uencrypt: add support for mbedtls

This commit includes some additional changes:
 - better handling of iv and keys in openssl/wolfssl variants
 - fix compiler warnings and whitespace
 - build all 3 variants as separate packages
 - adjust the new package name in targets' DEVICE_PACKAGES
 - remove PKG_FLAGS:=nonshared

[Beeline SmartBox Flash - OK]
Tested-by: Mikhail Zhilkin <csharper2005@gmail.com>
[after test: replaced a hardcoded IV size of 16 by cipher_info->iv_size]
Signed-off-by: Eneas U de Queiroz <cotequeiroz@gmail.com>

package/utils/uencrypt/Makefile

@@ -4,55 +4,80 @@
 include $(TOPDIR)/rules.mk
 
 PKG_NAME:=uencrypt
-PKG_RELEASE:=3
+PKG_RELEASE:=4
 
-PKG_FLAGS:=nonshared
 PKG_LICENSE:=GPL-2.0-or-later
 PKG_MAINTAINER:=Eneas U de Queiroz <cotequeiroz@gmail.com>
-PKG_CONFIG_DEPENDS:=\
-	CONFIG_UENCRYPT_OPENSSL \
-	CONFIG_UENCRYPT_WOLFSSL
 
 include $(INCLUDE_DIR)/package.mk
 include $(INCLUDE_DIR)/cmake.mk
 
 CMAKE_INSTALL:=1
-CMAKE_OPTIONS+=$(if $(CONFIG_UENCRYPT_WOLFSSL),-DUSE_WOLFSSL=1)
+ifeq ($(BUILD_VARIANT),mbedtls)
+  CMAKE_OPTIONS+=-DUSE_MBEDTLS=1
+else ifeq ($(BUILD_VARIANT),wolfssl)
+  CMAKE_OPTIONS+=-DUSE_WOLFSSL=1
+endif
 
-define Package/uencrypt
+define Package/uencrypt/default
   SECTION:=utils
   CATEGORY:=Base system
-  TITLE:=Decryption utility for Arcadyan WG4xx223 and TP-Link Deco S4
+  TITLE:=Small Decryption utility
-  DEPENDS:=+UENCRYPT_WOLFSSL:libwolfssl +UENCRYPT_OPENSSL:libopenssl
 endef
 
-define Package/uencrypt/description
+define Package/uencrypt/default/description
   This is a small encrypton/decryption program. It defaults
   to AES-128-CBC, but supports any encryption provided by
-  the available openssl/wolfssl library. Even though it can
+  the crypto library. Even though it can be used for
-  be used for regular encryption and decryption operations,
+  non-critical* regular encryption and decryption operations,
   it is included here to unencrypt the configuration from mtd
-  on Arcadyan WG430223/WG443223 and TP-Link Deco S4 routers
+  on some devices.
+
+  * Key and IV are exposed on cmdline
+
+  This variant uses $(1) as crypto provider
 endef
 
-define Package/uencrypt/config
+define Package/uencrypt-mbedtls
-  if PACKAGE_uencrypt
+  $(Package/uencrypt/default)
-    choice
+  VARIANT:=mbedtls
-	prompt "Crypto provider"
+  TITLE+= using mbedTLS
-	default UENCRYPT_WOLFSSL
+  DEPENDS:=+libmbedtls
-
+  CONFLICTS:=uencrypt-openssl uencrypt-wolfssl
-	config UENCRYPT_OPENSSL
-	bool "OpenSSL"
-
-	config UENCRYPT_WOLFSSL
-	bool "wolfSSL"
-    endchoice
-  endif
 endef
 
-define Package/uencrypt/install
+Package/uencrypt-mbedtls/description= \
+  $(call Package/uencrypt/default/description,mbedTLS)
+
+define Package/uencrypt-openssl
+  $(Package/uencrypt/default)
+  VARIANT:=openssl
+  TITLE+= using OpenSSL
+  DEPENDS:=+libopenssl
+  CONFLICTS:=uencrypt-wolfssl
+endef
+
+Package/uencrypt-openssl/description= \
+  $(call Package/uencrypt/default/description,OpenSSL)
+
+define Package/uencrypt-wolfssl
+  $(Package/uencrypt/default)
+  VARIANT:=wolfssl
+  TITLE+= using wolfSSL
+  DEPENDS:=+libwolfssl
+endef
+
+Package/uencrypt-wolfssl/description= \
+  $(call Package/uencrypt/default/description,wolfSSL)
+
+define Package/uencrypt/default/install
 	$(INSTALL_DIR) $(1)/usr/bin
 	$(INSTALL_BIN) $(PKG_INSTALL_DIR)/usr/bin/uencrypt $(1)/usr/bin
 endef
+Package/uencrypt-openssl/install = $(Package/uencrypt/default/install)
+Package/uencrypt-wolfssl/install = $(Package/uencrypt/default/install)
+Package/uencrypt-mbedtls/install = $(Package/uencrypt/default/install)
 
-$(eval $(call BuildPackage,uencrypt))
+$(eval $(call BuildPackage,uencrypt-mbedtls))
+$(eval $(call BuildPackage,uencrypt-openssl))
+$(eval $(call BuildPackage,uencrypt-wolfssl))

package/utils/uencrypt/src/CMakeLists.txt

@@ -5,6 +5,17 @@ cmake_minimum_required(VERSION 2.8.12 FATAL_ERROR)
 project(uencrypt LANGUAGES C)
 
 option(USE_WOLFSSL "Use WolfSSL as crypto provider" OFF)
+option(USE_MBEDTLS "Use mbedTLS as crypto provider" OFF)
+if (USE_MBEDTLS)
+	if (USE_WOLFSSL)
+		message(WARNING "USE_MBEDTLS and USE_WOLFSSL are both set. Building with USE_MBEDTLS.")
+	endif()
+	add_definitions(-DUSE_MBEDTLS)
+	find_library(MBEDCRYPTO_LIBRARY mbedcrypto REQUIRED)
+	set(CRYPTO_LIBRARIES ${MBEDCRYPTO_LIBRARY})
+	add_executable(${PROJECT_NAME} ${PROJECT_NAME}-mbedtls.c)
+else()
+	add_executable(${PROJECT_NAME} ${PROJECT_NAME}-openssl.c)
 	if (USE_WOLFSSL)
 		add_definitions(-DUSE_WOLFSSL)
 		find_library(WOLFSSL_LIBRARY wolfssl REQUIRED)
@@ -13,8 +24,8 @@ else()
 		find_package(OpenSSL REQUIRED)
 		set(CRYPTO_LIBRARIES ${OPENSSL_CRYPTO_LIBRARY})
 	endif()
+endif()
 
-add_executable(${PROJECT_NAME} ${PROJECT_NAME}.c)
 target_link_libraries(${PROJECT_NAME} ${CRYPTO_LIBRARIES})
 
 install(TARGETS ${PROJECT_NAME} RUNTIME DESTINATION bin)

package/utils/uencrypt/src/uencrypt-mbedtls.c

@@ -0,0 +1,212 @@
+/* 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;
+}

package/utils/uencrypt/src/uencrypt-openssl.c

@@ -1,5 +1,5 @@
 /* SPDX-License-Identifier: GPL-2.0-or-later
- * Copyright (C) 2022 Eneas Ulir de Queiroz
+ * Copyright (C) 2022-2023 Eneas Ulir de Queiroz
  */
 
 #include <errno.h>
@@ -15,8 +15,8 @@
 # include <openssl/evp.h>
 #endif
 
-int do_crypt(FILE *infile, FILE *outfile, const EVP_CIPHER *cipher, const char *key, const char *iv,
+int do_crypt(FILE *infile, FILE *outfile, const EVP_CIPHER *cipher, const unsigned char *key,
-	     int enc, int padding)
+	     const unsigned char *iv, int enc, int padding)
 {
     EVP_CIPHER_CTX *ctx;
     unsigned char inbuf[1024], outbuf[1024 + EVP_MAX_BLOCK_LENGTH];
@@ -65,7 +65,7 @@ static void check_cipher(const EVP_CIPHER *cipher)
     if (cipher == NULL) {
 	fprintf(stderr, "Error: invalid cipher: %s.\n", optarg);
 #ifndef USE_WOLFSSL
-        fprintf(stderr, "Supported ciphers: \n", optarg);
+	fprintf(stderr, "Supported ciphers: \n");
 	OBJ_NAME_do_all_sorted(OBJ_NAME_TYPE_CIPHER_METH, print_ciphers, stderr);
 #endif
 	exit(EXIT_FAILURE);
@@ -83,10 +83,10 @@ int main(int argc, char *argv[])
     int enc = -1;
     unsigned char *iv = NULL;
     unsigned char *key = NULL;
-    long len;
+    long ivlen = 0, keylen = 0;
+    int cipher_ivlen, cipher_keylen;
     int opt;
     int padding = 1;
-    int need_iv = 1;
     const EVP_CIPHER *cipher = EVP_aes_128_cbc();
     int ret;
 
@@ -95,9 +95,6 @@ int main(int argc, char *argv[])
 	case 'c':
 	    cipher = EVP_get_cipherbyname(optarg);
 	    check_cipher(cipher);
-	    int arglen = strlen(optarg);
-	    if (arglen > 3 && strncmp(optarg+arglen-3, "ecb", 3) == 0) //if ends with "ecb"
-	        need_iv = 0;
 	    break;
 	case 'd':
 	    check_enc_dec(enc);
@@ -108,7 +105,7 @@ int main(int argc, char *argv[])
 	    enc = 1;
 	    break;
 	case 'i':
-	    iv = OPENSSL_hexstr2buf((const char *)optarg, &len);
+	    iv = OPENSSL_hexstr2buf((const char *)optarg, &ivlen);
 	    if (iv == NULL) {
 		fprintf(stderr, "Error setting IV to %s. The IV should be encoded in hex.\n",
 			optarg);
@@ -116,7 +113,7 @@ int main(int argc, char *argv[])
 	    }
 	    break;
 	case 'k':
-	    key = OPENSSL_hexstr2buf((const char *)optarg, &len);
+	    key = OPENSSL_hexstr2buf((const char *)optarg, &keylen);
 	    if (key == NULL) {
 		fprintf(stderr, "Error setting key to %s. The key should be encoded in hex.\n",
 			optarg);
@@ -131,16 +128,28 @@ int main(int argc, char *argv[])
 	    exit(EINVAL);
 	}
     }
-    if (need_iv && iv == NULL) {
-        fprintf(stderr, "Error: iv not set.\n");
-        show_usage(argv[0]);
-        exit(EXIT_FAILURE);
-    }
     if (key == NULL) {
 	fprintf(stderr, "Error: key not set.\n");
 	show_usage(argv[0]);
 	exit(EXIT_FAILURE);
     }
+    if ((cipher_keylen = EVP_CIPHER_key_length(cipher)) != keylen) {
+	fprintf(stderr, "Error: key must be %d bytes; given key is %ld bytes.\n",
+		cipher_keylen, keylen);
+	exit(EXIT_FAILURE);
+    }
+    if ((cipher_ivlen = EVP_CIPHER_iv_length(cipher))) {
+	if (iv == NULL) {
+	    fprintf(stderr, "Error: IV not set.\n");
+	    show_usage(argv[0]);
+	    exit(EXIT_FAILURE);
+	}
+	if (cipher_ivlen != ivlen) {
+	    fprintf(stderr, "Error: IV must be %d bytes; given IV is %ld bytes.\n",
+		    cipher_ivlen, ivlen);
+	    exit(EXIT_FAILURE);
+	}
+    }
     ret = do_crypt(stdin, stdout, cipher, key, iv, !!enc, padding);
     if (ret)
 	fprintf(stderr, "Error during crypt operation.\n");

target/linux/ath79/image/generic-tp-link.mk

@@ -509,7 +509,7 @@ define Device/tplink_deco-s4-v2
   IMAGE_SIZE := 13824k
   DEVICE_MODEL := Deco S4
   DEVICE_VARIANT := v2
-  DEVICE_PACKAGES := kmod-ath10k-ct ath10k-firmware-qca9888-ct uencrypt
+  DEVICE_PACKAGES := kmod-ath10k-ct ath10k-firmware-qca9888-ct uencrypt-mbedtls
   SUPPORTED_DEVICES += deco-s4-v2
   TPLINK_BOARD_ID := DECO-S4-V2
 endef

target/linux/ramips/image/mt7621.mk

@@ -379,7 +379,7 @@ define Device/beeline_smartbox-flash
   IMAGES += factory.trx
   IMAGE/factory.trx := append-kernel | append-ubi | check-size
   IMAGE/sysupgrade.bin := sysupgrade-tar | append-metadata
-  DEVICE_PACKAGES := kmod-usb3 kmod-mt7615-firmware uencrypt
+  DEVICE_PACKAGES := kmod-usb3 kmod-mt7615-firmware uencrypt-mbedtls
 endef
 TARGET_DEVICES += beeline_smartbox-flash
 
@@ -1587,7 +1587,7 @@ define Device/mts_wg430223
   IMAGES += factory.trx
   IMAGE/factory.trx := append-kernel | append-ubi | check-size
   IMAGE/sysupgrade.bin := sysupgrade-tar | append-metadata
-  DEVICE_PACKAGES := kmod-mt7615-firmware uencrypt
+  DEVICE_PACKAGES := kmod-mt7615-firmware uencrypt-mbedtls
 endef
 TARGET_DEVICES += mts_wg430223