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Diffstat (limited to 'library/common.h')
| -rw-r--r-- | library/common.h | 435 |
1 files changed, 435 insertions, 0 deletions
diff --git a/library/common.h b/library/common.h new file mode 100644 index 00000000000..3936ffdfe1e --- /dev/null +++ b/library/common.h @@ -0,0 +1,435 @@ +/** + * \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 <assert.h> +#include <stddef.h> +#include <stdint.h> +#include <stddef.h> + +#if defined(__ARM_NEON) +#include <arm_neon.h> +#define MBEDTLS_HAVE_NEON_INTRINSICS +#elif defined(MBEDTLS_PLATFORM_IS_WINDOWS_ON_ARM64) +#include <arm64_neon.h> +#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 will expand to nothing on some systems. + * Can be used outside functions (but don't add a trailing ';' in that case: + * the semicolon is included here to avoid triggering -Wextra-semi when + * MBEDTLS_STATIC_ASSERT() expands to nothing). + * 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 +#define MBEDTLS_STATIC_ASSERT(expr, msg) +#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 */ |