Add botan_mac_query_keylen

3 files changed, 38 insertions, 1 deletions

diff --git a/src/lib/ffi/ffi.h b/src/lib/ffi/ffi.h
index 9deefffb5..5e27962d8 100644
--- a/src/lib/ffi/ffi.h
+++ b/src/lib/ffi/ffi.h
@@ -385,6 +385,18 @@ BOTAN_PUBLIC_API(2,0) int botan_mac_clear(botan_mac_t mac);
 BOTAN_PUBLIC_API(2,8) int botan_mac_name(botan_mac_t mac, char* name, size_t* name_len);
 
 /**
+* Get the key length limits of this auth code
+* @param mac the object to read
+* @param out_minimum_keylength if non-NULL, will be set to minimum keylength of MAC
+* @param out_maximum_keylength if non-NULL, will be set to maximum keylength of MAC
+* @param out_keylength_modulo if non-NULL will be set to byte multiple of valid keys
+*/
+BOTAN_PUBLIC_API(2,8) int botan_mac_query_keylen(botan_mac_t mac,
+                                                 size_t* out_minimum_keylength,
+                                                 size_t* out_maximum_keylength,
+                                                 size_t* out_keylength_modulo);
+
+/**
 * Frees all resources of the MAC object
 * @param mac mac object
 * @return always returns 0
@@ -572,7 +584,7 @@ BOTAN_PUBLIC_API(2,8) int botan_block_cipher_name(botan_block_cipher_t cipher,
 * @param out_maximum_keylength if non-NULL, will be set to maximum keylength of cipher
 * @param out_keylength_modulo if non-NULL will be set to byte multiple of valid keys
 */
-BOTAN_PUBLIC_API(2,8) int botan_block_cipher_query_keylen(botan_block_cipher_t,
+BOTAN_PUBLIC_API(2,8) int botan_block_cipher_query_keylen(botan_block_cipher_t cipher,
                                                           size_t* out_minimum_keylength,
                                                           size_t* out_maximum_keylength,
                                                           size_t* out_keylength_modulo);
diff --git a/src/lib/ffi/ffi_mac.cpp b/src/lib/ffi/ffi_mac.cpp
index 02ac7900c..4fbe171ec 100644
--- a/src/lib/ffi/ffi_mac.cpp
+++ b/src/lib/ffi/ffi_mac.cpp
@@ -67,4 +67,19 @@ int botan_mac_name(botan_mac_t mac, char* name, size_t* name_len)
       return write_str_output(name, name_len, m.name()); });
    }
 
+int botan_mac_query_keylen(botan_mac_t mac,
+                           size_t* out_minimum_keylength,
+                           size_t* out_maximum_keylength,
+                           size_t* out_keylength_modulo)
+   {
+   return BOTAN_FFI_DO(Botan::MessageAuthenticationCode, mac, m, {
+      if(out_minimum_keylength)
+         *out_minimum_keylength = m.minimum_keylength();
+      if(out_maximum_keylength)
+         *out_maximum_keylength = m.maximum_keylength();
+      if(out_keylength_modulo)
+         *out_keylength_modulo = m.key_spec().keylength_multiple();
+      });
+   }
+
 }
diff --git a/src/tests/test_ffi.cpp b/src/tests/test_ffi.cpp
index 5940a1009..de80f3e3b 100644
--- a/src/tests/test_ffi.cpp
+++ b/src/tests/test_ffi.cpp
@@ -736,6 +736,16 @@ class FFI_Unit_Tests final : public Test
                result.test_eq("name", std::string(namebuf), "HMAC(SHA-256)");
                }
 
+            size_t min_keylen = 0, max_keylen = 0, mod_keylen = 0;
+            TEST_FFI_RC(0, botan_mac_query_keylen, (mac, nullptr, nullptr, nullptr));
+            TEST_FFI_RC(0, botan_mac_query_keylen, (mac, &min_keylen, nullptr, nullptr));
+            TEST_FFI_RC(0, botan_mac_query_keylen, (mac, nullptr, &max_keylen, nullptr));
+            TEST_FFI_RC(0, botan_mac_query_keylen, (mac, nullptr, nullptr, &mod_keylen));
+
+            result.test_eq("Expected min keylen", min_keylen, 0);
+            result.test_eq("Expected max keylen", max_keylen, 4096);
+            result.test_eq("Expected mod keylen", mod_keylen, 1);
+
             size_t output_len;
             if(TEST_FFI_OK(botan_mac_output_length, (mac, &output_len)))
                {