New behavior. Backup no longer uses the encryption password. This is in
part because that is hard with patterns, in part because it is a security
issue - the off line backup is much easier to brute force than the phone.
Instead, we simply insist on an encryption password if your device is encrypted
and locked.
Bug: 17159330
Change-Id: Ia22f84722522abf0b569a3ef1e16ead5527c726d
This supersedes any backup-password that the user might supply. Per
design, the device encryption password is also always used to encrypt
the backup archive.
The CL introduces two new strings, used for prompting the user for
their device encryption password rather than their settings-defined
"backup password" when confirming a full backup or restore operation.
Bug 5382487
Change-Id: I0b03881b45437c944eaf636b6209278e1bba7a9f
Since the confirmation uses the same Activity but different layouts
for the backup vs restore cases, we have to do the title in code.
Along the way, fix the restore layout's padding [the backup layout
was already right].
Fixes bug 5164470
Change-Id: I4d636f666d97fc377e9cf36abf08d1625a05577f
We now don't automatically deny the operation if stopped, but instead
allow the activity to be destroyed and recreated as usual. We retain
the observer instance across that sequence so we keep getting progress
reports etc.
The UI now also uses the spiffy new button bar styles, and positions
the deny / confirm buttons according to ICS standards.
Bug 5115411
Change-Id: Ie760a0c8496c69f9d5881273a63ad5b5b76ff554
Now the textual content and password fields are placed in scroll view,
and the confirm/deny buttons pinned at the bottom of the layout.
Previously, in landscape mode on some devices the buttons would be
pushed off screen.
Bug 5115411
Change-Id: I8bf8fd1516735bf6111893df79636b519dbfb803
Specifically, we now also require the current password to confirm any
restore operation.
Bug 4901637
Change-Id: I39ecce7837f70cd05778cb7e0e6390ad8f6fe3f3
If the user has supplied a backup password in Settings, that password
is validated during the full backup process and is used as an encryption
key for encoding the backed-up data itself. This is the fundamental
mechanism whereby users can secure their data even against malicious
parties getting physical unlocked access to their device.
Technically the user-supplied password is not used as the encryption
key for the backed-up data itself. What is actually done is that a
random key is generated to use as the raw encryption key. THAT key,
in turn, is encrypted with the user-supplied password (after random
salting and key expansion with PBKDF2). The encrypted master key
and a checksum are stored in the backup header. At restore time,
the user supplies their password, which allows the system to decrypt
the master key, which in turn allows the decryption of the backup
data itself.
The checksum is part of the archive in order to permit validation
of the user-supplied password. The checksum is the result of running
the user-supplied password through PBKDF2 with a randomly selected
salt. At restore time, the proposed password is run through PBKDF2
with the salt described by the archive header. If the result does
not match the archive's stated checksum, then the user has supplied
the wrong decryption password.
Also, suppress backup consideration for a few packages whose
data is either nonexistent or inapplicable across devices or
factory reset operations.
Bug 4901637
Change-Id: Id0cc9d0fdfc046602b129f273d48e23b7a14df36
