp/syscalls/sys_enter_nanosleep") int strncmp_bad_not_const_str_size(void *ctx) { /* The value of string size is not const, so will fail */ cmp_ret = bpf_strncmp(str, no_const_str_size, target); return 0; } SEC("?tp/syscalls/sys_enter_nanosleep") int strncmp_bad_writable_target(void *ctx) { /* Compared target is not read-only, so will fail */ cmp_ret = bpf_strncmp(str, STRNCMP_STR_SZ, writable_target); return 0; } SEC("?tp/syscalls/sys_enter_nanosleep") int strncmp_bad_not_null_term_target(void *ctx) { /* Compared target is not null-terminated, so will fail */ cmp_ret = bpf_strncmp(str, STRNCMP_STR_SZ, no_str_target); return 0; }