// SPDX-License-Identifier: GPL-2.0/* * Copyright 2018 Google LLC */ /* * Implementation of the NH almost-universal hash function, specifically the * variant of NH used in Adiantum.  This is *not* a cryptographic hash function. * * Reference: section 6.3 of "Adiantum: length-preserving encryption for * entry-level processors" (https://eprint.iacr.org/2018/720.pdf). */ #include <crypto/nh.h>#include <linux/export.h>#include <linux/kernel.h>#include <linux/module.h>#include <linux/unaligned.h> #ifdef CONFIG_CRYPTO_LIB_NH_ARCH#include "nh.h" /* $(SRCARCH)/nh.h */#elsestatic bool nh_arch(const u32 *key, const u8 *message, size_t message_len,		    __le64 hash[NH_NUM_PASSES]){	return false;}#endif void nh(const u32 *key, const u8 *message, size_t message_len,	__le64 hash[NH_NUM_PASSES]){	u64 sums[4] = { 0, 0, 0, 0 }; 	if (nh_arch(key, message, message_len, hash))		return; 	static_assert(NH_PAIR_STRIDE == 2);	static_assert(NH_NUM_PASSES == 4); 	while (message_len) {		u32 m0 = get_unaligned_le32(message + 0);		u32 m1 = get_unaligned_le32(message + 4);		u32 m2 = get_unaligned_le32(message + 8);		u32 m3 = get_unaligned_le32(message + 12); 		sums[0] += (u64)(u32)(m0 + key[0]) * (u32)(m2 + key[2]);		sums[1] += (u64)(u32)(m0 + key[4]) * (u32)(m2 + key[6]);		sums[2] += (u64)(u32)(m0 + key[8]) * (u32)(m2 + key[10]);		sums[3] += (u64)(u32)(m0 + key[12]) * (u32)(m2 + key[14]);		sums[0] += (u64)(u32)(m1 + key[1]) * (u32)(m3 + key[3]);		sums[1] += (u64)(u32)(m1 + key[5]) * (u32)(m3 + key[7]);		sums[2] += (u64)(u32)(m1 + key[9]) * (u32)(m3 + key[11]);		sums[3] += (u64)(u32)(m1 + key[13]) * (u32)(m3 + key[15]);		key += NH_MESSAGE_UNIT / sizeof(key[0]);		message += NH_MESSAGE_UNIT;		message_len -= NH_MESSAGE_UNIT;	} 	hash[0] = cpu_to_le64(sums[0]);	hash[1] = cpu_to_le64(sums[1]);	hash[2] = cpu_to_le64(sums[2]);	hash[3] = cpu_to_le64(sums[3]);}EXPORT_SYMBOL_GPL(nh); #ifdef nh_mod_init_archstatic int __init nh_mod_init(void){	nh_mod_init_arch();	return 0;}subsys_initcall(nh_mod_init); static void __exit nh_mod_exit(void){}module_exit(nh_mod_exit);#endif MODULE_DESCRIPTION("NH almost-universal hash function");MODULE_LICENSE("GPL");