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authorDinesh K Garg <dineshg@codeaurora.org>2014-01-20 21:55:32 (GMT)
committerZhao Wei Liew <zhaoweiliew@gmail.com>2017-02-12 12:39:24 (GMT)
commitffb80b2c0a2f614941657a6952630c6523da26d2 (patch)
treea4833310777ff9ce46e8371321a55aa383fe27ac /cryptfs_hw.c
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vold: HW based device encryption
SW based device encryption uses SW crypto engine. This module provides the support for VOLD to utilize HW crypto engine. HW based crypto engine is more efficient both in terms of power and throughput. Change-Id: I34107a0ce50d9fc5c80c15ace0678a0bba7adee5
Diffstat (limited to 'cryptfs_hw.c')
-rw-r--r--cryptfs_hw.c167
1 files changed, 167 insertions, 0 deletions
diff --git a/cryptfs_hw.c b/cryptfs_hw.c
new file mode 100644
index 0000000..16b614c
--- /dev/null
+++ b/cryptfs_hw.c
@@ -0,0 +1,167 @@
+/* Copyright (c) 2014, The Linux Foundation. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ * * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following
+ * disclaimer in the documentation and/or other materials provided
+ * with the distribution.
+ * * Neither the name of The Linux Foundation nor the names of its
+ * contributors may be used to endorse or promote products derived
+ * from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED "AS IS" AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS
+ * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
+ * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
+ * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
+ * OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN
+ * IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <cryptfs_hw.h>
+#include <stdlib.h>
+#include <sys/limits.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <dirent.h>
+#include <dlfcn.h>
+#include "cutils/log.h"
+#include "cutils/android_reboot.h"
+
+
+// MAX_PASSWORD_ATTEMPTS must not be changed as it is enforced by HW
+#define MAX_PASSWORD_ATTEMPTS 50
+#define QSEECOM_DISK_ENCRYPTION 1
+#define MAX_PASSWORD_LEN 32
+
+/* Operations that be performed on HW based device encryption key */
+#define SET_HW_DISK_ENC_KEY 1
+#define UPDATE_HW_DISK_ENC_KEY 2
+
+static int password_attempts = 0;
+static int loaded_library = 0;
+static unsigned char current_passwd[MAX_PASSWORD_LEN];
+static int (*qseecom_create_key)(int, void*);
+static int (*qseecom_update_key)(int, void*, void*);
+
+static unsigned char* get_tmp_passwd(const char* passwd)
+{
+ int passwd_len = 0;
+ unsigned char * tmp_passwd = NULL;
+ if(passwd) {
+ tmp_passwd = (unsigned char*)malloc(MAX_PASSWORD_LEN);
+ if(tmp_passwd) {
+ memset(tmp_passwd, 0, MAX_PASSWORD_LEN);
+ passwd_len = (strlen(passwd) > MAX_PASSWORD_LEN) ? MAX_PASSWORD_LEN : strlen(passwd);
+ memcpy(tmp_passwd, passwd, passwd_len);
+ } else {
+ SLOGE("%s: Failed to allocate memory for tmp passwd \n", __func__);
+ }
+ } else {
+ SLOGE("%s: Passed argument is NULL \n", __func__);
+ }
+ return tmp_passwd;
+}
+
+static void wipe_userdata()
+{
+ mkdir("/cache/recovery", 0700);
+ int fd = open("/cache/recovery/command", O_RDWR|O_CREAT|O_TRUNC, 0600);
+ if (fd >= 0) {
+ write(fd, "--wipe_data", strlen("--wipe_data") + 1);
+ close(fd);
+ } else {
+ SLOGE("could not open /cache/recovery/command\n");
+ }
+ android_reboot(ANDROID_RB_RESTART2, 0, "recovery");
+}
+
+static int load_qseecom_library()
+{
+ const char *error = NULL;
+ if (loaded_library)
+ return loaded_library;
+
+ void * handle = dlopen("/vendor/lib/libQSEEComAPI.so", RTLD_NOW);
+ if(handle) {
+ dlerror(); /* Clear any existing error */
+ *(void **) (&qseecom_create_key) = dlsym(handle,"QSEECom_create_key");
+
+ if((error = dlerror()) == NULL) {
+ SLOGD("Success loading QSEECom_create_key \n");
+ *(void **) (&qseecom_update_key) = dlsym(handle,"QSEECom_update_key_user_info");
+ if ((error = dlerror()) == NULL)
+ loaded_library = 1;
+ else
+ SLOGE("Error %s loading symbols for QSEECom APIs \n", error);
+ }
+ } else {
+ SLOGE("Could not load libQSEEComAPI.so \n");
+ }
+
+ if(error)
+ dlclose(handle);
+
+ return loaded_library;
+}
+
+static int set_key(const char* passwd, const char* enc_mode, int operation)
+{
+ int ret = 0;
+ int err = -1;
+ if (is_hw_disk_encryption(enc_mode) && load_qseecom_library()) {
+ unsigned char* tmp_passwd = get_tmp_passwd(passwd);
+ if(tmp_passwd) {
+
+ if (operation == UPDATE_HW_DISK_ENC_KEY)
+ err = qseecom_update_key(QSEECOM_DISK_ENCRYPTION, current_passwd, tmp_passwd);
+ else if (operation == SET_HW_DISK_ENC_KEY)
+ err = (*qseecom_create_key)(QSEECOM_DISK_ENCRYPTION, tmp_passwd);
+
+ if(!err) {
+ memset(current_passwd, 0, MAX_PASSWORD_LEN);
+ memcpy(current_passwd, tmp_passwd, MAX_PASSWORD_LEN);
+ password_attempts = 0;
+ ret = 1;
+ } else {
+ if(++password_attempts >= MAX_PASSWORD_ATTEMPTS)
+ wipe_userdata();
+ }
+ SLOGD("Password attempt = %d", password_attempts);
+ free(tmp_passwd);
+ }
+ }
+ return ret;
+}
+
+int set_hw_device_encryption_key(const char* passwd, const char* enc_mode)
+{
+ return set_key(passwd, enc_mode, SET_HW_DISK_ENC_KEY);
+}
+
+int update_hw_device_encryption_key(const char* newpw, const char* enc_mode)
+{
+
+ return set_key(newpw, enc_mode, UPDATE_HW_DISK_ENC_KEY);
+}
+
+int is_hw_disk_encryption(const char* encryption_mode)
+{
+ int ret = 0;
+ if(encryption_mode) {
+ if (!strcmp(encryption_mode, "aes-xts")) {
+ SLOGD("HW based disk encryption is enabled \n");
+ ret = 1;
+ }
+ }
+ return ret;
+}