pigweed / third_party / boringssl / boringssl / df109ab3d4416f1c498f7ef24481cab3d3d72f1e / . / crypto / internal.h

/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com) | |

* All rights reserved. | |

* | |

* This package is an SSL implementation written | |

* by Eric Young (eay@cryptsoft.com). | |

* The implementation was written so as to conform with Netscapes SSL. | |

* | |

* This library is free for commercial and non-commercial use as long as | |

* the following conditions are aheared to. The following conditions | |

* apply to all code found in this distribution, be it the RC4, RSA, | |

* lhash, DES, etc., code; not just the SSL code. The SSL documentation | |

* included with this distribution is covered by the same copyright terms | |

* except that the holder is Tim Hudson (tjh@cryptsoft.com). | |

* | |

* Copyright remains Eric Young's, and as such any Copyright notices in | |

* the code are not to be removed. | |

* If this package is used in a product, Eric Young should be given attribution | |

* as the author of the parts of the library used. | |

* This can be in the form of a textual message at program startup or | |

* in documentation (online or textual) provided with the package. | |

* | |

* Redistribution and use in source and binary forms, with or without | |

* modification, are permitted provided that the following conditions | |

* are met: | |

* 1. Redistributions of source code must retain the copyright | |

* notice, this list of conditions and the following disclaimer. | |

* 2. Redistributions in binary form must reproduce the above copyright | |

* notice, this list of conditions and the following disclaimer in the | |

* documentation and/or other materials provided with the distribution. | |

* 3. All advertising materials mentioning features or use of this software | |

* must display the following acknowledgement: | |

* "This product includes cryptographic software written by | |

* Eric Young (eay@cryptsoft.com)" | |

* The word 'cryptographic' can be left out if the rouines from the library | |

* being used are not cryptographic related :-). | |

* 4. If you include any Windows specific code (or a derivative thereof) from | |

* the apps directory (application code) you must include an acknowledgement: | |

* "This product includes software written by Tim Hudson (tjh@cryptsoft.com)" | |

* | |

* THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND | |

* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE | |

* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE | |

* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE | |

* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL | |

* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS | |

* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) | |

* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT | |

* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY | |

* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF | |

* SUCH DAMAGE. | |

* | |

* The licence and distribution terms for any publically available version or | |

* derivative of this code cannot be changed. i.e. this code cannot simply be | |

* copied and put under another distribution licence | |

* [including the GNU Public Licence.] | |

*/ | |

/* ==================================================================== | |

* Copyright (c) 1998-2001 The OpenSSL Project. All rights reserved. | |

* | |

* Redistribution and use in source and binary forms, with or without | |

* modification, are permitted provided that the following conditions | |

* are met: | |

* | |

* 1. Redistributions of source code must retain the above copyright | |

* notice, this list of conditions and the following disclaimer. | |

* | |

* 2. Redistributions in binary form must reproduce the above copyright | |

* notice, this list of conditions and the following disclaimer in | |

* the documentation and/or other materials provided with the | |

* distribution. | |

* | |

* 3. All advertising materials mentioning features or use of this | |

* software must display the following acknowledgment: | |

* "This product includes software developed by the OpenSSL Project | |

* for use in the OpenSSL Toolkit. (http://www.openssl.org/)" | |

* | |

* 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to | |

* endorse or promote products derived from this software without | |

* prior written permission. For written permission, please contact | |

* openssl-core@openssl.org. | |

* | |

* 5. Products derived from this software may not be called "OpenSSL" | |

* nor may "OpenSSL" appear in their names without prior written | |

* permission of the OpenSSL Project. | |

* | |

* 6. Redistributions of any form whatsoever must retain the following | |

* acknowledgment: | |

* "This product includes software developed by the OpenSSL Project | |

* for use in the OpenSSL Toolkit (http://www.openssl.org/)" | |

* | |

* THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY | |

* EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE | |

* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR | |

* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR | |

* ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, | |

* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT | |

* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; | |

* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) | |

* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, | |

* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) | |

* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED | |

* OF THE POSSIBILITY OF SUCH DAMAGE. | |

* ==================================================================== | |

* | |

* This product includes cryptographic software written by Eric Young | |

* (eay@cryptsoft.com). This product includes software written by Tim | |

* Hudson (tjh@cryptsoft.com). */ | |

#ifndef OPENSSL_HEADER_CRYPTO_INTERNAL_H | |

#define OPENSSL_HEADER_CRYPTO_INTERNAL_H | |

#include <openssl/ex_data.h> | |

#if defined(__cplusplus) | |

extern "C" { | |

#endif | |

/* st_CRYPTO_EX_DATA_IMPL contains an ex_data implementation. See the comments | |

* in ex_data.h for details of the behaviour of each of the functions. */ | |

struct st_CRYPTO_EX_DATA_IMPL { | |

int (*new_class)(void); | |

void (*cleanup)(void); | |

int (*get_new_index)(int class_value, long argl, void *argp, | |

CRYPTO_EX_new *new_func, CRYPTO_EX_dup *dup_func, | |

CRYPTO_EX_free *free_func); | |

int (*new_ex_data)(int class_value, void *obj, CRYPTO_EX_DATA *ad); | |

int (*dup_ex_data)(int class_value, CRYPTO_EX_DATA *to, | |

const CRYPTO_EX_DATA *from); | |

void (*free_ex_data)(int class_value, void *obj, CRYPTO_EX_DATA *ad); | |

}; | |

#if defined(_MSC_VER) | |

#define OPENSSL_U64(x) x##UI64 | |

#else | |

#if defined(OPENSSL_64_BIT) | |

#define OPENSSL_U64(x) x##UL | |

#else | |

#define OPENSSL_U64(x) x##ULL | |

#endif | |

#endif /* defined(_MSC_VER) */ | |

#if defined(OPENSSL_X86) || defined(OPENSSL_X86_64) | |

/* OPENSSL_cpuid_setup initializes OPENSSL_ia32cap_P. */ | |

void OPENSSL_cpuid_setup(void); | |

#endif | |

#if !defined(inline) | |

#define inline __inline | |

#endif | |

/* Constant-time utility functions. | |

* | |

* The following methods return a bitmask of all ones (0xff...f) for true and 0 | |

* for false. This is useful for choosing a value based on the result of a | |

* conditional in constant time. For example, | |

* | |

* if (a < b) { | |

* c = a; | |

* } else { | |

* c = b; | |

* } | |

* | |

* can be written as | |

* | |

* unsigned int lt = constant_time_lt(a, b); | |

* c = constant_time_select(lt, a, b); */ | |

/* constant_time_msb returns the given value with the MSB copied to all the | |

* other bits. */ | |

static inline unsigned int constant_time_msb(unsigned int a) { | |

return (unsigned int)((int)(a) >> (sizeof(int) * 8 - 1)); | |

} | |

/* constant_time_lt returns 0xff..f if a < b and 0 otherwise. */ | |

static inline unsigned int constant_time_lt(unsigned int a, unsigned int b) { | |

/* Consider the two cases of the problem: | |

* msb(a) == msb(b): a < b iff the MSB of a - b is set. | |

* msb(a) != msb(b): a < b iff the MSB of b is set. | |

* | |

* If msb(a) == msb(b) then the following evaluates as: | |

* msb(a^((a^b)|((a-b)^a))) == | |

* msb(a^((a-b) ^ a)) == (because msb(a^b) == 0) | |

* msb(a^a^(a-b)) == (rearranging) | |

* msb(a-b) (because ∀x. x^x == 0) | |

* | |

* Else, if msb(a) != msb(b) then the following evaluates as: | |

* msb(a^((a^b)|((a-b)^a))) == | |

* msb(a^(𝟙 | ((a-b)^a))) == (because msb(a^b) == 1 and 𝟙 | |

* represents a value s.t. msb(𝟙) = 1) | |

* msb(a^𝟙) == (because ORing with 1 results in 1) | |

* msb(b) | |

* | |

* | |

* Here is an SMT-LIB verification of this formula: | |

* | |

* (define-fun lt ((a (_ BitVec 32)) (b (_ BitVec 32))) (_ BitVec 32) | |

* (bvxor a (bvor (bvxor a b) (bvxor (bvsub a b) a))) | |

* ) | |

* | |

* (declare-fun a () (_ BitVec 32)) | |

* (declare-fun b () (_ BitVec 32)) | |

* | |

* (assert (not (= (= #x00000001 (bvlshr (lt a b) #x0000001f)) (bvult a b)))) | |

* (check-sat) | |

* (get-model) | |

*/ | |

return constant_time_msb(a^((a^b)|((a-b)^a))); | |

} | |

/* constant_time_lt_8 acts like |constant_time_lt| but returns an 8-bit mask. */ | |

static inline uint8_t constant_time_lt_8(unsigned int a, unsigned int b) { | |

return (uint8_t)(constant_time_lt(a, b)); | |

} | |

/* constant_time_gt returns 0xff..f if a >= b and 0 otherwise. */ | |

static inline unsigned int constant_time_ge(unsigned int a, unsigned int b) { | |

return ~constant_time_lt(a, b); | |

} | |

/* constant_time_ge_8 acts like |constant_time_ge| but returns an 8-bit mask. */ | |

static inline uint8_t constant_time_ge_8(unsigned int a, unsigned int b) { | |

return (uint8_t)(constant_time_ge(a, b)); | |

} | |

/* constant_time_is_zero returns 0xff..f if a == 0 and 0 otherwise. */ | |

static inline unsigned int constant_time_is_zero(unsigned int a) { | |

/* Here is an SMT-LIB verification of this formula: | |

* | |

* (define-fun is_zero ((a (_ BitVec 32))) (_ BitVec 32) | |

* (bvand (bvnot a) (bvsub a #x00000001)) | |

* ) | |

* | |

* (declare-fun a () (_ BitVec 32)) | |

* | |

* (assert (not (= (= #x00000001 (bvlshr (is_zero a) #x0000001f)) (= a #x00000000)))) | |

* (check-sat) | |

* (get-model) | |

*/ | |

return constant_time_msb(~a & (a - 1)); | |

} | |

/* constant_time_is_zero_8 acts like constant_time_is_zero but returns an 8-bit | |

* mask. */ | |

static inline uint8_t constant_time_is_zero_8(unsigned int a) { | |

return (uint8_t)(constant_time_is_zero(a)); | |

} | |

/* constant_time_eq returns 0xff..f if a == b and 0 otherwise. */ | |

static inline unsigned int constant_time_eq(unsigned int a, unsigned int b) { | |

return constant_time_is_zero(a ^ b); | |

} | |

/* constant_time_eq_8 acts like |constant_time_eq| but returns an 8-bit mask. */ | |

static inline uint8_t constant_time_eq_8(unsigned int a, unsigned int b) { | |

return (uint8_t)(constant_time_eq(a, b)); | |

} | |

/* constant_time_eq_int acts like |constant_time_eq| but works on int values. */ | |

static inline unsigned int constant_time_eq_int(int a, int b) { | |

return constant_time_eq((unsigned)(a), (unsigned)(b)); | |

} | |

/* constant_time_eq_int_8 acts like |constant_time_eq_int| but returns an 8-bit | |

* mask. */ | |

static inline uint8_t constant_time_eq_int_8(int a, int b) { | |

return constant_time_eq_8((unsigned)(a), (unsigned)(b)); | |

} | |

/* constant_time_select returns (mask & a) | (~mask & b). When |mask| is all 1s | |

* or all 0s (as returned by the methods above), the select methods return | |

* either |a| (if |mask| is nonzero) or |b| (if |mask| is zero). */ | |

static inline unsigned int constant_time_select(unsigned int mask, | |

unsigned int a, unsigned int b) { | |

return (mask & a) | (~mask & b); | |

} | |

/* constant_time_select_8 acts like |constant_time_select| but operates on | |

* 8-bit values. */ | |

static inline uint8_t constant_time_select_8(uint8_t mask, uint8_t a, | |

uint8_t b) { | |

return (uint8_t)(constant_time_select(mask, a, b)); | |

} | |

/* constant_time_select_int acts like |constant_time_select| but operates on | |

* ints. */ | |

static inline int constant_time_select_int(unsigned int mask, int a, int b) { | |

return (int)(constant_time_select(mask, (unsigned)(a), (unsigned)(b))); | |

} | |

#if defined(__cplusplus) | |

} /* extern C */ | |

#endif | |

#endif /* OPENSSL_HEADER_CRYPTO_INTERNAL_H */ |