/** * \file common.h * * \brief Utility macros for internal use in the library */ /* * Copyright The Mbed TLS Contributors * SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later */ #ifndef MBEDTLS_LIBRARY_COMMON_H #define MBEDTLS_LIBRARY_COMMON_H #include "mbedtls/build_info.h" #include "alignment.h" #include #include #include #include #if defined(__ARM_NEON) #include #define MBEDTLS_HAVE_NEON_INTRINSICS #elif defined(MBEDTLS_PLATFORM_IS_WINDOWS_ON_ARM64) #include #define MBEDTLS_HAVE_NEON_INTRINSICS #endif /** Helper to define a function as static except when building invasive tests. * * If a function is only used inside its own source file and should be * declared `static` to allow the compiler to optimize for code size, * but that function has unit tests, define it with * ``` * MBEDTLS_STATIC_TESTABLE int mbedtls_foo(...) { ... } * ``` * and declare it in a header in the `library/` directory with * ``` * #if defined(MBEDTLS_TEST_HOOKS) * int mbedtls_foo(...); * #endif * ``` */ #if defined(MBEDTLS_TEST_HOOKS) #define MBEDTLS_STATIC_TESTABLE #else #define MBEDTLS_STATIC_TESTABLE static #endif #if defined(MBEDTLS_TEST_HOOKS) extern void (*mbedtls_test_hook_test_fail)(const char *test, int line, const char *file); #define MBEDTLS_TEST_HOOK_TEST_ASSERT(TEST) \ do { \ if ((!(TEST)) && ((*mbedtls_test_hook_test_fail) != NULL)) \ { \ (*mbedtls_test_hook_test_fail)( #TEST, __LINE__, __FILE__); \ } \ } while (0) #else #define MBEDTLS_TEST_HOOK_TEST_ASSERT(TEST) #endif /* defined(MBEDTLS_TEST_HOOKS) */ /** \def ARRAY_LENGTH * Return the number of elements of a static or stack array. * * \param array A value of array (not pointer) type. * * \return The number of elements of the array. */ /* A correct implementation of ARRAY_LENGTH, but which silently gives * a nonsensical result if called with a pointer rather than an array. */ #define ARRAY_LENGTH_UNSAFE(array) \ (sizeof(array) / sizeof(*(array))) #if defined(__GNUC__) /* Test if arg and &(arg)[0] have the same type. This is true if arg is * an array but not if it's a pointer. */ #define IS_ARRAY_NOT_POINTER(arg) \ (!__builtin_types_compatible_p(__typeof__(arg), \ __typeof__(&(arg)[0]))) /* A compile-time constant with the value 0. If `const_expr` is not a * compile-time constant with a nonzero value, cause a compile-time error. */ #define STATIC_ASSERT_EXPR(const_expr) \ (0 && sizeof(struct { unsigned int STATIC_ASSERT : 1 - 2 * !(const_expr); })) /* Return the scalar value `value` (possibly promoted). This is a compile-time * constant if `value` is. `condition` must be a compile-time constant. * If `condition` is false, arrange to cause a compile-time error. */ #define STATIC_ASSERT_THEN_RETURN(condition, value) \ (STATIC_ASSERT_EXPR(condition) ? 0 : (value)) #define ARRAY_LENGTH(array) \ (STATIC_ASSERT_THEN_RETURN(IS_ARRAY_NOT_POINTER(array), \ ARRAY_LENGTH_UNSAFE(array))) #else /* If we aren't sure the compiler supports our non-standard tricks, * fall back to the unsafe implementation. */ #define ARRAY_LENGTH(array) ARRAY_LENGTH_UNSAFE(array) #endif /** Allow library to access its structs' private members. * * Although structs defined in header files are publicly available, * their members are private and should not be accessed by the user. */ #define MBEDTLS_ALLOW_PRIVATE_ACCESS /** * \brief Securely zeroize a buffer then free it. * * Similar to making consecutive calls to * \c mbedtls_platform_zeroize() and \c mbedtls_free(), but has * code size savings, and potential for optimisation in the future. * * Guaranteed to be a no-op if \p buf is \c NULL and \p len is 0. * * \param buf Buffer to be zeroized then freed. * \param len Length of the buffer in bytes */ void mbedtls_zeroize_and_free(void *buf, size_t len); /** Return an offset into a buffer. * * This is just the addition of an offset to a pointer, except that this * function also accepts an offset of 0 into a buffer whose pointer is null. * (`p + n` has undefined behavior when `p` is null, even when `n == 0`. * A null pointer is a valid buffer pointer when the size is 0, for example * as the result of `malloc(0)` on some platforms.) * * \param p Pointer to a buffer of at least n bytes. * This may be \p NULL if \p n is zero. * \param n An offset in bytes. * \return Pointer to offset \p n in the buffer \p p. * Note that this is only a valid pointer if the size of the * buffer is at least \p n + 1. */ static inline unsigned char *mbedtls_buffer_offset( unsigned char *p, size_t n) { return p == NULL ? NULL : p + n; } /** Return an offset into a read-only buffer. * * Similar to mbedtls_buffer_offset(), but for const pointers. * * \param p Pointer to a buffer of at least n bytes. * This may be \p NULL if \p n is zero. * \param n An offset in bytes. * \return Pointer to offset \p n in the buffer \p p. * Note that this is only a valid pointer if the size of the * buffer is at least \p n + 1. */ static inline const unsigned char *mbedtls_buffer_offset_const( const unsigned char *p, size_t n) { return p == NULL ? NULL : p + n; } /* Always inline mbedtls_xor() for similar reasons as mbedtls_xor_no_simd(). */ #if defined(__IAR_SYSTEMS_ICC__) #pragma inline = forced #elif defined(__GNUC__) __attribute__((always_inline)) #endif /** * Perform a fast block XOR operation, such that * r[i] = a[i] ^ b[i] where 0 <= i < n * * \param r Pointer to result (buffer of at least \p n bytes). \p r * may be equal to either \p a or \p b, but behaviour when * it overlaps in other ways is undefined. * \param a Pointer to input (buffer of at least \p n bytes) * \param b Pointer to input (buffer of at least \p n bytes) * \param n Number of bytes to process. * * \note Depending on the situation, it may be faster to use either mbedtls_xor() or * mbedtls_xor_no_simd() (these are functionally equivalent). * If the result is used immediately after the xor operation in non-SIMD code (e.g, in * AES-CBC), there may be additional latency to transfer the data from SIMD to scalar * registers, and in this case, mbedtls_xor_no_simd() may be faster. In other cases where * the result is not used immediately (e.g., in AES-CTR), mbedtls_xor() may be faster. * For targets without SIMD support, they will behave the same. */ static inline void mbedtls_xor(unsigned char *r, const unsigned char *a, const unsigned char *b, size_t n) { size_t i = 0; #if defined(MBEDTLS_EFFICIENT_UNALIGNED_ACCESS) #if defined(MBEDTLS_HAVE_NEON_INTRINSICS) && \ (!(defined(MBEDTLS_COMPILER_IS_GCC) && MBEDTLS_GCC_VERSION < 70300)) /* Old GCC versions generate a warning here, so disable the NEON path for these compilers */ for (; (i + 16) <= n; i += 16) { uint8x16_t v1 = vld1q_u8(a + i); uint8x16_t v2 = vld1q_u8(b + i); uint8x16_t x = veorq_u8(v1, v2); vst1q_u8(r + i, x); } #if defined(__IAR_SYSTEMS_ICC__) /* This if statement helps some compilers (e.g., IAR) optimise out the byte-by-byte tail case * where n is a constant multiple of 16. * For other compilers (e.g. recent gcc and clang) it makes no difference if n is a compile-time * constant, and is a very small perf regression if n is not a compile-time constant. */ if (n % 16 == 0) { return; } #endif #elif defined(MBEDTLS_ARCH_IS_X64) || defined(MBEDTLS_ARCH_IS_ARM64) /* This codepath probably only makes sense on architectures with 64-bit registers */ for (; (i + 8) <= n; i += 8) { uint64_t x = mbedtls_get_unaligned_uint64(a + i) ^ mbedtls_get_unaligned_uint64(b + i); mbedtls_put_unaligned_uint64(r + i, x); } #if defined(__IAR_SYSTEMS_ICC__) if (n % 8 == 0) { return; } #endif #else for (; (i + 4) <= n; i += 4) { uint32_t x = mbedtls_get_unaligned_uint32(a + i) ^ mbedtls_get_unaligned_uint32(b + i); mbedtls_put_unaligned_uint32(r + i, x); } #if defined(__IAR_SYSTEMS_ICC__) if (n % 4 == 0) { return; } #endif #endif #endif for (; i < n; i++) { r[i] = a[i] ^ b[i]; } } /* Always inline mbedtls_xor_no_simd() as we see significant perf regressions when it does not get * inlined (e.g., observed about 3x perf difference in gcm_mult_largetable with gcc 7 - 12) */ #if defined(__IAR_SYSTEMS_ICC__) #pragma inline = forced #elif defined(__GNUC__) __attribute__((always_inline)) #endif /** * Perform a fast block XOR operation, such that * r[i] = a[i] ^ b[i] where 0 <= i < n * * In some situations, this can perform better than mbedtls_xor() (e.g., it's about 5% * better in AES-CBC). * * \param r Pointer to result (buffer of at least \p n bytes). \p r * may be equal to either \p a or \p b, but behaviour when * it overlaps in other ways is undefined. * \param a Pointer to input (buffer of at least \p n bytes) * \param b Pointer to input (buffer of at least \p n bytes) * \param n Number of bytes to process. * * \note Depending on the situation, it may be faster to use either mbedtls_xor() or * mbedtls_xor_no_simd() (these are functionally equivalent). * If the result is used immediately after the xor operation in non-SIMD code (e.g, in * AES-CBC), there may be additional latency to transfer the data from SIMD to scalar * registers, and in this case, mbedtls_xor_no_simd() may be faster. In other cases where * the result is not used immediately (e.g., in AES-CTR), mbedtls_xor() may be faster. * For targets without SIMD support, they will behave the same. */ static inline void mbedtls_xor_no_simd(unsigned char *r, const unsigned char *a, const unsigned char *b, size_t n) { size_t i = 0; #if defined(MBEDTLS_EFFICIENT_UNALIGNED_ACCESS) #if defined(MBEDTLS_ARCH_IS_X64) || defined(MBEDTLS_ARCH_IS_ARM64) /* This codepath probably only makes sense on architectures with 64-bit registers */ for (; (i + 8) <= n; i += 8) { uint64_t x = mbedtls_get_unaligned_uint64(a + i) ^ mbedtls_get_unaligned_uint64(b + i); mbedtls_put_unaligned_uint64(r + i, x); } #if defined(__IAR_SYSTEMS_ICC__) /* This if statement helps some compilers (e.g., IAR) optimise out the byte-by-byte tail case * where n is a constant multiple of 8. * For other compilers (e.g. recent gcc and clang) it makes no difference if n is a compile-time * constant, and is a very small perf regression if n is not a compile-time constant. */ if (n % 8 == 0) { return; } #endif #else for (; (i + 4) <= n; i += 4) { uint32_t x = mbedtls_get_unaligned_uint32(a + i) ^ mbedtls_get_unaligned_uint32(b + i); mbedtls_put_unaligned_uint32(r + i, x); } #if defined(__IAR_SYSTEMS_ICC__) if (n % 4 == 0) { return; } #endif #endif #endif for (; i < n; i++) { r[i] = a[i] ^ b[i]; } } /* Fix MSVC C99 compatible issue * MSVC support __func__ from visual studio 2015( 1900 ) * Use MSVC predefine macro to avoid name check fail. */ #if (defined(_MSC_VER) && (_MSC_VER <= 1900)) #define /*no-check-names*/ __func__ __FUNCTION__ #endif /* Define `asm` for compilers which don't define it. */ /* *INDENT-OFF* */ #ifndef asm #if defined(__IAR_SYSTEMS_ICC__) #define asm __asm #else #define asm __asm__ #endif #endif /* *INDENT-ON* */ /* * Define the constraint used for read-only pointer operands to aarch64 asm. * * This is normally the usual "r", but for aarch64_32 (aka ILP32, * as found in watchos), "p" is required to avoid warnings from clang. * * Note that clang does not recognise '+p' or '=p', and armclang * does not recognise 'p' at all. Therefore, to update a pointer from * aarch64 assembly, it is necessary to use something like: * * uintptr_t uptr = (uintptr_t) ptr; * asm( "ldr x4, [%x0], #8" ... : "+r" (uptr) : : ) * ptr = (void*) uptr; * * Note that the "x" in "%x0" is neccessary; writing "%0" will cause warnings. */ #if defined(__aarch64__) && defined(MBEDTLS_HAVE_ASM) #if UINTPTR_MAX == 0xfffffffful /* ILP32: Specify the pointer operand slightly differently, as per #7787. */ #define MBEDTLS_ASM_AARCH64_PTR_CONSTRAINT "p" #elif UINTPTR_MAX == 0xfffffffffffffffful /* Normal case (64-bit pointers): use "r" as the constraint for pointer operands to asm */ #define MBEDTLS_ASM_AARCH64_PTR_CONSTRAINT "r" #else #error "Unrecognised pointer size for aarch64" #endif #endif /* Always provide a static assert macro, so it can be used unconditionally. * It does nothing on systems where we don't know how to define a static assert. */ /* Can't use the C11-style `defined(static_assert)` on FreeBSD, since it * defines static_assert even with -std=c99, but then complains about it. */ #if defined(static_assert) && !defined(__FreeBSD__) #define MBEDTLS_STATIC_ASSERT(expr, msg) static_assert(expr, msg) #else /* Make sure `MBEDTLS_STATIC_ASSERT(expr, msg);` is valid both inside and * outside a function. We choose a struct declaration, which can be repeated * any number of times and does not need a matching definition. */ #define MBEDTLS_STATIC_ASSERT(expr, msg) \ struct ISO_C_does_not_allow_extra_semicolon_outside_of_a_function #endif #if defined(__has_builtin) #define MBEDTLS_HAS_BUILTIN(x) __has_builtin(x) #else #define MBEDTLS_HAS_BUILTIN(x) 0 #endif /* Define compiler branch hints */ #if MBEDTLS_HAS_BUILTIN(__builtin_expect) #define MBEDTLS_LIKELY(x) __builtin_expect(!!(x), 1) #define MBEDTLS_UNLIKELY(x) __builtin_expect(!!(x), 0) #else #define MBEDTLS_LIKELY(x) x #define MBEDTLS_UNLIKELY(x) x #endif /* MBEDTLS_ASSUME may be used to provide additional information to the compiler * which can result in smaller code-size. */ #if MBEDTLS_HAS_BUILTIN(__builtin_assume) /* clang provides __builtin_assume */ #define MBEDTLS_ASSUME(x) __builtin_assume(x) #elif MBEDTLS_HAS_BUILTIN(__builtin_unreachable) /* gcc and IAR can use __builtin_unreachable */ #define MBEDTLS_ASSUME(x) do { if (!(x)) __builtin_unreachable(); } while (0) #elif defined(_MSC_VER) /* Supported by MSVC since VS 2005 */ #define MBEDTLS_ASSUME(x) __assume(x) #else #define MBEDTLS_ASSUME(x) do { } while (0) #endif /* For gcc -Os, override with -O2 for a given function. * * This will not affect behaviour for other optimisation settings, e.g. -O0. */ #if defined(MBEDTLS_COMPILER_IS_GCC) && defined(__OPTIMIZE_SIZE__) #define MBEDTLS_OPTIMIZE_FOR_PERFORMANCE __attribute__((optimize("-O2"))) #else #define MBEDTLS_OPTIMIZE_FOR_PERFORMANCE #endif /* Suppress compiler warnings for unused functions and variables. */ #if !defined(MBEDTLS_MAYBE_UNUSED) && defined(__has_attribute) # if __has_attribute(unused) # define MBEDTLS_MAYBE_UNUSED __attribute__((unused)) # endif #endif #if !defined(MBEDTLS_MAYBE_UNUSED) && defined(__GNUC__) # define MBEDTLS_MAYBE_UNUSED __attribute__((unused)) #endif #if !defined(MBEDTLS_MAYBE_UNUSED) && defined(__IAR_SYSTEMS_ICC__) && defined(__VER__) /* IAR does support __attribute__((unused)), but only if the -e flag (extended language support) * is given; the pragma always works. * Unfortunately the pragma affects the rest of the file where it is used, but this is harmless. * Check for version 5.2 or later - this pragma may be supported by earlier versions, but I wasn't * able to find documentation). */ # if (__VER__ >= 5020000) # define MBEDTLS_MAYBE_UNUSED _Pragma("diag_suppress=Pe177") # endif #endif #if !defined(MBEDTLS_MAYBE_UNUSED) && defined(_MSC_VER) # define MBEDTLS_MAYBE_UNUSED __pragma(warning(suppress:4189)) #endif #if !defined(MBEDTLS_MAYBE_UNUSED) # define MBEDTLS_MAYBE_UNUSED #endif #endif /* MBEDTLS_LIBRARY_COMMON_H */