Add secure DSA nonce flag.

[openssl.git] / crypto / dsa / dsa_ossl.c

diff --git a/crypto/dsa/dsa_ossl.c b/crypto/dsa/dsa_ossl.c
index f1512a40dd0fcc335c40086522d9c333fc9c3352..d1f80609b1e578f5d8935dcac6846cae54f5b7b0 100644 (file)
--- a/crypto/dsa/dsa_ossl.c
+++ b/crypto/dsa/dsa_ossl.c
@@ -72,7 +72,9 @@
 #endif
 
 static DSA_SIG *dsa_do_sign(const unsigned char *dgst, int dlen, DSA *dsa);
-static int dsa_sign_setup(DSA *dsa, BN_CTX *ctx_in, BIGNUM **kinvp, BIGNUM **rp);
+static int dsa_sign_setup(DSA *dsa, BN_CTX *ctx_in,
+                         BIGNUM **kinvp, BIGNUM **rp,
+                         const unsigned char *dgst, int dlen);
 static int dsa_do_verify(const unsigned char *dgst, int dgst_len, DSA_SIG *sig,
                         DSA *dsa);
 static int dsa_init(DSA *dsa);
@@ -150,11 +152,14 @@ static DSA_SIG *dsa_do_sign(const unsigned char *dgst, int dlen, DSA *dsa)
            return NULL;
            }
 
-       if (FIPS_mode() && (BN_num_bits(dsa->p) < OPENSSL_DSA_FIPS_MIN_MODULUS_BITS))
+       if (FIPS_module_mode() && !(dsa->flags & DSA_FLAG_NON_FIPS_ALLOW) 
+               && (BN_num_bits(dsa->p) < OPENSSL_DSA_FIPS_MIN_MODULUS_BITS))
                {
                DSAerr(DSA_F_DSA_DO_SIGN, DSA_R_KEY_SIZE_TOO_SMALL);
                return NULL;
                }
+       if (!fips_check_dsa_prng(dsa, 0, 0))
+               goto err;
 #endif
 
        BN_init(&m);
@@ -173,7 +178,8 @@ static DSA_SIG *dsa_do_sign(const unsigned char *dgst, int dlen, DSA *dsa)
 redo:
        if ((dsa->kinv == NULL) || (dsa->r == NULL))
                {
-               if (!dsa->meth->dsa_sign_setup(dsa,ctx,&kinv,&r)) goto err;
+               if (!dsa->meth->dsa_sign_setup(dsa,ctx,&kinv,&r,dgst,dlen))
+                       goto err;
                }
        else
                {
@@ -199,6 +205,7 @@ redo:
        if (BN_cmp(s,dsa->q) > 0)
                if (!BN_sub(s,s,dsa->q)) goto err;
        if (!BN_mod_mul(s,s,kinv,dsa->q,ctx)) goto err;
+
        ret=DSA_SIG_new();
        if (ret == NULL) goto err;
        /* Redo if r or s is zero as required by FIPS 186-3: this is
@@ -231,7 +238,9 @@ err:
        return(ret);
        }
 
-static int dsa_sign_setup(DSA *dsa, BN_CTX *ctx_in, BIGNUM **kinvp, BIGNUM **rp)
+static int dsa_sign_setup(DSA *dsa, BN_CTX *ctx_in,
+                         BIGNUM **kinvp, BIGNUM **rp,
+                         const unsigned char *dgst, int dlen)
        {
        BN_CTX *ctx;
        BIGNUM k,kq,*K,*kinv=NULL,*r=NULL;
@@ -257,8 +266,22 @@ static int dsa_sign_setup(DSA *dsa, BN_CTX *ctx_in, BIGNUM **kinvp, BIGNUM **rp)
 
        /* Get random k */
        do
-               if (!BN_rand_range(&k, dsa->q)) goto err;
-       while (BN_is_zero(&k));
+               {
+#ifndef OPENSSL_NO_SHA512
+               if (dsa->flags & DSA_FLAG_NONCE_FROM_HASH)
+                       {
+                       /* If DSA_FLAG_NONCE_FROM_HASH is set then we calculate k from
+                        * SHA512(private_key + H(message) + random). This protects the
+                        * private key from a weak PRNG. */
+                       if (!BN_generate_dsa_nonce(&k, dsa->q, dsa->priv_key, dgst,
+                                                  dlen, ctx))
+                               goto err;
+                       }
+               else
+#endif
+                       if (!BN_rand_range(&k, dsa->q)) goto err;
+               } while (BN_is_zero(&k));
+
        if ((dsa->flags & DSA_FLAG_NO_EXP_CONSTTIME) == 0)
                {
                BN_set_flags(&k, BN_FLG_CONSTTIME);
@@ -350,7 +373,8 @@ static int dsa_do_verify(const unsigned char *dgst, int dgst_len, DSA_SIG *sig,
            return -1;
            }
 
-       if (FIPS_mode() && (BN_num_bits(dsa->p) < OPENSSL_DSA_FIPS_MIN_MODULUS_BITS))
+       if (FIPS_module_mode() && !(dsa->flags & DSA_FLAG_NON_FIPS_ALLOW) 
+               && (BN_num_bits(dsa->p) < OPENSSL_DSA_FIPS_MIN_MODULUS_BITS))
                {
                DSAerr(DSA_F_DSA_DO_VERIFY, DSA_R_KEY_SIZE_TOO_SMALL);
                return -1;