fix BIGNUM flag handling

diff --git a/CHANGES b/CHANGES
index d4426974ead67b6c78f3f50dbfd8d38e88488e50..2e1a6ae4d4ef235a1f7371f8bb6f0bb2919f791d 100644 (file)
--- a/CHANGES
+++ b/CHANGES
@@ -610,6 +610,10 @@
 
  Changes between 0.9.8g and 0.9.8h  [xx XXX xxxx]
 
+  *) Fix BN flag handling in RSA_eay_mod_exp() and BN_MONT_CTX_set()
+     to get the expected BN_FLG_CONSTTIME behavior.
+     [Bodo Moeller (Google)]
+  
   *) Netware support:
 
      - fixed wrong usage of ioctlsocket() when build for LIBC BSD sockets

diff --git a/crypto/bn/bn_mont.c b/crypto/bn/bn_mont.c
index dcee538d84764b03b45efaf007328dc2efca4101..ecbee2aacdb322c9add630321ca0804a31887d78 100644 (file)
--- a/crypto/bn/bn_mont.c
+++ b/crypto/bn/bn_mont.c
@@ -425,6 +425,7 @@ int BN_MONT_CTX_set(BN_MONT_CTX *mont, const BIGNUM *mod, BN_CTX *ctx)
                BIGNUM tmod;
                BN_ULONG buf[2];
 
+               BN_init(&tmod);
                tmod.d=buf;
                tmod.dmax=2;
                tmod.neg=0;

diff --git a/crypto/rsa/rsa_eay.c b/crypto/rsa/rsa_eay.c
index 15ebf5dfa3c844762a829974372944e38c301da2..a1ecd6d478732e446695dae95f27ad54601c66de 100644 (file)
--- a/crypto/rsa/rsa_eay.c
+++ b/crypto/rsa/rsa_eay.c
@@ -151,13 +151,13 @@ const RSA_METHOD *RSA_PKCS1_SSLeay(void)
        }
 
 /* Usage example;
- *    MONT_HELPER(rsa, bn_ctx, p, rsa->flags & RSA_FLAG_CACHE_PRIVATE, goto err);
+ *    MONT_HELPER(rsa->_method_mod_p, bn_ctx, rsa->p, rsa->flags & RSA_FLAG_CACHE_PRIVATE, goto err);
  */
-#define MONT_HELPER(rsa, ctx, m, pre_cond, err_instr) \
-       if((pre_cond) && ((rsa)->_method_mod_##m == NULL) && \
-                       !BN_MONT_CTX_set_locked(&((rsa)->_method_mod_##m), \
+#define MONT_HELPER(method_mod, ctx, m, pre_cond, err_instr) \
+       if ((pre_cond) && ((method_mod) == NULL) && \
+                       !BN_MONT_CTX_set_locked(&(method_mod), \
                                CRYPTO_LOCK_RSA, \
-                               (rsa)->m, (ctx))) \
+                               (m), (ctx))) \
                err_instr
 
 static int RSA_eay_public_encrypt(int flen, const unsigned char *from,
@@ -227,13 +227,13 @@ static int RSA_eay_public_encrypt(int flen, const unsigned char *from,
        if (BN_bin2bn(buf,num,f) == NULL) goto err;
        
        if (BN_ucmp(f, rsa->n) >= 0)
-               {       
+               {
                /* usually the padding functions would catch this */
                RSAerr(RSA_F_RSA_EAY_PUBLIC_ENCRYPT,RSA_R_DATA_TOO_LARGE_FOR_MODULUS);
                goto err;
                }
 
-       MONT_HELPER(rsa, ctx, n, rsa->flags & RSA_FLAG_CACHE_PUBLIC, goto err);
+       MONT_HELPER(rsa->_method_mod_n, ctx, rsa->n, rsa->flags & RSA_FLAG_CACHE_PUBLIC, goto err);
 
        if (!rsa->meth->bn_mod_exp(ret,f,rsa->e,rsa->n,ctx,
                rsa->_method_mod_n)) goto err;
@@ -436,9 +436,9 @@ static int RSA_eay_private_encrypt(int flen, const unsigned char *from,
                        BN_with_flags(d, rsa->d, BN_FLG_CONSTTIME);
                        }
                else
-                       d = rsa->d;
+                       d= rsa->d;
 
-               MONT_HELPER(rsa, ctx, n, rsa->flags & RSA_FLAG_CACHE_PUBLIC, goto err);
+               MONT_HELPER(rsa->_method_mod_n, ctx, rsa->n, rsa->flags & RSA_FLAG_CACHE_PUBLIC, goto err);
 
                if (!rsa->meth->bn_mod_exp(ret,f,d,rsa->n,ctx,
                                rsa->_method_mod_n)) goto err;
@@ -559,7 +559,7 @@ static int RSA_eay_private_decrypt(int flen, const unsigned char *from,
                else
                        d = rsa->d;
 
-               MONT_HELPER(rsa, ctx, n, rsa->flags & RSA_FLAG_CACHE_PUBLIC, goto err);
+               MONT_HELPER(rsa->_method_mod_n, ctx, rsa->n, rsa->flags & RSA_FLAG_CACHE_PUBLIC, goto err);
                if (!rsa->meth->bn_mod_exp(ret,f,d,rsa->n,ctx,
                                rsa->_method_mod_n))
                  goto err;
@@ -669,7 +669,7 @@ static int RSA_eay_public_decrypt(int flen, const unsigned char *from,
                goto err;
                }
 
-       MONT_HELPER(rsa, ctx, n, rsa->flags & RSA_FLAG_CACHE_PUBLIC, goto err);
+       MONT_HELPER(rsa->_method_mod_n, ctx, rsa->n, rsa->flags & RSA_FLAG_CACHE_PUBLIC, goto err);
 
        if (!rsa->meth->bn_mod_exp(ret,f,rsa->e,rsa->n,ctx,
                rsa->_method_mod_n)) goto err;
@@ -717,7 +717,6 @@ static int RSA_eay_mod_exp(BIGNUM *r0, const BIGNUM *I, RSA *rsa, BN_CTX *ctx)
        BIGNUM *r1,*m1,*vrfy;
        BIGNUM local_dmp1,local_dmq1,local_c,local_r1;
        BIGNUM *dmp1,*dmq1,*c,*pr1;
-       int bn_flags;
        int ret=0;
 
        BN_CTX_start(ctx);
@@ -725,31 +724,34 @@ static int RSA_eay_mod_exp(BIGNUM *r0, const BIGNUM *I, RSA *rsa, BN_CTX *ctx)
        m1 = BN_CTX_get(ctx);
        vrfy = BN_CTX_get(ctx);
 
-       /* Make sure mod_inverse in montgomerey intialization use correct 
-        * BN_FLG_CONSTTIME flag.
-        */
-       bn_flags = rsa->p->flags;
-       if (!(rsa->flags & RSA_FLAG_NO_CONSTTIME))
-               {
-               rsa->p->flags |= BN_FLG_CONSTTIME;
-               }
-       MONT_HELPER(rsa, ctx, p, rsa->flags & RSA_FLAG_CACHE_PRIVATE, goto err);
-       /* We restore bn_flags back */
-       rsa->p->flags = bn_flags;
+       {
+               BIGNUM local_p, local_q;
+               BIGNUM *p = NULL, *q = NULL;
 
-        /* Make sure mod_inverse in montgomerey intialization use correct
-         * BN_FLG_CONSTTIME flag.
-         */
-       bn_flags = rsa->q->flags;
-       if (!(rsa->flags & RSA_FLAG_NO_CONSTTIME))
-               {
-               rsa->q->flags |= BN_FLG_CONSTTIME;
-               }
-       MONT_HELPER(rsa, ctx, q, rsa->flags & RSA_FLAG_CACHE_PRIVATE, goto err);
-       /* We restore bn_flags back */
-       rsa->q->flags = bn_flags;       
+               /* Make sure BN_mod_inverse in Montgomery intialization uses the
+                * BN_FLG_CONSTTIME flag (unless RSA_FLAG_NO_CONSTTIME is set)
+                */
+               if (!(rsa->flags & RSA_FLAG_NO_CONSTTIME))
+                       {
+                       BN_init(&local_p);
+                       p = &local_p;
+                       BN_with_flags(p, rsa->p, BN_FLG_CONSTTIME);
+
+                       BN_init(&local_q);
+                       q = &local_q;
+                       BN_with_flags(q, rsa->q, BN_FLG_CONSTTIME);
+                       }
+               else
+                       {
+                       p = rsa->p;
+                       q = rsa->q;
+                       }
+
+               MONT_HELPER(rsa->_method_mod_p, ctx, p, rsa->flags & RSA_FLAG_CACHE_PRIVATE, goto err);
+               MONT_HELPER(rsa->_method_mod_q, ctx, q, rsa->flags & RSA_FLAG_CACHE_PRIVATE, goto err);
+       }
 
-       MONT_HELPER(rsa, ctx, n, rsa->flags & RSA_FLAG_CACHE_PUBLIC, goto err);
+       MONT_HELPER(rsa->_method_mod_n, ctx, rsa->n, rsa->flags & RSA_FLAG_CACHE_PUBLIC, goto err);
 
        /* compute I mod q */
        if (!(rsa->flags & RSA_FLAG_NO_CONSTTIME))