For block and stream ciphers, don't set the size of the key vectors

until we are actually setting a key. This avoids the problem of
prototype objects consuming not just memory but the precious few bytes
of mlock'able memory that we're given by Linux.

Use clear_mem instead of a loop in BigInt::mask_bits

If OS2ECP encounters an invalid format type, include what type it was
in the exception message.

2 files changed, 7 insertions, 12 deletions

diff --git a/src/block/rc5/rc5.cpp b/src/block/rc5/rc5.cpp
index 1ac421996..fe558076a 100644
--- a/src/block/rc5/rc5.cpp
+++ b/src/block/rc5/rc5.cpp
@@ -18,8 +18,6 @@ namespace Botan {
 */
 void RC5::encrypt_n(const byte in[], byte out[], size_t blocks) const
    {
-   const size_t rounds = (S.size() - 2) / 2;
-
    for(size_t i = 0; i != blocks; ++i)
       {
       u32bit A = load_le<u32bit>(in, 0);
@@ -53,8 +51,6 @@ void RC5::encrypt_n(const byte in[], byte out[], size_t blocks) const
 */
 void RC5::decrypt_n(const byte in[], byte out[], size_t blocks) const
    {
-   const size_t rounds = (S.size() - 2) / 2;
-
    for(size_t i = 0; i != blocks; ++i)
       {
       u32bit A = load_le<u32bit>(in, 0);
@@ -88,6 +84,8 @@ void RC5::decrypt_n(const byte in[], byte out[], size_t blocks) const
 */
 void RC5::key_schedule(const byte key[], size_t length)
    {
+   S.resize(2*rounds + 2);
+
    const size_t WORD_KEYLENGTH = (((length - 1) / 4) + 1);
    const size_t MIX_ROUNDS     = 3 * std::max(WORD_KEYLENGTH, S.size());
 
@@ -116,19 +114,17 @@ void RC5::key_schedule(const byte key[], size_t length)
 */
 std::string RC5::name() const
    {
-   return "RC5(" + std::to_string(get_rounds()) + ")";
+   return "RC5(" + std::to_string(rounds) + ")";
    }
 
 /*
 * RC5 Constructor
 */
-RC5::RC5(size_t rounds)
+RC5::RC5(size_t r) : rounds(r)
    {
    if(rounds < 8 || rounds > 32 || (rounds % 4 != 0))
       throw Invalid_Argument("RC5: Invalid number of rounds " +
                              std::to_string(rounds));
-
-   S.resize(2*rounds + 2);
    }
 
 }
diff --git a/src/block/rc5/rc5.h b/src/block/rc5/rc5.h
index bf059a996..2279260a3 100644
--- a/src/block/rc5/rc5.h
+++ b/src/block/rc5/rc5.h
@@ -21,9 +21,9 @@ class BOTAN_DLL RC5 : public Block_Cipher_Fixed_Params<8, 1, 32>
       void encrypt_n(const byte in[], byte out[], size_t blocks) const;
       void decrypt_n(const byte in[], byte out[], size_t blocks) const;
 
-      void clear() { zeroise(S); }
+      void clear() { S.clear(); }
       std::string name() const;
-      BlockCipher* clone() const { return new RC5(get_rounds()); }
+      BlockCipher* clone() const { return new RC5(rounds); }
 
       /**
       * @param rounds the number of RC5 rounds to run. Must be between
@@ -31,10 +31,9 @@ class BOTAN_DLL RC5 : public Block_Cipher_Fixed_Params<8, 1, 32>
       */
       RC5(size_t rounds);
    private:
-      size_t get_rounds() const { return (S.size() - 2) / 2; }
-
       void key_schedule(const byte[], size_t);
 
+      size_t rounds;
       secure_vector<u32bit> S;
    };