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SUSE:SLE-12-SP4:Update
openssl.17568
openssl-bn_mul_mont_fixed_top.patch
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File openssl-bn_mul_mont_fixed_top.patch of Package openssl.17568
From 71883868ea5b33416ae8283bcc38dd2d97e5006b Mon Sep 17 00:00:00 2001 From: Andy Polyakov <appro@openssl.org> Date: Fri, 6 Jul 2018 15:13:15 +0200 Subject: [PATCH] bn/bn_{mont|exp}.c: switch to zero-padded intermediate vectors. Note that exported functions maintain original behaviour, so that external callers won't observe difference. While internally we can now perform Montogomery multiplication on fixed-length vectors, fixed at modulus size. The new functions, bn_to_mont_fixed_top and bn_mul_mont_fixed_top, are declared in bn_int.h, because one can use them even outside bn, e.g. in RSA, DSA, ECDSA... Reviewed-by: Rich Salz <rsalz@openssl.org> Reviewed-by: David Benjamin <davidben@google.com> (Merged from https://github.com/openssl/openssl/pull/6662) --- crypto/bn/bn_exp.c | 47 ++++++++++++++++++-------------- crypto/bn/bn_lcl.h | 3 +- crypto/bn/bn_mont.c | 45 ++++++++++++++++++++++-------- crypto/bn_int.h | 12 ++++++++ 4 files changed, 74 insertions(+), 33 deletions(-) Index: openssl-1.0.2j/crypto/bn/bn_exp.c =================================================================== --- openssl-1.0.2j.orig/crypto/bn/bn_exp.c +++ openssl-1.0.2j/crypto/bn/bn_exp.c @@ -465,17 +465,17 @@ int BN_mod_exp_mont(BIGNUM *rr, const BI ret = 1; goto err; } - if (!BN_to_montgomery(val[0], aa, mont, ctx)) + if (!bn_to_mont_fixed_top(val[0], aa, mont, ctx)) goto err; /* 1 */ window = BN_window_bits_for_exponent_size(bits); if (window > 1) { - if (!BN_mod_mul_montgomery(d, val[0], val[0], mont, ctx)) + if (!bn_mul_mont_fixed_top(d, val[0], val[0], mont, ctx)) goto err; /* 2 */ j = 1 << (window - 1); for (i = 1; i < j; i++) { if (((val[i] = BN_CTX_get(ctx)) == NULL) || - !BN_mod_mul_montgomery(val[i], val[i - 1], d, mont, ctx)) + !bn_mul_mont_fixed_top(val[i], val[i - 1], d, mont, ctx)) goto err; } } @@ -497,19 +497,15 @@ int BN_mod_exp_mont(BIGNUM *rr, const BI for (i = 1; i < j; i++) r->d[i] = (~m->d[i]) & BN_MASK2; r->top = j; - /* - * Upper words will be zero if the corresponding words of 'm' were - * 0xfff[...], so decrement r->top accordingly. - */ - bn_correct_top(r); + r->flags |= BN_FLG_FIXED_TOP; } else #endif - if (!BN_to_montgomery(r, BN_value_one(), mont, ctx)) + if (!bn_to_mont_fixed_top(r, BN_value_one(), mont, ctx)) goto err; for (;;) { if (BN_is_bit_set(p, wstart) == 0) { if (!start) { - if (!BN_mod_mul_montgomery(r, r, r, mont, ctx)) + if (!bn_mul_mont_fixed_top(r, r, r, mont, ctx)) goto err; } if (wstart == 0) @@ -540,12 +536,12 @@ int BN_mod_exp_mont(BIGNUM *rr, const BI /* add the 'bytes above' */ if (!start) for (i = 0; i < j; i++) { - if (!BN_mod_mul_montgomery(r, r, r, mont, ctx)) + if (!bn_mul_mont_fixed_top(r, r, r, mont, ctx)) goto err; } /* wvalue will be an odd number < 2^window */ - if (!BN_mod_mul_montgomery(r, r, val[wvalue >> 1], mont, ctx)) + if (!bn_mul_mont_fixed_top(r, r, val[wvalue >> 1], mont, ctx)) goto err; /* move the 'window' down further */ @@ -555,6 +551,11 @@ int BN_mod_exp_mont(BIGNUM *rr, const BI if (wstart < 0) break; } + /* + * Done with zero-padded intermediate BIGNUMs. Final BN_from_montgomery + * removes padding [if any] and makes return value suitable for public + * API consumer. + */ #if defined(SPARC_T4_MONT) if (OPENSSL_sparcv9cap_P[0] & (SPARCV9_VIS3 | SPARCV9_PREFER_FPU)) { j = mont->N.top; /* borrow j */ @@ -671,7 +672,7 @@ static int MOD_EXP_CTIME_COPY_FROM_PREBU } b->top = top; - bn_correct_top(b); + b->flags |= BN_FLG_FIXED_TOP; return 1; } @@ -838,16 +839,16 @@ int BN_mod_exp_mont_consttime(BIGNUM *rr tmp.top = top; } else #endif - if (!BN_to_montgomery(&tmp, BN_value_one(), mont, ctx)) + if (!bn_to_mont_fixed_top(&tmp, BN_value_one(), mont, ctx)) goto err; /* prepare a^1 in Montgomery domain */ if (a->neg || BN_ucmp(a, m) >= 0) { if (!BN_mod(&am, a, m, ctx)) goto err; - if (!BN_to_montgomery(&am, &am, mont, ctx)) + if (!bn_to_mont_fixed_top(&am, &am, mont, ctx)) goto err; - } else if (!BN_to_montgomery(&am, a, mont, ctx)) + } else if (!bn_to_mont_fixed_top(&am, a, mont, ctx)) goto err; #if defined(SPARC_T4_MONT) @@ -1125,14 +1126,14 @@ int BN_mod_exp_mont_consttime(BIGNUM *rr * performance advantage of sqr over mul). */ if (window > 1) { - if (!BN_mod_mul_montgomery(&tmp, &am, &am, mont, ctx)) + if (!bn_mul_mont_fixed_top(&tmp, &am, &am, mont, ctx)) goto err; if (!MOD_EXP_CTIME_COPY_TO_PREBUF(&tmp, top, powerbuf, 2, window)) goto err; for (i = 3; i < numPowers; i++) { /* Calculate a^i = a^(i-1) * a */ - if (!BN_mod_mul_montgomery(&tmp, &am, &tmp, mont, ctx)) + if (!bn_mul_mont_fixed_top(&tmp, &am, &tmp, mont, ctx)) goto err; if (!MOD_EXP_CTIME_COPY_TO_PREBUF(&tmp, top, powerbuf, i, window)) @@ -1163,7 +1164,7 @@ int BN_mod_exp_mont_consttime(BIGNUM *rr /* Square the result window-size times */ for (i = 0; i < window; i++) - if (!BN_mod_mul_montgomery(&tmp, &tmp, &tmp, mont, ctx)) + if (!bn_mul_mont_fixed_top(&tmp, &tmp, &tmp, mont, ctx)) goto err; /* @@ -1186,12 +1187,16 @@ int BN_mod_exp_mont_consttime(BIGNUM *rr goto err; /* Multiply the result into the intermediate result */ - if (!BN_mod_mul_montgomery(&tmp, &tmp, &am, mont, ctx)) + if (!bn_mul_mont_fixed_top(&tmp, &tmp, &am, mont, ctx)) goto err; } } - /* Convert the final result from montgomery to standard format */ + /* + * Done with zero-padded intermediate BIGNUMs. Final BN_from_montgomery + * removes padding [if any] and makes return value suitable for public + * API consumer. + */ #if defined(SPARC_T4_MONT) if (OPENSSL_sparcv9cap_P[0] & (SPARCV9_VIS3 | SPARCV9_PREFER_FPU)) { am.d[0] = 1; /* borrow am */ Index: openssl-1.0.2j/crypto/bn/bn_mont.c =================================================================== --- openssl-1.0.2j.orig/crypto/bn/bn_mont.c +++ openssl-1.0.2j/crypto/bn/bn_mont.c @@ -123,12 +123,23 @@ #define MONT_WORD /* use the faster word-based algorithm */ #ifdef MONT_WORD -static int BN_from_montgomery_word(BIGNUM *ret, BIGNUM *r, BN_MONT_CTX *mont); +static int bn_from_montgomery_word(BIGNUM *ret, BIGNUM *r, BN_MONT_CTX *mont); #endif int BN_mod_mul_montgomery(BIGNUM *r, const BIGNUM *a, const BIGNUM *b, BN_MONT_CTX *mont, BN_CTX *ctx) { + int ret = bn_mul_mont_fixed_top(r, a, b, mont, ctx); + + bn_correct_top(r); + bn_check_top(r); + + return ret; +} + +int bn_mul_mont_fixed_top(BIGNUM *r, const BIGNUM *a, const BIGNUM *b, + BN_MONT_CTX *mont, BN_CTX *ctx) +{ BIGNUM *tmp; int ret = 0; #if defined(OPENSSL_BN_ASM_MONT) && defined(MONT_WORD) @@ -140,7 +151,7 @@ int BN_mod_mul_montgomery(BIGNUM *r, con if (bn_mul_mont(r->d, a->d, b->d, mont->N.d, mont->n0, num)) { r->neg = a->neg ^ b->neg; r->top = num; - bn_correct_top(r); + r->flags |= BN_FLG_FIXED_TOP; return (1); } } @@ -161,13 +172,12 @@ int BN_mod_mul_montgomery(BIGNUM *r, con } /* reduce from aRR to aR */ #ifdef MONT_WORD - if (!BN_from_montgomery_word(r, tmp, mont)) + if (!bn_from_montgomery_word(r, tmp, mont)) goto err; #else if (!BN_from_montgomery(r, tmp, mont, ctx)) goto err; #endif - bn_check_top(r); ret = 1; err: BN_CTX_end(ctx); @@ -175,7 +185,7 @@ int BN_mod_mul_montgomery(BIGNUM *r, con } #ifdef MONT_WORD -static int BN_from_montgomery_word(BIGNUM *ret, BIGNUM *r, BN_MONT_CTX *mont) +static int bn_from_montgomery_word(BIGNUM *ret, BIGNUM *r, BN_MONT_CTX *mont) { BIGNUM *n; BN_ULONG *ap, *np, *rp, n0, v, carry; @@ -204,6 +214,7 @@ static int BN_from_montgomery_word(BIGNU } r->top = max; + r->flags |= BN_FLG_FIXED_TOP; n0 = mont->n0[0]; # ifdef BN_COUNT @@ -235,6 +246,7 @@ static int BN_from_montgomery_word(BIGNU if (bn_wexpand(ret, nl) == NULL) return (0); ret->top = nl; + ret->flags |= BN_FLG_FIXED_TOP; ret->neg = r->neg; rp = ret->d; @@ -306,8 +318,11 @@ int bn_from_mont_fixed_top(BIGNUM *ret, BIGNUM *t; BN_CTX_start(ctx); - if ((t = BN_CTX_get(ctx)) && BN_copy(t, a)) - retn = BN_from_montgomery_word(ret, t, mont); + if ((t = BN_CTX_get(ctx)) && BN_copy(t, a)) { + retn = bn_from_montgomery_word(ret, t, mont); + bn_correct_top(ret); + bn_check_top(ret); + } BN_CTX_end(ctx); #else /* !MONT_WORD */ BIGNUM *t1, *t2; @@ -345,6 +360,12 @@ int bn_from_mont_fixed_top(BIGNUM *ret, return (retn); } +int bn_to_mont_fixed_top(BIGNUM *r, const BIGNUM *a, BN_MONT_CTX *mont, + BN_CTX *ctx) +{ + return bn_mul_mont_fixed_top(r, a, &(mont->RR), mont, ctx); +} + BN_MONT_CTX *BN_MONT_CTX_new(void) { BN_MONT_CTX *ret; @@ -381,7 +402,7 @@ void BN_MONT_CTX_free(BN_MONT_CTX *mont) int BN_MONT_CTX_set(BN_MONT_CTX *mont, const BIGNUM *mod, BN_CTX *ctx) { - int ret = 0; + int i, ret = 0; BIGNUM *Ri, *R; if (BN_is_zero(mod)) @@ -507,6 +528,11 @@ int BN_MONT_CTX_set(BN_MONT_CTX *mont, c if (!BN_mod(&(mont->RR), &(mont->RR), &(mont->N), ctx)) goto err; + for (i = mont->RR.top, ret = mont->N.top; i < ret; i++) + mont->RR.d[i] = 0; + mont->RR.top = ret; + mont->RR.flags |= BN_FLG_FIXED_TOP; + ret = 1; err: BN_CTX_end(ctx); Index: openssl-1.0.2j/crypto/bn/bn.h =================================================================== --- openssl-1.0.2j.orig/crypto/bn/bn.h +++ openssl-1.0.2j/crypto/bn/bn.h @@ -323,7 +323,8 @@ struct bignum_st { /* Used for montgomery multiplication */ struct bn_mont_ctx_st { int ri; /* number of bits in R */ - BIGNUM RR; /* used to convert to montgomery form */ + BIGNUM RR; /* used to convert to montgomery form, + possibly zero-padded */ BIGNUM N; /* The modulus */ BIGNUM Ni; /* R*(1/R mod N) - N*Ni = 1 (Ni is only * stored for bignum algorithm) */ @@ -583,6 +584,12 @@ int BN_mod_mul_montgomery(BIGNUM *r, con int BN_from_montgomery(BIGNUM *r, const BIGNUM *a, BN_MONT_CTX *mont, BN_CTX *ctx); int bn_bn2binpad(const BIGNUM *a, unsigned char *to, int tolen); +int bn_mul_mont_fixed_top(BIGNUM *r, const BIGNUM *a, const BIGNUM *b, + BN_MONT_CTX *mont, BN_CTX *ctx); +int bn_to_mont_fixed_top(BIGNUM *r, const BIGNUM *a, BN_MONT_CTX *mont, + BN_CTX *ctx); +int bn_mod_add_fixed_top(BIGNUM *r, const BIGNUM *a, const BIGNUM *b, + const BIGNUM *m); int bn_from_mont_fixed_top(BIGNUM *r, const BIGNUM *a, BN_MONT_CTX *mont, BN_CTX *ctx); int bn_mod_sub_fixed_top(BIGNUM *r, const BIGNUM *a, const BIGNUM *b,
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