diff options
Diffstat (limited to '')
| -rw-r--r-- | src/box.c | 294 |
1 files changed, 294 insertions, 0 deletions
@@ -8,6 +8,8 @@ #include <aesni/all.h> +#include <stdlib.h> + static const AesNI_BoxAlgorithmInterface* aesni_box_algorithms[] = { &aesni_box_algorithm_aes128, @@ -253,3 +255,295 @@ AesNI_StatusCode aesni_box_decrypt_block( { return aesni_box_decrypt_block_in_mode[box->mode](box, input, output, err_details); } + +static AesNI_StatusCode aesni_box_get_encrypted_buffer_size( + AesNI_Box* box, + size_t src_size, + size_t* dest_size, + size_t* padding_size, + AesNI_ErrorDetails* err_details) +{ + AesNI_StatusCode status = AESNI_SUCCESS; + + switch (box->mode) + { + case AESNI_ECB: + case AESNI_CBC: + { + size_t block_size; + + if (aesni_is_error(status = box->algorithm->get_block_size( + &block_size, err_details))) + return status; + + *padding_size = block_size - src_size % block_size; + *dest_size = src_size + *padding_size; + return status; + } + + case AESNI_CFB: + case AESNI_OFB: + case AESNI_CTR: + *dest_size = src_size; + *padding_size = 0; + return status; + + default: + return aesni_error_not_implemented(err_details, "unsupported mode of operation"); + } +} + +static AesNI_StatusCode aesni_box_encrypt_buffer_block( + AesNI_Box* box, + const void* src, + void* dest, + AesNI_ErrorDetails* err_details) +{ + AesNI_StatusCode status = AESNI_SUCCESS; + + AesNI_BoxBlock plaintext; + + if (aesni_is_error(status = box->algorithm->load_block( + &plaintext, src, err_details))) + return status; + + AesNI_BoxBlock ciphertext; + + if (aesni_is_error(status = aesni_box_encrypt_block( + box, &plaintext, &ciphertext, err_details))) + return status; + + if (aesni_is_error(status = box->algorithm->store_block( + dest, &ciphertext, err_details))) + return status; + + return status; +} + +AesNI_StatusCode aesni_box_encrypt_buffer( + AesNI_Box* box, + const void* src, + size_t src_size, + void* dest, + size_t* dest_size, + AesNI_ErrorDetails* err_details) +{ + if (box == NULL) + return aesni_error_null_argument(err_details, "box"); + if (dest_size == NULL) + return aesni_error_null_argument(err_details, "dest_size"); + + AesNI_StatusCode status = AESNI_SUCCESS; + size_t padding_size = 0; + + if (aesni_is_error(status = aesni_box_get_encrypted_buffer_size( + box, src_size, dest_size, &padding_size, err_details))) + return status; + + if (dest == NULL) + return AESNI_SUCCESS; + if (src == NULL) + return aesni_error_null_argument(err_details, "src"); + + size_t block_size; + + if (aesni_is_error(status = box->algorithm->get_block_size( + &block_size, err_details))) + return status; + + const size_t src_len = src_size / block_size; + + for (size_t i = 0; i < src_len; ++i, (char*) src += block_size, (char*) dest += block_size) + if (aesni_is_error(status = aesni_box_encrypt_buffer_block( + box, src, dest, err_details))) + return status; + + if (padding_size == 0) + { + const size_t partial_block_size = src_size % block_size; + + if (partial_block_size != 0) + { + AesNI_BoxBlock plaintext; + + if (aesni_is_error(status = box->algorithm->load_partial_block( + &plaintext, src, partial_block_size, err_details))) + return status; + + AesNI_BoxBlock ciphertext; + + if (aesni_is_error(status = aesni_box_encrypt_block( + box, &plaintext, &ciphertext, err_details))) + return status; + + if (aesni_is_error(status = box->algorithm->store_partial_block( + dest, &ciphertext, partial_block_size, err_details))) + return status; + } + } + else + { + AesNI_BoxBlock plaintext; + + if (aesni_is_error(status = box->algorithm->load_block_with_padding( + &plaintext, src, src_size % block_size, err_details))) + return status; + + AesNI_BoxBlock ciphertext; + + if (aesni_is_error(status = aesni_box_encrypt_block( + box, &plaintext, &ciphertext, err_details))) + return status; + + if (aesni_is_error(status = box->algorithm->store_block( + dest, &ciphertext, err_details))) + return status; + } + + return status; +} + +static AesNI_StatusCode aesni_box_get_decrypted_buffer_size( + AesNI_Box* box, + size_t src_size, + size_t* dest_size, + size_t* max_padding_size, + AesNI_ErrorDetails* err_details) +{ + AesNI_StatusCode status = AESNI_SUCCESS; + + switch (box->mode) + { + case AESNI_ECB: + case AESNI_CBC: + { + size_t block_size; + + if (aesni_is_error(status = box->algorithm->get_block_size( + &block_size, err_details))) + return status; + + if (src_size % block_size != 0) + return aesni_error_invalid_plaintext_length(err_details); + + *dest_size = src_size; + *max_padding_size = block_size; + return status; + } + + case AESNI_CFB: + case AESNI_OFB: + case AESNI_CTR: + *dest_size = src_size; + *max_padding_size = 0; + return status; + + default: + return aesni_error_not_implemented(err_details, "unsupported mode of operation"); + } +} + +static AesNI_StatusCode aesni_box_decrypt_buffer_block( + AesNI_Box* box, + const void* src, + void* dest, + AesNI_ErrorDetails* err_details) +{ + AesNI_StatusCode status = AESNI_SUCCESS; + + AesNI_BoxBlock ciphertext; + + if (aesni_is_error(status = box->algorithm->load_block( + &ciphertext, src, err_details))) + return status; + + AesNI_BoxBlock plaintext; + + if (aesni_is_error(status = aesni_box_decrypt_block( + box, &ciphertext, &plaintext, err_details))) + return status; + + if (aesni_is_error(status = box->algorithm->store_block( + dest, &plaintext, err_details))) + return status; + + return status; +} + +AesNI_StatusCode aesni_box_decrypt_buffer( + AesNI_Box* box, + const void* src, + size_t src_size, + void* dest, + size_t* dest_size, + AesNI_ErrorDetails* err_details) +{ + if (box == NULL) + return aesni_error_null_argument(err_details, "box"); + if (dest_size == NULL) + return aesni_error_null_argument(err_details, "dest_size"); + + AesNI_StatusCode status = AESNI_SUCCESS; + size_t padding_size = 0; + + if (aesni_is_error(status = aesni_box_get_decrypted_buffer_size( + box, src_size, dest_size, &padding_size, err_details))) + return status; + + if (dest == NULL) + return AESNI_SUCCESS; + if (src == NULL) + return aesni_error_null_argument(err_details, "src"); + + size_t block_size; + + if (aesni_is_error(status = box->algorithm->get_block_size( + &block_size, err_details))) + return status; + + const size_t src_len = src_size / block_size; + + for (size_t i = 0; i < src_len; ++i, (char*) src += block_size, (char*) dest += block_size) + if (aesni_is_error(status = aesni_box_decrypt_buffer_block( + box, src, dest, err_details))) + return status; + + if (padding_size == 0) + { + const size_t partial_block_size = src_size % block_size; + + if (partial_block_size != 0) + { + AesNI_BoxBlock ciphertext; + + if (aesni_is_error(status = box->algorithm->load_partial_block( + &ciphertext, src, partial_block_size, err_details))) + return status; + + AesNI_BoxBlock plaintext; + + if (aesni_is_error(status = aesni_box_decrypt_block( + box, &ciphertext, &plaintext, err_details))) + return status; + + if (aesni_is_error(status = box->algorithm->store_partial_block( + dest, &plaintext, partial_block_size, err_details))) + return status; + } + } + else + { + padding_size = ((unsigned char*) dest)[-1]; + + if (padding_size > block_size) + return aesni_error_invalid_pkcs7_padding(err_details); + + for (size_t i = 1; i < padding_size; ++i) + if (((unsigned char*) dest)[0 - i] != padding_size) + return aesni_error_invalid_pkcs7_padding(err_details); + + *dest_size -= padding_size; + } + + return status; +} |