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/*
* Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
*
* Licensed under the Apache License, Version 2.0 (the "License").
* You may not use this file except in compliance with the License.
* A copy of the License is located at
*
* http://aws.amazon.com/apache2.0
*
* or in the "license" file accompanying this file. This file is distributed
* on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either
* express or implied. See the License for the specific language governing
* permissions and limitations under the License.
*/
#pragma once
#include <stdbool.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#include "error/s2n_errno.h"
#include "utils/s2n_ensure.h"
#include "utils/s2n_result.h"
#include "utils/s2n_safety_macros.h"
/**
* The goal of s2n_safety is to provide helpers to perform common
* checks, which help with code readability.
*/
/**
* Marks a case of a switch statement as able to fall through to the next case
*/
#if defined(S2N_FALL_THROUGH_SUPPORTED)
#define FALL_THROUGH __attribute__((fallthrough))
#else
#define FALL_THROUGH ((void) 0)
#endif
/* Returns `true` if s2n is in unit test mode, `false` otherwise */
bool s2n_in_unit_test();
/* Sets whether s2n is in unit test mode */
int s2n_in_unit_test_set(bool newval);
#define S2N_IN_INTEG_TEST (getenv("S2N_INTEG_TEST") != NULL)
#define S2N_IN_TEST (s2n_in_unit_test() || S2N_IN_INTEG_TEST)
/* Returns 1 if a and b are equal, in constant time */
bool s2n_constant_time_equals(const uint8_t* a, const uint8_t* b, const uint32_t len);
/* Copy src to dst, or don't copy it, in constant time */
int s2n_constant_time_copy_or_dont(uint8_t* dst, const uint8_t* src, uint32_t len, uint8_t dont);
/* If src contains valid PKCS#1 v1.5 padding of exactly expectlen bytes, decode
* it into dst, otherwise leave dst alone, in constant time.
* Always returns zero. */
int s2n_constant_time_pkcs1_unpad_or_dont(uint8_t* dst, const uint8_t* src, uint32_t srclen, uint32_t expectlen);
/**
* Runs _thecleanup function on _thealloc once _thealloc went out of scope
*/
#define DEFER_CLEANUP(_thealloc, _thecleanup) \
__attribute__((cleanup(_thecleanup))) _thealloc
/**
* Often we want to free memory on an error, but not on a success.
* We do this by declaring a variable with DEFER_CLEANUP, then zeroing
* that variable after success to prevent DEFER_CLEANUP from accessing
* and freeing any memory it allocated.
*
* This pattern is not intuitive, so a named macro makes it more readable.
*/
#define ZERO_TO_DISABLE_DEFER_CLEANUP(_thealloc) memset(&_thealloc, 0, sizeof(_thealloc))
/* We want to apply blinding whenever `action` fails.
* Unfortunately, because functions in S2N do not have a consistent return type, determining failure is difficult.
* Instead, let's rely on the consistent error handling behavior of returning from a method early on error
* and apply blinding if our tracking variable goes out of scope early.
*/
S2N_CLEANUP_RESULT s2n_connection_apply_error_blinding(struct s2n_connection** conn);
#define WITH_ERROR_BLINDING(conn, action) \
do { \
DEFER_CLEANUP(struct s2n_connection* _conn_to_blind = conn, s2n_connection_apply_error_blinding); \
action; \
/* The `if` here is to avoid a redundantInitialization warning from cppcheck */ \
if (_conn_to_blind) { \
_conn_to_blind = NULL; \
} \
} while (0)
/* Creates cleanup function for pointers from function func which accepts a pointer.
* This is useful for DEFER_CLEANUP as it passes &_thealloc into _thecleanup function,
* so if _thealloc is a pointer _thecleanup will receive a pointer to a pointer.*/
#define DEFINE_POINTER_CLEANUP_FUNC(type, func) \
static inline void func##_pointer(type* p) \
{ \
if (p && *p) \
func(*p); \
} \
struct __useless_struct_to_allow_trailing_semicolon__
#define s2n_array_len(array) ((array != NULL) ? (sizeof(array) / sizeof(array[0])) : 0)
int s2n_mul_overflow(uint32_t a, uint32_t b, uint32_t* out);
/**
* Rounds "initial" up to a multiple of "alignment", and stores the result in "out".
* Raises an error if overflow would occur.
* NOT CONSTANT TIME.
*/
int s2n_align_to(uint32_t initial, uint32_t alignment, uint32_t* out);
int s2n_add_overflow(uint32_t a, uint32_t b, uint32_t* out);
int s2n_sub_overflow(uint32_t a, uint32_t b, uint32_t* out);
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