feat(nvs_flash): Add a minimal XTS-AES layer for the bootloader

components/nvs_flash/private_include/nvs_bootloader_aes.h

@@ -0,0 +1,23 @@
+/*
+ * SPDX-FileCopyrightText: 2024 Espressif Systems (Shanghai) CO LTD
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+#pragma once
+
+#include <stdint.h>
+#include "sdkconfig.h"
+#include "rom/aes.h"
+
+#if CONFIG_IDF_TARGET_ESP32
+enum AES_TYPE {
+    AES_ENC,
+    AES_DEC,
+};
+#endif /* CONFIG_IDF_TARGET_ESP32 */
+
+int nvs_bootloader_aes_crypt_ecb(enum AES_TYPE mode,
+                                const unsigned char *key,
+                                enum AES_BITS key_bits,
+                                const unsigned char input[16],
+                                unsigned char output[16]);

components/nvs_flash/private_include/nvs_bootloader_xts_aes.h

@@ -0,0 +1,94 @@
+/*
+ * SPDX-FileCopyrightText: 2024-2025 Espressif Systems (Shanghai) CO LTD
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+#pragma once
+
+#include <stdint.h>
+#include "esp_err.h"
+#include "nvs_bootloader_aes.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/**
+ * \brief The XTS-AES context-type definition.
+ */
+typedef struct
+{
+    uint8_t crypt_key[32]; /*!< The AES context to use for AES block
+                                        encryption or decryption. */
+    uint8_t tweak_key[32]; /*!< The AES context used for tweak
+                                        computation. */
+} nvs_bootloader_xts_aes_context;
+
+/** Invalid key length. */
+#define NVS_BOOTLOADER_ERR_AES_INVALID_KEY_LENGTH                -0x0020
+/** Invalid data input length. */
+#define NVS_BOOTLOADER_ERR_AES_INVALID_INPUT_LENGTH              -0x0022
+
+/**
+ * @brief Initializes the specified XTS-AES context.
+ *
+ * @param ctx The XTS-AES context to be initialized. This must not be \c NULL.
+ */
+void nvs_bootloader_xts_aes_init(nvs_bootloader_xts_aes_context *ctx);
+
+/**
+ * @brief Clears the specified XTS-AES context.
+ *
+ * @param ctx The XTS-AES context to clear.
+ *            If this is \c NULL, this function does nothing.
+ *            Otherwise, the context must have been at least initialized.
+ */
+void nvs_bootloader_xts_aes_free(nvs_bootloader_xts_aes_context *ctx);
+
+/**
+ * @brief Sets the XTS-AES encryption-decryption key
+ *
+ * @param ctx The XTS-AES context to which the key should be bound.
+ *            It must be initialized.
+ * @param key The encryption key.
+ *            This must be a readable buffer of size \p key_bytes bytes.
+ * @param key_bytes The size of data passed in bits. Valid options are:
+ *                 <ul><li>128 bits</li>
+ *                 <li>192 bits</li>
+ *                 <li>256 bits</li></ul>
+ * @return \c 0 indicating success.
+ */
+int nvs_bootloader_xts_aes_setkey(nvs_bootloader_xts_aes_context *ctx,
+                                const unsigned char *key,
+                                unsigned int key_bytes);
+
+/**
+ * @brief Performs an XTS-AES encryption or decryption operation for an entire XTS data unit.
+ *
+ * @param ctx The XTS-AES context to use for XTS-AES operation
+ *            It must be initialized and bound to a key.
+ * @param mode The AES operation: AES_ENC or AES_DEC.
+ * @param length The length of a data unit in bytes.
+ * @param data_unit The address of the data unit encoded as an array of 16
+ *                  bytes in little-endian format. For disk encryption, this
+ *                  is typically the index of the block device sector that
+ *                  contains the data.
+ * @param input The buffer holding the input data (which is an entire
+ *              data unit). This function reads \p length Bytes from \p
+ *                     input.
+ * @param output The buffer holding the output data (which is an entire
+ *               data unit). This function writes \p length Bytes to \p
+ *               output.
+ * @return \c 0 on success.
+ *            1 on failure.
+ */
+int nvs_bootloader_aes_crypt_xts(nvs_bootloader_xts_aes_context *ctx,
+                                enum AES_TYPE mode,
+                                size_t length,
+                                const unsigned char data_unit[16],
+                                const unsigned char *input,
+                                unsigned char *output);
+
+#ifdef __cplusplus
+}
+#endif