add "dsa_dsa_mod_exp" - This mimics the software dsa_mod_exp funtion

using two mod_exp operations - otherwise we use BN_mod_exp2 entirely
in software, which makes dsa verifications glacially slow while
signatures, (which use mod_exp) are fast. This lets cards that can
only do bn_mod_exp decently offload most of dsa.

1 files changed, 37 insertions, 3 deletions

diff --git a/src/lib/libcrypto/engine/hw_cryptodev.c b/src/lib/libcrypto/engine/hw_cryptodev.c
index 8eea1935a6..44ac38179f 100644
--- a/src/lib/libcrypto/engine/hw_cryptodev.c
+++ b/src/lib/libcrypto/engine/hw_cryptodev.c
@@ -795,6 +795,38 @@ cryptodev_dsa_bn_mod_exp(DSA *dsa, BIGNUM *r, BIGNUM *a, const BIGNUM *p,
         return (cryptodev_bn_mod_exp(r, a, p, m, ctx, m_ctx));
 }
 
+static int
+cryptodev_dsa_dsa_mod_exp(DSA *dsa, BIGNUM *t1, BIGNUM *g,
+    BIGNUM *u1, BIGNUM *pub_key, BIGNUM *u2, BIGNUM *p,
+    BN_CTX *ctx, BN_MONT_CTX *mont)
+{
+        BIGNUM t2;
+        int ret = 0;
+        
+        BN_init(&t2);
+ 
+        /* v = ( g^u1 * y^u2 mod p ) mod q */
+        /* let t1 = g ^ u1 mod p */
+        ret = 0; 
+
+        if (!dsa->meth->bn_mod_exp(dsa,t1,dsa->g,u1,dsa->p,ctx,mont))
+                goto err;
+
+        /* let t2 = y ^ u2 mod p */
+        if (!dsa->meth->bn_mod_exp(dsa,&t2,dsa->pub_key,u2,dsa->p,ctx,mont))
+                goto err;
+        /* let u1 = t1 * t2 mod p */
+        if (!BN_mod_mul(u1,t1,&t2,dsa->p,ctx))
+                goto err;
+
+        BN_copy(t1,u1);
+
+        ret = 1;
+err:
+        BN_free(&t2);
+        return(ret);
+}
+
 static DSA_SIG *
 cryptodev_dsa_do_sign(const unsigned char *dgst, int dlen, DSA *dsa)
 {
@@ -850,7 +882,6 @@ cryptodev_dsa_verify(const unsigned char *dgst, int dlen,
         struct crypt_kop kop;
         int dsaret = 1;
 
-        printf("foo\n");
         memset(&kop, 0, sizeof kop);
         kop.crk_op = CRK_DSA_VERIFY;
 
@@ -1029,10 +1060,12 @@ ENGINE_load_cryptodev(void)
                 memcpy(&cryptodev_dsa, meth, sizeof(DSA_METHOD)); 
                 if (cryptodev_asymfeat & CRF_DSA_SIGN) 
                         cryptodev_dsa.dsa_do_sign = cryptodev_dsa_do_sign;   
+                if (cryptodev_asymfeat & CRF_MOD_EXP) {
+                        cryptodev_dsa.bn_mod_exp = cryptodev_dsa_bn_mod_exp;
+                        cryptodev_dsa.dsa_mod_exp = cryptodev_dsa_dsa_mod_exp;
+                }
                 if (cryptodev_asymfeat & CRF_DSA_VERIFY)
                         cryptodev_dsa.dsa_do_verify = cryptodev_dsa_verify;   
-                if (cryptodev_asymfeat & CRF_MOD_EXP)
-                        cryptodev_dsa.bn_mod_exp = cryptodev_dsa_bn_mod_exp;
         }
                 
 
@@ -1054,3 +1087,4 @@ ENGINE_load_cryptodev(void)
         ENGINE_free(engine);
         ERR_clear_error();
 }
+