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