FFI function for DSA key generation

Adds function for DSA key generation that allows
usage of 'p' and 'q' chosen by the caller.

3 files changed, 35 insertions, 7 deletions

diff --git a/src/lib/ffi/ffi.h b/src/lib/ffi/ffi.h
index 1a6014f71..77d4eb306 100644
--- a/src/lib/ffi/ffi.h
+++ b/src/lib/ffi/ffi.h
@@ -702,6 +702,7 @@ BOTAN_PUBLIC_API(2,0) int botan_privkey_create_ecdsa(botan_privkey_t* key, botan
 BOTAN_PUBLIC_API(2,0) int botan_privkey_create_ecdh(botan_privkey_t* key, botan_rng_t rng, const char* params);
 BOTAN_PUBLIC_API(2,0) int botan_privkey_create_mceliece(botan_privkey_t* key, botan_rng_t rng, size_t n, size_t t);
 BOTAN_PUBLIC_API(2,0) int botan_privkey_create_dh(botan_privkey_t* key, botan_rng_t rng, const char* param);
+BOTAN_PUBLIC_API(2,0) int botan_privkey_create_dsa(botan_privkey_t* key, botan_rng_t rng, size_t pbits, size_t qbits);
 
 /*
 * Input currently assumed to be PKCS #8 structure;
diff --git a/src/lib/ffi/ffi_pkey_algs.cpp b/src/lib/ffi/ffi_pkey_algs.cpp
index 694edfeb3..1a2737834 100644
--- a/src/lib/ffi/ffi_pkey_algs.cpp
+++ b/src/lib/ffi/ffi_pkey_algs.cpp
@@ -333,6 +333,24 @@ int botan_pubkey_rsa_get_n(botan_mp_t n, botan_pubkey_t key)
    }
 
 /* DSA specific operations */
+int botan_privkey_create_dsa(botan_privkey_t* key, botan_rng_t rng_obj, size_t pbits, size_t qbits)
+   {
+#if defined(BOTAN_HAS_DSA)
+
+    if(rng_obj == nullptr)
+      return BOTAN_FFI_ERROR_NULL_POINTER;
+
+    return ffi_guard_thunk(BOTAN_CURRENT_FUNCTION, [=]() -> int {
+      Botan::RandomNumberGenerator& rng = safe_get(rng_obj);
+      Botan::DL_Group group(rng, Botan::DL_Group::Prime_Subgroup, pbits, qbits);
+      *key = new botan_privkey_struct(new Botan::DSA_PrivateKey(rng, group));
+      return BOTAN_FFI_SUCCESS;
+    });
+#else
+    BOTAN_UNUSED(key, rng_obj, pbits, qbits);
+    return BOTAN_FFI_ERROR_NOT_IMPLEMENTED;
+#endif
+   }
 
 int botan_privkey_load_dsa(botan_privkey_t* key,
                            botan_mp_t p, botan_mp_t q, botan_mp_t g, botan_mp_t x)
diff --git a/src/tests/test_ffi.cpp b/src/tests/test_ffi.cpp
index 53bd7d0e7..974909563 100644
--- a/src/tests/test_ffi.cpp
+++ b/src/tests/test_ffi.cpp
@@ -1300,13 +1300,7 @@ class FFI_Unit_Tests final : public Test
          return result;
          }
 
-      Test::Result ffi_test_dsa(botan_rng_t rng)
-         {
-         Test::Result result("FFI DSA");
-
-         botan_privkey_t priv;
-
-         if(TEST_FFI_OK(botan_privkey_create, (&priv, "DSA", "dsa/jce/1024", rng)))
+         void do_dsa_test(botan_privkey_t priv, botan_rng_t rng, Test::Result &result)
             {
             TEST_FFI_OK(botan_privkey_check_key, (priv, rng, 0));
 
@@ -1404,6 +1398,21 @@ class FFI_Unit_Tests final : public Test
             TEST_FFI_OK(botan_privkey_destroy, (priv));
             }
 
+      Test::Result ffi_test_dsa(botan_rng_t rng)
+         {
+         Test::Result result("FFI DSA");
+         botan_privkey_t priv;
+
+         if(TEST_FFI_OK(botan_privkey_create, (&priv, "DSA", "dsa/jce/1024", rng)))
+            {
+               do_dsa_test(priv, rng, result);
+            }
+
+         if(TEST_FFI_OK(botan_privkey_create_dsa, (&priv, rng, 1024, 160)))
+            {
+               do_dsa_test(priv, rng, result);
+            }
+
          return result;
          }
       Test::Result ffi_test_ecdsa(botan_rng_t rng)