1 /* SPDX-License-Identifier: GPL-2.0-or-later */ 2 /* 3 * Cryptographic utilities 4 * 5 * Copyright (c) 2023 Herbert Xu <herbert@gondor.apana.org.au> 6 */ 7 #ifndef _CRYPTO_UTILS_H 8 #define _CRYPTO_UTILS_H 9 10 #include <asm/unaligned.h> 11 #include <linux/compiler_attributes.h> 12 #include <linux/types.h> 13 14 void __crypto_xor(u8 *dst, const u8 *src1, const u8 *src2, unsigned int size); 15 16 static inline void crypto_xor(u8 *dst, const u8 *src, unsigned int size) 17 { 18 if (IS_ENABLED(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) && 19 __builtin_constant_p(size) && 20 (size % sizeof(unsigned long)) == 0) { 21 unsigned long *d = (unsigned long *)dst; 22 unsigned long *s = (unsigned long *)src; 23 unsigned long l; 24 25 while (size > 0) { 26 l = get_unaligned(d) ^ get_unaligned(s++); 27 put_unaligned(l, d++); 28 size -= sizeof(unsigned long); 29 } 30 } else { 31 __crypto_xor(dst, dst, src, size); 32 } 33 } 34 35 static inline void crypto_xor_cpy(u8 *dst, const u8 *src1, const u8 *src2, 36 unsigned int size) 37 { 38 if (IS_ENABLED(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) && 39 __builtin_constant_p(size) && 40 (size % sizeof(unsigned long)) == 0) { 41 unsigned long *d = (unsigned long *)dst; 42 unsigned long *s1 = (unsigned long *)src1; 43 unsigned long *s2 = (unsigned long *)src2; 44 unsigned long l; 45 46 while (size > 0) { 47 l = get_unaligned(s1++) ^ get_unaligned(s2++); 48 put_unaligned(l, d++); 49 size -= sizeof(unsigned long); 50 } 51 } else { 52 __crypto_xor(dst, src1, src2, size); 53 } 54 } 55 56 noinline unsigned long __crypto_memneq(const void *a, const void *b, size_t size); 57 58 /** 59 * crypto_memneq - Compare two areas of memory without leaking 60 * timing information. 61 * 62 * @a: One area of memory 63 * @b: Another area of memory 64 * @size: The size of the area. 65 * 66 * Returns 0 when data is equal, 1 otherwise. 67 */ 68 static inline int crypto_memneq(const void *a, const void *b, size_t size) 69 { 70 return __crypto_memneq(a, b, size) != 0UL ? 1 : 0; 71 } 72 73 #endif /* _CRYPTO_UTILS_H */ 74