From d671917d0dd1dcc498ee384dacafdbad674d7c88 Mon Sep 17 00:00:00 2001 From: Gilles Peskine Date: Fri, 10 Mar 2023 22:37:11 +0100 Subject: [PATCH] AESNI: add implementation with intrinsics As of this commit, to use the intrinsics for MBEDTLS_AESNI_C: * With MSVC, this should be the default. * With Clang, build with `clang -maes -mpclmul` or equivalent. * With GCC, build with `gcc -mpclmul -msse2` or equivalent. In particular, for now, with a GCC-like compiler, when building specifically for a target that supports both the AES and GCM instructions, the old implementation using assembly is selected. This method for platform selection will likely be improved in the future. Signed-off-by: Gilles Peskine --- library/aes.c | 17 +++ library/aesni.c | 339 +++++++++++++++++++++++++++++++++++++++++++++++- 2 files changed, 355 insertions(+), 1 deletion(-) diff --git a/library/aes.c b/library/aes.c index e41810a54d..69d4eadfa8 100644 --- a/library/aes.c +++ b/library/aes.c @@ -543,6 +543,13 @@ int mbedtls_aes_setkey_enc(mbedtls_aes_context *ctx, const unsigned char *key, #if defined(MBEDTLS_AESNI_HAVE_CODE) if (mbedtls_aesni_has_support(MBEDTLS_AESNI_AES)) { + /* The intrinsics-based implementation needs 16-byte alignment + * for the round key array. */ + unsigned delta = (uintptr_t) ctx->buf & 0x0000000f; + if (delta != 0) { + ctx->rk_offset = 4 - delta / 4; // 16 bytes = 4 uint32_t + } + RK = ctx->buf + ctx->rk_offset; return mbedtls_aesni_setkey_enc((unsigned char *) RK, key, keybits); } #endif @@ -643,6 +650,16 @@ int mbedtls_aes_setkey_dec(mbedtls_aes_context *ctx, const unsigned char *key, if (aes_padlock_ace) { ctx->rk_offset = MBEDTLS_PADLOCK_ALIGN16(ctx->buf) - ctx->buf; } +#endif +#if defined(MBEDTLS_AESNI_HAVE_CODE) + if (mbedtls_aesni_has_support(MBEDTLS_AESNI_AES)) { + /* The intrinsics-based implementation needs 16-byte alignment + * for the round key array. */ + unsigned delta = (uintptr_t) ctx->buf & 0x0000000f; + if (delta != 0) { + ctx->rk_offset = 4 - delta / 4; // 16 bytes = 4 uint32_t + } + } #endif RK = ctx->buf + ctx->rk_offset; diff --git a/library/aesni.c b/library/aesni.c index 77243ea387..3acc329712 100644 --- a/library/aesni.c +++ b/library/aesni.c @@ -30,7 +30,12 @@ #include -#if defined(MBEDTLS_HAVE_X86_64) +#if defined(MBEDTLS_HAVE_AESNI_INTRINSICS) || defined(MBEDTLS_HAVE_X86_64) + +#if defined(MBEDTLS_HAVE_AESNI_INTRINSICS) +#include +#include +#endif /* * AES-NI support detection routine @@ -41,17 +46,347 @@ int mbedtls_aesni_has_support(unsigned int what) static unsigned int c = 0; if (!done) { +#if defined(MBEDTLS_HAVE_AESNI_INTRINSICS) + static unsigned info[4] = { 0, 0, 0, 0 }; +#if defined(_MSC_VER) + __cpuid(info, 1); +#else + __cpuid(1, info[0], info[1], info[2], info[3]); +#endif + c = info[2]; +#else asm ("movl $1, %%eax \n\t" "cpuid \n\t" : "=c" (c) : : "eax", "ebx", "edx"); +#endif done = 1; } return (c & what) != 0; } +#if defined(MBEDTLS_HAVE_AESNI_INTRINSICS) + +/* + * AES-NI AES-ECB block en(de)cryption + */ +int mbedtls_aesni_crypt_ecb(mbedtls_aes_context *ctx, + int mode, + const unsigned char input[16], + unsigned char output[16]) +{ + const __m128i *rk = (const __m128i *) (ctx->buf + ctx->rk_offset); + unsigned nr = ctx->nr; // Number of remaining rounds + // Load round key 0 + __m128i xmm0; + memcpy(&xmm0, input, 16); + xmm0 ^= *rk; + ++rk; + --nr; + + if (mode == 0) { + while (nr != 0) { + xmm0 = _mm_aesdec_si128(xmm0, *rk); + ++rk; + --nr; + } + xmm0 = _mm_aesdeclast_si128(xmm0, *rk); + } else { + while (nr != 0) { + xmm0 = _mm_aesenc_si128(xmm0, *rk); + ++rk; + --nr; + } + xmm0 = _mm_aesenclast_si128(xmm0, *rk); + } + + memcpy(output, &xmm0, 16); + return 0; +} + +/* + * GCM multiplication: c = a times b in GF(2^128) + * Based on [CLMUL-WP] algorithms 1 (with equation 27) and 5. + */ + +static void gcm_clmul(const __m128i aa, const __m128i bb, + __m128i *cc, __m128i *dd) +{ + /* + * Caryless multiplication dd:cc = aa * bb + * using [CLMUL-WP] algorithm 1 (p. 12). + */ + *cc = _mm_clmulepi64_si128(aa, bb, 0x00); // a0*b0 = c1:c0 + *dd = _mm_clmulepi64_si128(aa, bb, 0x11); // a1*b1 = d1:d0 + __m128i ee = _mm_clmulepi64_si128(aa, bb, 0x10); // a0*b1 = e1:e0 + __m128i ff = _mm_clmulepi64_si128(aa, bb, 0x01); // a1*b0 = f1:f0 + ff ^= ee; // e1+f1:e0+f0 + ee = ff; // e1+f1:e0+f0 + ff = _mm_srli_si128(ff, 8); // 0:e1+f1 + ee = _mm_slli_si128(ee, 8); // e0+f0:0 + *dd ^= ff; // d1:d0+e1+f1 + *cc ^= ee; // c1+e0+f1:c0 +} + +static void gcm_shift(__m128i *cc, __m128i *dd) +{ + /* + * Now shift the result one bit to the left, + * taking advantage of [CLMUL-WP] eq 27 (p. 18) + */ + // // *cc = r1:r0 + // // *dd = r3:r2 + __m128i xmm1 = _mm_slli_epi64(*cc, 1); // r1<<1:r0<<1 + __m128i xmm2 = _mm_slli_epi64(*dd, 1); // r3<<1:r2<<1 + __m128i xmm3 = _mm_srli_epi64(*cc, 63); // r1>>63:r0>>63 + __m128i xmm4 = _mm_srli_epi64(*dd, 63); // r3>>63:r2>>63 + __m128i xmm5 = _mm_srli_si128(xmm3, 8); // 0:r1>>63 + xmm3 = _mm_slli_si128(xmm3, 8); // r0>>63:0 + xmm4 = _mm_slli_si128(xmm4, 8); // 0:r1>>63 + + *cc = xmm1 | xmm3; // r1<<1|r0>>63:r0<<1 + *dd = xmm2 | xmm4 | xmm5; // r3<<1|r2>>62:r2<<1|r1>>63 +} + +static __m128i gcm_reduce1(__m128i xx) +{ + // // xx = x1:x0 + /* [CLMUL-WP] Algorithm 5 Step 2 */ + __m128i aa = _mm_slli_epi64(xx, 63); // x1<<63:x0<<63 = stuff:a + __m128i bb = _mm_slli_epi64(xx, 62); // x1<<62:x0<<62 = stuff:b + __m128i cc = _mm_slli_epi64(xx, 57); // x1<<57:x0<<57 = stuff:c + __m128i dd = _mm_slli_si128(aa ^ bb ^ cc, 8); // a+b+c:0 + return dd ^ xx; // x1+a+b+c:x0 = d:x0 +} + +static __m128i gcm_reduce2(__m128i dx) +{ + /* [CLMUL-WP] Algorithm 5 Steps 3 and 4 */ + __m128i ee = _mm_srli_epi64(dx, 1); // e1:x0>>1 = e1:e0' + __m128i ff = _mm_srli_epi64(dx, 2); // f1:x0>>2 = f1:f0' + __m128i gg = _mm_srli_epi64(dx, 7); // g1:x0>>7 = g1:g0' + + // e0'+f0'+g0' is almost e0+f0+g0, except for some missing + // bits carried from d. Now get those bits back in. + __m128i eh = _mm_slli_epi64(dx, 63); // d<<63:stuff + __m128i fh = _mm_slli_epi64(dx, 62); // d<<62:stuff + __m128i gh = _mm_slli_epi64(dx, 57); // d<<57:stuff + __m128i hh = _mm_srli_si128(eh ^ fh ^ gh, 8); // 0:missing bits of d + + return ee ^ ff ^ gg ^ hh ^ dx; +} + +void mbedtls_aesni_gcm_mult(unsigned char c[16], + const unsigned char a[16], + const unsigned char b[16]) +{ + __m128i aa, bb, cc, dd; + + /* The inputs are in big-endian order, so byte-reverse them */ + for (size_t i = 0; i < 16; i++) { + ((uint8_t *) &aa)[i] = a[15 - i]; + ((uint8_t *) &bb)[i] = b[15 - i]; + } + + gcm_clmul(aa, bb, &cc, &dd); + gcm_shift(&cc, &dd); + /* + * Now reduce modulo the GCM polynomial x^128 + x^7 + x^2 + x + 1 + * using [CLMUL-WP] algorithm 5 (p. 18). + * Currently dd:cc holds x3:x2:x1:x0 (already shifted). + */ + __m128i dx = gcm_reduce1(cc); + __m128i xh = gcm_reduce2(dx); + cc = xh ^ dd; // x3+h1:x2+h0 + + /* Now byte-reverse the outputs */ + for (size_t i = 0; i < 16; i++) { + c[i] = ((uint8_t *) &cc)[15 - i]; + } + + return; +} + +/* + * Compute decryption round keys from encryption round keys + */ +void mbedtls_aesni_inverse_key(unsigned char *invkey, + const unsigned char *fwdkey, int nr) +{ + __m128i *ik = (__m128i *) invkey; + const __m128i *fk = (const __m128i *) fwdkey + nr; + + *ik = *fk; + for (--fk, ++ik; fk > (const __m128i *) fwdkey; --fk, ++ik) { + *ik = _mm_aesimc_si128(*fk); + } + *ik = *fk; +} + +/* + * Key expansion, 128-bit case + */ +static __m128i aesni_set_rk_128(__m128i xmm0, __m128i xmm1) +{ + /* + * Finish generating the next round key. + * + * On entry xmm0 is r3:r2:r1:r0 and xmm1 is X:stuff:stuff:stuff + * with X = rot( sub( r3 ) ) ^ RCON. + * + * On exit, xmm1 is r7:r6:r5:r4 + * with r4 = X + r0, r5 = r4 + r1, r6 = r5 + r2, r7 = r6 + r3 + * and this is returned, to be written to the round key buffer. + */ + xmm1 = _mm_shuffle_epi32(xmm1, 0xff); // X:X:X:X + xmm1 ^= xmm0; // X+r3:X+r2:X+r1:r4 + xmm0 = _mm_slli_si128(xmm0, 4); // r2:r1:r0:0 + xmm1 ^= xmm0; // X+r3+r2:X+r2+r1:r5:r4 + xmm0 = _mm_slli_si128(xmm0, 4); // r1:r0:0:0 + xmm1 ^= xmm0; // X+r3+r2+r1:r6:r5:r4 + xmm0 = _mm_slli_si128(xmm0, 4); // r0:0:0:0 + xmm1 ^= xmm0; // r7:r6:r5:r4 + return xmm1; +} + +static void aesni_setkey_enc_128(unsigned char *rk_bytes, + const unsigned char *key) +{ + __m128i *rk = (__m128i *) rk_bytes; + + memcpy(&rk[0], key, 16); + rk[1] = aesni_set_rk_128(rk[0], _mm_aeskeygenassist_si128(rk[0], 0x01)); + rk[2] = aesni_set_rk_128(rk[1], _mm_aeskeygenassist_si128(rk[1], 0x02)); + rk[3] = aesni_set_rk_128(rk[2], _mm_aeskeygenassist_si128(rk[2], 0x04)); + rk[4] = aesni_set_rk_128(rk[3], _mm_aeskeygenassist_si128(rk[3], 0x08)); + rk[5] = aesni_set_rk_128(rk[4], _mm_aeskeygenassist_si128(rk[4], 0x10)); + rk[6] = aesni_set_rk_128(rk[5], _mm_aeskeygenassist_si128(rk[5], 0x20)); + rk[7] = aesni_set_rk_128(rk[6], _mm_aeskeygenassist_si128(rk[6], 0x40)); + rk[8] = aesni_set_rk_128(rk[7], _mm_aeskeygenassist_si128(rk[7], 0x80)); + rk[9] = aesni_set_rk_128(rk[8], _mm_aeskeygenassist_si128(rk[8], 0x1B)); + rk[10] = aesni_set_rk_128(rk[9], _mm_aeskeygenassist_si128(rk[9], 0x36)); +} + +/* + * Key expansion, 192-bit case + */ +static void aesni_set_rk_192(__m128i *xmm0, __m128i *xmm1, __m128i xmm2, + unsigned char *rk) +{ + /* + * Finish generating the next 6 quarter-keys. + * + * On entry xmm0 is r3:r2:r1:r0, xmm1 is stuff:stuff:r5:r4 + * and xmm2 is stuff:stuff:X:stuff with X = rot( sub( r3 ) ) ^ RCON. + * + * On exit, xmm0 is r9:r8:r7:r6 and xmm1 is stuff:stuff:r11:r10 + * and those are written to the round key buffer. + */ + xmm2 = _mm_shuffle_epi32(xmm2, 0x55); // X:X:X:X + xmm2 = _mm_xor_si128(xmm2, *xmm0); // X+r3:X+r2:X+r1:X+r0 + *xmm0 = _mm_slli_si128(*xmm0, 4); // r2:r1:r0:0 + xmm2 = _mm_xor_si128(xmm2, *xmm0); // X+r3+r2:X+r2+r1:X+r1+r0:X+r0 + *xmm0 = _mm_slli_si128(*xmm0, 4); // r1:r0:0:0 + xmm2 = _mm_xor_si128(xmm2, *xmm0); // X+r3+r2+r1:X+r2+r1+r0:X+r1+r0:X+r0 + *xmm0 = _mm_slli_si128(*xmm0, 4); // r0:0:0:0 + xmm2 = _mm_xor_si128(xmm2, *xmm0); // X+r3+r2+r1+r0:X+r2+r1+r0:X+r1+r0:X+r0 + *xmm0 = xmm2; // = r9:r8:r7:r6 + + xmm2 = _mm_shuffle_epi32(xmm2, 0xff); // r9:r9:r9:r9 + xmm2 = _mm_xor_si128(xmm2, *xmm1); // stuff:stuff:r9+r5:r9+r4 + *xmm1 = _mm_slli_si128(*xmm1, 4); // stuff:stuff:r4:0 + xmm2 = _mm_xor_si128(xmm2, *xmm1); // stuff:stuff:r9+r5+r4:r9+r4 + *xmm1 = xmm2; // = stuff:stuff:r11:r10 + + /* Store xmm0 and the low half of xmm1 into rk, which is conceptually + * an array of 24-byte elements. Since 24 is not a multiple of 16, + * rk is not necessarily aligned so just `*rk = *xmm0` doesn't work. */ + memcpy(rk, xmm0, 16); + _mm_storeu_si64(rk + 16, *xmm1); +} + +static void aesni_setkey_enc_192(unsigned char *rk, + const unsigned char *key) +{ + /* First round: use original key */ + memcpy(rk, key, 24); + /* aes.c guarantees that rk is aligned on a 16-byte boundary. */ + __m128i xmm0 = ((__m128i *) rk)[0]; + __m128i xmm1 = _mm_loadl_epi64(((__m128i *) rk) + 1); + + aesni_set_rk_192(&xmm0, &xmm1, _mm_aeskeygenassist_si128(xmm1, 0x01), rk + 24 * 1); + aesni_set_rk_192(&xmm0, &xmm1, _mm_aeskeygenassist_si128(xmm1, 0x02), rk + 24 * 2); + aesni_set_rk_192(&xmm0, &xmm1, _mm_aeskeygenassist_si128(xmm1, 0x04), rk + 24 * 3); + aesni_set_rk_192(&xmm0, &xmm1, _mm_aeskeygenassist_si128(xmm1, 0x08), rk + 24 * 4); + aesni_set_rk_192(&xmm0, &xmm1, _mm_aeskeygenassist_si128(xmm1, 0x10), rk + 24 * 5); + aesni_set_rk_192(&xmm0, &xmm1, _mm_aeskeygenassist_si128(xmm1, 0x20), rk + 24 * 6); + aesni_set_rk_192(&xmm0, &xmm1, _mm_aeskeygenassist_si128(xmm1, 0x40), rk + 24 * 7); + aesni_set_rk_192(&xmm0, &xmm1, _mm_aeskeygenassist_si128(xmm1, 0x80), rk + 24 * 8); +} + +/* + * Key expansion, 256-bit case + */ +static void aesni_set_rk_256(__m128i xmm0, __m128i xmm1, __m128i xmm2, + __m128i *rk0, __m128i *rk1) +{ + /* + * Finish generating the next two round keys. + * + * On entry xmm0 is r3:r2:r1:r0, xmm1 is r7:r6:r5:r4 and + * xmm2 is X:stuff:stuff:stuff with X = rot( sub( r7 )) ^ RCON + * + * On exit, *rk0 is r11:r10:r9:r8 and *rk1 is r15:r14:r13:r12 + */ + xmm2 = _mm_shuffle_epi32(xmm2, 0xff); + xmm2 ^= xmm0; + xmm0 = _mm_slli_si128(xmm0, 4); + xmm2 ^= xmm0; + xmm0 = _mm_slli_si128(xmm0, 4); + xmm2 ^= xmm0; + xmm0 = _mm_slli_si128(xmm0, 4); + xmm0 ^= xmm2; + *rk0 = xmm0; + + /* Set xmm2 to stuff:Y:stuff:stuff with Y = subword( r11 ) + * and proceed to generate next round key from there */ + xmm2 = _mm_aeskeygenassist_si128(xmm0, 0x00); + xmm2 = _mm_shuffle_epi32(xmm2, 0xaa); + xmm2 ^= xmm1; + xmm1 = _mm_slli_si128(xmm1, 4); + xmm2 ^= xmm1; + xmm1 = _mm_slli_si128(xmm1, 4); + xmm2 ^= xmm1; + xmm1 = _mm_slli_si128(xmm1, 4); + xmm1 ^= xmm2; + *rk1 = xmm1; +} + +static void aesni_setkey_enc_256(unsigned char *rk_bytes, + const unsigned char *key) +{ + __m128i *rk = (__m128i *) rk_bytes; + + memcpy(&rk[0], key, 16); + memcpy(&rk[1], key + 16, 16); + + /* + * Main "loop" - Generating one more key than necessary, + * see definition of mbedtls_aes_context.buf + */ + aesni_set_rk_256(rk[0], rk[1], _mm_aeskeygenassist_si128(rk[1], 0x01), &rk[2], &rk[3]); + aesni_set_rk_256(rk[2], rk[3], _mm_aeskeygenassist_si128(rk[3], 0x02), &rk[4], &rk[5]); + aesni_set_rk_256(rk[4], rk[5], _mm_aeskeygenassist_si128(rk[5], 0x04), &rk[6], &rk[7]); + aesni_set_rk_256(rk[6], rk[7], _mm_aeskeygenassist_si128(rk[7], 0x08), &rk[8], &rk[9]); + aesni_set_rk_256(rk[8], rk[9], _mm_aeskeygenassist_si128(rk[9], 0x10), &rk[10], &rk[11]); + aesni_set_rk_256(rk[10], rk[11], _mm_aeskeygenassist_si128(rk[11], 0x20), &rk[12], &rk[13]); + aesni_set_rk_256(rk[12], rk[13], _mm_aeskeygenassist_si128(rk[13], 0x40), &rk[14], &rk[15]); +} + +#else /* MBEDTLS_HAVE_AESNI_INTRINSICS */ + #if defined(__has_feature) #if __has_feature(memory_sanitizer) #warning \ @@ -438,6 +773,8 @@ static void aesni_setkey_enc_256(unsigned char *rk, : "memory", "cc", "0"); } +#endif /* MBEDTLS_HAVE_AESNI_INTRINSICS */ + /* * Key expansion, wrapper */