diff options
Diffstat (limited to 'crypto/xts.c')
| -rw-r--r-- | crypto/xts.c | 200 |
1 files changed, 110 insertions, 90 deletions
diff --git a/crypto/xts.c b/crypto/xts.c index 95212341f6..4277ad40de 100644 --- a/crypto/xts.c +++ b/crypto/xts.c @@ -24,52 +24,75 @@ */ #include "qemu/osdep.h" +#include "qemu/bswap.h" #include "crypto/xts.h" -static void xts_mult_x(uint8_t *I) +typedef union { + uint8_t b[XTS_BLOCK_SIZE]; + uint64_t u[2]; +} xts_uint128; + +static inline void xts_uint128_xor(xts_uint128 *D, + const xts_uint128 *S1, + const xts_uint128 *S2) { - int x; - uint8_t t, tt; + D->u[0] = S1->u[0] ^ S2->u[0]; + D->u[1] = S1->u[1] ^ S2->u[1]; +} - for (x = t = 0; x < 16; x++) { - tt = I[x] >> 7; - I[x] = ((I[x] << 1) | t) & 0xFF; - t = tt; - } - if (tt) { - I[0] ^= 0x87; +static inline void xts_uint128_cpu_to_les(xts_uint128 *v) +{ + cpu_to_le64s(&v->u[0]); + cpu_to_le64s(&v->u[1]); +} + +static inline void xts_uint128_le_to_cpus(xts_uint128 *v) +{ + le64_to_cpus(&v->u[0]); + le64_to_cpus(&v->u[1]); +} + +static void xts_mult_x(xts_uint128 *I) +{ + uint64_t tt; + + xts_uint128_le_to_cpus(I); + + tt = I->u[0] >> 63; + I->u[0] <<= 1; + + if (I->u[1] >> 63) { + I->u[0] ^= 0x87; } + I->u[1] <<= 1; + I->u[1] |= tt; + + xts_uint128_cpu_to_les(I); } /** - * xts_tweak_uncrypt: + * xts_tweak_encdec: * @param ctxt: the cipher context * @param func: the cipher function - * @src: buffer providing the cipher text of XTS_BLOCK_SIZE bytes - * @dst: buffer to output the plain text of XTS_BLOCK_SIZE bytes + * @src: buffer providing the input text of XTS_BLOCK_SIZE bytes + * @dst: buffer to output the output text of XTS_BLOCK_SIZE bytes * @iv: the initialization vector tweak of XTS_BLOCK_SIZE bytes * - * Decrypt data with a tweak + * Encrypt/decrypt data with a tweak */ -static void xts_tweak_decrypt(const void *ctx, - xts_cipher_func *func, - const uint8_t *src, - uint8_t *dst, - uint8_t *iv) +static inline void xts_tweak_encdec(const void *ctx, + xts_cipher_func *func, + const xts_uint128 *src, + xts_uint128 *dst, + xts_uint128 *iv) { - unsigned long x; - /* tweak encrypt block i */ - for (x = 0; x < XTS_BLOCK_SIZE; x++) { - dst[x] = src[x] ^ iv[x]; - } + xts_uint128_xor(dst, src, iv); - func(ctx, XTS_BLOCK_SIZE, dst, dst); + func(ctx, XTS_BLOCK_SIZE, dst->b, dst->b); - for (x = 0; x < XTS_BLOCK_SIZE; x++) { - dst[x] = dst[x] ^ iv[x]; - } + xts_uint128_xor(dst, dst, iv); /* LFSR the tweak */ xts_mult_x(iv); @@ -85,7 +108,7 @@ void xts_decrypt(const void *datactx, uint8_t *dst, const uint8_t *src) { - uint8_t PP[XTS_BLOCK_SIZE], CC[XTS_BLOCK_SIZE], T[XTS_BLOCK_SIZE]; + xts_uint128 PP, CC, T; unsigned long i, m, mo, lim; /* get number of blocks */ @@ -102,72 +125,53 @@ void xts_decrypt(const void *datactx, } /* encrypt the iv */ - encfunc(tweakctx, XTS_BLOCK_SIZE, T, iv); - - for (i = 0; i < lim; i++) { - xts_tweak_decrypt(datactx, decfunc, src, dst, T); - - src += XTS_BLOCK_SIZE; - dst += XTS_BLOCK_SIZE; + encfunc(tweakctx, XTS_BLOCK_SIZE, T.b, iv); + + if (QEMU_PTR_IS_ALIGNED(src, sizeof(uint64_t)) && + QEMU_PTR_IS_ALIGNED(dst, sizeof(uint64_t))) { + xts_uint128 *S = (xts_uint128 *)src; + xts_uint128 *D = (xts_uint128 *)dst; + for (i = 0; i < lim; i++, S++, D++) { + xts_tweak_encdec(datactx, decfunc, S, D, &T); + } + } else { + xts_uint128 D; + + for (i = 0; i < lim; i++) { + memcpy(&D, src, XTS_BLOCK_SIZE); + xts_tweak_encdec(datactx, decfunc, &D, &D, &T); + memcpy(dst, &D, XTS_BLOCK_SIZE); + src += XTS_BLOCK_SIZE; + dst += XTS_BLOCK_SIZE; + } } /* if length is not a multiple of XTS_BLOCK_SIZE then */ if (mo > 0) { - memcpy(CC, T, XTS_BLOCK_SIZE); - xts_mult_x(CC); + xts_uint128 S, D; + memcpy(&CC, &T, XTS_BLOCK_SIZE); + xts_mult_x(&CC); /* PP = tweak decrypt block m-1 */ - xts_tweak_decrypt(datactx, decfunc, src, PP, CC); + memcpy(&S, src, XTS_BLOCK_SIZE); + xts_tweak_encdec(datactx, decfunc, &S, &PP, &CC); /* Pm = first length % XTS_BLOCK_SIZE bytes of PP */ for (i = 0; i < mo; i++) { - CC[i] = src[XTS_BLOCK_SIZE + i]; - dst[XTS_BLOCK_SIZE + i] = PP[i]; + CC.b[i] = src[XTS_BLOCK_SIZE + i]; + dst[XTS_BLOCK_SIZE + i] = PP.b[i]; } for (; i < XTS_BLOCK_SIZE; i++) { - CC[i] = PP[i]; + CC.b[i] = PP.b[i]; } /* Pm-1 = Tweak uncrypt CC */ - xts_tweak_decrypt(datactx, decfunc, CC, dst, T); + xts_tweak_encdec(datactx, decfunc, &CC, &D, &T); + memcpy(dst, &D, XTS_BLOCK_SIZE); } /* Decrypt the iv back */ - decfunc(tweakctx, XTS_BLOCK_SIZE, iv, T); -} - - -/** - * xts_tweak_crypt: - * @param ctxt: the cipher context - * @param func: the cipher function - * @src: buffer providing the plain text of XTS_BLOCK_SIZE bytes - * @dst: buffer to output the cipher text of XTS_BLOCK_SIZE bytes - * @iv: the initialization vector tweak of XTS_BLOCK_SIZE bytes - * - * Encrypt data with a tweak - */ -static void xts_tweak_encrypt(const void *ctx, - xts_cipher_func *func, - const uint8_t *src, - uint8_t *dst, - uint8_t *iv) -{ - unsigned long x; - - /* tweak encrypt block i */ - for (x = 0; x < XTS_BLOCK_SIZE; x++) { - dst[x] = src[x] ^ iv[x]; - } - - func(ctx, XTS_BLOCK_SIZE, dst, dst); - - for (x = 0; x < XTS_BLOCK_SIZE; x++) { - dst[x] = dst[x] ^ iv[x]; - } - - /* LFSR the tweak */ - xts_mult_x(iv); + decfunc(tweakctx, XTS_BLOCK_SIZE, iv, T.b); } @@ -180,7 +184,7 @@ void xts_encrypt(const void *datactx, uint8_t *dst, const uint8_t *src) { - uint8_t PP[XTS_BLOCK_SIZE], CC[XTS_BLOCK_SIZE], T[XTS_BLOCK_SIZE]; + xts_uint128 PP, CC, T; unsigned long i, m, mo, lim; /* get number of blocks */ @@ -197,34 +201,50 @@ void xts_encrypt(const void *datactx, } /* encrypt the iv */ - encfunc(tweakctx, XTS_BLOCK_SIZE, T, iv); + encfunc(tweakctx, XTS_BLOCK_SIZE, T.b, iv); + + if (QEMU_PTR_IS_ALIGNED(src, sizeof(uint64_t)) && + QEMU_PTR_IS_ALIGNED(dst, sizeof(uint64_t))) { + xts_uint128 *S = (xts_uint128 *)src; + xts_uint128 *D = (xts_uint128 *)dst; + for (i = 0; i < lim; i++, S++, D++) { + xts_tweak_encdec(datactx, encfunc, S, D, &T); + } + } else { + xts_uint128 D; - for (i = 0; i < lim; i++) { - xts_tweak_encrypt(datactx, encfunc, src, dst, T); + for (i = 0; i < lim; i++) { + memcpy(&D, src, XTS_BLOCK_SIZE); + xts_tweak_encdec(datactx, encfunc, &D, &D, &T); + memcpy(dst, &D, XTS_BLOCK_SIZE); - dst += XTS_BLOCK_SIZE; - src += XTS_BLOCK_SIZE; + dst += XTS_BLOCK_SIZE; + src += XTS_BLOCK_SIZE; + } } /* if length is not a multiple of XTS_BLOCK_SIZE then */ if (mo > 0) { + xts_uint128 S, D; /* CC = tweak encrypt block m-1 */ - xts_tweak_encrypt(datactx, encfunc, src, CC, T); + memcpy(&S, src, XTS_BLOCK_SIZE); + xts_tweak_encdec(datactx, encfunc, &S, &CC, &T); /* Cm = first length % XTS_BLOCK_SIZE bytes of CC */ for (i = 0; i < mo; i++) { - PP[i] = src[XTS_BLOCK_SIZE + i]; - dst[XTS_BLOCK_SIZE + i] = CC[i]; + PP.b[i] = src[XTS_BLOCK_SIZE + i]; + dst[XTS_BLOCK_SIZE + i] = CC.b[i]; } for (; i < XTS_BLOCK_SIZE; i++) { - PP[i] = CC[i]; + PP.b[i] = CC.b[i]; } /* Cm-1 = Tweak encrypt PP */ - xts_tweak_encrypt(datactx, encfunc, PP, dst, T); + xts_tweak_encdec(datactx, encfunc, &PP, &D, &T); + memcpy(dst, &D, XTS_BLOCK_SIZE); } /* Decrypt the iv back */ - decfunc(tweakctx, XTS_BLOCK_SIZE, iv, T); + decfunc(tweakctx, XTS_BLOCK_SIZE, iv, T.b); } |