/********************************************************************** * Copyright (c) 2013, 2014 Pieter Wuille * * Distributed under the MIT software license, see the accompanying * * file COPYING or http://www.opensource.org/licenses/mit-license.php.* **********************************************************************/ #ifndef SECP256K1_UTIL_H #define SECP256K1_UTIL_H #if defined HAVE_CONFIG_H #include "libsecp256k1-config.h" #endif #include #include #include #include typedef struct { void (*fn)(const char *text, void* data); const void* data; } secp256k1_callback; static SECP256K1_INLINE void secp256k1_callback_call(const secp256k1_callback * const cb, const char * const text) { cb->fn(text, (void*)cb->data); } #ifdef DETERMINISTIC #define TEST_FAILURE(msg) do { \ fprintf(stderr, "%s\n", msg); \ abort(); \ } while(0); #else #define TEST_FAILURE(msg) do { \ fprintf(stderr, "%s:%d: %s\n", __FILE__, __LINE__, msg); \ abort(); \ } while(0) #endif #if SECP256K1_GNUC_PREREQ(3, 0) #define EXPECT(x,c) __builtin_expect((x),(c)) #else #define EXPECT(x,c) (x) #endif #ifdef DETERMINISTIC #define CHECK(cond) do { \ if (EXPECT(!(cond), 0)) { \ TEST_FAILURE("test condition failed"); \ } \ } while(0) #else #define CHECK(cond) do { \ if (EXPECT(!(cond), 0)) { \ TEST_FAILURE("test condition failed: " #cond); \ } \ } while(0) #endif /* Like assert(), but when VERIFY is defined, and side-effect safe. */ #if defined(COVERAGE) #define VERIFY_CHECK(check) #define VERIFY_SETUP(stmt) #elif defined(VERIFY) #define VERIFY_CHECK CHECK #define VERIFY_SETUP(stmt) do { stmt; } while(0) #else #define VERIFY_CHECK(cond) do { (void)(cond); } while(0) #define VERIFY_SETUP(stmt) #endif /* Define `VG_UNDEF` and `VG_CHECK` when VALGRIND is defined */ #if !defined(VG_CHECK) # if defined(VALGRIND) # include # define VG_UNDEF(x,y) VALGRIND_MAKE_MEM_UNDEFINED((x),(y)) # define VG_CHECK(x,y) VALGRIND_CHECK_MEM_IS_DEFINED((x),(y)) # else # define VG_UNDEF(x,y) # define VG_CHECK(x,y) # endif #endif /* Like `VG_CHECK` but on VERIFY only */ #if defined(VERIFY) #define VG_CHECK_VERIFY(x,y) VG_CHECK((x), (y)) #else #define VG_CHECK_VERIFY(x,y) #endif static SECP256K1_INLINE void *checked_malloc(const secp256k1_callback* cb, size_t size) { void *ret = malloc(size); if (ret == NULL) { secp256k1_callback_call(cb, "Out of memory"); } return ret; } static SECP256K1_INLINE void *checked_realloc(const secp256k1_callback* cb, void *ptr, size_t size) { void *ret = realloc(ptr, size); if (ret == NULL) { secp256k1_callback_call(cb, "Out of memory"); } return ret; } #if defined(__BIGGEST_ALIGNMENT__) #define ALIGNMENT __BIGGEST_ALIGNMENT__ #else /* Using 16 bytes alignment because common architectures never have alignment * requirements above 8 for any of the types we care about. In addition we * leave some room because currently we don't care about a few bytes. */ #define ALIGNMENT 16 #endif #define ROUND_TO_ALIGN(size) (((size + ALIGNMENT - 1) / ALIGNMENT) * ALIGNMENT) /* Assume there is a contiguous memory object with bounds [base, base + max_size) * of which the memory range [base, *prealloc_ptr) is already allocated for usage, * where *prealloc_ptr is an aligned pointer. In that setting, this functions * reserves the subobject [*prealloc_ptr, *prealloc_ptr + alloc_size) of * alloc_size bytes by increasing *prealloc_ptr accordingly, taking into account * alignment requirements. * * The function returns an aligned pointer to the newly allocated subobject. * * This is useful for manual memory management: if we're simply given a block * [base, base + max_size), the caller can use this function to allocate memory * in this block and keep track of the current allocation state with *prealloc_ptr. * * It is VERIFY_CHECKed that there is enough space left in the memory object and * *prealloc_ptr is aligned relative to base. */ static SECP256K1_INLINE void *manual_alloc(void** prealloc_ptr, size_t alloc_size, void* base, size_t max_size) { size_t aligned_alloc_size = ROUND_TO_ALIGN(alloc_size); void* ret; VERIFY_CHECK(prealloc_ptr != NULL); VERIFY_CHECK(*prealloc_ptr != NULL); VERIFY_CHECK(base != NULL); VERIFY_CHECK((unsigned char*)*prealloc_ptr >= (unsigned char*)base); VERIFY_CHECK(((unsigned char*)*prealloc_ptr - (unsigned char*)base) % ALIGNMENT == 0); VERIFY_CHECK((unsigned char*)*prealloc_ptr - (unsigned char*)base + aligned_alloc_size <= max_size); ret = *prealloc_ptr; *((unsigned char**)prealloc_ptr) += aligned_alloc_size; return ret; } /* Macro for restrict, when available and not in a VERIFY build. */ #if defined(SECP256K1_BUILD) && defined(VERIFY) # define SECP256K1_RESTRICT #else # if (!defined(__STDC_VERSION__) || (__STDC_VERSION__ < 199901L) ) # if SECP256K1_GNUC_PREREQ(3,0) # define SECP256K1_RESTRICT __restrict__ # elif (defined(_MSC_VER) && _MSC_VER >= 1400) # define SECP256K1_RESTRICT __restrict # else # define SECP256K1_RESTRICT # endif # else # define SECP256K1_RESTRICT restrict # endif #endif #if defined(_WIN32) # define I64FORMAT "I64d" # define I64uFORMAT "I64u" #else # define I64FORMAT "lld" # define I64uFORMAT "llu" #endif #if defined(__GNUC__) # define SECP256K1_GNUC_EXT __extension__ #else # define SECP256K1_GNUC_EXT #endif /* If SECP256K1_{LITTLE,BIG}_ENDIAN is not explicitly provided, infer from various other system macros. */ #if !defined(SECP256K1_LITTLE_ENDIAN) && !defined(SECP256K1_BIG_ENDIAN) /* Inspired by https://github.com/rofl0r/endianness.h/blob/9853923246b065a3b52d2c43835f3819a62c7199/endianness.h#L52L73 */ # if (defined(__BYTE_ORDER__) && defined(__ORDER_LITTLE_ENDIAN__) && __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__) || \ defined(_X86_) || defined(__x86_64__) || defined(__i386__) || \ defined(__i486__) || defined(__i586__) || defined(__i686__) || \ defined(__MIPSEL) || defined(_MIPSEL) || defined(MIPSEL) || \ defined(__ARMEL__) || defined(__AARCH64EL__) || \ (defined(__LITTLE_ENDIAN__) && __LITTLE_ENDIAN__ == 1) || \ (defined(_LITTLE_ENDIAN) && _LITTLE_ENDIAN == 1) || \ defined(_M_IX86) || defined(_M_AMD64) || defined(_M_ARM) /* MSVC */ # define SECP256K1_LITTLE_ENDIAN # endif # if (defined(__BYTE_ORDER__) && defined(__ORDER_BIG_ENDIAN__) && __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__) || \ defined(__MIPSEB) || defined(_MIPSEB) || defined(MIPSEB) || \ defined(__MICROBLAZEEB__) || defined(__ARMEB__) || defined(__AARCH64EB__) || \ (defined(__BIG_ENDIAN__) && __BIG_ENDIAN__ == 1) || \ (defined(_BIG_ENDIAN) && _BIG_ENDIAN == 1) # define SECP256K1_BIG_ENDIAN # endif #endif #if defined(SECP256K1_LITTLE_ENDIAN) == defined(SECP256K1_BIG_ENDIAN) # error Please make sure that either SECP256K1_LITTLE_ENDIAN or SECP256K1_BIG_ENDIAN is set, see src/util.h. #endif /* Zero memory if flag == 1. Flag must be 0 or 1. Constant time. */ static SECP256K1_INLINE void memczero(void *s, size_t len, int flag) { unsigned char *p = (unsigned char *)s; /* Access flag with a volatile-qualified lvalue. This prevents clang from figuring out (after inlining) that flag can take only be 0 or 1, which leads to variable time code. */ volatile int vflag = flag; unsigned char mask = -(unsigned char) vflag; while (len) { *p &= ~mask; p++; len--; } } /** Semantics like memcmp. Variable-time. * * We use this to avoid possible compiler bugs with memcmp, e.g. * https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95189 */ static SECP256K1_INLINE int secp256k1_memcmp_var(const void *s1, const void *s2, size_t n) { const unsigned char *p1 = s1, *p2 = s2; size_t i; for (i = 0; i < n; i++) { int diff = p1[i] - p2[i]; if (diff != 0) { return diff; } } return 0; } /** If flag is true, set *r equal to *a; otherwise leave it. Constant-time. Both *r and *a must be initialized and non-negative.*/ static SECP256K1_INLINE void secp256k1_int_cmov(int *r, const int *a, int flag) { unsigned int mask0, mask1, r_masked, a_masked; /* Access flag with a volatile-qualified lvalue. This prevents clang from figuring out (after inlining) that flag can take only be 0 or 1, which leads to variable time code. */ volatile int vflag = flag; /* Casting a negative int to unsigned and back to int is implementation defined behavior */ VERIFY_CHECK(*r >= 0 && *a >= 0); mask0 = (unsigned int)vflag + ~0u; mask1 = ~mask0; r_masked = ((unsigned int)*r & mask0); a_masked = ((unsigned int)*a & mask1); *r = (int)(r_masked | a_masked); } /* If USE_FORCE_WIDEMUL_{INT128,INT64} is set, use that wide multiplication implementation. * Otherwise use the presence of __SIZEOF_INT128__ to decide. */ #if defined(USE_FORCE_WIDEMUL_INT128) # define SECP256K1_WIDEMUL_INT128 1 #elif defined(USE_FORCE_WIDEMUL_INT64) # define SECP256K1_WIDEMUL_INT64 1 #elif defined(__SIZEOF_INT128__) # define SECP256K1_WIDEMUL_INT128 1 #else # define SECP256K1_WIDEMUL_INT64 1 #endif #if defined(SECP256K1_WIDEMUL_INT128) SECP256K1_GNUC_EXT typedef unsigned __int128 uint128_t; SECP256K1_GNUC_EXT typedef __int128 int128_t; #endif #endif /* SECP256K1_UTIL_H */