Merge GH #529 Add block cipher padding tests, fix off by one in X9.23 padding

4 files changed, 147 insertions, 2 deletions

diff --git a/src/lib/modes/mode_pad/mode_pad.cpp b/src/lib/modes/mode_pad/mode_pad.cpp
index 0f1df9e8a..7b4546c86 100644
--- a/src/lib/modes/mode_pad/mode_pad.cpp
+++ b/src/lib/modes/mode_pad/mode_pad.cpp
@@ -69,8 +69,10 @@ void ANSI_X923_Padding::add_padding(secure_vector<byte>& buffer,
    {
    const byte pad_value = static_cast<byte>(block_size - last_byte_pos);
 
-   for(size_t i = last_byte_pos; i < block_size; ++i)
+   for(size_t i = last_byte_pos; i < block_size-1; ++i)
+      {
       buffer.push_back(0);
+      }
    buffer.push_back(pad_value);
    }
 
diff --git a/src/lib/modes/mode_pad/mode_pad.h b/src/lib/modes/mode_pad/mode_pad.h
index 0a775b1ea..bc2b7c132 100644
--- a/src/lib/modes/mode_pad/mode_pad.h
+++ b/src/lib/modes/mode_pad/mode_pad.h
@@ -32,6 +32,7 @@ class BOTAN_DLL BlockCipherModePaddingMethod
       /**
       * @param block the last block
       * @param size the of the block
+      * @return number of padding bytes
       */
       virtual size_t unpad(const byte block[],
                            size_t size) const = 0;
@@ -119,7 +120,7 @@ class BOTAN_DLL Null_Padding final : public BlockCipherModePaddingMethod
       std::string name() const override { return "NoPadding"; }
    };
 
-BlockCipherModePaddingMethod* get_bc_pad(const std::string& algo_spec);
+BOTAN_DLL BlockCipherModePaddingMethod* get_bc_pad(const std::string& algo_spec);
 
 }
 
diff --git a/src/tests/data/pad.vec b/src/tests/data/pad.vec
new file mode 100644
index 000000000..3c47959c9
--- /dev/null
+++ b/src/tests/data/pad.vec
@@ -0,0 +1,83 @@
+[NoPadding]
+In = FFFFFF
+Out = FFFFFF
+Blocksize = 16
+
+In = FFFFFFFF
+Out = FFFFFFFF
+Blocksize = 32
+
+In = FFFFFFFFFFFF
+Out = FFFFFFFFFFFF
+Blocksize = 64
+
+In = FFFFFFFFFFFFFFFF
+Out = FFFFFFFFFFFFFFFF
+Blocksize = 8
+
+In = FFFFFFFFFFFFFFFFFF
+Out = FFFFFFFFFFFFFFFFFF
+Blocksize = 8
+
+[PKCS7]
+In = FFFFFF
+Out = FFFFFF0D0D0D0D0D0D0D0D0D0D0D0D0D
+Blocksize = 16
+
+In = FFFFFFFF
+Out = FFFFFFFF1C1C1C1C1C1C1C1C1C1C1C1C1C1C1C1C1C1C1C1C1C1C1C1C1C1C1C1C
+Blocksize = 32
+
+In = FFFFFFFFFFFF
+Out = FFFFFFFFFFFF3A3A3A3A3A3A3A3A3A3A3A3A3A3A3A3A3A3A3A3A3A3A3A3A3A3A3A3A3A3A3A3A3A3A3A3A3A3A3A3A3A3A3A3A3A3A3A3A3A3A3A3A3A3A3A3A3A3A
+Blocksize = 64
+
+In = FFFFFFFFFFFFFFFF
+Out = FFFFFFFFFFFFFFFF0808080808080808
+Blocksize = 8
+
+In = FFFFFFFFFFFFFFFFFF
+Out = FFFFFFFFFFFFFFFFFF07070707070707
+Blocksize = 8
+
+[OneAndZeros]
+In = FFFFFF
+Out = FFFFFF80000000000000000000000000
+Blocksize = 16
+
+In = FFFFFFFF
+Out = FFFFFFFF80000000000000000000000000000000000000000000000000000000
+Blocksize = 32
+
+In = FFFFFFFFFFFF
+Out = FFFFFFFFFFFF80000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000
+Blocksize = 64
+
+In = FFFFFFFFFFFFFFFF
+Out = FFFFFFFFFFFFFFFF8000000000000000
+Blocksize = 8
+
+In = FFFFFFFFFFFFFFFFFF
+Out = FFFFFFFFFFFFFFFFFF80000000000000
+Blocksize = 8
+
+[X9.23]
+In = FFFFFF
+Out = FFFFFF0000000000000000000000000D
+Blocksize = 16
+
+In = FFFFFFFF
+Out = FFFFFFFF0000000000000000000000000000000000000000000000000000001C
+Blocksize = 32
+
+In = FFFFFFFFFFFF
+Out = FFFFFFFFFFFF0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000003A
+Blocksize = 64
+
+In = FFFFFFFFFFFFFFFF
+Out = FFFFFFFFFFFFFFFF0000000000000008
+Blocksize = 8
+
+In = FFFFFFFFFFFFFFFFFF
+Out = FFFFFFFFFFFFFFFFFF00000000000007
+Blocksize = 8
\ No newline at end of file
diff --git a/src/tests/test_pad.cpp b/src/tests/test_pad.cpp
new file mode 100644
index 000000000..43ac3dfb5
--- /dev/null
+++ b/src/tests/test_pad.cpp
@@ -0,0 +1,59 @@
+/*
+* (C) 2016 René Korthaus, Rohde & Schwarz Cybersecurity
+*
+* Botan is released under the Simplified BSD License (see license.txt)
+*/
+
+#include "tests.h"
+
+#if defined(BOTAN_HAS_CIPHER_MODE_PADDING)
+  #include <botan/mode_pad.h>
+#endif
+
+namespace Botan_Tests {
+
+#if defined(BOTAN_HAS_CIPHER_MODE_PADDING)
+
+class Cipher_Mode_Padding_Tests : public Text_Based_Test
+   {
+   public:
+      Cipher_Mode_Padding_Tests() :
+         Text_Based_Test("pad.vec", {"In", "Out", "Blocksize"})
+         {}
+
+      Test::Result run_one_test(const std::string& algo, const VarMap& vars) override
+         {
+         const std::vector<uint8_t> input    = get_req_bin(vars, "In");
+         const std::vector<uint8_t> expected = get_req_bin(vars, "Out");
+         const size_t block_size = get_req_sz(vars, "Blocksize");
+
+         Test::Result result(algo);
+
+         std::unique_ptr<Botan::BlockCipherModePaddingMethod> pad(Botan::get_bc_pad(algo));
+
+         if(!pad)
+            {
+            result.test_failure("Invalid padding method: " + algo);
+            return result;
+            }
+
+         Botan::secure_vector<uint8_t> buf(input.begin(), input.end());
+         pad->add_padding(buf, input.size() % block_size, block_size);
+         result.test_eq("pad", buf, expected);
+
+         buf.assign(expected.begin(), expected.end());
+
+         const size_t last_block = ( buf.size() < block_size ) ? 0 : buf.size() - block_size;
+         const size_t pad_bytes = block_size - pad->unpad(&buf[last_block], block_size);
+         buf.resize(buf.size() - pad_bytes); // remove padding
+         result.test_eq("unpad", buf, input);
+
+         return result;
+         }
+   };
+
+BOTAN_REGISTER_TEST("bc-padding", Cipher_Mode_Padding_Tests);
+
+#endif
+
+}