From 2c4226c42b2606a43a41ebc5c97a96b24de4216a Mon Sep 17 00:00:00 2001 From: Andy Polyakov Date: Wed, 9 Apr 2008 11:36:04 +0000 Subject: [PATCH] Do BN_nist_mod_384 by the book, as cheating doesn't work. Other functions will be revised too. PR: 1593 --- crypto/bn/bn_nist.c | 122 +++++++++++++++++++++++--------------------- 1 file changed, 63 insertions(+), 59 deletions(-) diff --git a/crypto/bn/bn_nist.c b/crypto/bn/bn_nist.c index fd15c28777..6b88c5fa13 100644 --- a/crypto/bn/bn_nist.c +++ b/crypto/bn/bn_nist.c @@ -176,10 +176,6 @@ const BIGNUM *BN_get0_nist_prime_521(void) static BN_ULONG _256_data[BN_NIST_256_TOP*6]; static int _is_set_256_data = 0; static void _init_256_data(void); - -static BN_ULONG _384_data[BN_NIST_384_TOP*8]; -static int _is_set_384_data = 0; -static void _init_384_data(void); #endif #define BN_NIST_ADD_ONE(a) while (!(*(a)=(*(a)+1)&BN_MASK2)) ++(a); @@ -527,26 +523,6 @@ int BN_nist_mod_256(BIGNUM *r, const BIGNUM *a, const BIGNUM *field, #endif } -#if BN_BITS2 == 32 -static void _init_384_data(void) - { - int i; - BN_ULONG *tmp1 = _384_data; - const BN_ULONG *tmp2 = tmp1; - - memcpy(tmp1, _nist_p_384, BN_NIST_384_TOP * sizeof(BN_ULONG)); - tmp1 += BN_NIST_384_TOP; - - for (i=0; i<7; i++) - { - bn_add_words(tmp1, _nist_p_384, tmp2, BN_NIST_384_TOP); - tmp2 = tmp1; - tmp1 += BN_NIST_384_TOP; - } - _is_set_384_data = 1; - } -#endif - #define nist_set_384(to,from,a1,a2,a3,a4,a5,a6,a7,a8,a9,a10,a11,a12) \ { \ if (a12 != 0) bn_cp_32(to, 0, from, (a12) - 12) else bn_32_set_0(to, 0)\ @@ -571,17 +547,10 @@ int BN_nist_mod_384(BIGNUM *r, const BIGNUM *a, const BIGNUM *field, int carry = 0; register BN_ULONG *r_d, *a_d = a->d; BN_ULONG t_d[BN_NIST_384_TOP], - buf[BN_NIST_384_TOP]; - - if (!_is_set_384_data) - { - CRYPTO_w_lock(CRYPTO_LOCK_BN); - - if (!_is_set_384_data) - _init_384_data(); - - CRYPTO_w_unlock(CRYPTO_LOCK_BN); - } + buf[BN_NIST_384_TOP], + c_d[BN_NIST_384_TOP], + *res; + size_t mask; i = BN_ucmp(field, a); if (i == 0) @@ -624,48 +593,83 @@ int BN_nist_mod_384(BIGNUM *r, const BIGNUM *a, const BIGNUM *field, } carry = bn_add_words(r_d+(128/BN_BITS2), r_d+(128/BN_BITS2), t_d, BN_NIST_256_TOP); + /* this is equivalent to if (result >= module) */ + mask = 0-(size_t)bn_sub_words(c_d,r_d,_nist_p_384,BN_NIST_384_TOP); + mask = ~mask | (0-(size_t)carry); + res = (BN_ULONG *)(((size_t)c_d&mask) | ((size_t)r_d&~mask)); + /*S2 */ - carry += bn_add_words(r_d, r_d, buf, BN_NIST_384_TOP); + carry = bn_add_words(r_d, res, buf, BN_NIST_384_TOP); + mask = 0-(size_t)bn_sub_words(c_d,r_d,_nist_p_384,BN_NIST_384_TOP); + mask = ~mask | (0-(size_t)carry); + res = (BN_ULONG *)(((size_t)c_d&mask) | ((size_t)r_d&~mask)); + /*S3*/ nist_set_384(t_d,buf,20,19,18,17,16,15,14,13,12,23,22,21); - carry += bn_add_words(r_d, r_d, t_d, BN_NIST_384_TOP); + carry = bn_add_words(r_d, res, t_d, BN_NIST_384_TOP); + mask = 0-(size_t)bn_sub_words(c_d,r_d,_nist_p_384,BN_NIST_384_TOP); + mask = ~mask | (0-(size_t)carry); + res = (BN_ULONG *)(((size_t)c_d&mask) | ((size_t)r_d&~mask)); + /*S4*/ nist_set_384(t_d,buf,19,18,17,16,15,14,13,12,20,0,23,0); - carry += bn_add_words(r_d, r_d, t_d, BN_NIST_384_TOP); + carry = bn_add_words(r_d, res, t_d, BN_NIST_384_TOP); + mask = 0-(size_t)bn_sub_words(c_d,r_d,_nist_p_384,BN_NIST_384_TOP); + mask = ~mask | (0-(size_t)carry); + res = (BN_ULONG *)(((size_t)c_d&mask) | ((size_t)r_d&~mask)); + /*S5*/ - nist_set_256(t_d, buf, 0, 0, 0, 0, 23-4, 22-4, 21-4, 20-4); - carry += bn_add_words(r_d+(128/BN_BITS2), r_d+(128/BN_BITS2), - t_d, BN_NIST_256_TOP); + nist_set_384(t_d, buf,0,0,0,0,23,22,21,20,0,0,0,0); + carry = bn_add_words(r_d, res, t_d, BN_NIST_384_TOP); + mask = 0-(size_t)bn_sub_words(c_d,r_d,_nist_p_384,BN_NIST_384_TOP); + mask = ~mask | (0-(size_t)carry); + res = (BN_ULONG *)(((size_t)c_d&mask) | ((size_t)r_d&~mask)); + /*S6*/ nist_set_384(t_d,buf,0,0,0,0,0,0,23,22,21,0,0,20); - carry += bn_add_words(r_d, r_d, t_d, BN_NIST_384_TOP); - - if (carry) - bn_sub_words(r_d, r_d, _384_data + BN_NIST_384_TOP * - (carry-1), BN_NIST_384_TOP); + carry = bn_add_words(r_d, res, t_d, BN_NIST_384_TOP); + mask = 0-(size_t)bn_sub_words(c_d,r_d,_nist_p_384,BN_NIST_384_TOP); + mask = ~mask | (0-(size_t)carry); + res = (BN_ULONG *)(((size_t)c_d&mask) | ((size_t)r_d&~mask)); /*D1*/ nist_set_384(t_d,buf,22,21,20,19,18,17,16,15,14,13,12,23); - carry = bn_sub_words(r_d, r_d, t_d, BN_NIST_384_TOP); +#if BRANCH_FREE + carry = bn_sub_words(r_d, res, t_d, BN_NIST_384_TOP); + bn_add_words(c_d,r_d,_nist_p_384,BN_NIST_384_TOP); + mask = 0-(size_t)carry; + res = (BN_ULONG *)(((size_t)c_d&mask) | ((size_t)r_d&~mask)); +#else + if (bn_sub_words(r_d, res, t_d, BN_NIST_384_TOP)) + bn_add_words(r_d,r_d,_nist_p_384,BN_NIST_384_TOP); +#endif /*D2*/ nist_set_384(t_d,buf,0,0,0,0,0,0,0,23,22,21,20,0); - carry += bn_sub_words(r_d, r_d, t_d, BN_NIST_384_TOP); +#if BRANCH_FREE + carry = bn_sub_words(r_d, res, t_d, BN_NIST_384_TOP); + bn_add_words(c_d,r_d,_nist_p_384,BN_NIST_384_TOP); + mask = 0-(size_t)carry; + res = (BN_ULONG *)(((size_t)c_d&mask) | ((size_t)r_d&~mask)); +#else + if (bn_sub_words(r_d, r_d, t_d, BN_NIST_384_TOP)) + bn_add_words(r_d,r_d,_nist_p_384,BN_NIST_384_TOP); +#endif /*D3*/ nist_set_384(t_d,buf,0,0,0,0,0,0,0,23,23,0,0,0); - carry += bn_sub_words(r_d, r_d, t_d, BN_NIST_384_TOP); - - if (carry) - bn_add_words(r_d, r_d, _384_data + BN_NIST_384_TOP * - (carry-1), BN_NIST_384_TOP); +#if BRANCH_FREE + carry = bn_sub_words(r_d, res, t_d, BN_NIST_384_TOP); + bn_add_words(c_d,r_d,_nist_p_384,BN_NIST_384_TOP); + mask = 0-(size_t)carry; + res = (BN_ULONG *)(((size_t)c_d&mask) | ((size_t)r_d&~mask)); + nist_cp_bn(r_d, res, BN_NIST_384_TOP); +#else + if (bn_sub_words(r_d, r_d, t_d, BN_NIST_384_TOP)) + bn_add_words(r_d,r_d,_nist_p_384,BN_NIST_384_TOP); +#endif r->top = BN_NIST_384_TOP; bn_correct_top(r); - if (BN_ucmp(r, field) >= 0) - { - bn_sub_words(r_d, r_d, _nist_p_384, BN_NIST_384_TOP); - bn_correct_top(r); - } - bn_check_top(r); + return 1; #else return 0; -- GitLab