1/** 2 * \file common.h 3 * 4 * \brief Utility macros for internal use in the library 5 */ 6/* 7 * Copyright The Mbed TLS Contributors 8 * SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later 9 */ 10 11#ifndef MBEDTLS_LIBRARY_COMMON_H 12#define MBEDTLS_LIBRARY_COMMON_H 13 14#include "mbedtls/build_info.h" 15#include "alignment.h" 16 17#include <assert.h> 18#include <stddef.h> 19#include <stdint.h> 20#include <stddef.h> 21 22#if defined(__ARM_NEON) 23#include <arm_neon.h> 24#define MBEDTLS_HAVE_NEON_INTRINSICS 25#elif defined(MBEDTLS_PLATFORM_IS_WINDOWS_ON_ARM64) 26#include <arm64_neon.h> 27#define MBEDTLS_HAVE_NEON_INTRINSICS 28#endif 29 30/** Helper to define a function as static except when building invasive tests. 31 * 32 * If a function is only used inside its own source file and should be 33 * declared `static` to allow the compiler to optimize for code size, 34 * but that function has unit tests, define it with 35 * ``` 36 * MBEDTLS_STATIC_TESTABLE int mbedtls_foo(...) { ... } 37 * ``` 38 * and declare it in a header in the `library/` directory with 39 * ``` 40 * #if defined(MBEDTLS_TEST_HOOKS) 41 * int mbedtls_foo(...); 42 * #endif 43 * ``` 44 */ 45#if defined(MBEDTLS_TEST_HOOKS) 46#define MBEDTLS_STATIC_TESTABLE 47#else 48#define MBEDTLS_STATIC_TESTABLE static 49#endif 50 51#if defined(MBEDTLS_TEST_HOOKS) 52extern void (*mbedtls_test_hook_test_fail)(const char *test, int line, const char *file); 53#define MBEDTLS_TEST_HOOK_TEST_ASSERT(TEST) \ 54 do { \ 55 if ((!(TEST)) && ((*mbedtls_test_hook_test_fail) != NULL)) \ 56 { \ 57 (*mbedtls_test_hook_test_fail)( #TEST, __LINE__, __FILE__); \ 58 } \ 59 } while (0) 60#else 61#define MBEDTLS_TEST_HOOK_TEST_ASSERT(TEST) 62#endif /* defined(MBEDTLS_TEST_HOOKS) */ 63 64/** \def ARRAY_LENGTH 65 * Return the number of elements of a static or stack array. 66 * 67 * \param array A value of array (not pointer) type. 68 * 69 * \return The number of elements of the array. 70 */ 71/* A correct implementation of ARRAY_LENGTH, but which silently gives 72 * a nonsensical result if called with a pointer rather than an array. */ 73#define ARRAY_LENGTH_UNSAFE(array) \ 74 (sizeof(array) / sizeof(*(array))) 75 76#if defined(__GNUC__) 77/* Test if arg and &(arg)[0] have the same type. This is true if arg is 78 * an array but not if it's a pointer. */ 79#define IS_ARRAY_NOT_POINTER(arg) \ 80 (!__builtin_types_compatible_p(__typeof__(arg), \ 81 __typeof__(&(arg)[0]))) 82/* A compile-time constant with the value 0. If `const_expr` is not a 83 * compile-time constant with a nonzero value, cause a compile-time error. */ 84#define STATIC_ASSERT_EXPR(const_expr) \ 85 (0 && sizeof(struct { unsigned int STATIC_ASSERT : 1 - 2 * !(const_expr); })) 86 87/* Return the scalar value `value` (possibly promoted). This is a compile-time 88 * constant if `value` is. `condition` must be a compile-time constant. 89 * If `condition` is false, arrange to cause a compile-time error. */ 90#define STATIC_ASSERT_THEN_RETURN(condition, value) \ 91 (STATIC_ASSERT_EXPR(condition) ? 0 : (value)) 92 93#define ARRAY_LENGTH(array) \ 94 (STATIC_ASSERT_THEN_RETURN(IS_ARRAY_NOT_POINTER(array), \ 95 ARRAY_LENGTH_UNSAFE(array))) 96 97#else 98/* If we aren't sure the compiler supports our non-standard tricks, 99 * fall back to the unsafe implementation. */ 100#define ARRAY_LENGTH(array) ARRAY_LENGTH_UNSAFE(array) 101#endif 102/** Allow library to access its structs' private members. 103 * 104 * Although structs defined in header files are publicly available, 105 * their members are private and should not be accessed by the user. 106 */ 107#define MBEDTLS_ALLOW_PRIVATE_ACCESS 108 109/** 110 * \brief Securely zeroize a buffer then free it. 111 * 112 * Similar to making consecutive calls to 113 * \c mbedtls_platform_zeroize() and \c mbedtls_free(), but has 114 * code size savings, and potential for optimisation in the future. 115 * 116 * Guaranteed to be a no-op if \p buf is \c NULL and \p len is 0. 117 * 118 * \param buf Buffer to be zeroized then freed. 119 * \param len Length of the buffer in bytes 120 */ 121void mbedtls_zeroize_and_free(void *buf, size_t len); 122 123/** Return an offset into a buffer. 124 * 125 * This is just the addition of an offset to a pointer, except that this 126 * function also accepts an offset of 0 into a buffer whose pointer is null. 127 * (`p + n` has undefined behavior when `p` is null, even when `n == 0`. 128 * A null pointer is a valid buffer pointer when the size is 0, for example 129 * as the result of `malloc(0)` on some platforms.) 130 * 131 * \param p Pointer to a buffer of at least n bytes. 132 * This may be \p NULL if \p n is zero. 133 * \param n An offset in bytes. 134 * \return Pointer to offset \p n in the buffer \p p. 135 * Note that this is only a valid pointer if the size of the 136 * buffer is at least \p n + 1. 137 */ 138static inline unsigned char *mbedtls_buffer_offset( 139 unsigned char *p, size_t n) 140{ 141 return p == NULL ? NULL : p + n; 142} 143 144/** Return an offset into a read-only buffer. 145 * 146 * Similar to mbedtls_buffer_offset(), but for const pointers. 147 * 148 * \param p Pointer to a buffer of at least n bytes. 149 * This may be \p NULL if \p n is zero. 150 * \param n An offset in bytes. 151 * \return Pointer to offset \p n in the buffer \p p. 152 * Note that this is only a valid pointer if the size of the 153 * buffer is at least \p n + 1. 154 */ 155static inline const unsigned char *mbedtls_buffer_offset_const( 156 const unsigned char *p, size_t n) 157{ 158 return p == NULL ? NULL : p + n; 159} 160 161void mbedtls_xor(unsigned char *r, const unsigned char *a, const unsigned char *b, size_t n); 162 163void mbedtls_xor_no_simd(unsigned char *r, 164 const unsigned char *a, 165 const unsigned char *b, 166 size_t n); 167 168/* Fix MSVC C99 compatible issue 169 * MSVC support __func__ from visual studio 2015( 1900 ) 170 * Use MSVC predefine macro to avoid name check fail. 171 */ 172#if (defined(_MSC_VER) && (_MSC_VER <= 1900)) 173#define /*no-check-names*/ __func__ __FUNCTION__ 174#endif 175 176/* Define `asm` for compilers which don't define it. */ 177/* *INDENT-OFF* */ 178#ifndef asm 179#if defined(__IAR_SYSTEMS_ICC__) 180#define asm __asm 181#else 182#define asm __asm__ 183#endif 184#endif 185/* *INDENT-ON* */ 186 187/* 188 * Define the constraint used for read-only pointer operands to aarch64 asm. 189 * 190 * This is normally the usual "r", but for aarch64_32 (aka ILP32, 191 * as found in watchos), "p" is required to avoid warnings from clang. 192 * 193 * Note that clang does not recognise '+p' or '=p', and armclang 194 * does not recognise 'p' at all. Therefore, to update a pointer from 195 * aarch64 assembly, it is necessary to use something like: 196 * 197 * uintptr_t uptr = (uintptr_t) ptr; 198 * asm( "ldr x4, [%x0], #8" ... : "+r" (uptr) : : ) 199 * ptr = (void*) uptr; 200 * 201 * Note that the "x" in "%x0" is neccessary; writing "%0" will cause warnings. 202 */ 203#if defined(__aarch64__) && defined(MBEDTLS_HAVE_ASM) 204#if UINTPTR_MAX == 0xfffffffful 205/* ILP32: Specify the pointer operand slightly differently, as per #7787. */ 206#define MBEDTLS_ASM_AARCH64_PTR_CONSTRAINT "p" 207#elif UINTPTR_MAX == 0xfffffffffffffffful 208/* Normal case (64-bit pointers): use "r" as the constraint for pointer operands to asm */ 209#define MBEDTLS_ASM_AARCH64_PTR_CONSTRAINT "r" 210#else 211#error "Unrecognised pointer size for aarch64" 212#endif 213#endif 214 215/* Always provide a static assert macro, so it can be used unconditionally. 216 * It will expand to nothing on some systems. 217 * Can be used outside functions (but don't add a trailing ';' in that case: 218 * the semicolon is included here to avoid triggering -Wextra-semi when 219 * MBEDTLS_STATIC_ASSERT() expands to nothing). 220 * Can't use the C11-style `defined(static_assert)` on FreeBSD, since it 221 * defines static_assert even with -std=c99, but then complains about it. 222 */ 223#if defined(static_assert) && !defined(__FreeBSD__) 224#define MBEDTLS_STATIC_ASSERT(expr, msg) static_assert(expr, msg); 225#else 226#define MBEDTLS_STATIC_ASSERT(expr, msg) 227#endif 228 229#if defined(__has_builtin) 230#define MBEDTLS_HAS_BUILTIN(x) __has_builtin(x) 231#else 232#define MBEDTLS_HAS_BUILTIN(x) 0 233#endif 234 235/* Define compiler branch hints */ 236#if MBEDTLS_HAS_BUILTIN(__builtin_expect) 237#define MBEDTLS_LIKELY(x) __builtin_expect(!!(x), 1) 238#define MBEDTLS_UNLIKELY(x) __builtin_expect(!!(x), 0) 239#else 240#define MBEDTLS_LIKELY(x) x 241#define MBEDTLS_UNLIKELY(x) x 242#endif 243 244/* MBEDTLS_ASSUME may be used to provide additional information to the compiler 245 * which can result in smaller code-size. */ 246#if MBEDTLS_HAS_BUILTIN(__builtin_assume) 247/* clang provides __builtin_assume */ 248#define MBEDTLS_ASSUME(x) __builtin_assume(x) 249#elif MBEDTLS_HAS_BUILTIN(__builtin_unreachable) 250/* gcc and IAR can use __builtin_unreachable */ 251#define MBEDTLS_ASSUME(x) do { if (!(x)) __builtin_unreachable(); } while (0) 252#elif defined(_MSC_VER) 253/* Supported by MSVC since VS 2005 */ 254#define MBEDTLS_ASSUME(x) __assume(x) 255#else 256#define MBEDTLS_ASSUME(x) do { } while (0) 257#endif 258 259/* For gcc -Os, override with -O2 for a given function. 260 * 261 * This will not affect behaviour for other optimisation settings, e.g. -O0. 262 */ 263#if defined(MBEDTLS_COMPILER_IS_GCC) && defined(__OPTIMIZE_SIZE__) 264#define MBEDTLS_OPTIMIZE_FOR_PERFORMANCE __attribute__((optimize("-O2"))) 265#else 266#define MBEDTLS_OPTIMIZE_FOR_PERFORMANCE 267#endif 268 269/* Suppress compiler warnings for unused functions and variables. */ 270#if !defined(MBEDTLS_MAYBE_UNUSED) && defined(__has_attribute) 271# if __has_attribute(unused) 272# define MBEDTLS_MAYBE_UNUSED __attribute__((unused)) 273# endif 274#endif 275#if !defined(MBEDTLS_MAYBE_UNUSED) && defined(__GNUC__) 276# define MBEDTLS_MAYBE_UNUSED __attribute__((unused)) 277#endif 278#if !defined(MBEDTLS_MAYBE_UNUSED) && defined(__IAR_SYSTEMS_ICC__) && defined(__VER__) 279/* IAR does support __attribute__((unused)), but only if the -e flag (extended language support) 280 * is given; the pragma always works. 281 * Unfortunately the pragma affects the rest of the file where it is used, but this is harmless. 282 * Check for version 5.2 or later - this pragma may be supported by earlier versions, but I wasn't 283 * able to find documentation). 284 */ 285# if (__VER__ >= 5020000) 286# define MBEDTLS_MAYBE_UNUSED _Pragma("diag_suppress=Pe177") 287# endif 288#endif 289#if !defined(MBEDTLS_MAYBE_UNUSED) && defined(_MSC_VER) 290# define MBEDTLS_MAYBE_UNUSED __pragma(warning(suppress:4189)) 291#endif 292#if !defined(MBEDTLS_MAYBE_UNUSED) 293# define MBEDTLS_MAYBE_UNUSED 294#endif 295 296#endif /* MBEDTLS_LIBRARY_COMMON_H */ 297