Avoid BN_MONT_CTX incompatibility.

diff --git a/CHANGES b/CHANGES
index 27c74e2ef649451f3512aad573f4b9d953930cfd..910fcb36eb0ff1b41e6757743f87f6d1a3fc83f8 100644 (file)
--- a/CHANGES
+++ b/CHANGES
@@ -6,25 +6,22 @@
 
   *) Partial backport from 0.9.9-dev:
 
-     New candidate for BIGNUM assembler implementation, bn_mul_mont,
-     dedicated Montgomery multiplication procedure, is introduced.
-     While 0.9.9-dev has assembler for various architectures, here
-     in the 0.9.8 branch, only x86_64 is available by default.
-
-     With Configure option "enable-montasm" (which exists only for
-     this backport), the 32-bit x86 assembler implementation can be
-     activated at compile-time.  In 0.9.9-dev, BN_MONT_CTX is modified
-     to allow bn_mul_mont to reach for higher "64-bit" performance on
-     certain 32-bit targets.  With "enable-montasm", this BN_MONT_CTX
-     change is activated in the 0.9.8 branch.
-
-     Warning: Using "enable-montasm" thus means losing binary
-     compatibility between patchlevels!  (I.e., applications will
-     have to be recompiled to match the particular library.)
-     So you may want to avoid this setting for shared libraries.
-     Use at your own risk.
-
-     [Andy Polyakov (32-bit x86 backport: Bodo Moeller)]
+     Introduce bn_mul_mont (dedicated Montgomery multiplication
+     procedure) as a candidate for BIGNUM assembler implementation.
+     While 0.9.9-dev uses assembler for various architectures, only
+     x86_64 is available by default here in the 0.9.8 branch, and
+     32-bit x86 is available through a compile-time setting.
+
+     To try the 32-bit x86 assembler implementation, use Configure
+     option "enable-montasm" (which exists only for this backport).
+
+     As "enable-montasm" for 32-bit x86 disclaims code stability
+     anyway, in this constellation we activate additional code
+     backported from 0.9.9-dev for further performance improvements,
+     namely BN_from_montgomery_word.  (To enable this otherwise,
+     e.g. x86_64, try "-DMONT_FROM_WORD___NON_DEFAULT_0_9_8_BUILD".)
+
+     [Andy Polyakov (backport partially by Bodo Moeller)]
 
   *) Add TLS session ticket callback. This allows an application to set
      TLS ticket cipher and HMAC keys rather than relying on hardcoded fixed

diff --git a/crypto/bn/bn.h b/crypto/bn/bn.h
index de39a720749cc4c0f25910cf30bfe4a837251e41..6d754d5547767dbcdbda979312d876e0436eec1e 100644 (file)
--- a/crypto/bn/bn.h
+++ b/crypto/bn/bn.h
@@ -303,12 +303,10 @@ struct bn_mont_ctx_st
        BIGNUM N;      /* The modulus */
        BIGNUM Ni;     /* R*(1/R mod N) - N*Ni = 1
                        * (Ni is only stored for bignum algorithm) */
-#if defined(OPENSSL_BN_ASM_MONT) && (BN_BITS2<=32)
-       /* Non-default compile (can only happen with "enable-montasm"),
-        * uses the new type from 0.9.9 to accomodate two words: */
+#if 0
+       /* OpenSSL 0.9.9 preview: */
        BN_ULONG n0[2];/* least significant word(s) of Ni */
 #else
-       /* By default, use old type: */
        BN_ULONG n0;   /* least significant word of Ni */
 #endif
        int flags;

diff --git a/crypto/bn/bn_mont.c b/crypto/bn/bn_mont.c
index e17c697e392538e365c279fb0acb75ceb814aaf8..4799b152ddcba426584dfca10ee03dac100619c4 100644 (file)
--- a/crypto/bn/bn_mont.c
+++ b/crypto/bn/bn_mont.c
@@ -123,6 +123,20 @@
 #define MONT_WORD /* use the faster word-based algorithm */
 
 #if defined(MONT_WORD) && defined(OPENSSL_BN_ASM_MONT) && (BN_BITS2<=32)
+/* This condition means we have a specific non-default build:
+ * In the 0.9.8 branch, OPENSSL_BN_ASM_MONT is normally not set for any
+ * BN_BITS2<=32 platform; an explicit "enable-montasm" is required.
+ * I.e., if we are here, the user intentionally deviates from the
+ * normal stable build to get better Montgomery performance from
+ * the 0.9.9-dev backport.
+ *
+ * In this case only, we also enable BN_from_montgomery_word()
+ * (another non-stable feature from 0.9.9-dev).
+ */
+#define MONT_FROM_WORD___NON_DEFAULT_0_9_8_BUILD
+#endif
+
+#ifdef MONT_FROM_WORD___NON_DEFAULT_0_9_8_BUILD
 static int BN_from_montgomery_word(BIGNUM *ret, BIGNUM *r, BN_MONT_CTX *mont);
 #endif
 
@@ -139,7 +153,7 @@ int BN_mod_mul_montgomery(BIGNUM *r, const BIGNUM *a, const BIGNUM *b,
        if (num>1 && a->top==num && b->top==num)
                {
                if (bn_wexpand(r,num) == NULL) return(0);
-#if defined(OPENSSL_BN_ASM_MONT) && (BN_BITS2<=32) /* non-default compile */
+#if 0 /* for OpenSSL 0.9.9 mont->n0 */
                if (bn_mul_mont(r->d,a->d,b->d,mont->N.d,mont->n0,num))
 #else
                if (bn_mul_mont(r->d,a->d,b->d,mont->N.d,&mont->n0,num))
@@ -167,7 +181,7 @@ int BN_mod_mul_montgomery(BIGNUM *r, const BIGNUM *a, const BIGNUM *b,
                if (!BN_mul(tmp,a,b,ctx)) goto err;
                }
        /* reduce from aRR to aR */
-#if defined(MONT_WORD) && defined(OPENSSL_BN_ASM_MONT) && (BN_BITS2<=32)
+#ifdef MONT_FROM_WORD___NON_DEFAULT_0_9_8_BUILD
        if (!BN_from_montgomery_word(r,tmp,mont)) goto err;
 #else
        if (!BN_from_montgomery(r,tmp,mont,ctx)) goto err;
@@ -179,7 +193,7 @@ err:
        return(ret);
        }
 
-#if defined(MONT_WORD) && defined(OPENSSL_BN_ASM_MONT) && (BN_BITS2<=32)
+#ifdef MONT_FROM_WORD___NON_DEFAULT_0_9_8_BUILD
 static int BN_from_montgomery_word(BIGNUM *ret, BIGNUM *r, BN_MONT_CTX *mont)
        {
        BIGNUM *n;
@@ -207,7 +221,11 @@ static int BN_from_montgomery_word(BIGNUM *ret, BIGNUM *r, BN_MONT_CTX *mont)
                r->d[i]=0;
 
        r->top=max;
+#if 0 /* for OpenSSL 0.9.9 mont->n0 */
        n0=mont->n0[0];
+#else
+       n0=mont->n0;
+#endif
 
 #ifdef BN_COUNT
        fprintf(stderr,"word BN_from_montgomery_word %d * %d\n",nl,nl);
@@ -316,7 +334,8 @@ int BN_from_montgomery(BIGNUM *ret, const BIGNUM *a, BN_MONT_CTX *mont,
        BN_CTX_end(ctx);
        return retn;
        }
-#else
+
+#else /* !MONT_FROM_WORD___NON_DEFAULT_0_9_8_BUILD */
 
 int BN_from_montgomery(BIGNUM *ret, const BIGNUM *a, BN_MONT_CTX *mont,
             BN_CTX *ctx)
@@ -510,7 +529,7 @@ int BN_from_montgomery(BIGNUM *ret, const BIGNUM *a, BN_MONT_CTX *mont,
        BN_CTX_end(ctx);
        return(retn);
        }
-#endif /* defined(MONT_WORD) && defined(OPENSSL_BN_ASM_MONT) && (BN_BITS2<=32) */
+#endif /* MONT_FROM_WORD___NON_DEFAULT_0_9_8_BUILD */
 
 BN_MONT_CTX *BN_MONT_CTX_new(void)
        {
@@ -530,7 +549,7 @@ void BN_MONT_CTX_init(BN_MONT_CTX *ctx)
        BN_init(&(ctx->RR));
        BN_init(&(ctx->N));
        BN_init(&(ctx->Ni));
-#if defined(OPENSSL_BN_ASM_MONT) && (BN_BITS2<=32) /* non-default compile */
+#if 0 /* for OpenSSL 0.9.9 mont->n0 */
        ctx->n0[0] = ctx->n0[1] = 0;
 #else
        ctx->n0 = 0;
@@ -568,7 +587,8 @@ int BN_MONT_CTX_set(BN_MONT_CTX *mont, const BIGNUM *mod, BN_CTX *ctx)
 
                mont->ri=(BN_num_bits(mod)+(BN_BITS2-1))/BN_BITS2*BN_BITS2;
                BN_zero(R);
-#if defined(OPENSSL_BN_ASM_MONT) && (BN_BITS2<=32) /* non-default compile */
+#if 0 /* for OpenSSL 0.9.9 mont->n0, would be "#if defined(OPENSSL_BN_ASM_MONT) && (BN_BITS2<=32)",
+         only certain BN_BITS2<=32 platforms actually need this */
                if (!(BN_set_bit(R,2*BN_BITS2))) goto err;      /* R */
 #else
                if (!(BN_set_bit(R,BN_BITS2))) goto err;        /* R */
@@ -583,7 +603,8 @@ int BN_MONT_CTX_set(BN_MONT_CTX *mont, const BIGNUM *mod, BN_CTX *ctx)
                tmod.dmax=2;
                tmod.neg=0;
 
-#if defined(OPENSSL_BN_ASM_MONT) && (BN_BITS2<=32)
+#if 0 /* for OpenSSL 0.9.9 mont->n0, would be "#if defined(OPENSSL_BN_ASM_MONT) && (BN_BITS2<=32)";
+         only certain BN_BITS2<=32 platforms actually need this */
                                                                tmod.top=0;
                if ((buf[0] = mod->d[0]))                       tmod.top=1;
                if ((buf[1] = mod->top>1 ? mod->d[1] : 0))      tmod.top=2;
@@ -626,7 +647,12 @@ int BN_MONT_CTX_set(BN_MONT_CTX *mont, const BIGNUM *mod, BN_CTX *ctx)
                if (!BN_div(Ri,NULL,Ri,&tmod,ctx)) goto err;
                /* Ni = (R*Ri-1)/N,
                 * keep only least significant word: */
+# if 0 /* for OpenSSL 0.9.9 mont->n0 */
+               mont->n0[0] = (Ri->top > 0) ? Ri->d[0] : 0;
+               mont->n0[1] = 0;
+# else
                mont->n0 = (Ri->top > 0) ? Ri->d[0] : 0;
+# endif
 #endif
                }
 #else /* !MONT_WORD */
@@ -663,7 +689,7 @@ BN_MONT_CTX *BN_MONT_CTX_copy(BN_MONT_CTX *to, BN_MONT_CTX *from)
        if (!BN_copy(&(to->N),&(from->N))) return NULL;
        if (!BN_copy(&(to->Ni),&(from->Ni))) return NULL;
        to->ri=from->ri;
-#if defined(OPENSSL_BN_ASM_MONT) && (BN_BITS2<=32) /* non-default compile */
+#if 0 /* for OpenSSL 0.9.9 mont->n0 */
        to->n0[0]=from->n0[0];
        to->n0[1]=from->n0[1];
 #else