Merge GH #977 Add block cipher interface to C API

5 files changed, 208 insertions, 2 deletions

diff --git a/doc/manual/ffi.rst b/doc/manual/ffi.rst
index 5cf0dbac5..8acbf225a 100644
--- a/doc/manual/ffi.rst
+++ b/doc/manual/ffi.rst
@@ -89,6 +89,50 @@ Random Number Generators
 
    Destroy the object created by :cpp:func:`botan_rng_init`.
 
+Block Ciphers
+----------------------------------------
+
+This is a 'raw' interface to ECB mode block ciphers. Most applications
+want the higher level cipher API which provides authenticated
+encryption. This API exists as an escape hatch for applications which
+need to implement custom primitives using a PRP.
+
+.. cpp:type:: opaque* botan_block_cipher_t
+
+   An opauqe data type for a block cipher. Don't mess with it.
+
+.. cpp:function:: int botan_block_cipher_init(botan_block_cipher_t* bc, const char* cipher_name)
+
+   Create a new cipher mode object, `cipher_name` should be for example "AES-128" or "Threefish-512"
+
+.. cpp:function:: int botan_block_cipher_block_size(botan_block_cipher_t bc)
+
+   Return the block size of this cipher.
+
+.. cpp:function:: int botan_block_cipher_clear(botan_block_cipher_t bc)
+
+   Clear the internal state (such as keys) of this cipher object, but do not deallocate it.
+
+.. cpp:function:: int botan_block_cipher_set_key(botan_block_cipher_t bc, const uint8_t key[], size_t key_len)
+
+   Set the cipher key, which is required before encrypting or decrypting.
+
+.. cpp:function:: int botan_block_cipher_encrypt_blocks(botan_block_cipher_t bc, const uint8_t in[], uint8_t out[], size_t blocks)
+
+   The key must have been set first with
+   Encrypt *blocks* blocks of data stored in *in* and place the ciphertext into *out*.
+   The two parameters may be the same buffer, but must not overlap.
+
+.. cpp:function:: int botan_block_cipher_decrypt_blocks(botan_block_cipher_t bc, const uint8_t in[], uint8_t out[], size_t blocks)
+
+   Decrypt *blocks* blocks of data stored in *in* and place the ciphertext into *out*.
+   The two parameters may be the same buffer, but must not overlap.
+
+.. cpp:function:: int botan_block_cipher_destroy(botan_block_cipher_t rng)
+
+   Destroy the object created by :cpp:func:`botan_block_cipher_init`.
+
+
 Hash Functions
 ----------------------------------------
 
diff --git a/doc/todo.rst b/doc/todo.rst
index b3ad697e8..4a7d60191 100644
--- a/doc/todo.rst
+++ b/doc/todo.rst
@@ -108,6 +108,11 @@ New Protocols / Formats
   - Subset #2: Process OpenPGP public keys
   - Subset #3: Verification of OpenPGP signatures
 
+Cleanups
+-----------
+
+* Split ffi.cpp and test_ffi.cpp into multiple files
+
 Compat Headers
 ----------------
 
@@ -119,9 +124,7 @@ Compat Headers
 FFI and Bindings
 ----------------------------------------
 
-* Expose BigInt
 * Expose compression
-* Expose a raw block cipher interface
 * Expose more of X.509 (CRLs, OCSP, cert signing, etc)
 * Expose TLS
 * Write a CLI or HTTPS client in Python
diff --git a/src/lib/ffi/ffi.cpp b/src/lib/ffi/ffi.cpp
index 945eacaf8..b4f0412d6 100644
--- a/src/lib/ffi/ffi.cpp
+++ b/src/lib/ffi/ffi.cpp
@@ -9,6 +9,7 @@
 #include <botan/exceptn.h>
 #include <botan/auto_rng.h>
 #include <botan/aead.h>
+#include <botan/block_cipher.h>
 #include <botan/hash.h>
 #include <botan/mac.h>
 #include <botan/pbkdf.h>
@@ -217,6 +218,7 @@ struct botan_cipher_struct : public botan_struct<Botan::Cipher_Mode, 0xB4A2BF9C>
 
 BOTAN_FFI_DECLARE_STRUCT(botan_rng_struct, Botan::RandomNumberGenerator, 0x4901F9C1);
 BOTAN_FFI_DECLARE_STRUCT(botan_mp_struct, Botan::BigInt, 0xC828B9D2);
+BOTAN_FFI_DECLARE_STRUCT(botan_block_cipher_struct, Botan::BlockCipher, 0x64C29716);
 BOTAN_FFI_DECLARE_STRUCT(botan_hash_struct, Botan::HashFunction, 0x1F0A4F84);
 BOTAN_FFI_DECLARE_STRUCT(botan_mac_struct, Botan::MessageAuthenticationCode, 0xA06E8FC1);
 BOTAN_FFI_DECLARE_STRUCT(botan_pubkey_struct, Botan::Public_Key, 0x2C286519);
@@ -593,6 +595,81 @@ int botan_mp_num_bytes(const botan_mp_t mp, size_t* bytes)
    return BOTAN_FFI_DO(Botan::BigInt, mp, n, { *bytes = n.bytes(); });
    }
 
+int botan_block_cipher_init(botan_block_cipher_t* bc, const char* bc_name)
+   {
+   try
+      {
+      if(bc == nullptr || bc_name == nullptr || *bc_name == 0)
+         return BOTAN_FFI_ERROR_NULL_POINTER;
+
+      std::unique_ptr<Botan::BlockCipher> cipher(Botan::BlockCipher::create(bc_name));
+      if(cipher)
+         {
+         *bc = new botan_block_cipher_struct(cipher.release());
+         return 0;
+         }
+      }
+   catch(std::exception& e)
+      {
+      log_exception(BOTAN_CURRENT_FUNCTION, e.what());
+      }
+   catch(...)
+      {
+      log_exception(BOTAN_CURRENT_FUNCTION, "unknown");
+      }
+
+   return BOTAN_FFI_ERROR_EXCEPTION_THROWN;
+
+   }
+
+/**
+* Destroy a block cipher object
+*/
+int botan_block_cipher_destroy(botan_block_cipher_t bc)
+   {
+   delete bc;
+   return 0;
+   }
+
+int botan_block_cipher_clear(botan_block_cipher_t bc)
+   {
+   return BOTAN_FFI_DO(Botan::BlockCipher, bc, b, { b.clear(); });
+   }
+
+/**
+* Set the key for a block cipher instance
+*/
+int botan_block_cipher_set_key(botan_block_cipher_t bc,
+                               const uint8_t key[], size_t len)
+   {
+   return BOTAN_FFI_DO(Botan::BlockCipher, bc, b, { b.set_key(key, len); });
+   }
+
+/**
+* Return the positive block size of this block cipher, or negative to
+* indicate an error
+*/
+int botan_block_cipher_block_size(botan_block_cipher_t bc)
+   {
+   return BOTAN_FFI_DO(Botan::BlockCipher, bc, b, { return b.block_size(); });
+   }
+
+int botan_block_cipher_encrypt_blocks(botan_block_cipher_t bc,
+                                      const uint8_t in[],
+                                      uint8_t out[],
+                                      size_t blocks)
+   {
+   return BOTAN_FFI_DO(Botan::BlockCipher, bc, b, { b.encrypt_n(in, out, blocks); });
+   }
+
+int botan_block_cipher_decrypt_blocks(botan_block_cipher_t bc,
+                                      const uint8_t in[],
+                                      uint8_t out[],
+                                      size_t blocks)
+   {
+   return BOTAN_FFI_DO(Botan::BlockCipher, bc, b, { b.decrypt_n(in, out, blocks); });
+   }
+
 int botan_hash_init(botan_hash_t* hash, const char* hash_name, uint32_t flags)
    {
    try
diff --git a/src/lib/ffi/ffi.h b/src/lib/ffi/ffi.h
index 0901c4d4d..76cdaa145 100644
--- a/src/lib/ffi/ffi.h
+++ b/src/lib/ffi/ffi.h
@@ -456,6 +456,51 @@ BOTAN_DLL int botan_bcrypt_generate(uint8_t* out, size_t* out_len,
                                     uint32_t flags);
 
 /*
+* Raw Block Cipher (PRP) interface
+*/
+typedef struct botan_block_cipher_struct* botan_block_cipher_t;
+
+/**
+* Initialize a block cipher object
+*/
+BOTAN_DLL int botan_block_cipher_init(botan_block_cipher_t* bc,
+                                      const char* cipher_name);
+
+/**
+* Destroy a block cipher object
+*/
+BOTAN_DLL int botan_block_cipher_destroy(botan_block_cipher_t bc);
+
+/**
+* Reinitializes the block cipher
+* @return 0 on success, a negative value on failure
+*/
+BOTAN_DLL int botan_block_cipher_clear(botan_block_cipher_t bc);
+
+/**
+* Set the key for a block cipher instance
+*/
+BOTAN_DLL int botan_block_cipher_set_key(botan_block_cipher_t bc,
+                                         const uint8_t key[], size_t len);
+
+/**
+* Return the positive block size of this block cipher, or negative to
+* indicate an error
+*/
+BOTAN_DLL int botan_block_cipher_block_size(botan_block_cipher_t bc);
+
+BOTAN_DLL int botan_block_cipher_encrypt_blocks(botan_block_cipher_t bc,
+                                                const uint8_t in[],
+                                                uint8_t out[],
+                                                size_t blocks);
+
+BOTAN_DLL int botan_block_cipher_decrypt_blocks(botan_block_cipher_t bc,
+                                                const uint8_t in[],
+                                                uint8_t out[],
+                                                size_t blocks);
+
+
+/*
 * Multiple precision integers
 */
 typedef struct botan_mp_struct* botan_mp_t;
diff --git a/src/tests/test_ffi.cpp b/src/tests/test_ffi.cpp
index eee5fc39d..c84dfd224 100644
--- a/src/tests/test_ffi.cpp
+++ b/src/tests/test_ffi.cpp
@@ -387,6 +387,7 @@ class FFI_Unit_Tests : public Test
 
          std::vector<Test::Result> results;
          results.push_back(ffi_test_mp(rng));
+         results.push_back(ffi_test_block_ciphers());
 
 #if defined(BOTAN_HAS_RSA)
          results.push_back(ffi_test_rsa(rng));
@@ -415,6 +416,42 @@ class FFI_Unit_Tests : public Test
          }
 
    private:
+      Test::Result ffi_test_block_ciphers()
+         {
+         Test::Result result("FFI block ciphers");
+
+         botan_block_cipher_t cipher;
+
+         if(TEST_FFI_OK(botan_block_cipher_init, (&cipher, "AES-128")))
+            {
+            const std::vector<uint8_t> zero16(16, 0);
+            std::vector<uint8_t> block(16, 0);
+
+            TEST_FFI_OK(botan_block_cipher_clear, (cipher));
+
+            TEST_FFI_RC(16, botan_block_cipher_block_size, (cipher));
+
+            TEST_FFI_OK(botan_block_cipher_set_key, (cipher, zero16.data(), zero16.size()));
+
+            TEST_FFI_OK(botan_block_cipher_encrypt_blocks, (cipher, block.data(), block.data(), 1));
+            result.test_eq("AES-128 encryption works", block, "66E94BD4EF8A2C3B884CFA59CA342B2E");
+
+            TEST_FFI_OK(botan_block_cipher_encrypt_blocks, (cipher, block.data(), block.data(), 1));
+            result.test_eq("AES-128 encryption works", block, "F795BD4A52E29ED713D313FA20E98DBC");
+
+            TEST_FFI_OK(botan_block_cipher_decrypt_blocks, (cipher, block.data(), block.data(), 1));
+            result.test_eq("AES-128 decryption works", block, "66E94BD4EF8A2C3B884CFA59CA342B2E");
+
+            TEST_FFI_OK(botan_block_cipher_decrypt_blocks, (cipher, block.data(), block.data(), 1));
+            result.test_eq("AES-128 decryption works", block, "00000000000000000000000000000000");
+
+            TEST_FFI_OK(botan_block_cipher_clear, (cipher));
+            botan_block_cipher_destroy(cipher);
+            }
+
+         return result;
+         }
+
       Test::Result ffi_test_mp(botan_rng_t rng)
          {
          Test::Result result("FFI MP");