Unifdef MONT_WORD.

It does not make sense to use code that is slower, currently broken and
prevents the use of assembly Montgomery implementations.

This is the result of `unifdef -m -DMONT_WORD`, followed by some manual
clean up and the removal of the Ni bignum from BN_MONT_CTX (which was only
used in the non-MONT_WORD case).

ok miod@ tb@

diff --git a/lib/libcrypto/bn/bn_local.h b/lib/libcrypto/bn/bn_local.h
index d2c7a39..c763890 100644 (file)
--- a/lib/libcrypto/bn/bn_local.h
+++ b/lib/libcrypto/bn/bn_local.h
@@ -1,4 +1,4 @@
-/* $OpenBSD: bn_local.h,v 1.13 2023/02/19 15:45:14 tb Exp $ */
+/* $OpenBSD: bn_local.h,v 1.14 2023/02/21 05:58:08 jsing Exp $ */
 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
  * All rights reserved.
  *
@@ -132,9 +132,7 @@ struct bn_mont_ctx_st {
        int ri;        /* number of bits in R */
        BIGNUM RR;     /* used to convert to montgomery form */
        BIGNUM N;      /* The modulus */
-       BIGNUM Ni;     /* R*(1/R mod N) - N*Ni = 1
-                       * (Ni is only stored for bignum algorithm) */
-       BN_ULONG n0[2];/* least significant word(s) of Ni;
+       BN_ULONG n0[2];/* least significant word(s) of Ni; R*(1/R mod N) - N*Ni = 1
                          (type changed with 0.9.9, was "BN_ULONG n0;" before) */
        int flags;
 };

diff --git a/lib/libcrypto/bn/bn_mont.c b/lib/libcrypto/bn/bn_mont.c
index 89df675..53ad5aa 100644 (file)
--- a/lib/libcrypto/bn/bn_mont.c
+++ b/lib/libcrypto/bn/bn_mont.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: bn_mont.c,v 1.42 2023/02/19 15:45:14 tb Exp $ */
+/* $OpenBSD: bn_mont.c,v 1.43 2023/02/21 05:58:08 jsing Exp $ */
 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
  * All rights reserved.
  *
@@ -122,8 +122,6 @@
 
 #include "bn_local.h"
 
-#define MONT_WORD /* use the faster word-based algorithm */
-
 BN_MONT_CTX *
 BN_MONT_CTX_new(void)
 {
@@ -135,7 +133,6 @@ BN_MONT_CTX_new(void)
 
        BN_init(&mctx->RR);
        BN_init(&mctx->N);
-       BN_init(&mctx->Ni);
 
        return mctx;
 }
@@ -147,7 +144,6 @@ BN_MONT_CTX_init(BN_MONT_CTX *mctx)
 
        BN_init(&mctx->RR);
        BN_init(&mctx->N);
-       BN_init(&mctx->Ni);
 }
 
 void
@@ -158,7 +154,6 @@ BN_MONT_CTX_free(BN_MONT_CTX *mctx)
 
        BN_free(&mctx->RR);
        BN_free(&mctx->N);
-       BN_free(&mctx->Ni);
 
        if (mctx->flags & BN_FLG_MALLOCED)
                free(mctx);
@@ -174,8 +169,6 @@ BN_MONT_CTX_copy(BN_MONT_CTX *dst, BN_MONT_CTX *src)
                return NULL;
        if (!BN_copy(&dst->N, &src->N))
                return NULL;
-       if (!BN_copy(&dst->Ni, &src->Ni))
-               return NULL;
 
        dst->ri = src->ri;
        dst->n0[0] = src->n0[0];
@@ -201,7 +194,6 @@ BN_MONT_CTX_set(BN_MONT_CTX *mont, const BIGNUM *mod, BN_CTX *ctx)
                 goto err;                              /* Set N */
        mont->N.neg = 0;
 
-#ifdef MONT_WORD
        {
                BIGNUM tmod;
                BN_ULONG buf[2];
@@ -284,24 +276,6 @@ BN_MONT_CTX_set(BN_MONT_CTX *mont, const BIGNUM *mod, BN_CTX *ctx)
                mont->n0[1] = 0;
 #endif
        }
-#else /* !MONT_WORD */
-       { /* bignum version */
-               mont->ri = BN_num_bits(&mont->N);
-               BN_zero(R);
-               if (!BN_set_bit(R, mont->ri))
-                       goto err;  /* R = 2^ri */
-               /* Ri = R^-1 mod N*/
-               if ((BN_mod_inverse_ct(Ri, R, &mont->N, ctx)) == NULL)
-                       goto err;
-               if (!BN_lshift(Ri, Ri, mont->ri))
-                       goto err; /* R*Ri */
-               if (!BN_sub_word(Ri, 1))
-                       goto err;
-               /* Ni = (R*Ri-1) / N */
-               if (!BN_div_ct(&(mont->Ni), NULL, Ri, &mont->N, ctx))
-                       goto err;
-       }
-#endif
 
        /* setup RR for conversions */
        BN_zero(&(mont->RR));
@@ -406,9 +380,7 @@ bn_mul_mont(BN_ULONG *rp, const BN_ULONG *ap, const BN_ULONG *bp,
 #endif /* !OPENSSL_BN_ASM_MONT */
 #endif /* OPENSSL_NO_ASM */
 
-#ifdef MONT_WORD
 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,
@@ -416,7 +388,8 @@ BN_mod_mul_montgomery(BIGNUM *r, const BIGNUM *a, const BIGNUM *b,
 {
        BIGNUM *tmp;
        int ret = 0;
-#if defined(OPENSSL_BN_ASM_MONT) && defined(MONT_WORD)
+
+#if defined(OPENSSL_BN_ASM_MONT)
        int num = mont->N.top;
 
        if (num > 1 && a->top == num && b->top == num) {
@@ -443,13 +416,8 @@ BN_mod_mul_montgomery(BIGNUM *r, const BIGNUM *a, const BIGNUM *b,
                        goto err;
        }
        /* reduce from aRR to aR */
-#ifdef MONT_WORD
        if (!BN_from_montgomery_word(r, tmp, mont))
                goto err;
-#else
-       if (!BN_from_montgomery(r, tmp, mont, ctx))
-               goto err;
-#endif
        ret = 1;
 err:
        BN_CTX_end(ctx);
@@ -462,7 +430,6 @@ BN_to_montgomery(BIGNUM *r, const BIGNUM *a, BN_MONT_CTX *mont, BN_CTX *ctx)
        return BN_mod_mul_montgomery(r, a, &mont->RR, mont, ctx);
 }
 
-#ifdef MONT_WORD
 static int
 BN_from_montgomery_word(BIGNUM *ret, BIGNUM *r, BN_MONT_CTX *mont)
 {
@@ -553,51 +520,16 @@ BN_from_montgomery_word(BIGNUM *ret, BIGNUM *r, BN_MONT_CTX *mont)
 
        return (1);
 }
-#endif /* MONT_WORD */
 
 int
 BN_from_montgomery(BIGNUM *ret, const BIGNUM *a, BN_MONT_CTX *mont, BN_CTX *ctx)
 {
        int retn = 0;
-#ifdef MONT_WORD
        BIGNUM *t;
 
        BN_CTX_start(ctx);
        if ((t = BN_CTX_get(ctx)) && BN_copy(t, a))
                retn = BN_from_montgomery_word(ret, t, mont);
        BN_CTX_end(ctx);
-#else /* !MONT_WORD */
-       BIGNUM *t1, *t2;
-
-       BN_CTX_start(ctx);
-       if ((t1 = BN_CTX_get(ctx)) == NULL)
-               goto err;
-       if ((t2 = BN_CTX_get(ctx)) == NULL)
-               goto err;
-
-       if (!BN_copy(t1, a))
-               goto err;
-       BN_mask_bits(t1, mont->ri);
-
-       if (!BN_mul(t2, t1, &mont->Ni, ctx))
-               goto err;
-       BN_mask_bits(t2, mont->ri);
-
-       if (!BN_mul(t1, t2, &mont->N, ctx))
-               goto err;
-       if (!BN_add(t2, a, t1))
-               goto err;
-       if (!BN_rshift(ret, t2, mont->ri))
-               goto err;
-
-       if (BN_ucmp(ret, &(mont->N)) >= 0) {
-               if (!BN_usub(ret, ret, &(mont->N)))
-                       goto err;
-       }
-       retn = 1;
-
-err:
-       BN_CTX_end(ctx);
-#endif /* MONT_WORD */
        return (retn);
 }