初始版本

components/libraries/crypto/nrf_crypto_aes_shared.c

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+/**
+ * Copyright (c) 2018 - 2020, Nordic Semiconductor ASA
+ *
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without modification,
+ * are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice, this
+ *    list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form, except as embedded into a Nordic
+ *    Semiconductor ASA integrated circuit in a product or a software update for
+ *    such product, must reproduce the above copyright notice, this list of
+ *    conditions and the following disclaimer in the documentation and/or other
+ *    materials provided with the distribution.
+ *
+ * 3. Neither the name of Nordic Semiconductor ASA nor the names of its
+ *    contributors may be used to endorse or promote products derived from this
+ *    software without specific prior written permission.
+ *
+ * 4. This software, with or without modification, must only be used with a
+ *    Nordic Semiconductor ASA integrated circuit.
+ *
+ * 5. Any software provided in binary form under this license must not be reverse
+ *    engineered, decompiled, modified and/or disassembled.
+ *
+ * THIS SOFTWARE IS PROVIDED BY NORDIC SEMICONDUCTOR ASA "AS IS" AND ANY EXPRESS
+ * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY, NONINFRINGEMENT, AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL NORDIC SEMICONDUCTOR ASA OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
+ * GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
+ * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#include "sdk_common.h"
+#if NRF_MODULE_ENABLED(NRF_CRYPTO)
+
+#include "nrf_crypto_error.h"
+#include "sdk_config.h"
+#include "nrf_crypto_types.h"
+
+
+ret_code_t padding_pkcs7_add(uint8_t * p_padding_buff,
+                             uint8_t * p_message_buff,
+                             uint8_t   msg_ending_len)
+{
+    uint8_t padding_count;
+
+    if ((p_padding_buff == NULL) || (p_message_buff == NULL))
+    {
+        return NRF_ERROR_CRYPTO_INPUT_NULL;
+    }
+
+    if (msg_ending_len >= NRF_CRYPTO_AES_BLOCK_SIZE)
+    {
+        return NRF_ERROR_CRYPTO_INVALID_PARAM;
+    }
+
+    /* Creating padding buffer in two steps */
+    /* step 1 add remaining message */
+    memcpy(p_padding_buff, p_message_buff, msg_ending_len);
+
+    /* step 2: add padding */
+    padding_count   = NRF_CRYPTO_AES_BLOCK_SIZE - msg_ending_len;
+    p_padding_buff += msg_ending_len;
+
+    for (size_t i = 0; i < padding_count; i++)
+    {
+        p_padding_buff[i] = padding_count;
+    }
+
+    return NRF_SUCCESS;
+}
+
+ret_code_t padding_pkcs7_remove(uint8_t * p_padded_message,
+                                size_t  * p_message_len)
+{
+    if (p_padded_message == NULL)
+    {
+        return NRF_ERROR_CRYPTO_INPUT_NULL;
+    }
+    if (p_message_len == NULL)
+    {
+        return NRF_ERROR_CRYPTO_OUTPUT_NULL;
+    }
+
+    /* padded_msg_len must be multiple of 16 */
+    if ((*p_message_len == 0) || ((*p_message_len & 0x0F) != 0))
+    {
+        return NRF_ERROR_CRYPTO_INVALID_PARAM;
+    }
+
+    size_t padded_bytes = p_padded_message[*p_message_len - 1];
+
+    if ((padded_bytes == 0) || (padded_bytes > NRF_CRYPTO_AES_BLOCK_SIZE))
+    {
+        return NRF_ERROR_CRYPTO_AES_INVALID_PADDING;
+    }
+
+    /* i = 2: 1 for valid string and 1 for already checked *p_message_len - 1 */
+    for (size_t i = 2; i < padded_bytes; i++)
+    {
+        if (p_padded_message[*p_message_len - i] != padded_bytes)
+        {
+            return NRF_ERROR_CRYPTO_AES_INVALID_PADDING;
+        }
+    }
+
+    *p_message_len -= padded_bytes;
+
+    return NRF_SUCCESS;
+}
+
+#endif // NRF_MODULE_ENABLED(NRF_CRYPTO)
+