/* * AES-NI support functions * * Copyright (C) 2013, Brainspark B.V. * * This file is part of PolarSSL (http://www.polarssl.org) * Lead Maintainer: Paul Bakker * * All rights reserved. * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License along * with this program; if not, write to the Free Software Foundation, Inc., * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. */ /* * [AES-WP] http://software.intel.com/en-us/articles/intel-advanced-encryption-standard-aes-instructions-set * [CLMUL-WP] http://software.intel.com/en-us/articles/intel-carry-less-multiplication-instruction-and-its-usage-for-computing-the-gcm-mode/ */ #include "polarssl/config.h" #if defined(POLARSSL_AESNI_C) #include "polarssl/aesni.h" #include #if defined(POLARSSL_HAVE_X86_64) /* * AES-NI support detection routine */ int aesni_supports( unsigned int what ) { static int done = 0; static unsigned int c = 0; if( ! done ) { asm( "movl $1, %%eax \n" "cpuid \n" : "=c" (c) : : "eax", "ebx", "edx" ); done = 1; } return( ( c & what ) != 0 ); } /* * AES-NI AES-ECB block en(de)cryption */ int aesni_crypt_ecb( aes_context *ctx, int mode, const unsigned char input[16], unsigned char output[16] ) { asm( "movdqu (%3), %%xmm0 \n" // load input "movdqu (%1), %%xmm1 \n" // load round key 0 "pxor %%xmm1, %%xmm0 \n" // round 0 "addq $16, %1 \n" // point to next round key "subl $1, %0 \n" // normal rounds = nr - 1 "test %2, %2 \n" // mode? "jz 2f \n" // 0 = decrypt "1: \n" // encryption loop "movdqu (%1), %%xmm1 \n" // load round key "aesenc %%xmm1, %%xmm0 \n" // do round "addq $16, %1 \n" // point to next round key "subl $1, %0 \n" // loop "jnz 1b \n" "movdqu (%1), %%xmm1 \n" // load round key "aesenclast %%xmm1, %%xmm0 \n" // last round "jmp 3f \n" "2: \n" // decryption loop "movdqu (%1), %%xmm1 \n" "aesdec %%xmm1, %%xmm0 \n" "addq $16, %1 \n" "subl $1, %0 \n" "jnz 2b \n" "movdqu (%1), %%xmm1 \n" // load round key "aesdeclast %%xmm1, %%xmm0 \n" // last round "3: \n" "movdqu %%xmm0, (%4) \n" // export output : : "r" (ctx->nr), "r" (ctx->rk), "r" (mode), "r" (input), "r" (output) : "memory", "cc", "xmm0", "xmm1" ); return( 0 ); } /* * GCM multiplication: c = a times b in GF(2^128) * Based on [CLMUL-WP] algorithms 1 (with equation 27) and 5. */ int aesni_gcm_mult( unsigned char c[16], const unsigned char a[16], const unsigned char b[16] ) { unsigned char aa[16], bb[16], cc[16]; size_t i; /* The inputs are in big-endian order, so byte-reverse them */ for( i = 0; i < 16; i++ ) { aa[i] = a[15 - i]; bb[i] = b[15 - i]; } asm( "movdqu (%0), %%xmm0 \n" // a1:a0 "movdqu (%1), %%xmm1 \n" // b1:b0 /* * Caryless multiplication xmm2:xmm1 = xmm0 * xmm1 * using [CLMUL-WP] algorithm 1 (p. 13). */ "movdqa %%xmm1, %%xmm2 \n" // copy of b1:b0 "movdqa %%xmm1, %%xmm3 \n" // same "movdqa %%xmm1, %%xmm4 \n" // same "pclmulqdq $0x00, %%xmm0, %%xmm1 \n" // a0*b0 = c1:c0 "pclmulqdq $0x11, %%xmm0, %%xmm2 \n" // a1*b1 = d1:d0 "pclmulqdq $0x10, %%xmm0, %%xmm3 \n" // a0*b1 = e1:e0 "pclmulqdq $0x01, %%xmm0, %%xmm4 \n" // a1*b0 = f1:f0 "pxor %%xmm3, %%xmm4 \n" // e1+f1:e0+f0 "movdqa %%xmm4, %%xmm3 \n" // same "psrldq $8, %%xmm4 \n" // 0:e1+f1 "pslldq $8, %%xmm3 \n" // e0+f0:0 "pxor %%xmm4, %%xmm2 \n" // d1:d0+e1+f1 "pxor %%xmm3, %%xmm1 \n" // c1+e0+f1:c0 /* * Now shift the result one bit to the left, * taking advantage of [CLMUL-WP] eq 27 (p. 20) */ "movdqa %%xmm1, %%xmm3 \n" // r1:r0 "movdqa %%xmm2, %%xmm4 \n" // r3:r2 "psllq $1, %%xmm1 \n" // r1<<1:r0<<1 "psllq $1, %%xmm2 \n" // r3<<1:r2<<1 "psrlq $63, %%xmm3 \n" // r1>>63:r0>>63 "psrlq $63, %%xmm4 \n" // r3>>63:r2>>63 "movdqa %%xmm3, %%xmm5 \n" // r1>>63:r0>>63 "pslldq $8, %%xmm3 \n" // r0>>63:0 "pslldq $8, %%xmm4 \n" // r2>>63:0 "psrldq $8, %%xmm5 \n" // 0:r1>>63 "por %%xmm3, %%xmm1 \n" // r1<<1|r0>>63:r0<<1 "por %%xmm4, %%xmm2 \n" // r3<<1|r2>>62:r2<<1 "por %%xmm5, %%xmm2 \n" // r3<<1|r2>>62:r2<<1|r1>>63 /* * Now reduce modulo the GCM polynomial x^128 + x^7 + x^2 + x + 1 * using [CLMUL-WP] algorithm 5 (p. 20). * Currently xmm2:xmm1 holds x3:x2:x1:x0 (already shifted). */ /* Step 2 (1) */ "movdqa %%xmm1, %%xmm3 \n" // x1:x0 "movdqa %%xmm1, %%xmm4 \n" // same "movdqa %%xmm1, %%xmm5 \n" // same "psllq $63, %%xmm3 \n" // x1<<63:x0<<63 = stuff:a "psllq $62, %%xmm4 \n" // x1<<62:x0<<62 = stuff:b "psllq $57, %%xmm5 \n" // x1<<57:x0<<57 = stuff:c /* Step 2 (2) */ "pxor %%xmm4, %%xmm3 \n" // stuff:a+b "pxor %%xmm5, %%xmm3 \n" // stuff:a+b+c "pslldq $8, %%xmm3 \n" // a+b+c:0 "pxor %%xmm3, %%xmm1 \n" // x1+a+b+c:x0 = d:x0 /* Steps 3 and 4 */ "movdqa %%xmm1,%%xmm0 \n" // d:x0 "movdqa %%xmm1,%%xmm4 \n" // same "movdqa %%xmm1,%%xmm5 \n" // same "psrlq $1, %%xmm0 \n" // e1:x0>>1 = e1:e0' "psrlq $2, %%xmm4 \n" // f1:x0>>2 = f1:f0' "psrlq $7, %%xmm5 \n" // g1:x0>>7 = g1:g0' "pxor %%xmm4, %%xmm0 \n" // e1+f1:e0'+f0' "pxor %%xmm5, %%xmm0 \n" // e1+f1+g1:e0'+f0'+g0' // e0'+f0'+g0' is almost e0+f0+g0, except for some missing // bits carried from d. Now get those bits back in. "movdqa %%xmm1,%%xmm3 \n" // d:x0 "movdqa %%xmm1,%%xmm4 \n" // same "movdqa %%xmm1,%%xmm5 \n" // same "psllq $63, %%xmm3 \n" // d<<63:stuff "psllq $62, %%xmm4 \n" // d<<62:stuff "psllq $57, %%xmm5 \n" // d<<57:stuff "pxor %%xmm4, %%xmm3 \n" // d<<63+d<<62:stuff "pxor %%xmm5, %%xmm3 \n" // missing bits of d:stuff "psrldq $8, %%xmm3 \n" // 0:missing bits of d "pxor %%xmm3, %%xmm0 \n" // e1+f1+g1:e0+f0+g0 "pxor %%xmm1, %%xmm0 \n" // h1:h0 "pxor %%xmm2, %%xmm0 \n" // x3+h1:x2+h0 "movdqu %%xmm0, (%2) \n" // done : : "r" (aa), "r" (bb), "r" (cc) : "memory", "cc", "xmm0", "xmm1", "xmm2", "xmm3", "xmm4", "xmm5" ); /* Now byte-reverse the outputs */ for( i = 0; i < 16; i++ ) c[i] = cc[15 - i]; return( 0 ); } /* * Compute decryption round keys from encryption round keys */ void aesni_inverse_key( unsigned char *invkey, const unsigned char *fwdkey, int nr ) { unsigned char *ik = invkey; const unsigned char *fk = fwdkey + 16 * nr; memcpy( ik, fk, 16 ); for( fk -= 16, ik += 16; fk > fwdkey; fk -= 16, ik += 16 ) asm( "movdqu (%0), %%xmm0 \n" "aesimc %%xmm0, %%xmm0 \n" "movdqu %%xmm0, (%1) \n" : : "r" (fk), "r" (ik) : "memory", "xmm0" ); memcpy( ik, fk, 16 ); } /* * Key expansion, 128-bit case */ void aesni_setkey_enc_128( unsigned char *rk, const unsigned char *key ) { asm( "movdqu (%1), %%xmm0 \n" // copy the original key "movdqu %%xmm0, (%0) \n" // as round key 0 "jmp 2f \n" // skip auxiliary routine /* * On entry xmm0 is r3:r2:r1:r0 and xmm1 is X:stuff:stuff:stuff * with X = rot( sub( r3 ) ) ^ RCON. * * On exit, xmm0 is r7:r6:r5:r4 * with r4 = X + r0, r5 = r4 + r1, r6 = r5 + r2, r7 = r6 + r3 * and those are written to the round key buffer. */ "1: \n" "pshufd $0xff, %%xmm1, %%xmm1 \n" // X:X:X:X "pxor %%xmm0, %%xmm1 \n" // X+r3:X+r2:X+r1:r4 "pslldq $4, %%xmm0 \n" // r2:r1:r0:0 "pxor %%xmm0, %%xmm1 \n" // X+r3+r2:X+r2+r1:r5:r4 "pslldq $4, %%xmm0 \n" // etc "pxor %%xmm0, %%xmm1 \n" "pslldq $4, %%xmm0 \n" "pxor %%xmm1, %%xmm0 \n" // update xmm0 for next time! "add $16, %0 \n" // point to next round key "movdqu %%xmm0, (%0) \n" // write it "ret \n" /* Main "loop" */ "2: \n" "aeskeygenassist $0x01, %%xmm0, %%xmm1 \ncall 1b \n" "aeskeygenassist $0x02, %%xmm0, %%xmm1 \ncall 1b \n" "aeskeygenassist $0x04, %%xmm0, %%xmm1 \ncall 1b \n" "aeskeygenassist $0x08, %%xmm0, %%xmm1 \ncall 1b \n" "aeskeygenassist $0x10, %%xmm0, %%xmm1 \ncall 1b \n" "aeskeygenassist $0x20, %%xmm0, %%xmm1 \ncall 1b \n" "aeskeygenassist $0x40, %%xmm0, %%xmm1 \ncall 1b \n" "aeskeygenassist $0x80, %%xmm0, %%xmm1 \ncall 1b \n" "aeskeygenassist $0x1B, %%xmm0, %%xmm1 \ncall 1b \n" "aeskeygenassist $0x36, %%xmm0, %%xmm1 \ncall 1b \n" : : "r" (rk), "r" (key) : "memory", "cc", "0" ); } /* * Key expansion, wrapper */ int aesni_setkey_enc( unsigned char *rk, const unsigned char *key, size_t bits ) { switch( bits ) { case 128: aesni_setkey_enc_128( rk, key ); break; default : return( POLARSSL_ERR_AES_INVALID_KEY_LENGTH ); } return( 0 ); } #endif /* POLARSSL_HAVE_X86_64 */ #endif /* POLARSSL_AESNI_C */