Deprecate the flags that switch off constant time

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

diff --git a/crypto/dsa/dsa_ossl.c b/crypto/dsa/dsa_ossl.c
index beb62b2ff058d3e2bde0397fbddd355e11cd457b..ea09afd9534be107ca1860c111ea1e15e2e98718 100644 (file)
--- a/crypto/dsa/dsa_ossl.c
+++ b/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;
@@ -171,7 +135,7 @@ static int dsa_sign_setup(DSA *dsa, BN_CTX *ctx_in,
                           const unsigned char *dgst, int dlen)
 {
     BN_CTX *ctx = NULL;
-    BIGNUM *k, *kq, *K, *kinv = NULL, *r = *rp;
+    BIGNUM *k, *kq, *kinv = NULL, *r = *rp;
     int ret = 0;
 
     if (!dsa->p || !dsa->q || !dsa->g) {
@@ -212,35 +176,35 @@ static int dsa_sign_setup(DSA *dsa, BN_CTX *ctx_in,
 
     /* Compute r = (g^k mod p) mod q */
 
-    if ((dsa->flags & DSA_FLAG_NO_EXP_CONSTTIME) == 0) {
-        if (!BN_copy(kq, k))
-            goto err;
+    if (!BN_copy(kq, k))
+        goto err;
 
-        /*
-         * We do not want timing information to leak the length of k, so we
-         * compute g^k using an equivalent exponent of fixed length. (This
-         * is a kludge that we need because the BN_mod_exp_mont() does not
-         * let us specify the desired timing behaviour.)
-         */
+    /*
+     * We do not want timing information to leak the length of k, so we
+     * compute g^k using an equivalent exponent of fixed length. (This
+     * is a kludge that we need because the BN_mod_exp_mont() does not
+     * let us specify the desired timing behaviour.)
+     */
 
+    if (!BN_add(kq, kq, dsa->q))
+        goto err;
+    if (BN_num_bits(kq) <= BN_num_bits(dsa->q)) {
         if (!BN_add(kq, kq, dsa->q))
             goto err;
-        if (BN_num_bits(kq) <= BN_num_bits(dsa->q)) {
-            if (!BN_add(kq, kq, dsa->q))
-                goto err;
-        }
+    }
 
-        K = kq;
+    BN_set_flags(kq, BN_FLG_CONSTTIME);
+
+    if ((dsa)->meth->bn_mod_exp != NULL) {
+            if (!dsa->meth->bn_mod_exp(dsa, r, dsa->g, kq, dsa->p, ctx,
+                                       dsa->method_mont_p))
+                goto err;
     } else {
-        K = k;
+            if (!BN_mod_exp_mont(r, dsa->g, kq, dsa->p, ctx, dsa->method_mont_p))
+                goto err;
     }
 
-    if ((dsa->flags & DSA_FLAG_NO_EXP_CONSTTIME) == 0) {
-        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 (!BN_mod(r, r, dsa->q, ctx))
         goto err;
 
@@ -338,9 +302,16 @@ 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;