Modify interfaces of KDF and PBKDF to write output to an array, with

higher level functions on interface handling returning a vector.

9 files changed, 138 insertions, 148 deletions

diff --git a/src/lib/kdf/kdf.h b/src/lib/kdf/kdf.h
index 9d8ca57fc..dc23a82bd 100644
--- a/src/lib/kdf/kdf.h
+++ b/src/lib/kdf/kdf.h
@@ -25,6 +25,30 @@ class BOTAN_DLL KDF
 
       virtual std::string name() const = 0;
 
+      virtual size_t kdf(byte key[], size_t key_len,
+                         const byte secret[], size_t secret_len,
+                         const byte salt[], size_t salt_len) const = 0;
+
+
+      /**
+      * Derive a key
+      * @param key_len the desired output length in bytes
+      * @param secret the secret input
+      * @param secret_len size of secret in bytes
+      * @param salt a diversifier
+      * @param salt_len size of salt in bytes
+      */
+      secure_vector<byte> derive_key(size_t key_len,
+                                    const byte secret[],
+                                    size_t secret_len,
+                                    const byte salt[],
+                                    size_t salt_len) const
+         {
+         secure_vector<byte> key(key_len);
+         key.resize(kdf(&key[0], key.size(), secret, secret_len, salt, salt_len));
+         return key;
+         }
+
       /**
       * Derive a key
       * @param key_len the desired output length in bytes
@@ -90,31 +114,10 @@ class BOTAN_DLL KDF
                            salt.length());
          }
 
-      /**
-      * Derive a key
-      * @param key_len the desired output length in bytes
-      * @param secret the secret input
-      * @param secret_len size of secret in bytes
-      * @param salt a diversifier
-      * @param salt_len size of salt in bytes
-      */
-      secure_vector<byte> derive_key(size_t key_len,
-                                    const byte secret[],
-                                    size_t secret_len,
-                                    const byte salt[],
-                                    size_t salt_len) const
-         {
-         return derive(key_len, secret, secret_len, salt, salt_len);
-         }
-
       virtual KDF* clone() const = 0;
 
       typedef SCAN_Name Spec;
-   private:
-      virtual secure_vector<byte>
-         derive(size_t key_len,
-                const byte secret[], size_t secret_len,
-                const byte salt[], size_t salt_len) const = 0;
+
    };
 
 /**
diff --git a/src/lib/kdf/kdf1/kdf1.cpp b/src/lib/kdf/kdf1/kdf1.cpp
index df84a1a00..c2a74027b 100644
--- a/src/lib/kdf/kdf1/kdf1.cpp
+++ b/src/lib/kdf/kdf1/kdf1.cpp
@@ -12,16 +12,22 @@ namespace Botan {
 
 BOTAN_REGISTER_KDF_1HASH(KDF1, "KDF1");
 
-/*
-* KDF1 Key Derivation Mechanism
-*/
-secure_vector<byte> KDF1::derive(size_t,
-                                const byte secret[], size_t secret_len,
-                                const byte P[], size_t P_len) const
+size_t KDF1::kdf(byte key[], size_t key_len,
+                 const byte secret[], size_t secret_len,
+                 const byte salt[], size_t salt_len) const
    {
-   hash->update(secret, secret_len);
-   hash->update(P, P_len);
-   return hash->final();
+   m_hash->update(secret, secret_len);
+   m_hash->update(salt, salt_len);
+
+   if(key_len < m_hash->output_length())
+      {
+      secure_vector<byte> v = m_hash->final();
+      copy_mem(key, &v[0], key_len);
+      return key_len;
+      }
+
+   m_hash->final(key);
+   return m_hash->output_length();
    }
 
 }
diff --git a/src/lib/kdf/kdf1/kdf1.h b/src/lib/kdf/kdf1/kdf1.h
index 9f617878b..a22d19d97 100644
--- a/src/lib/kdf/kdf1/kdf1.h
+++ b/src/lib/kdf/kdf1/kdf1.h
@@ -19,16 +19,17 @@ namespace Botan {
 class BOTAN_DLL KDF1 : public KDF
    {
    public:
-      secure_vector<byte> derive(size_t,
-                                const byte secret[], size_t secret_len,
-                                const byte P[], size_t P_len) const;
+      std::string name() const override { return "KDF1(" + m_hash->name() + ")"; }
 
-      std::string name() const { return "KDF1(" + hash->name() + ")"; }
-      KDF* clone() const { return new KDF1(hash->clone()); }
+      KDF* clone() const override { return new KDF1(m_hash->clone()); }
 
-      KDF1(HashFunction* h) : hash(h) {}
+      size_t kdf(byte key[], size_t key_len,
+                 const byte secret[], size_t secret_len,
+                 const byte salt[], size_t salt_len) const override;
+
+      KDF1(HashFunction* h) : m_hash(h) {}
    private:
-      std::unique_ptr<HashFunction> hash;
+      std::unique_ptr<HashFunction> m_hash;
    };
 
 }
diff --git a/src/lib/kdf/kdf2/kdf2.cpp b/src/lib/kdf/kdf2/kdf2.cpp
index c7b355580..f1a702887 100644
--- a/src/lib/kdf/kdf2/kdf2.cpp
+++ b/src/lib/kdf/kdf2/kdf2.cpp
@@ -12,32 +12,27 @@ namespace Botan {
 
 BOTAN_REGISTER_KDF_1HASH(KDF2, "KDF2");
 
-/*
-* KDF2 Key Derivation Mechanism
-*/
-secure_vector<byte> KDF2::derive(size_t out_len,
-                                const byte secret[], size_t secret_len,
-                                const byte P[], size_t P_len) const
+size_t KDF2::kdf(byte key[], size_t key_len,
+                 const byte secret[], size_t secret_len,
+                 const byte salt[], size_t salt_len) const
    {
-   secure_vector<byte> output;
    u32bit counter = 1;
+   secure_vector<byte> h;
 
-   while(out_len && counter)
+   size_t offset = 0;
+   while(offset != key_len && counter != 0)
       {
-      hash->update(secret, secret_len);
-      hash->update_be(counter);
-      hash->update(P, P_len);
-
-      secure_vector<byte> hash_result = hash->final();
-
-      size_t added = std::min(hash_result.size(), out_len);
-      output += std::make_pair(&hash_result[0], added);
-      out_len -= added;
-
-      ++counter;
+      m_hash->update(secret, secret_len);
+      m_hash->update_be(counter++);
+      m_hash->update(salt, salt_len);
+      m_hash->final(h);
+
+      const size_t added = std::min(h.size(), key_len - offset);
+      copy_mem(&key[offset], &h[0], added);
+      offset += added;
       }
 
-   return output;
+   return offset;
    }
 
 }
diff --git a/src/lib/kdf/kdf2/kdf2.h b/src/lib/kdf/kdf2/kdf2.h
index c574336b6..e8a8be1fa 100644
--- a/src/lib/kdf/kdf2/kdf2.h
+++ b/src/lib/kdf/kdf2/kdf2.h
@@ -19,15 +19,17 @@ namespace Botan {
 class BOTAN_DLL KDF2 : public KDF
    {
    public:
-      secure_vector<byte> derive(size_t, const byte[], size_t,
-                                const byte[], size_t) const;
+      std::string name() const override { return "KDF2(" + m_hash->name() + ")"; }
 
-      std::string name() const { return "KDF2(" + hash->name() + ")"; }
-      KDF* clone() const { return new KDF2(hash->clone()); }
+      KDF* clone() const override { return new KDF2(m_hash->clone()); }
 
-      KDF2(HashFunction* h) : hash(h) {}
+      size_t kdf(byte key[], size_t key_len,
+                 const byte secret[], size_t secret_len,
+                 const byte salt[], size_t salt_len) const override;
+
+      KDF2(HashFunction* h) : m_hash(h) {}
    private:
-      std::unique_ptr<HashFunction> hash;
+      std::unique_ptr<HashFunction> m_hash;
    };
 
 }
diff --git a/src/lib/kdf/prf_tls/prf_tls.cpp b/src/lib/kdf/prf_tls/prf_tls.cpp
index f1061fd10..9161dc71e 100644
--- a/src/lib/kdf/prf_tls/prf_tls.cpp
+++ b/src/lib/kdf/prf_tls/prf_tls.cpp
@@ -23,15 +23,21 @@ TLS_12_PRF* TLS_12_PRF::make(const Spec& spec)
 BOTAN_REGISTER_NAMED_T(KDF, "TLS-12-PRF", TLS_12_PRF, TLS_12_PRF::make);
 BOTAN_REGISTER_KDF_NOARGS(TLS_PRF, "TLS-PRF");
 
+TLS_PRF::TLS_PRF()
+   {
+   m_hmac_md5.reset(make_a<MessageAuthenticationCode>("HMAC(MD5)"));
+   m_hmac_sha1.reset(make_a<MessageAuthenticationCode>("HMAC(SHA-1)"));
+   }
+
 namespace {
 
 /*
 * TLS PRF P_hash function
 */
-void P_hash(secure_vector<byte>& output,
+void P_hash(byte out[], size_t out_len,
             MessageAuthenticationCode& mac,
             const byte secret[], size_t secret_len,
-            const byte seed[], size_t seed_len)
+            const byte salt[], size_t salt_len)
    {
    try
       {
@@ -44,73 +50,47 @@ void P_hash(secure_vector<byte>& output,
                            " bytes is too long for the PRF");
       }
 
-   secure_vector<byte> A(seed, seed + seed_len);
+   secure_vector<byte> A(salt, salt + salt_len);
+   secure_vector<byte> h;
 
    size_t offset = 0;
 
-   while(offset != output.size())
+   while(offset != out_len)
       {
-      const size_t this_block_len =
-         std::min<size_t>(mac.output_length(), output.size() - offset);
-
       A = mac.process(A);
 
       mac.update(A);
-      mac.update(seed, seed_len);
-      secure_vector<byte> block = mac.final();
+      mac.update(salt, salt_len);
+      mac.final(h);
 
-      xor_buf(&output[offset], &block[0], this_block_len);
-      offset += this_block_len;
+      const size_t writing = std::min(h.size(), out_len - offset);
+      xor_buf(&out[offset], &h[0], writing);
+      offset += writing;
       }
    }
 
 }
 
-/*
-* TLS PRF Constructor and Destructor
-*/
-TLS_PRF::TLS_PRF()
-   {
-   hmac_md5.reset(make_a<MessageAuthenticationCode>("HMAC(MD5)"));
-   hmac_sha1.reset(make_a<MessageAuthenticationCode>("HMAC(SHA-1)"));
-   }
-
-/*
-* TLS PRF
-*/
-secure_vector<byte> TLS_PRF::derive(size_t key_len,
-                                   const byte secret[], size_t secret_len,
-                                   const byte seed[], size_t seed_len) const
+size_t TLS_PRF::kdf(byte key[], size_t key_len,
+                    const byte secret[], size_t secret_len,
+                    const byte salt[], size_t salt_len) const
    {
-   secure_vector<byte> output(key_len);
-
-   size_t S1_len = (secret_len + 1) / 2,
-          S2_len = (secret_len + 1) / 2;
+   const size_t S1_len = (secret_len + 1) / 2,
+                S2_len = (secret_len + 1) / 2;
    const byte* S1 = secret;
    const byte* S2 = secret + (secret_len - S2_len);
 
-   P_hash(output, *hmac_md5,  S1, S1_len, seed, seed_len);
-   P_hash(output, *hmac_sha1, S2, S2_len, seed, seed_len);
-
-   return output;
+   P_hash(key, key_len, *m_hmac_md5,  S1, S1_len, salt, salt_len);
+   P_hash(key, key_len, *m_hmac_sha1, S2, S2_len, salt, salt_len);
+   return key_len;
    }
 
-/*
-* TLS v1.2 PRF Constructor and Destructor
-*/
-TLS_12_PRF::TLS_12_PRF(MessageAuthenticationCode* mac) : m_mac(mac)
+size_t TLS_12_PRF::kdf(byte key[], size_t key_len,
+                       const byte secret[], size_t secret_len,
+                       const byte salt[], size_t salt_len) const
    {
-   }
-
-secure_vector<byte> TLS_12_PRF::derive(size_t key_len,
-                                      const byte secret[], size_t secret_len,
-                                      const byte seed[], size_t seed_len) const
-   {
-   secure_vector<byte> output(key_len);
-
-   P_hash(output, *m_mac, secret, secret_len, seed, seed_len);
-
-   return output;
+   P_hash(key, key_len, *m_mac, secret, secret_len, salt, salt_len);
+   return key_len;
    }
 
 }
diff --git a/src/lib/kdf/prf_tls/prf_tls.h b/src/lib/kdf/prf_tls/prf_tls.h
index c3adc6caf..e2289a6e8 100644
--- a/src/lib/kdf/prf_tls/prf_tls.h
+++ b/src/lib/kdf/prf_tls/prf_tls.h
@@ -19,17 +19,18 @@ namespace Botan {
 class BOTAN_DLL TLS_PRF : public KDF
    {
    public:
-      secure_vector<byte> derive(size_t key_len,
-                                const byte secret[], size_t secret_len,
-                                const byte seed[], size_t seed_len) const;
-
       std::string name() const { return "TLS-PRF"; }
+
       KDF* clone() const { return new TLS_PRF; }
 
+      size_t kdf(byte key[], size_t key_len,
+                 const byte secret[], size_t secret_len,
+                 const byte salt[], size_t salt_len) const override;
+
       TLS_PRF();
    private:
-      std::unique_ptr<MessageAuthenticationCode> hmac_md5;
-      std::unique_ptr<MessageAuthenticationCode> hmac_sha1;
+      std::unique_ptr<MessageAuthenticationCode> m_hmac_md5;
+      std::unique_ptr<MessageAuthenticationCode> m_hmac_sha1;
    };
 
 /**
@@ -38,14 +39,15 @@ class BOTAN_DLL TLS_PRF : public KDF
 class BOTAN_DLL TLS_12_PRF : public KDF
    {
    public:
-      secure_vector<byte> derive(size_t key_len,
-                                const byte secret[], size_t secret_len,
-                                const byte seed[], size_t seed_len) const;
-
       std::string name() const { return "TLS-12-PRF(" + m_mac->name() + ")"; }
+
       KDF* clone() const { return new TLS_12_PRF(m_mac->clone()); }
 
-      TLS_12_PRF(MessageAuthenticationCode* mac);
+      size_t kdf(byte key[], size_t key_len,
+                 const byte secret[], size_t secret_len,
+                 const byte salt[], size_t salt_len) const override;
+
+      TLS_12_PRF(MessageAuthenticationCode* mac) : m_mac(mac) {}
 
       static TLS_12_PRF* make(const Spec& spec);
    private:
diff --git a/src/lib/kdf/prf_x942/prf_x942.cpp b/src/lib/kdf/prf_x942/prf_x942.cpp
index 30bf737a9..5ca0f01ff 100644
--- a/src/lib/kdf/prf_x942/prf_x942.cpp
+++ b/src/lib/kdf/prf_x942/prf_x942.cpp
@@ -9,7 +9,7 @@
 #include <botan/prf_x942.h>
 #include <botan/der_enc.h>
 #include <botan/oids.h>
-#include <botan/sha160.h>
+#include <botan/hash.h>
 #include <botan/loadstor.h>
 #include <algorithm>
 
@@ -31,24 +31,22 @@ std::vector<byte> encode_x942_int(u32bit n)
 
 }
 
-/*
-* X9.42 PRF
-*/
-secure_vector<byte> X942_PRF::derive(size_t key_len,
-                                    const byte secret[], size_t secret_len,
-                                    const byte salt[], size_t salt_len) const
+size_t X942_PRF::kdf(byte key[], size_t key_len,
+                     const byte secret[], size_t secret_len,
+                     const byte salt[], size_t salt_len) const
    {
-   SHA_160 hash;
-   const OID kek_algo(key_wrap_oid);
+   std::unique_ptr<HashFunction> hash(make_a<HashFunction>("SHA-160"));
+   const OID kek_algo(m_key_wrap_oid);
 
-   secure_vector<byte> key;
+   secure_vector<byte> h;
+   size_t offset = 0;
    u32bit counter = 1;
 
-   while(key.size() != key_len && counter)
+   while(offset != key_len && counter)
       {
-      hash.update(secret, secret_len);
+      hash->update(secret, secret_len);
 
-      hash.update(
+      hash->update(
          DER_Encoder().start_cons(SEQUENCE)
 
             .start_cons(SEQUENCE)
@@ -70,14 +68,15 @@ secure_vector<byte> X942_PRF::derive(size_t key_len,
          .end_cons().get_contents()
          );
 
-      secure_vector<byte> digest = hash.final();
-      const size_t needed = std::min(digest.size(), key_len - key.size());
-      key += std::make_pair(&digest[0], needed);
+      hash->final(h);
+      const size_t copied = std::min(h.size(), key_len - offset);
+      copy_mem(&key[offset], &h[0], copied);
+      offset += copied;
 
       ++counter;
       }
 
-   return key;
+   return offset;
    }
 
 /*
@@ -86,9 +85,9 @@ secure_vector<byte> X942_PRF::derive(size_t key_len,
 X942_PRF::X942_PRF(const std::string& oid)
    {
    if(OIDS::have_oid(oid))
-      key_wrap_oid = OIDS::lookup(oid).as_string();
+      m_key_wrap_oid = OIDS::lookup(oid).as_string();
    else
-      key_wrap_oid = oid;
+      m_key_wrap_oid = oid;
    }
 
 }
diff --git a/src/lib/kdf/prf_x942/prf_x942.h b/src/lib/kdf/prf_x942/prf_x942.h
index d2678c127..242a83150 100644
--- a/src/lib/kdf/prf_x942/prf_x942.h
+++ b/src/lib/kdf/prf_x942/prf_x942.h
@@ -18,15 +18,17 @@ namespace Botan {
 class BOTAN_DLL X942_PRF : public KDF
    {
    public:
-      secure_vector<byte> derive(size_t, const byte[], size_t,
-                                const byte[], size_t) const;
+      std::string name() const { return "X942_PRF(" + m_key_wrap_oid + ")"; }
 
-      std::string name() const { return "X942_PRF(" + key_wrap_oid + ")"; }
-      KDF* clone() const { return new X942_PRF(key_wrap_oid); }
+      KDF* clone() const { return new X942_PRF(m_key_wrap_oid); }
+
+      size_t kdf(byte key[], size_t key_len,
+                 const byte secret[], size_t secret_len,
+                 const byte salt[], size_t salt_len) const override;
 
       X942_PRF(const std::string& oid);
    private:
-      std::string key_wrap_oid;
+      std::string m_key_wrap_oid;
    };
 
 }