Simplify dsa_ossl.c

The dsa_ossl.c file defined a couple of multi-line macros, but then only
used each one once. The macros just serve to complicate the code and make
it more difficult to understand what is really going on. Hence they are
removed.
Reviewed-by: NRichard Levitte <levitte@openssl.org>

crypto/dsa/dsa_ossl.c

@@ -42,42 +42,6 @@ static DSA_METHOD openssl_dsa_meth = {
     NULL
 };
 
-/*-
- * These macro wrappers replace attempts to use the dsa_mod_exp() and
- * bn_mod_exp() handlers in the DSA_METHOD structure. We avoid the problem of
- * having a the macro work as an expression by bundling an "err_instr". So;
- *
- *     if (!dsa->meth->bn_mod_exp(dsa, r,dsa->g,&k,dsa->p,ctx,
- *                 dsa->method_mont_p)) goto err;
- *
- * can be replaced by;
- *
- *     DSA_BN_MOD_EXP(goto err, dsa, r, dsa->g, &k, dsa->p, ctx,
- *                 dsa->method_mont_p);
- */
-
-#define DSA_MOD_EXP(err_instr,dsa,rr,a1,p1,a2,p2,m,ctx,in_mont) \
-        do { \
-        int _tmp_res53; \
-        if ((dsa)->meth->dsa_mod_exp) \
-                _tmp_res53 = (dsa)->meth->dsa_mod_exp((dsa), (rr), (a1), (p1), \
-                                (a2), (p2), (m), (ctx), (in_mont)); \
-        else \
-                _tmp_res53 = BN_mod_exp2_mont((rr), (a1), (p1), (a2), (p2), \
-                                (m), (ctx), (in_mont)); \
-        if (!_tmp_res53) err_instr; \
-        } while(0)
-#define DSA_BN_MOD_EXP(err_instr,dsa,r,a,p,m,ctx,m_ctx) \
-        do { \
-        int _tmp_res53; \
-        if ((dsa)->meth->bn_mod_exp) \
-                _tmp_res53 = (dsa)->meth->bn_mod_exp((dsa), (r), (a), (p), \
-                                (m), (ctx), (m_ctx)); \
-        else \
-                _tmp_res53 = BN_mod_exp_mont((r), (a), (p), (m), (ctx), (m_ctx)); \
-        if (!_tmp_res53) err_instr; \
-        } while(0)
-
 const DSA_METHOD *DSA_OpenSSL(void)
 {
     return &openssl_dsa_meth;
@@ -239,8 +203,16 @@ static int dsa_sign_setup(DSA *dsa, BN_CTX *ctx_in,
         BN_set_flags(K, BN_FLG_CONSTTIME);
     }
 
-    DSA_BN_MOD_EXP(goto err, dsa, r, dsa->g, K, dsa->p, ctx,
-                   dsa->method_mont_p);
+    if ((dsa)->meth->bn_mod_exp != NULL) {
+            if (!dsa->meth->bn_mod_exp(dsa, r, dsa->g, K, dsa->p, ctx,
+                                       dsa->method_mont_p))
+                goto err;
+    } else {
+            if (!BN_mod_exp_mont(r, dsa->g, K, dsa->p, ctx, dsa->method_mont_p))
+                goto err;
+    }
+
+
     if (!BN_mod(r, r, dsa->q, ctx))
         goto err;
 
@@ -338,9 +310,16 @@ static int dsa_do_verify(const unsigned char *dgst, int dgst_len,
             goto err;
     }
 
-    DSA_MOD_EXP(goto err, dsa, t1, dsa->g, u1, dsa->pub_key, u2, dsa->p, ctx,
-                mont);
-    /* BN_copy(&u1,&t1); */
+    if (dsa->meth->dsa_mod_exp != NULL) {
+        if (!dsa->meth->dsa_mod_exp(dsa, t1, dsa->g, u1, dsa->pub_key, u2,
+                                    dsa->p, ctx, mont))
+            goto err;
+    } else {
+        if (!BN_mod_exp2_mont(t1, dsa->g, u1, dsa->pub_key, u2, dsa->p, ctx,
+                              mont))
+            goto err;
+    }
+
     /* let u1 = u1 mod q */
     if (!BN_mod(u1, t1, dsa->q, ctx))
         goto err;