vold works with two broad classes of block devices: untrusted devices
that come in from the wild, and trusted devices like PrivateVolume
which are encrypted.
When running blkid and fsck, we pick which SELinux execution domain
to use based on which class the device belongs to.
Bug: 19993667
Change-Id: I2695f028710a4863f0c3b2ed6da437f466401272
This adds support for private volumes which is just a filesystem
wrapped in a dm-crypt layer. For now we're using the exact same
configuration as internal encryption (aes-cbc-essiv:sha256), but we
don't store any key material on the removable media. Instead, we
store the key on internal storage, and use the GPT partition GUID
to identify which key should be used.
This means that private external storage is effectively as secure as
the internal storage of the device. That is, if the internal storage
is encrypted, then our external storage key is also encrypted.
When partitioning disks, we now support a "private" mode which has
a PrivateVolume partition, and a currently unused 16MB metadata
partition reserved for future use. It also supports a "mixed" mode
which creates both a PublicVolume and PrivateVolume on the same
disk. Mixed mode is currently experimental.
For now, just add ext4 support to PrivateVolume; we'll look at f2fs
in a future change. Add VolumeBase lifecycle for setting up crypto
mappings, and extract blkid logic into shared method. Sprinkle some
more "static" around the cryptfs code to improve invariants.
Bug: 19993667
Change-Id: Ibd1df6250735b706959a1eb9d9f7219ea85912a0
Wire up new Disk and VolumeBase objects and events to start replacing
older DirectVolume code. Use filesystem UUID as visible PublicVolume
name to be more deterministic.
When starting, create DiskSource instances based on fstab, and watch
for kernel devices to appear. Turn matching devices into Disk
objects, scan for partitions, and create any relevant VolumeBase
objects. Broadcast all of these events towards userspace so the
framework can decide what to mount.
Keep track of the primary VolumeBase, and update the new per-user
/storage/self/primary symlink for all started users.
Provide a reset command that framework uses to start from a known
state when runtime is restarted. When vold is unexpectedly killed,
try recovering by unmounting everything under /mnt and /storage
before moving forward.
Remove UMS sharing support for now, since no current devices support
it; MTP is the recommended solution going forward because it offers
better multi-user support.
Switch killProcessesWithOpenFiles() to directly take signal. Fix
one SOCK_CLOEXEC bug, but SELinux says there are more lurking.
Bug: 19993667
Change-Id: I2dad1303aa4667ec14c52f774e2a28b3c1c1ff6d
This is the first in a series of changes that are designed to
introduce better support for dynamic block devices.
It starts by defining a new Volume object which represents a storage
endpoint that knows how to mount, unmount, and format itself. This
could be a filesystem directly on a partition, or it could be an
emulated FUSE filesystem, an ASEC, or an OBB.
These new volumes can be "stacked" so that unmounting a volume will
also unmount any volumes stacked above it. Volumes that provide
shared storage can also be asked to present themselves (through bind
mounts) into user-specific mount areas.
This change also adds a Disk class which is created based on block
kernel netlink events. Instead of waiting for partition events from
the kernel, it uses gptfdisk to read partition details and creates
the relevant Volume objects.
Change-Id: I0e8bc1f8f9dcb24405f5e795c0658998e22ae2f7
Jeff Sharkey
Dan Albert