vold: Add encrypted ASEC support via devmapper
- Supports up to 4096 containers
- Keys are now implemented - specifying a key of 'none' means no encryption.
Otherwise, the key must be a string of 32 characters
Signed-off-by: San Mehat <san@google.com>
diff --git a/Devmapper.cpp b/Devmapper.cpp
new file mode 100644
index 0000000..2b7d9a0
--- /dev/null
+++ b/Devmapper.cpp
@@ -0,0 +1,210 @@
+/*
+ * Copyright (C) 2008 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <stdio.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <errno.h>
+#include <string.h>
+
+#include <sys/types.h>
+#include <sys/ioctl.h>
+#include <sys/stat.h>
+
+#define LOG_TAG "Vold"
+
+#include <cutils/log.h>
+
+#include "Devmapper.h"
+
+void Devmapper::ioctlInit(struct dm_ioctl *io, size_t dataSize,
+ const char *name, unsigned flags) {
+ memset(io, 0, dataSize);
+ io->data_size = dataSize;
+ io->data_start = sizeof(struct dm_ioctl);
+ io->version[0] = 4;
+ io->version[1] = 0;
+ io->version[2] = 0;
+ io->flags = flags;
+ strncpy(io->name, name, sizeof(io->name));
+}
+
+int Devmapper::lookupActive(const char *name, char *ubuffer, size_t len) {
+ char *buffer = (char *) malloc(4096);
+ if (!buffer) {
+ LOGE("Error allocating memory (%s)", strerror(errno));
+ return -1;
+ }
+
+ int fd;
+ if ((fd = open("/dev/device-mapper", O_RDWR)) < 0) {
+ LOGE("Error opening devmapper (%s)", strerror(errno));
+ free(buffer);
+ return -1;
+ }
+
+ struct dm_ioctl *io = (struct dm_ioctl *) buffer;
+
+ ioctlInit(io, 4096, name, 0);
+ if (ioctl(fd, DM_DEV_STATUS, io)) {
+ if (errno != ENODEV) {
+ LOGE("Error retrieving device status (%s)", strerror(errno));
+ }
+ free(buffer);
+ close(fd);
+ return -1;
+ }
+ close(fd);
+
+ unsigned minor = (io->dev & 0xff) | ((io->dev >> 12) & 0xfff00);
+ free(buffer);
+ LOGD("Newly created devmapper instance minor = %d\n", minor);
+ snprintf(ubuffer, len, "/dev/block/dm-%u", minor);
+ return 0;
+}
+
+int Devmapper::create(const char *name, const char *loopFile, const char *key, int sizeMb,
+ char *ubuffer, size_t len) {
+ char *buffer = (char *) malloc(4096);
+ if (!buffer) {
+ LOGE("Error allocating memory (%s)", strerror(errno));
+ return -1;
+ }
+
+ int fd;
+ if ((fd = open("/dev/device-mapper", O_RDWR)) < 0) {
+ LOGE("Error opening devmapper (%s)", strerror(errno));
+ free(buffer);
+ return -1;
+ }
+
+ struct dm_ioctl *io = (struct dm_ioctl *) buffer;
+
+ // Create the DM device
+ ioctlInit(io, 4096, name, 0);
+
+ if (ioctl(fd, DM_DEV_CREATE, io)) {
+ LOGE("Error creating device mapping (%s)", strerror(errno));
+ free(buffer);
+ close(fd);
+ return -1;
+ }
+
+ // Set the legacy geometry
+ ioctlInit(io, 4096, name, 0);
+
+ char *geoParams = buffer + sizeof(struct dm_ioctl);
+ // bps=512 spc=8 res=32 nft=2 sec=8190 mid=0xf0 spt=63 hds=64 hid=0 bspf=8 rdcl=2 infs=1 bkbs=2
+ strcpy(geoParams, "0 64 63 0");
+ geoParams += strlen(geoParams) + 1;
+ geoParams = (char *) _align(geoParams, 8);
+ if (ioctl(fd, DM_DEV_SET_GEOMETRY, io)) {
+ LOGE("Error setting device geometry (%s)", strerror(errno));
+ free(buffer);
+ close(fd);
+ return -1;
+ }
+
+ // Retrieve the device number we were allocated
+ ioctlInit(io, 4096, name, 0);
+ if (ioctl(fd, DM_DEV_STATUS, io)) {
+ LOGE("Error retrieving device status (%s)", strerror(errno));
+ free(buffer);
+ close(fd);
+ return -1;
+ }
+
+ unsigned minor = (io->dev & 0xff) | ((io->dev >> 12) & 0xfff00);
+ LOGD("Newly created devmapper instance minor = %d\n", minor);
+ snprintf(ubuffer, len, "/dev/block/dm-%u", minor);
+
+ // Load the table
+ struct dm_target_spec *tgt;
+ tgt = (struct dm_target_spec *) &buffer[sizeof(struct dm_ioctl)];
+
+ ioctlInit(io, 4096, name, DM_STATUS_TABLE_FLAG);
+ io->target_count = 1;
+ tgt->status = 0;
+ tgt->sector_start = 0;
+ tgt->length = (sizeMb * (1024 * 1024)) / 512;
+ strcpy(tgt->target_type, "crypt");
+
+ char *cryptParams = buffer + sizeof(struct dm_ioctl) + sizeof(struct dm_target_spec);
+ sprintf(cryptParams, "twofish %s 0 %s 0", key, loopFile);
+ cryptParams += strlen(cryptParams) + 1;
+ cryptParams = (char *) _align(cryptParams, 8);
+ tgt->next = cryptParams - buffer;
+
+ if (ioctl(fd, DM_TABLE_LOAD, io)) {
+ LOGE("Error loading mapping table (%s)", strerror(errno));
+ free(buffer);
+ close(fd);
+ return -1;
+ }
+
+ // Resume the new table
+ ioctlInit(io, 4096, name, 0);
+
+ if (ioctl(fd, DM_DEV_SUSPEND, io)) {
+ LOGE("Error Resuming (%s)", strerror(errno));
+ free(buffer);
+ close(fd);
+ return -1;
+ }
+
+ free(buffer);
+
+ return 0;
+}
+
+int Devmapper::destroy(const char *name) {
+ char *buffer = (char *) malloc(4096);
+ if (!buffer) {
+ LOGE("Error allocating memory (%s)", strerror(errno));
+ return -1;
+ }
+
+ int fd;
+ if ((fd = open("/dev/device-mapper", O_RDWR)) < 0) {
+ LOGE("Error opening devmapper (%s)", strerror(errno));
+ free(buffer);
+ return -1;
+ }
+
+ struct dm_ioctl *io = (struct dm_ioctl *) buffer;
+
+ // Create the DM device
+ ioctlInit(io, 4096, name, 0);
+
+ if (ioctl(fd, DM_DEV_REMOVE, io)) {
+ LOGE("Error destroying device mapping (%s)", strerror(errno));
+ free(buffer);
+ close(fd);
+ return -1;
+ }
+
+ free(buffer);
+ close(fd);
+ return 0;
+}
+
+void *Devmapper::_align(void *ptr, unsigned int a)
+{
+ register unsigned long agn = --a;
+
+ return (void *) (((unsigned long) ptr + agn) & ~agn);
+}
+