1 files changed, 189 insertions, 146 deletions

diff --git a/src/lib/libcrypto/bn/bn_mont.c b/src/lib/libcrypto/bn/bn_mont.c
index e435df61f8..c9ebdbaabe 100644
--- a/src/lib/libcrypto/bn/bn_mont.c
+++ b/src/lib/libcrypto/bn/bn_mont.c
@@ -56,59 +56,67 @@
  * [including the GNU Public Licence.]
  */
 
+/*
+ * Details about Montgomery multiplication algorithms can be found at
+ * http://security.ece.orst.edu/publications.html, e.g.
+ * http://security.ece.orst.edu/koc/papers/j37acmon.pdf and
+ * sections 3.8 and 4.2 in http://security.ece.orst.edu/koc/papers/r01rsasw.pdf
+ */
+
 #include <stdio.h>
 #include "cryptlib.h"
 #include "bn_lcl.h"
 
-int BN_mod_mul_montgomery(r,a,b,mont,ctx)
-BIGNUM *r,*a,*b;
-BN_MONT_CTX *mont;
-BN_CTX *ctx;
+#define MONT_WORD /* use the faster word-based algorithm */
+
+int BN_mod_mul_montgomery(BIGNUM *r, const BIGNUM *a, const BIGNUM *b,
+                          BN_MONT_CTX *mont, BN_CTX *ctx)
         {
         BIGNUM *tmp;
+        int ret=0;
 
-        tmp=ctx->bn[ctx->tos++];
+        BN_CTX_start(ctx);
+        tmp = BN_CTX_get(ctx);
+        if (tmp == NULL) goto err;
 
+        bn_check_top(tmp);
         if (a == b)
                 {
                 if (!BN_sqr(tmp,a,ctx)) goto err;
                 }
         else
                 {
-                if (!BN_mul(tmp,a,b)) goto err;
+                if (!BN_mul(tmp,a,b,ctx)) goto err;
                 }
         /* reduce from aRR to aR */
         if (!BN_from_montgomery(r,tmp,mont,ctx)) goto err;
-        ctx->tos--;
-        return(1);
+        ret=1;
 err:
-        return(0);
+        BN_CTX_end(ctx);
+        return(ret);
         }
 
-#define MONT_WORD
+int BN_from_montgomery(BIGNUM *ret, const BIGNUM *a, BN_MONT_CTX *mont,
+             BN_CTX *ctx)
+        {
+        int retn=0;
 
 #ifdef MONT_WORD
-int BN_from_montgomery(ret,a,mont,ctx)
-BIGNUM *ret;
-BIGNUM *a;
-BN_MONT_CTX *mont;
-BN_CTX *ctx;
-        {
-        BIGNUM *n,*t1,*r;
-        BN_ULONG *ap,*np,*rp,n0,v;
+        BIGNUM *n,*r;
+        BN_ULONG *ap,*np,*rp,n0,v,*nrp;
         int al,nl,max,i,x,ri;
-        int retn=0;
 
-        t1=ctx->bn[ctx->tos];
-        r=ctx->bn[ctx->tos+1];
+        BN_CTX_start(ctx);
+        if ((r = BN_CTX_get(ctx)) == NULL) goto err;
 
         if (!BN_copy(r,a)) goto err;
-        n=mont->N;
+        n= &(mont->N);
 
         ap=a->d;
-        /* mont->ri is the size of mont->N in bits/words */
+        /* mont->ri is the size of mont->N in bits (rounded up
+           to the word size) */
         al=ri=mont->ri/BN_BITS2;
-
+        
         nl=n->top;
         if ((al == 0) || (nl == 0)) { r->top=0; return(1); }
 
@@ -119,6 +127,7 @@ BN_CTX *ctx;
         r->neg=a->neg^n->neg;
         np=n->d;
         rp=r->d;
+        nrp= &(r->d[nl]);
 
         /* clear the top words of T */
 #if 1
@@ -131,176 +140,210 @@ BN_CTX *ctx;
         r->top=max;
         n0=mont->n0;
 
+#ifdef BN_COUNT
+        fprintf(stderr,"word BN_from_montgomery %d * %d\n",nl,nl);
+#endif
         for (i=0; i<nl; i++)
                 {
-#if 0
-                int x1,x2;
-
-                if (i+4 > nl)
-                        {
-                        x2=nl;
-                        x1=0;
-                        }
-                else
-                        {
-                        x2=i+4;
-                        x1=nl-x2;
-                        }
-                v=bn_mul_add_words(&(rp[x1]),&(np[x1]),x2,(rp[x1]*n0)&BN_MASK2);
+#ifdef __TANDEM
+                {
+                   long long t1;
+                   long long t2;
+                   long long t3;
+                   t1 = rp[0] * (n0 & 0177777);
+                   t2 = 037777600000l;
+                   t2 = n0 & t2;
+                   t3 = rp[0] & 0177777;
+                   t2 = (t3 * t2) & BN_MASK2;
+                   t1 = t1 + t2;
+                   v=bn_mul_add_words(rp,np,nl,(BN_ULONG) t1);
+                }
 #else
                 v=bn_mul_add_words(rp,np,nl,(rp[0]*n0)&BN_MASK2);
 #endif
-
-                if (((rp[nl]+=v)&BN_MASK2) < v)
+                nrp++;
+                rp++;
+                if (((nrp[-1]+=v)&BN_MASK2) >= v)
+                        continue;
+                else
                         {
-                        for (x=(nl+1); (((++rp[x])&BN_MASK2) == 0); x++)
-                                ;
+                        if (((++nrp[0])&BN_MASK2) != 0) continue;
+                        if (((++nrp[1])&BN_MASK2) != 0) continue;
+                        for (x=2; (((++nrp[x])&BN_MASK2) == 0); x++) ;
                         }
-                rp++;
                 }
-        while (r->d[r->top-1] == 0)
-                r->top--;
-
+        bn_fix_top(r);
+        
         /* mont->ri will be a multiple of the word size */
 #if 0
         BN_rshift(ret,r,mont->ri);
 #else
-        ap=r->d;
-        rp=ret->d;
+        ret->neg = r->neg;
         x=ri;
-        al=r->top-x;
-        for (i=0; i<al; i++)
-                {
-                rp[i]=ap[i+x];
-                }
+        rp=ret->d;
+        ap= &(r->d[x]);
+        if (r->top < x)
+                al=0;
+        else
+                al=r->top-x;
         ret->top=al;
-#endif
-
-        if (BN_ucmp(ret,mont->N) >= 0)
+        al-=4;
+        for (i=0; i<al; i+=4)
                 {
-                bn_qsub(ret,ret,mont->N); /* XXX */
+                BN_ULONG t1,t2,t3,t4;
+                
+                t1=ap[i+0];
+                t2=ap[i+1];
+                t3=ap[i+2];
+                t4=ap[i+3];
+                rp[i+0]=t1;
+                rp[i+1]=t2;
+                rp[i+2]=t3;
+                rp[i+3]=t4;
                 }
-        retn=1;
-err:
-        return(retn);
-        }
-#else
-int BN_from_montgomery(r,a,mont,ctx)
-BIGNUM *r;
-BIGNUM *a;
-BN_MONT_CTX *mont;
-BN_CTX *ctx;
-        {
+        al+=4;
+        for (; i<al; i++)
+                rp[i]=ap[i];
+#endif
+#else /* !MONT_WORD */ 
         BIGNUM *t1,*t2;
 
-        t1=ctx->bn[ctx->tos];
-        t2=ctx->bn[ctx->tos+1];
-
+        BN_CTX_start(ctx);
+        t1 = BN_CTX_get(ctx);
+        t2 = BN_CTX_get(ctx);
+        if (t1 == NULL || t2 == NULL) goto err;
+        
         if (!BN_copy(t1,a)) goto err;
-        /* can cheat */
         BN_mask_bits(t1,mont->ri);
 
-        if (!BN_mul(t2,t1,mont->Ni)) goto err;
+        if (!BN_mul(t2,t1,&mont->Ni,ctx)) goto err;
         BN_mask_bits(t2,mont->ri);
 
-        if (!BN_mul(t1,t2,mont->N)) goto err;
+        if (!BN_mul(t1,t2,&mont->N,ctx)) goto err;
         if (!BN_add(t2,a,t1)) goto err;
-        BN_rshift(r,t2,mont->ri);
+        if (!BN_rshift(ret,t2,mont->ri)) goto err;
+#endif /* MONT_WORD */
 
-        if (BN_ucmp(r,mont->N) >= 0)
-                bn_qsub(r,r,mont->N);
-
-        return(1);
-err:
-        return(0);
+        if (BN_ucmp(ret, &(mont->N)) >= 0)
+                {
+                if (!BN_usub(ret,ret,&(mont->N))) goto err;
+                }
+        retn=1;
+ err:
+        BN_CTX_end(ctx);
+        return(retn);
         }
-#endif
 
-BN_MONT_CTX *BN_MONT_CTX_new()
+BN_MONT_CTX *BN_MONT_CTX_new(void)
         {
         BN_MONT_CTX *ret;
 
-        if ((ret=(BN_MONT_CTX *)Malloc(sizeof(BN_MONT_CTX))) == NULL)
-                return(NULL);
-        ret->ri=0;
-        ret->RR=BN_new();
-        ret->N=BN_new();
-        ret->Ni=NULL;
-        if ((ret->RR == NULL) || (ret->N == NULL))
-                {
-                BN_MONT_CTX_free(ret);
+        if ((ret=(BN_MONT_CTX *)OPENSSL_malloc(sizeof(BN_MONT_CTX))) == NULL)
                 return(NULL);
-                }
+
+        BN_MONT_CTX_init(ret);
+        ret->flags=BN_FLG_MALLOCED;
         return(ret);
         }
 
-void BN_MONT_CTX_free(mont)
-BN_MONT_CTX *mont;
+void BN_MONT_CTX_init(BN_MONT_CTX *ctx)
         {
-        if (mont->RR != NULL) BN_free(mont->RR);
-        if (mont->N != NULL) BN_free(mont->N);
-        if (mont->Ni != NULL) BN_free(mont->Ni);
-        Free(mont);
+        ctx->ri=0;
+        BN_init(&(ctx->RR));
+        BN_init(&(ctx->N));
+        BN_init(&(ctx->Ni));
+        ctx->flags=0;
         }
 
-int BN_MONT_CTX_set(mont,mod,ctx)
-BN_MONT_CTX *mont;
-BIGNUM *mod;
-BN_CTX *ctx;
+void BN_MONT_CTX_free(BN_MONT_CTX *mont)
         {
-        BIGNUM *Ri=NULL,*R=NULL;
+        if(mont == NULL)
+            return;
+
+        BN_free(&(mont->RR));
+        BN_free(&(mont->N));
+        BN_free(&(mont->Ni));
+        if (mont->flags & BN_FLG_MALLOCED)
+                OPENSSL_free(mont);
+        }
 
-        if (mont->RR == NULL) mont->RR=BN_new();
-        if (mont->N == NULL)  mont->N=BN_new();
+int BN_MONT_CTX_set(BN_MONT_CTX *mont, const BIGNUM *mod, BN_CTX *ctx)
+        {
+        BIGNUM Ri,*R;
 
-        R=mont->RR;                                     /* grab RR as a temp */
-        BN_copy(mont->N,mod);                           /* Set N */
+        BN_init(&Ri);
+        R= &(mont->RR);                                 /* grab RR as a temp */
+        BN_copy(&(mont->N),mod);                        /* Set N */
+        mont->N.neg = 0;
 
 #ifdef MONT_WORD
-{
-        BIGNUM tmod;
-        BN_ULONG buf[2];
-        /* int z; */
-
-        mont->ri=(BN_num_bits(mod)+(BN_BITS2-1))/BN_BITS2*BN_BITS2;
-        BN_lshift(R,BN_value_one(),BN_BITS2);           /* R */
-        /* I was bad, this modification of a passed variable was
-         * breaking the multithreaded stuff :-(
-         * z=mod->top;
-         * mod->top=1; */
-
-        buf[0]=mod->d[0];
-        buf[1]=0;
-        tmod.d=buf;
-        tmod.top=1;
-        tmod.max=mod->max;
-        tmod.neg=mod->neg;
-
-        if ((Ri=BN_mod_inverse(R,&tmod,ctx)) == NULL) goto err; /* Ri */
-        BN_lshift(Ri,Ri,BN_BITS2);                      /* R*Ri */
-        bn_qsub(Ri,Ri,BN_value_one());                  /* R*Ri - 1 */
-        BN_div(Ri,NULL,Ri,&tmod,ctx);
-        mont->n0=Ri->d[0];
-        BN_free(Ri);
-        /* mod->top=z; */
-}
-#else
-        mont->ri=BN_num_bits(mod);
-        BN_lshift(R,BN_value_one(),mont->ri);                   /* R */
-        if ((Ri=BN_mod_inverse(R,mod,ctx)) == NULL) goto err;   /* Ri */
-        BN_lshift(Ri,Ri,mont->ri);                              /* R*Ri */
-        bn_qsub(Ri,Ri,BN_value_one());                          /* R*Ri - 1 */
-        BN_div(Ri,NULL,Ri,mod,ctx);
-        if (mont->Ni != NULL) BN_free(mont->Ni);
-        mont->Ni=Ri;                                    /* Ni=(R*Ri-1)/N */
+                {
+                BIGNUM tmod;
+                BN_ULONG buf[2];
+
+                mont->ri=(BN_num_bits(mod)+(BN_BITS2-1))/BN_BITS2*BN_BITS2;
+                if (!(BN_zero(R))) goto err;
+                if (!(BN_set_bit(R,BN_BITS2))) goto err;        /* R */
+
+                buf[0]=mod->d[0]; /* tmod = N mod word size */
+                buf[1]=0;
+                tmod.d=buf;
+                tmod.top=1;
+                tmod.dmax=2;
+                tmod.neg=0;
+                                                        /* Ri = R^-1 mod N*/
+                if ((BN_mod_inverse(&Ri,R,&tmod,ctx)) == NULL)
+                        goto err;
+                if (!BN_lshift(&Ri,&Ri,BN_BITS2)) goto err; /* R*Ri */
+                if (!BN_is_zero(&Ri))
+                        {
+                        if (!BN_sub_word(&Ri,1)) goto err;
+                        }
+                else /* if N mod word size == 1 */
+                        {
+                        if (!BN_set_word(&Ri,BN_MASK2)) goto err;  /* Ri-- (mod word size) */
+                        }
+                if (!BN_div(&Ri,NULL,&Ri,&tmod,ctx)) goto err;
+                /* Ni = (R*Ri-1)/N,
+                 * keep only least significant word: */
+                mont->n0 = (Ri.top > 0) ? Ri.d[0] : 0;
+                BN_free(&Ri);
+                }
+#else /* !MONT_WORD */
+                { /* bignum version */
+                mont->ri=BN_num_bits(&mont->N);
+                if (!BN_zero(R)) goto err;
+                if (!BN_set_bit(R,mont->ri)) goto err;  /* R = 2^ri */
+                                                        /* Ri = R^-1 mod N*/
+                if ((BN_mod_inverse(&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(&(mont->Ni),NULL,&Ri,&mont->N,ctx)) goto err;
+                BN_free(&Ri);
+                }
 #endif
 
         /* setup RR for conversions */
-        BN_lshift(mont->RR,BN_value_one(),mont->ri*2);
-        BN_mod(mont->RR,mont->RR,mont->N,ctx);
+        if (!BN_zero(&(mont->RR))) goto err;
+        if (!BN_set_bit(&(mont->RR),mont->ri*2)) goto err;
+        if (!BN_mod(&(mont->RR),&(mont->RR),&(mont->N),ctx)) goto err;
 
         return(1);
 err:
         return(0);
         }
 
+BN_MONT_CTX *BN_MONT_CTX_copy(BN_MONT_CTX *to, BN_MONT_CTX *from)
+        {
+        if (to == from) return(to);
+
+        if (!BN_copy(&(to->RR),&(from->RR))) return NULL;
+        if (!BN_copy(&(to->N),&(from->N))) return NULL;
+        if (!BN_copy(&(to->Ni),&(from->Ni))) return NULL;
+        to->ri=from->ri;
+        to->n0=from->n0;
+        return(to);
+        }
+