cx_aes.c

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/* @BANNER@ */
 
#include "app_config.h"
 
#ifdef HAVE_AES
 
#include "cx_cipher.h"
#include "cx_ram.h"
 
#include <stddef.h>
#include <string.h>
 
cx_err_t cx_aes_init_key_no_throw(const uint8_t *raw_key, size_t key_len, cx_aes_key_t *key)
{
    memset(key, 0, sizeof(cx_aes_key_t));
    switch (key_len) {
        case 16:
        case 24:
        case 32:
            key->size = key_len;
            memmove(key->keys, raw_key, key_len);
            return CX_OK;
        default:
            return CX_INVALID_PARAMETER;
    }
}
 
cx_err_t cx_aes_enc_block(const cx_aes_key_t *key, const uint8_t *inblock, uint8_t *outblock)
{
    cx_err_t error;
    cx_err_t err_reset = CX_INTERNAL_ERROR;
    CX_CHECK(cx_aes_set_key_hw(key, CX_ENCRYPT));
    CX_CHECK(cx_aes_block_hw(inblock, outblock));
end:
    err_reset = cx_aes_reset_hw();
    return error == CX_OK ? err_reset : error;
}
 
cx_err_t cx_aes_dec_block(const cx_aes_key_t *key, const uint8_t *inblock, uint8_t *outblock)
{
    cx_err_t error;
    cx_err_t err_reset = CX_INTERNAL_ERROR;
    CX_CHECK(cx_aes_set_key_hw(key, CX_ENCRYPT));
    CX_CHECK(cx_aes_set_key_hw(key, CX_DECRYPT));
    CX_CHECK(cx_aes_block_hw(inblock, outblock));
end:
    err_reset = cx_aes_reset_hw();
    return error == CX_OK ? err_reset : error;
}
 
cx_err_t cx_aes_iv_no_throw(const cx_aes_key_t *key,
                            uint32_t            mode,
                            const uint8_t      *iv,
                            size_t              iv_len,
                            const uint8_t      *in,
                            size_t              in_len,
                            uint8_t            *out,
                            size_t             *out_len)
{
    cx_cipher_context_t *ctx;
    cx_cipher_id_t       type;
    cx_err_t             error;
    uint32_t             operation;
 
    switch (key->size) {
        case 16:
            type = CX_CIPHER_AES_128;
            break;
        case 24:
            type = CX_CIPHER_AES_192;
            break;
        case 32:
            type = CX_CIPHER_AES_256;
            break;
        default:
            return CX_INVALID_PARAMETER;
    }
 
    ctx       = &G_cx.cipher;
    operation = mode & CX_MASK_SIGCRYPT;
    if ((operation != CX_ENCRYPT) && (operation != CX_DECRYPT) && (operation != CX_SIGN)
        && (operation != CX_VERIFY)) {
        return CX_INVALID_PARAMETER_VALUE;
    }
    CX_CHECK(cx_cipher_init(ctx));
    // Set key
    ctx->key_bitlen = key->size * 8;
    ctx->operation  = operation;
    ctx->cipher_key = (const cipher_key_t *) key;
    operation |= mode & CX_MASK_CHAIN;
    CX_CHECK(cx_cipher_setup(ctx, type, mode & CX_MASK_CHAIN));
    CX_CHECK(cx_aes_set_key_hw(key, operation));
    CX_CHECK(cx_cipher_set_padding(ctx, mode & CX_MASK_PAD));
    CX_CHECK(cx_cipher_enc_dec(ctx, iv, iv_len, in, in_len, out, out_len));
 
end:
    explicit_bzero(ctx, sizeof(cx_cipher_context_t));
    return error;
}
 
cx_err_t cx_aes_no_throw(const cx_aes_key_t *key,
                         uint32_t            mode,
                         const uint8_t      *in,
                         size_t              in_len,
                         uint8_t            *out,
                         size_t             *out_len)
{
    return cx_aes_iv_no_throw(key, mode, NULL, 0, in, in_len, out, out_len);
}
 
cx_err_t aes_ctr(cx_aes_key_t  *ctx_key,
                 size_t         len,
                 size_t        *nc_off,
                 uint8_t       *nonce_counter,
                 uint8_t       *stream_block,
                 const uint8_t *input,
                 uint8_t       *output)
{
    uint8_t  c;
    size_t   n     = *nc_off;
    cx_err_t error = CX_INVALID_PARAMETER;
    UNUSED(ctx_key);
 
    while (len--) {
        if (n == 0) {
            CX_CHECK(cx_aes_block_hw(nonce_counter, stream_block));
            for (int i = CX_AES_BLOCK_SIZE; i > 0; i--) {
                if (++nonce_counter[i - 1] != 0) {
                    break;
                }
            }
        }
        c         = *input++;
        *output++ = c ^ stream_block[n];
        n         = (n + 1) & 0x0F;
    }
    *nc_off = n;
    error   = CX_OK;
 
end:
    return error;
}
 
cx_err_t aes_setkey(cx_aes_key_t  *ctx_key,
                    uint32_t       operation,
                    const uint8_t *key,
                    uint32_t       key_bitlen)
{
    cx_err_t error;
    CX_CHECK(cx_aes_init_key_no_throw(key, key_bitlen / 8, ctx_key));
    CX_CHECK(cx_aes_set_key_hw(ctx_key, operation));
end:
    return error;
}
 
static const cx_cipher_base_t aes_base = {
    (cx_err_t(*)(const uint8_t *inblock, uint8_t *outblock)) cx_aes_block_hw,
    (cx_err_t(*)(const uint8_t *inblock, uint8_t *outblock)) cx_aes_block_hw,
    (cx_err_t(*)(const cipher_key_t *ctx_key,
                 size_t              len,
                 size_t             *nc_off,
                 uint8_t            *nonce_counter,
                 uint8_t            *stream_block,
                 const uint8_t      *input,
                 uint8_t            *output)) aes_ctr,
    (cx_err_t(*)(const cipher_key_t *ctx_key,
                 uint32_t            operation,
                 const uint8_t      *key,
                 uint32_t            key_bitlen)) aes_setkey,
    (cx_err_t(*)(void)) cx_aes_reset_hw,
};
 
const cx_cipher_info_t cx_aes_128_info = {128,
                                          16,
                                          CX_AES_BLOCK_SIZE,
#ifdef BOLOS_OS_UPGRADER_APP
                                          (cx_cipher_base_t *)
#endif
                                          &aes_base};
 
const cx_cipher_info_t cx_aes_192_info = {192,
                                          16,
                                          CX_AES_BLOCK_SIZE,
#ifdef BOLOS_OS_UPGRADER_APP
                                          (cx_cipher_base_t *)
#endif
                                          &aes_base};
 
const cx_cipher_info_t cx_aes_256_info = {256,
                                          16,
                                          CX_AES_BLOCK_SIZE,
#ifdef BOLOS_OS_UPGRADER_APP
                                          (cx_cipher_base_t *)
#endif
                                          &aes_base};
 
#endif  // HAVE_AES