Minor tweaks for coverage

3 files changed, 11 insertions, 6 deletions

diff --git a/src/lib/block/cascade/cascade.cpp b/src/lib/block/cascade/cascade.cpp
index e54d3e5b5..6607fd5b2 100644
--- a/src/lib/block/cascade/cascade.cpp
+++ b/src/lib/block/cascade/cascade.cpp
@@ -58,7 +58,7 @@ namespace {
 
 size_t euclids_algorithm(size_t a, size_t b)
    {
-   while(b != 0) // gcd
+   while(b != 0)
       {
       size_t t = b;
       b = a % b;
@@ -73,7 +73,7 @@ size_t block_size_for_cascade(size_t bs, size_t bs2)
    if(bs == bs2)
       return bs;
 
-   size_t gcd = euclids_algorithm(bs, bs2);
+   const size_t gcd = euclids_algorithm(bs, bs2);
 
    return (bs * bs2) / gcd;
    }
@@ -85,8 +85,9 @@ Cascade_Cipher::Cascade_Cipher(BlockCipher* c1, BlockCipher* c2) :
    {
    m_block = block_size_for_cascade(c1->block_size(), c2->block_size());
 
-   if(block_size() % c1->block_size() || block_size() % c2->block_size())
-      throw Internal_Error("Failure in " + name() + " constructor");
+   BOTAN_ASSERT(m_block % c1->block_size() == 0 &&
+                m_block % c2->block_size() == 0,
+                "Combined block size is a multiple of each ciphers block");
    }
 
 }
diff --git a/src/lib/modes/aead/gcm/gcm.cpp b/src/lib/modes/aead/gcm/gcm.cpp
index dfaffedb7..b0240eb7f 100644
--- a/src/lib/modes/aead/gcm/gcm.cpp
+++ b/src/lib/modes/aead/gcm/gcm.cpp
@@ -86,8 +86,7 @@ void GCM_Mode::set_associated_data(const uint8_t ad[], size_t ad_len)
 
 void GCM_Mode::start_msg(const uint8_t nonce[], size_t nonce_len)
    {
-   if(!valid_nonce_length(nonce_len))
-      throw Invalid_IV_Length(name(), nonce_len);
+   // any size is valid for GCM nonce
 
    secure_vector<uint8_t> y0(GCM_BS);
 
diff --git a/src/tests/test_modes.cpp b/src/tests/test_modes.cpp
index d707f4419..89b201873 100644
--- a/src/tests/test_modes.cpp
+++ b/src/tests/test_modes.cpp
@@ -78,6 +78,11 @@ class Cipher_Mode_Tests final : public Text_Based_Test
             result.test_gte("enc buffer sizes ok", enc->update_granularity(), enc->minimum_final_size());
             result.test_gte("dec buffer sizes ok", dec->update_granularity(), dec->minimum_final_size());
 
+            result.confirm("default nonce size is allowed",
+                           enc->valid_nonce_length(enc->default_nonce_length()));
+            result.confirm("default nonce size is allowed",
+                           dec->valid_nonce_length(dec->default_nonce_length()));
+
             // Test that disallowed nonce sizes result in an exception
             const size_t large_nonce_size = 65000;
             result.test_eq("Large nonce not allowed", enc->valid_nonce_length(large_nonce_size), false);