diff options
Diffstat (limited to 'adb/disable_verity_service.c')
| -rw-r--r-- | adb/disable_verity_service.c | 199 |
1 files changed, 199 insertions, 0 deletions
diff --git a/adb/disable_verity_service.c b/adb/disable_verity_service.c new file mode 100644 index 0000000..ed3da52 --- /dev/null +++ b/adb/disable_verity_service.c @@ -0,0 +1,199 @@ +/* + * Copyright (C) 2014 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 "sysdeps.h" + +#define TRACE_TAG TRACE_ADB +#include "adb.h" + +#include <stdio.h> +#include <stdarg.h> +#include <sys/stat.h> +#include <fcntl.h> +#include <inttypes.h> + +#include "cutils/properties.h" +#include "ext4_sb.h" +#include <fs_mgr.h> + +#define FSTAB_PREFIX "/fstab." +struct fstab *fstab; + +__attribute__((__format__(printf, 2, 3))) __nonnull((2)) +static void write_console(int fd, const char* format, ...) +{ + char buffer[256]; + va_list args; + va_start (args, format); + vsnprintf (buffer, sizeof(buffer), format, args); + va_end (args); + + adb_write(fd, buffer, strnlen(buffer, sizeof(buffer))); +} + +static int get_target_device_size(int fd, const char *blk_device, + uint64_t *device_size) +{ + int data_device; + struct ext4_super_block sb; + struct fs_info info; + + info.len = 0; /* Only len is set to 0 to ask the device for real size. */ + + data_device = adb_open(blk_device, O_RDONLY | O_CLOEXEC); + if (data_device < 0) { + write_console(fd, "Error opening block device (%s)\n", strerror(errno)); + return -1; + } + + if (lseek64(data_device, 1024, SEEK_SET) < 0) { + write_console(fd, "Error seeking to superblock\n"); + adb_close(data_device); + return -1; + } + + if (adb_read(data_device, &sb, sizeof(sb)) != sizeof(sb)) { + write_console(fd, "Error reading superblock\n"); + adb_close(data_device); + return -1; + } + + ext4_parse_sb(&sb, &info); + *device_size = info.len; + + adb_close(data_device); + return 0; +} + +static int disable_verity(int fd, const char *block_device, + const char* mount_point) +{ + uint32_t magic_number; + const uint32_t voff = VERITY_METADATA_MAGIC_DISABLE; + uint64_t device_length; + int device; + int retval = -1; + + device = adb_open(block_device, O_RDWR | O_CLOEXEC); + if (device == -1) { + write_console(fd, "Could not open block device %s (%s).\n", + block_device, strerror(errno)); + write_console(fd, "Maybe run adb remount?\n"); + goto errout; + } + + // find the start of the verity metadata + if (get_target_device_size(fd, (char*)block_device, &device_length) < 0) { + write_console(fd, "Could not get target device size.\n"); + goto errout; + } + + if (lseek64(device, device_length, SEEK_SET) < 0) { + write_console(fd, + "Could not seek to start of verity metadata block.\n"); + goto errout; + } + + // check the magic number + if (adb_read(device, &magic_number, sizeof(magic_number)) + != sizeof(magic_number)) { + write_console(fd, "Couldn't read magic number!\n"); + goto errout; + } + + if (magic_number == VERITY_METADATA_MAGIC_DISABLE) { + write_console(fd, "Verity already disabled on %s\n", mount_point); + goto errout; + } + + if (magic_number != VERITY_METADATA_MAGIC_NUMBER) { + write_console(fd, + "Couldn't find verity metadata at offset %"PRIu64"!\n", + device_length); + goto errout; + } + + if (lseek64(device, device_length, SEEK_SET) < 0) { + write_console(fd, + "Could not seek to start of verity metadata block.\n"); + goto errout; + } + + if (adb_write(device, &voff, sizeof(voff)) != sizeof(voff)) { + write_console(fd, "Could not set verity disabled flag on device %s\n", + block_device); + goto errout; + } + + write_console(fd, "Verity disabled on %s\n", mount_point); + retval = 0; +errout: + if (device != -1) + adb_close(device); + return retval; +} + +void disable_verity_service(int fd, void* cookie) +{ +#ifdef ALLOW_ADBD_DISABLE_VERITY + char fstab_filename[PROPERTY_VALUE_MAX + sizeof(FSTAB_PREFIX)]; + char propbuf[PROPERTY_VALUE_MAX]; + int i; + bool any_disabled = false; + + property_get("ro.secure", propbuf, "0"); + if (strcmp(propbuf, "1")) { + write_console(fd, "verity not enabled - ENG build\n"); + goto errout; + } + + property_get("ro.debuggable", propbuf, "0"); + if (strcmp(propbuf, "1")) { + write_console(fd, "verity cannot be disabled - USER build\n"); + goto errout; + } + + property_get("ro.hardware", propbuf, ""); + snprintf(fstab_filename, sizeof(fstab_filename), FSTAB_PREFIX"%s", propbuf); + + fstab = fs_mgr_read_fstab(fstab_filename); + if (!fstab) { + write_console(fd, "Failed to open %s\nMaybe run adb root?\n", + fstab_filename); + goto errout; + } + + /* Loop through entries looking for ones that vold manages */ + for (i = 0; i < fstab->num_entries; i++) { + if(fs_mgr_is_verified(&fstab->recs[i])) { + if (!disable_verity(fd, fstab->recs[i].blk_device, + fstab->recs[i].mount_point)) { + any_disabled = true; + } + } + } + + if (any_disabled) { + write_console(fd, + "Now reboot your device for settings to take effect\n"); + } +#else + write_console(fd, "disable-verity only works for userdebug builds\n"); +#endif + +errout: + adb_close(fd); +} |