Add an interface to Keyed_Filter returning a Key_Length_Specification

so the full details of what keylength(s) the filter supports are now
available.

14 files changed, 43 insertions, 63 deletions

diff --git a/src/filters/aead/eax/eax.cpp b/src/filters/aead/eax/eax.cpp
index 57f62833b..d4a982aaf 100644
--- a/src/filters/aead/eax/eax.cpp
+++ b/src/filters/aead/eax/eax.cpp
@@ -58,16 +58,6 @@ EAX_Mode::EAX_Mode(BlockCipher* cipher, size_t tag_size, bool decrypting) :
    }
 
 /*
-* Check if a keylength is valid for EAX
-*/
-bool EAX_Mode::valid_keylength(size_t n) const
-   {
-   if(!ctr->valid_keylength(n))
-      return false;
-   return true;
-   }
-
-/*
 * Set the EAX key
 */
 void EAX_Mode::set_key(const SymmetricKey& key)
diff --git a/src/filters/aead/eax/eax.h b/src/filters/aead/eax/eax.h
index e219487cb..a85377524 100644
--- a/src/filters/aead/eax/eax.h
+++ b/src/filters/aead/eax/eax.h
@@ -32,7 +32,7 @@ class BOTAN_DLL EAX_Mode : public AEAD_Mode,
 
       std::string name() const override;
 
-      bool valid_keylength(size_t key_len) const override;
+      Key_Length_Specification key_spec() const override { return ctr->key_spec(); }
 
       // EAX supports arbitrary IV lengths
       bool valid_iv_length(size_t) const override { return true; }
diff --git a/src/filters/aead/gcm/gcm.cpp b/src/filters/aead/gcm/gcm.cpp
index 013757b59..32a763df7 100644
--- a/src/filters/aead/gcm/gcm.cpp
+++ b/src/filters/aead/gcm/gcm.cpp
@@ -107,16 +107,6 @@ GCM_Mode::GCM_Mode(BlockCipher* cipher, size_t tag_size, bool decrypting) :
       throw Invalid_Argument(name() + ": Bad tag size " + std::to_string(m_tag_size));
    }
 
-/*
-* Check if a keylength is valid for GCM
-*/
-bool GCM_Mode::valid_keylength(size_t n) const
-   {
-   if(!m_ctr->valid_keylength(n))
-      return false;
-   return true;
-   }
-
 void GCM_Mode::set_key(const SymmetricKey& key)
    {
    m_ctr->set_key(key);
diff --git a/src/filters/aead/gcm/gcm.h b/src/filters/aead/gcm/gcm.h
index fa13597ce..067b19298 100644
--- a/src/filters/aead/gcm/gcm.h
+++ b/src/filters/aead/gcm/gcm.h
@@ -32,7 +32,7 @@ class BOTAN_DLL GCM_Mode : public AEAD_Mode,
       */
       void set_associated_data(const byte ad[], size_t ad_len) override;
 
-      bool valid_keylength(size_t key_len) const override;
+      Key_Length_Specification key_spec() const override { return m_ctr->key_spec(); }
 
       // GCM supports arbitrary IV lengths
       bool valid_iv_length(size_t) const override { return true; }
diff --git a/src/filters/aead/ocb/ocb.cpp b/src/filters/aead/ocb/ocb.cpp
index ebf440d32..eb10b6e9f 100644
--- a/src/filters/aead/ocb/ocb.cpp
+++ b/src/filters/aead/ocb/ocb.cpp
@@ -180,11 +180,6 @@ OCB_Mode::OCB_Mode(BlockCipher* cipher, size_t tag_size, bool decrypting) :
 
 OCB_Mode::~OCB_Mode() { /* for unique_ptr destructor */ }
 
-bool OCB_Mode::valid_keylength(size_t n) const
-   {
-   return m_cipher->valid_keylength(n);
-   }
-
 std::string OCB_Mode::name() const
    {
    return m_cipher->name() + "/OCB"; // include tag size
diff --git a/src/filters/aead/ocb/ocb.h b/src/filters/aead/ocb/ocb.h
index 5e3c5cf0a..f5209df12 100644
--- a/src/filters/aead/ocb/ocb.h
+++ b/src/filters/aead/ocb/ocb.h
@@ -37,7 +37,7 @@ class BOTAN_DLL OCB_Mode : public AEAD_Mode,
 
       void set_associated_data(const byte ad[], size_t ad_len) override;
 
-      bool valid_keylength(size_t n) const override;
+      Key_Length_Specification key_spec() const override { return m_cipher->key_spec(); }
 
       std::string name() const override;
 
diff --git a/src/filters/filters.h b/src/filters/filters.h
index 08b505bc0..8fcc2d85d 100644
--- a/src/filters/filters.h
+++ b/src/filters/filters.h
@@ -58,13 +58,7 @@ class BOTAN_DLL StreamCipher_Filter : public Keyed_Filter
       */
       void set_key(const SymmetricKey& key) { cipher->set_key(key); }
 
-      /**
-      * Check whether a key length is valid for this filter.
-      * @param length the key length to be checked for validity
-      * @return true if the key length is valid, false otherwise
-      */
-      bool valid_keylength(size_t length) const
-         { return cipher->valid_keylength(length); }
+      Key_Length_Specification key_spec() const override { return cipher->key_spec(); }
 
       /**
       * Construct a stream cipher filter.
@@ -153,13 +147,7 @@ class BOTAN_DLL MAC_Filter : public Keyed_Filter
       */
       void set_key(const SymmetricKey& key) { mac->set_key(key); }
 
-      /**
-      * Check whether a key length is valid for this filter.
-      * @param length the key length to be checked for validity
-      * @return true if the key length is valid, false otherwise
-      */
-      bool valid_keylength(size_t length) const
-         { return mac->valid_keylength(length); }
+      Key_Length_Specification key_spec() const override { return mac->key_spec(); }
 
       /**
       * Construct a MAC filter. The MAC key will be left empty.
diff --git a/src/filters/key_filt.h b/src/filters/key_filt.h
index 3c79ebac9..6d69d6b83 100644
--- a/src/filters/key_filt.h
+++ b/src/filters/key_filt.h
@@ -38,7 +38,15 @@ class BOTAN_DLL Keyed_Filter : public Filter
       * @param length the key length to be checked for validity
       * @return true if the key length is valid, false otherwise
       */
-      virtual bool valid_keylength(size_t length) const = 0;
+      bool valid_keylength(size_t length) const
+         {
+         return key_spec().valid_keylength(length);
+         }
+
+      /**
+      * @return object describing limits on key size
+      */
+      virtual Key_Length_Specification key_spec() const = 0;
 
       /**
       * Check whether an IV length is valid for this filter
diff --git a/src/filters/modes/cbc/cbc.h b/src/filters/modes/cbc/cbc.h
index 4fd0f7d66..51e217e70 100644
--- a/src/filters/modes/cbc/cbc.h
+++ b/src/filters/modes/cbc/cbc.h
@@ -28,8 +28,7 @@ class BOTAN_DLL CBC_Encryption : public Keyed_Filter,
 
       void set_key(const SymmetricKey& key) { cipher->set_key(key); }
 
-      bool valid_keylength(size_t key_len) const
-         { return cipher->valid_keylength(key_len); }
+      Key_Length_Specification key_spec() const override { return cipher->key_spec(); }
 
       bool valid_iv_length(size_t iv_len) const
          { return (iv_len == cipher->block_size()); }
@@ -68,8 +67,7 @@ class BOTAN_DLL CBC_Decryption : public Keyed_Filter,
 
       void set_key(const SymmetricKey& key) { cipher->set_key(key); }
 
-      bool valid_keylength(size_t key_len) const
-         { return cipher->valid_keylength(key_len); }
+      Key_Length_Specification key_spec() const override { return cipher->key_spec(); }
 
       bool valid_iv_length(size_t iv_len) const
          { return (iv_len == cipher->block_size()); }
diff --git a/src/filters/modes/cfb/cfb.h b/src/filters/modes/cfb/cfb.h
index 212ac76da..02154ebb9 100644
--- a/src/filters/modes/cfb/cfb.h
+++ b/src/filters/modes/cfb/cfb.h
@@ -25,8 +25,7 @@ class BOTAN_DLL CFB_Encryption : public Keyed_Filter
 
       void set_key(const SymmetricKey& key) { cipher->set_key(key); }
 
-      bool valid_keylength(size_t key_len) const
-         { return cipher->valid_keylength(key_len); }
+      Key_Length_Specification key_spec() const override { return cipher->key_spec(); }
 
       bool valid_iv_length(size_t iv_len) const
          { return (iv_len == cipher->block_size()); }
@@ -59,8 +58,7 @@ class BOTAN_DLL CFB_Decryption : public Keyed_Filter
 
       void set_key(const SymmetricKey& key) { cipher->set_key(key); }
 
-      bool valid_keylength(size_t key_len) const
-         { return cipher->valid_keylength(key_len); }
+      Key_Length_Specification key_spec() const override { return cipher->key_spec(); }
 
       bool valid_iv_length(size_t iv_len) const
          { return (iv_len == cipher->block_size()); }
diff --git a/src/filters/modes/cts/cts.h b/src/filters/modes/cts/cts.h
index ac296316f..b0efb6944 100644
--- a/src/filters/modes/cts/cts.h
+++ b/src/filters/modes/cts/cts.h
@@ -25,8 +25,7 @@ class BOTAN_DLL CTS_Encryption : public Keyed_Filter
 
       void set_key(const SymmetricKey& key) { cipher->set_key(key); }
 
-      bool valid_keylength(size_t key_len) const
-         { return cipher->valid_keylength(key_len); }
+      Key_Length_Specification key_spec() const override { return cipher->key_spec(); }
 
       bool valid_iv_length(size_t iv_len) const
          { return (iv_len == cipher->block_size()); }
@@ -60,8 +59,7 @@ class BOTAN_DLL CTS_Decryption : public Keyed_Filter
 
       void set_key(const SymmetricKey& key) { cipher->set_key(key); }
 
-      bool valid_keylength(size_t key_len) const
-         { return cipher->valid_keylength(key_len); }
+      Key_Length_Specification key_spec() const override { return cipher->key_spec(); }
 
       bool valid_iv_length(size_t iv_len) const
          { return (iv_len == cipher->block_size()); }
diff --git a/src/filters/modes/ecb/ecb.h b/src/filters/modes/ecb/ecb.h
index e6476ab5d..8f4e6f1b5 100644
--- a/src/filters/modes/ecb/ecb.h
+++ b/src/filters/modes/ecb/ecb.h
@@ -26,8 +26,7 @@ class BOTAN_DLL ECB_Encryption : public Keyed_Filter,
 
       void set_key(const SymmetricKey& key) { cipher->set_key(key); }
 
-      bool valid_keylength(size_t key_len) const
-         { return cipher->valid_keylength(key_len); }
+      Key_Length_Specification key_spec() const override { return cipher->key_spec(); }
 
       ECB_Encryption(BlockCipher* ciph,
                      BlockCipherModePaddingMethod* pad);
@@ -60,8 +59,7 @@ class BOTAN_DLL ECB_Decryption : public Keyed_Filter,
 
       void set_key(const SymmetricKey& key) { cipher->set_key(key); }
 
-      bool valid_keylength(size_t key_len) const
-         { return cipher->valid_keylength(key_len); }
+      Key_Length_Specification key_spec() const override { return cipher->key_spec(); }
 
       ECB_Decryption(BlockCipher* ciph,
                      BlockCipherModePaddingMethod* pad);
diff --git a/src/filters/modes/xts/xts.cpp b/src/filters/modes/xts/xts.cpp
index e29ef6b98..df38614bb 100644
--- a/src/filters/modes/xts/xts.cpp
+++ b/src/filters/modes/xts/xts.cpp
@@ -39,6 +39,15 @@ size_t xts_parallelism(BlockCipher* cipher)
                            2 * cipher->block_size());
    }
 
+Key_Length_Specification xts_key_spec(const BlockCipher& cipher)
+   {
+   const Key_Length_Specification& spec = cipher.key_spec();
+
+   return Key_Length_Specification(2*spec.minimum_keylength(),
+                                   2*spec.maximum_keylength(),
+                                   2*spec.keylength_multiple());
+   }
+
 }
 
 /*
@@ -82,6 +91,11 @@ std::string XTS_Encryption::name() const
    return (cipher->name() + "/XTS");
    }
 
+Key_Length_Specification XTS_Encryption::key_spec() const
+   {
+   return xts_key_spec(*cipher);
+   }
+
 /*
 * Set new tweak
 */
@@ -256,6 +270,11 @@ std::string XTS_Decryption::name() const
    return (cipher->name() + "/XTS");
    }
 
+Key_Length_Specification XTS_Decryption::key_spec() const
+   {
+   return xts_key_spec(*cipher);
+   }
+
 /*
 * Set new tweak
 */
diff --git a/src/filters/modes/xts/xts.h b/src/filters/modes/xts/xts.h
index d4801cd37..05a779703 100644
--- a/src/filters/modes/xts/xts.h
+++ b/src/filters/modes/xts/xts.h
@@ -24,8 +24,7 @@ class BOTAN_DLL XTS_Encryption : public Keyed_Filter,
       void set_key(const SymmetricKey& key);
       void set_iv(const InitializationVector& iv);
 
-      bool valid_keylength(size_t key_len) const
-         { return cipher->valid_keylength(key_len); }
+      Key_Length_Specification key_spec() const override;
 
       bool valid_iv_length(size_t iv_len) const
          { return (iv_len == cipher->block_size()); }
@@ -61,8 +60,7 @@ class BOTAN_DLL XTS_Decryption : public Keyed_Filter,
       void set_key(const SymmetricKey& key);
       void set_iv(const InitializationVector& iv);
 
-      bool valid_keylength(size_t key_len) const
-         { return cipher->valid_keylength(key_len); }
+      Key_Length_Specification key_spec() const override;
 
       bool valid_iv_length(size_t iv_len) const
          { return (iv_len == cipher->block_size()); }