diff options
Diffstat (limited to 'tools/encrypt_fw/src/encrypt.c')
| -rw-r--r-- | tools/encrypt_fw/src/encrypt.c | 167 |
1 files changed, 167 insertions, 0 deletions
diff --git a/tools/encrypt_fw/src/encrypt.c b/tools/encrypt_fw/src/encrypt.c new file mode 100644 index 0000000..18a514c --- /dev/null +++ b/tools/encrypt_fw/src/encrypt.c @@ -0,0 +1,167 @@ +/* + * Copyright (c) 2019, Linaro Limited. All rights reserved. + * Author: Sumit Garg <sumit.garg@linaro.org> + * + * SPDX-License-Identifier: BSD-3-Clause + */ + +#include <firmware_encrypted.h> +#include <openssl/evp.h> +#include <stdio.h> +#include <string.h> +#include "debug.h" +#include "encrypt.h" + +#define BUFFER_SIZE 256 +#define IV_SIZE 12 +#define IV_STRING_SIZE 24 +#define TAG_SIZE 16 +#define KEY_SIZE 32 +#define KEY_STRING_SIZE 64 + +static int gcm_encrypt(unsigned short fw_enc_status, char *key_string, + char *nonce_string, const char *ip_name, + const char *op_name) +{ + FILE *ip_file; + FILE *op_file; + EVP_CIPHER_CTX *ctx; + unsigned char data[BUFFER_SIZE], enc_data[BUFFER_SIZE]; + unsigned char key[KEY_SIZE], iv[IV_SIZE], tag[TAG_SIZE]; + int bytes, enc_len = 0, i, j, ret = 0; + struct fw_enc_hdr header; + + memset(&header, 0, sizeof(struct fw_enc_hdr)); + + if (strlen(key_string) != KEY_STRING_SIZE) { + ERROR("Unsupported key size: %lu\n", strlen(key_string)); + return -1; + } + + for (i = 0, j = 0; i < KEY_SIZE; i++, j += 2) { + if (sscanf(&key_string[j], "%02hhx", &key[i]) != 1) { + ERROR("Incorrect key format\n"); + return -1; + } + } + + if (strlen(nonce_string) != IV_STRING_SIZE) { + ERROR("Unsupported IV size: %lu\n", strlen(nonce_string)); + return -1; + } + + for (i = 0, j = 0; i < IV_SIZE; i++, j += 2) { + if (sscanf(&nonce_string[j], "%02hhx", &iv[i]) != 1) { + ERROR("Incorrect IV format\n"); + return -1; + } + } + + ip_file = fopen(ip_name, "rb"); + if (ip_file == NULL) { + ERROR("Cannot read %s\n", ip_name); + return -1; + } + + op_file = fopen(op_name, "wb"); + if (op_file == NULL) { + ERROR("Cannot write %s\n", op_name); + fclose(ip_file); + return -1; + } + + ret = fseek(op_file, sizeof(struct fw_enc_hdr), SEEK_SET); + if (ret) { + ERROR("fseek failed\n"); + goto out_file; + } + + ctx = EVP_CIPHER_CTX_new(); + if (ctx == NULL) { + ERROR("EVP_CIPHER_CTX_new failed\n"); + ret = -1; + goto out_file; + } + + ret = EVP_EncryptInit_ex(ctx, EVP_aes_256_gcm(), NULL, NULL, NULL); + if (ret != 1) { + ERROR("EVP_EncryptInit_ex failed\n"); + ret = -1; + goto out; + } + + ret = EVP_EncryptInit_ex(ctx, NULL, NULL, key, iv); + if (ret != 1) { + ERROR("EVP_EncryptInit_ex failed\n"); + goto out; + } + + while ((bytes = fread(data, 1, BUFFER_SIZE, ip_file)) != 0) { + ret = EVP_EncryptUpdate(ctx, enc_data, &enc_len, data, bytes); + if (ret != 1) { + ERROR("EVP_EncryptUpdate failed\n"); + ret = -1; + goto out; + } + + fwrite(enc_data, 1, enc_len, op_file); + } + + ret = EVP_EncryptFinal_ex(ctx, enc_data, &enc_len); + if (ret != 1) { + ERROR("EVP_EncryptFinal_ex failed\n"); + ret = -1; + goto out; + } + + ret = EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_GCM_GET_TAG, TAG_SIZE, tag); + if (ret != 1) { + ERROR("EVP_CIPHER_CTX_ctrl failed\n"); + ret = -1; + goto out; + } + + header.magic = ENC_HEADER_MAGIC; + header.flags |= fw_enc_status & FW_ENC_STATUS_FLAG_MASK; + header.dec_algo = KEY_ALG_GCM; + header.iv_len = IV_SIZE; + header.tag_len = TAG_SIZE; + memcpy(header.iv, iv, IV_SIZE); + memcpy(header.tag, tag, TAG_SIZE); + + ret = fseek(op_file, 0, SEEK_SET); + if (ret) { + ERROR("fseek failed\n"); + goto out; + } + + fwrite(&header, 1, sizeof(struct fw_enc_hdr), op_file); + +out: + EVP_CIPHER_CTX_free(ctx); + +out_file: + fclose(ip_file); + fclose(op_file); + + /* + * EVP_* APIs returns 1 as success but enctool considers + * 0 as success. + */ + if (ret == 1) + ret = 0; + + return ret; +} + +int encrypt_file(unsigned short fw_enc_status, int enc_alg, char *key_string, + char *nonce_string, const char *ip_name, const char *op_name) +{ + switch (enc_alg) { + case KEY_ALG_GCM: + return gcm_encrypt(fw_enc_status, key_string, nonce_string, + ip_name, op_name); + default: + return -1; + } +} |