X-Git-Url: https://bearssl.org/gitweb//home/git/?p=BearSSL;a=blobdiff_plain;f=src%2Finner.h;h=3830c7c5b916d95a4301a4ffc1e65b4fe278486e;hp=47431c00b9411cedc96fbaae05c567da0a1fcb03;hb=d021b7eb7fada2acbe16b1b56f6e2cbdf8eee362;hpb=2f88a673049d1e183d1a8f78e2030bf02362b8bf diff --git a/src/inner.h b/src/inner.h index 47431c0..3830c7c 100644 --- a/src/inner.h +++ b/src/inner.h @@ -118,7 +118,6 @@ * Determine whether x86 AES instructions are understood by the compiler. */ #ifndef BR_AES_X86NI - #if (__i386__ || __x86_64__) \ && ((__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 8)) \ || (__clang_major__ > 3 \ @@ -158,10 +157,12 @@ * GCC versions from 4.4 to 4.8 (inclusive) must use a special #pragma * to activate extra opcodes before including the relevant intrinsic * headers. But these don't work with Clang (which does not need them - * either). + * either). We also need that #pragma for GCC 4.9 in order to work + * around a compiler bug (it tends to blow up on ghash_pclmul code + * otherwise). */ #if BR_AES_X86NI_GCC && !defined BR_AES_X86NI_GCC_OLD -#if __GNUC__ == 4 && __GNUC_MINOR__ >= 4 && __GNUC_MINOR__ <= 8 && !__clang__ +#if __GNUC__ == 4 && __GNUC_MINOR__ >= 4 && __GNUC_MINOR__ <= 9 && !__clang__ #define BR_AES_X86NI_GCC_OLD 1 #endif #endif @@ -209,58 +210,135 @@ #endif #endif +/* + * Detect support for 128-bit integers. + */ +#if !defined BR_INT128 && !defined BR_UMUL128 +#ifdef __SIZEOF_INT128__ +#define BR_INT128 1 +#elif _M_X64 +#define BR_UMUL128 1 +#endif +#endif + +/* + * Detect support for unaligned accesses with known endianness. + * + * x86 (both 32-bit and 64-bit) is little-endian and allows unaligned + * accesses. + * + * POWER/PowerPC allows unaligned accesses when big-endian. POWER8 and + * later also allow unaligned accesses when little-endian. + */ +#if !defined BR_LE_UNALIGNED && !defined BR_BE_UNALIGNED + +#if __i386 || __i386__ || __x86_64__ || _M_IX86 || _M_X64 +#define BR_LE_UNALIGNED 1 +#elif BR_POWER8_BE +#define BR_BE_UNALIGNED 1 +#elif BR_POWER8_LE +#define BR_LE_UNALIGNED 1 +#elif (__powerpc__ || __powerpc64__ || _M_PPC || _ARCH_PPC || _ARCH_PPC64) \ + && __BIG_ENDIAN__ +#define BR_BE_UNALIGNED 1 +#endif + +#endif + /* ==================================================================== */ /* * Encoding/decoding functions. * * 32-bit and 64-bit decoding, both little-endian and big-endian, is - * implemented with the inline functions below. These functions are - * generic: they don't depend on the architecture natural endianness, - * and they can handle unaligned accesses. Optimized versions for some - * specific architectures may be implemented at a later time. - */ + * implemented with the inline functions below. + * + * When allowed by some compile-time options (autodetected or provided), + * optimised code is used, to perform direct memory access when the + * underlying architecture supports it, both for endianness and + * alignment. This, however, may trigger strict aliasing issues; the + * code below uses unions to perform (supposedly) safe type punning. + * Since the C aliasing rules are relatively complex and were amended, + * or at least re-explained with different phrasing, in all successive + * versions of the C standard, it is always a bit risky to bet that any + * specific version of a C compiler got it right, for some notion of + * "right". + */ + +typedef union { + uint16_t u; + unsigned char b[sizeof(uint16_t)]; +} br_union_u16; + +typedef union { + uint32_t u; + unsigned char b[sizeof(uint32_t)]; +} br_union_u32; + +typedef union { + uint64_t u; + unsigned char b[sizeof(uint64_t)]; +} br_union_u64; static inline void br_enc16le(void *dst, unsigned x) { +#if BR_LE_UNALIGNED + ((br_union_u16 *)dst)->u = x; +#else unsigned char *buf; buf = dst; buf[0] = (unsigned char)x; buf[1] = (unsigned char)(x >> 8); +#endif } static inline void br_enc16be(void *dst, unsigned x) { +#if BR_BE_UNALIGNED + ((br_union_u16 *)dst)->u = x; +#else unsigned char *buf; buf = dst; buf[0] = (unsigned char)(x >> 8); buf[1] = (unsigned char)x; +#endif } static inline unsigned br_dec16le(const void *src) { +#if BR_LE_UNALIGNED + return ((const br_union_u16 *)src)->u; +#else const unsigned char *buf; buf = src; return (unsigned)buf[0] | ((unsigned)buf[1] << 8); +#endif } static inline unsigned br_dec16be(const void *src) { +#if BR_BE_UNALIGNED + return ((const br_union_u16 *)src)->u; +#else const unsigned char *buf; buf = src; return ((unsigned)buf[0] << 8) | (unsigned)buf[1]; +#endif } static inline void br_enc32le(void *dst, uint32_t x) { +#if BR_LE_UNALIGNED + ((br_union_u32 *)dst)->u = x; +#else unsigned char *buf; buf = dst; @@ -268,11 +346,15 @@ br_enc32le(void *dst, uint32_t x) buf[1] = (unsigned char)(x >> 8); buf[2] = (unsigned char)(x >> 16); buf[3] = (unsigned char)(x >> 24); +#endif } static inline void br_enc32be(void *dst, uint32_t x) { +#if BR_BE_UNALIGNED + ((br_union_u32 *)dst)->u = x; +#else unsigned char *buf; buf = dst; @@ -280,11 +362,15 @@ br_enc32be(void *dst, uint32_t x) buf[1] = (unsigned char)(x >> 16); buf[2] = (unsigned char)(x >> 8); buf[3] = (unsigned char)x; +#endif } static inline uint32_t br_dec32le(const void *src) { +#if BR_LE_UNALIGNED + return ((const br_union_u32 *)src)->u; +#else const unsigned char *buf; buf = src; @@ -292,11 +378,15 @@ br_dec32le(const void *src) | ((uint32_t)buf[1] << 8) | ((uint32_t)buf[2] << 16) | ((uint32_t)buf[3] << 24); +#endif } static inline uint32_t br_dec32be(const void *src) { +#if BR_BE_UNALIGNED + return ((const br_union_u32 *)src)->u; +#else const unsigned char *buf; buf = src; @@ -304,46 +394,63 @@ br_dec32be(const void *src) | ((uint32_t)buf[1] << 16) | ((uint32_t)buf[2] << 8) | (uint32_t)buf[3]; +#endif } static inline void br_enc64le(void *dst, uint64_t x) { +#if BR_LE_UNALIGNED + ((br_union_u64 *)dst)->u = x; +#else unsigned char *buf; buf = dst; br_enc32le(buf, (uint32_t)x); br_enc32le(buf + 4, (uint32_t)(x >> 32)); +#endif } static inline void br_enc64be(void *dst, uint64_t x) { +#if BR_BE_UNALIGNED + ((br_union_u64 *)dst)->u = x; +#else unsigned char *buf; buf = dst; br_enc32be(buf, (uint32_t)(x >> 32)); br_enc32be(buf + 4, (uint32_t)x); +#endif } static inline uint64_t br_dec64le(const void *src) { +#if BR_LE_UNALIGNED + return ((const br_union_u64 *)src)->u; +#else const unsigned char *buf; buf = src; return (uint64_t)br_dec32le(buf) | ((uint64_t)br_dec32le(buf + 4) << 32); +#endif } static inline uint64_t br_dec64be(const void *src) { +#if BR_BE_UNALIGNED + return ((const br_union_u64 *)src)->u; +#else const unsigned char *buf; buf = src; return ((uint64_t)br_dec32be(buf) << 32) | (uint64_t)br_dec32be(buf + 4); +#endif } /* @@ -1166,6 +1273,25 @@ void br_i31_from_monty(uint32_t *x, const uint32_t *m, uint32_t m0i); void br_i31_modpow(uint32_t *x, const unsigned char *e, size_t elen, const uint32_t *m, uint32_t m0i, uint32_t *t1, uint32_t *t2); +/* + * Compute a modular exponentiation. x[] MUST be an integer modulo m[] + * (same announced bit length, lower value). m[] MUST be odd. The + * exponent is in big-endian unsigned notation, over 'elen' bytes. The + * "m0i" parameter is equal to -(1/m0) mod 2^31, where m0 is the least + * significant value word of m[] (this works only if m[] is an odd + * integer). The tmp[] array is used for temporaries, and has size + * 'twlen' words; it must be large enough to accommodate at least two + * temporary values with the same size as m[] (including the leading + * "bit length" word). If there is room for more temporaries, then this + * function may use the extra room for window-based optimisation, + * resulting in faster computations. + * + * Returned value is 1 on success, 0 on error. An error is reported if + * the provided tmp[] array is too short. + */ +uint32_t br_i31_modpow_opt(uint32_t *x, const unsigned char *e, size_t elen, + const uint32_t *m, uint32_t m0i, uint32_t *tmp, size_t twlen); + /* * Compute d+a*b, result in d. The initial announced bit length of d[] * MUST match that of a[]. The d[] array MUST be large enough to @@ -1233,6 +1359,9 @@ void br_i15_reduce(uint16_t *x, const uint16_t *a, const uint16_t *m); void br_i15_mulacc(uint16_t *d, const uint16_t *a, const uint16_t *b); +uint32_t br_i62_modpow_opt(uint32_t *x31, const unsigned char *e, size_t elen, + const uint32_t *m31, uint32_t m0i31, uint64_t *tmp, size_t twlen); + /* ==================================================================== */ static inline size_t