Make `safe' (EC)DSA nonces the default.

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

diff --git a/crypto/dsa/dsa_ossl.c b/crypto/dsa/dsa_ossl.c
index 33ac3e130e3dfd1677c847dfcf7c8f6e2b553c9f..fb82c16d010ea1c3be8bd2e7ebeb43044003f9a6 100644 (file)
--- a/crypto/dsa/dsa_ossl.c
+++ b/crypto/dsa/dsa_ossl.c
@@ -58,6 +58,8 @@
 
 /* Original version from Steven Schoch <schoch@sheba.arc.nasa.gov> */
 
+#define OPENSSL_FIPSAPI
+
 #include <stdio.h>
 #include "cryptlib.h"
 #include <openssl/bn.h>
@@ -71,6 +73,9 @@
 
 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_with_digest(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);
@@ -148,11 +153,14 @@ 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);
@@ -166,21 +174,13 @@ static DSA_SIG *dsa_do_sign(const unsigned char *dgst, int dlen, DSA *dsa)
 
        s=BN_new();
        if (s == NULL) goto err;
-
-       /* reject a excessive digest length (currently at most
-        * dsa-with-SHA256 is supported) */
-       if (dlen > SHA256_DIGEST_LENGTH)
-               {
-               reason=DSA_R_DATA_TOO_LARGE_FOR_KEY_SIZE;
-               goto err;
-               }
-
        ctx=BN_CTX_new();
        if (ctx == NULL) goto err;
 redo:
        if ((dsa->kinv == NULL) || (dsa->r == NULL))
                {
-               if (!DSA_sign_setup(dsa,ctx,&kinv,&r)) goto err;
+               if (!dsa_sign_setup_with_digest(dsa,ctx,&kinv,&r,dgst,dlen))
+                       goto err;
                }
        else
                {
@@ -239,7 +239,14 @@ 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) {
+       return dsa_sign_setup_with_digest(dsa, ctx_in, kinvp, rp, NULL, 0);
+}
+
+static int dsa_sign_setup_with_digest(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;
@@ -265,8 +272,22 @@ 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 (dgst != NULL)
+                       {
+                       /* 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);
@@ -358,7 +379,8 @@ 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;
@@ -370,15 +392,6 @@ static int dsa_do_verify(const unsigned char *dgst, int dgst_len, DSA_SIG *sig,
                DSAerr(DSA_F_DSA_DO_VERIFY,DSA_R_MODULUS_TOO_LARGE);
                return -1;
                }
-
-       /* reject a excessive digest length (currently at most
-        * dsa-with-SHA256 is supported) */
-       if (dgst_len > SHA256_DIGEST_LENGTH)
-               {
-               DSAerr(DSA_F_DSA_DO_VERIFY,DSA_R_DATA_TOO_LARGE_FOR_KEY_SIZE);
-               return -1;
-               }
-
        BN_init(&u1);
        BN_init(&u2);
        BN_init(&t1);