Add implementation for AES CBC in Sys.Security.Crypto

- Add wrapper for mbedTLS API.
- Update assembly declaration.

src/nanoFramework.System.Security.Cryptography/nf_sys_sec_cryptography.cpp

@@ -16,8 +16,12 @@ static const CLR_RT_MethodHandler method_lookup[] =
     NULL,
     NULL,
     NULL,
+    NULL,
+    NULL,
     Library_nf_sys_sec_cryptography_System_Security_Cryptography_Aes::EncryptAesEcb___SZARRAY_U1__SZARRAY_U1,
     Library_nf_sys_sec_cryptography_System_Security_Cryptography_Aes::DecryptAesEcb___SZARRAY_U1__SZARRAY_U1,
+    Library_nf_sys_sec_cryptography_System_Security_Cryptography_Aes::EncryptAesCbc___SZARRAY_U1__SZARRAY_U1,
+    Library_nf_sys_sec_cryptography_System_Security_Cryptography_Aes::DecryptAesCbc___SZARRAY_U1__SZARRAY_U1,
     NULL,
     NULL,
     NULL,
@@ -33,9 +37,9 @@ static const CLR_RT_MethodHandler method_lookup[] =
 const CLR_RT_NativeAssemblyData g_CLR_AssemblyNative_nanoFramework_System_Security_Cryptography =
 {
     "nanoFramework.System.Security.Cryptography",
-    0xF4AEFE6C,
+    0x343142CA,
     method_lookup,
-    { 100, 0, 0, 2 }
+    { 100, 0, 0, 3 }
 };
 
 // clang-format on

src/nanoFramework.System.Security.Cryptography/nf_sys_sec_cryptography.h

@@ -26,16 +26,20 @@
 typedef enum __nfpack CipherMode
 {
     CipherMode_None = 0,
+    CipherMode_CBC = 1,
     CipherMode_ECB = 2,
 } CipherMode;
 
 struct Library_nf_sys_sec_cryptography_System_Security_Cryptography_Aes
 {
     static const int FIELD___mode = 1;
     static const int FIELD___key = 2;
+    static const int FIELD___iv = 3;
 
     NANOCLR_NATIVE_DECLARE(EncryptAesEcb___SZARRAY_U1__SZARRAY_U1);
     NANOCLR_NATIVE_DECLARE(DecryptAesEcb___SZARRAY_U1__SZARRAY_U1);
+    NANOCLR_NATIVE_DECLARE(EncryptAesCbc___SZARRAY_U1__SZARRAY_U1);
+    NANOCLR_NATIVE_DECLARE(DecryptAesCbc___SZARRAY_U1__SZARRAY_U1);
 
     //--//
 };

src/nanoFramework.System.Security.Cryptography/nf_sys_sec_cryptography_System_Security_Cryptography_Aes.cpp

@@ -136,3 +136,149 @@ HRESULT Library_nf_sys_sec_cryptography_System_Security_Cryptography_Aes::Decryp
 
     NANOCLR_CLEANUP_END();
 }
+
+HRESULT Library_nf_sys_sec_cryptography_System_Security_Cryptography_Aes::EncryptAesCbc___SZARRAY_U1__SZARRAY_U1(
+    CLR_RT_StackFrame &stack)
+{
+    NANOCLR_HEADER();
+
+    mbedtls_aes_context encodeContext;
+
+    CLR_RT_HeapBlock_Array *keyArray;
+    CLR_RT_HeapBlock_Array *ivArray;
+    CLR_RT_HeapBlock_Array *plainTextArray;
+    CLR_RT_HeapBlock_Array *cipherTextArray;
+    CLR_RT_HeapBlock *pThis;
+
+    pThis = (CLR_RT_HeapBlock *)stack.This();
+    FAULT_ON_NULL(pThis);
+
+    // grab key and check for NULL
+    keyArray = pThis[FIELD___key].DereferenceArray();
+    if (keyArray == NULL)
+    {
+        NANOCLR_SET_AND_LEAVE(CLR_E_INVALID_OPERATION);
+    }
+
+    // grab IV
+    // (expecting this to be filled with the IV from managed code)
+    ivArray = pThis[FIELD___key].DereferenceArray();
+
+    // grab plain text and check for NULL
+    plainTextArray = stack.Arg1().DereferenceArray();
+    FAULT_ON_NULL_ARG(plainTextArray);
+
+    // data has to be multiple of 16
+    if (plainTextArray->m_numOfElements % 16 != 0)
+    {
+        NANOCLR_SET_AND_LEAVE(CLR_E_INVALID_PARAMETER);
+    }
+
+    // create the return array (same length as the input)
+    stack.PushValueAndClear();
+    NANOCLR_CHECK_HRESULT(CLR_RT_HeapBlock_Array::CreateInstance(
+        stack.TopValue(),
+        plainTextArray->m_numOfElements,
+        g_CLR_RT_WellKnownTypes.m_UInt8));
+    cipherTextArray = stack.TopValue().DereferenceArray();
+
+    // init mbedtls context
+    mbedtls_aes_init(&encodeContext);
+
+    if (mbedtls_aes_setkey_enc(&encodeContext, keyArray->GetFirstElement(), keyArray->m_numOfElements * 8) ==
+        MBEDTLS_ERR_AES_INVALID_KEY_LENGTH)
+    {
+        NANOCLR_SET_AND_LEAVE(CLR_E_INVALID_PARAMETER);
+    }
+
+    if (mbedtls_aes_crypt_cbc(
+            &encodeContext,
+            MBEDTLS_AES_ENCRYPT,
+            plainTextArray->m_numOfElements,
+            ivArray->GetFirstElement(),
+            plainTextArray->GetFirstElement(),
+            cipherTextArray->GetFirstElement()) != 0)
+    {
+        NANOCLR_SET_AND_LEAVE(CLR_E_FAIL);
+    }
+
+    NANOCLR_CLEANUP();
+
+    // make sure nothing is left in memory
+    mbedtls_aes_free(&encodeContext);
+
+    NANOCLR_CLEANUP_END();
+}
+
+HRESULT Library_nf_sys_sec_cryptography_System_Security_Cryptography_Aes::DecryptAesCbc___SZARRAY_U1__SZARRAY_U1(
+    CLR_RT_StackFrame &stack)
+{
+    NANOCLR_HEADER();
+
+    mbedtls_aes_context decodeContext;
+
+    CLR_RT_HeapBlock_Array *keyArray;
+    CLR_RT_HeapBlock_Array *ivArray;
+    CLR_RT_HeapBlock_Array *plainTextArray;
+    CLR_RT_HeapBlock_Array *cipherTextArray;
+    CLR_RT_HeapBlock *pThis;
+
+    pThis = (CLR_RT_HeapBlock *)stack.This();
+    FAULT_ON_NULL(pThis);
+
+    // grab key and check for NULL
+    keyArray = pThis[FIELD___key].DereferenceArray();
+    if (keyArray == NULL)
+    {
+        NANOCLR_SET_AND_LEAVE(CLR_E_INVALID_OPERATION);
+    }
+
+    // grab cipher text and check for NULL
+    cipherTextArray = stack.Arg1().DereferenceArray();
+    FAULT_ON_NULL_ARG(cipherTextArray);
+
+    // data has to be multiple of 16
+    if (cipherTextArray->m_numOfElements % 16 != 0)
+    {
+        NANOCLR_SET_AND_LEAVE(CLR_E_INVALID_PARAMETER);
+    }
+
+    // grab IV
+    // (expecting this to be filled with the IV from managed code)
+    ivArray = pThis[FIELD___key].DereferenceArray();
+
+    // create the return array (same length as the input)
+    stack.PushValueAndClear();
+    NANOCLR_CHECK_HRESULT(CLR_RT_HeapBlock_Array::CreateInstance(
+        stack.TopValue(),
+        cipherTextArray->m_numOfElements,
+        g_CLR_RT_WellKnownTypes.m_UInt8));
+    plainTextArray = stack.TopValue().DereferenceArray();
+
+    // init mbedtls context
+    mbedtls_aes_init(&decodeContext);
+
+    if (mbedtls_aes_setkey_dec(&decodeContext, keyArray->GetFirstElement(), keyArray->m_numOfElements * 8) ==
+        MBEDTLS_ERR_AES_INVALID_KEY_LENGTH)
+    {
+        NANOCLR_SET_AND_LEAVE(CLR_E_INVALID_PARAMETER);
+    }
+
+    if (mbedtls_aes_crypt_cbc(
+            &decodeContext,
+            MBEDTLS_AES_DECRYPT,
+            plainTextArray->m_numOfElements,
+            ivArray->GetFirstElement(),
+            plainTextArray->GetFirstElement(),
+            cipherTextArray->GetFirstElement()) != 0)
+    {
+        NANOCLR_SET_AND_LEAVE(CLR_E_FAIL);
+    }
+
+    NANOCLR_CLEANUP();
+
+    // make sure nothing is left in memory
+    mbedtls_aes_free(&decodeContext);
+
+    NANOCLR_CLEANUP_END();
+}