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/* SPDX-License-Identifier: GPL-2.0-or-later
* Copyright (C) 2023 Eneas Ulir de Queiroz
*/
#include <ctype.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <mbedtls/cipher.h>
int do_crypt(FILE *infile, FILE *outfile, const mbedtls_cipher_info_t *cipher_info,
const unsigned char *key, const unsigned char *iv, int enc, int padding)
{
mbedtls_cipher_context_t ctx;
unsigned char inbuf[1024], outbuf[1024 + MBEDTLS_MAX_BLOCK_LENGTH];
size_t inlen, outlen;
int ret = 0;
int step;
mbedtls_cipher_init(&ctx);
if ((ret = mbedtls_cipher_setup(&ctx, cipher_info))) {
fprintf(stderr, "Error: mbedtls_cipher_setup: %d\n", ret);
goto out;
}
step = iv ? 1024 : mbedtls_cipher_get_block_size(&ctx);
if ((ret = mbedtls_cipher_setkey(&ctx, key, (int) mbedtls_cipher_get_key_bitlen(&ctx),
enc ? MBEDTLS_ENCRYPT : MBEDTLS_DECRYPT))) {
fprintf(stderr, "Error: mbedtls_cipher_setkey: %d\n", ret);
goto out;
}
if (iv && (ret = mbedtls_cipher_set_iv(&ctx, iv, cipher_info->iv_size))) {
fprintf(stderr, "Error: mbedtls_cipher_set_iv: %d\n", ret);
goto out;
}
if (cipher_info->block_size > 1) {
if (cipher_info->mode == MBEDTLS_MODE_CBC) {
if ((ret = mbedtls_cipher_set_padding_mode(&ctx,
padding ? MBEDTLS_PADDING_PKCS7
: MBEDTLS_PADDING_NONE))) {
fprintf(stderr, "Error: mbedtls_cipher_set_padding_mode: %d\n", ret);
goto out;
}
} else {
if (cipher_info->mode != MBEDTLS_MODE_CBC && padding) {
fprintf(stderr, "Error: mbedTLS only supports padding with CBC ciphers.\n");
goto out;
}
}
}
if ((ret = mbedtls_cipher_reset(&ctx))) {
fprintf(stderr, "Error: mbedtls_cipher_reset: %d\n", ret);
goto out;
}
for (;;) {
inlen = fread(inbuf, 1, step, infile);
if (inlen <= 0)
break;
if ((ret = mbedtls_cipher_update(&ctx, inbuf, inlen, outbuf, &outlen))) {
fprintf(stderr, "Error: mbedtls_cipher_update: %d\n", ret);
goto out;
}
fwrite(outbuf, 1, outlen, outfile);
}
if ((ret = mbedtls_cipher_finish(&ctx, outbuf, &outlen))) {
fprintf(stderr, "Error: mbedtls_cipher_finish: %d\n", ret);
goto out;
}
fwrite(outbuf, 1, outlen, outfile);
out:
mbedtls_cipher_free(&ctx);
return ret;
}
static void check_enc_dec(const int enc)
{
if (enc == -1)
return;
fprintf(stderr, "Error: both -d and -e were specified.\n");
exit(EXIT_FAILURE);
}
static void check_cipher(const mbedtls_cipher_info_t *cipher_info)
{
const int *list;
if (cipher_info == NULL) {
fprintf(stderr, "Error: invalid cipher: %s.\n", optarg);
fprintf(stderr, "Supported ciphers: \n");
for (list = mbedtls_cipher_list(); *list; list++) {
cipher_info = mbedtls_cipher_info_from_type(*list);
if (!cipher_info)
continue;
fprintf(stderr, "\t%s\n", cipher_info->name);
}
exit(EXIT_FAILURE);
}
}
static void show_usage(const char* name)
{
fprintf(stderr, "Usage: %s: [-d | -e] [-n] -k key [-i iv] [-c cipher]\n"
"-d = decrypt; -e = encrypt; -n = no padding\n", name);
}
char *hexstr2buf(const char *str, size_t *len)
{
char *buf;
size_t inlen = strlen(str);
*len = 0;
if (inlen % 2)
return NULL;
*len = inlen >> 1;
buf = malloc(*len);
for (size_t x = 0; x < *len; x++)
sscanf(str + x * 2, "%2hhx", buf + x);
return buf;
}
static char* upperstr(char *str) {
for (char *s = str; *s; s++)
*s = toupper((unsigned char) *s);
return str;
}
int main(int argc, char *argv[])
{
int enc = -1;
unsigned char *iv = NULL;
unsigned char *key = NULL;
size_t keylen = 0, ivlen = 0;
int opt;
int padding = 1;
const mbedtls_cipher_info_t *cipher_info =
mbedtls_cipher_info_from_type (MBEDTLS_CIPHER_AES_128_CBC);
int ret;
while ((opt = getopt(argc, argv, "c:dei:k:n")) != -1) {
switch (opt) {
case 'c':
cipher_info = mbedtls_cipher_info_from_string(upperstr(optarg));
check_cipher(cipher_info);
break;
case 'd':
check_enc_dec(enc);
enc = 0;
break;
case 'e':
check_enc_dec(enc);
enc = 1;
break;
case 'i':
iv = (unsigned char *) hexstr2buf((const char *)optarg, &ivlen);
if (iv == NULL) {
fprintf(stderr, "Error setting IV to %s. The IV should be encoded in hex.\n",
optarg);
exit(EINVAL);
}
break;
case 'k':
key = (unsigned char *) hexstr2buf((const char *)optarg, &keylen);
if (key == NULL) {
fprintf(stderr, "Error setting key to %s. The key should be encoded in hex.\n",
optarg);
exit(EINVAL);
}
break;
case 'n':
padding = 0;
break;
default:
show_usage(argv[0]);
exit(EINVAL);
}
}
if (cipher_info->iv_size) {
if (iv == NULL) {
fprintf(stderr, "Error: iv not set.\n");
show_usage(argv[0]);
exit(EXIT_FAILURE);
}
if (ivlen != cipher_info->iv_size) {
fprintf(stderr, "Error: IV must be %d bytes; given IV is %zd bytes.\n",
cipher_info->iv_size, ivlen);
exit(EXIT_FAILURE);
}
}
if (key == NULL) {
fprintf(stderr, "Error: key not set.\n");
show_usage(argv[0]);
exit(EXIT_FAILURE);
}
if (keylen != cipher_info->key_bitlen >> 3) {
fprintf(stderr, "Error: key must be %d bytes; given key is %zd bytes.\n",
cipher_info->key_bitlen >> 3, keylen);
exit(EXIT_FAILURE);
}
ret = do_crypt(stdin, stdout, cipher_info, key, iv, !!enc, padding);
if (iv)
memset(iv, 0, ivlen);
memset(key, 0, keylen);
free(iv);
free(key);
return ret;
}
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