Commit graph

23 commits

Author SHA1 Message Date
Eric Biggers
d86a8abec7 Replace most references to Keymaster with Keystore
Now that vold uses Keystore2 rather than the Keymaster HAL directly, and
also the new version of Keymaster is called "KeyMint" instead, replace
most of the references to Keymaster in vold with Keystore.

(I decided not to include the "2" in most places, as it seemed
unnecessarily precise in most places, and it would be something that
might need to keep being updated.  Only Keystore.{cpp,h} really need to
care about the version number.)

I didn't rename many things in cryptfs.cpp, as that file will be going
away soon anyway.  I also left "wait_for_keymaster" and "vdc keymaster
earlyBootEnded" as-is for now, as those are referenced outside vold.

Bug: 183669495
Change-Id: I92cd648fae09f8c9769f7cf34dbf6c6e956be4e8
2021-06-15 12:07:15 -07:00
Satya Tangirala
351a4af716 Don't export storeKey(), and update comments
storeKey() is no longer used outside KeyStorage.cpp, so make it a static
function.  Also fix the documentation for storeKey() (e.g. it's no
longer safe to directly move/rename directories created by storeKey() --
one must use RenameKeyDir() instead).

No functional changes.

[ebiggers@ - cleaned up slightly from satyat@'s original change]

Bug: 190398249
Change-Id: I85918359e77bef414dfddfe5ded30fcde6514013
2021-06-08 15:57:31 -07:00
Satya Tangirala
0f890a93e1 Always use RenameKeyDir() when moving/renaming key directories
Make fixate_user_ce_key() use RenameKeyDir() to rename key directories
so that any deferred commits for these directories are also updated
appropriately.

This fixes a potential lost Keymaster key upgrade if a key were to be
re-wrapped while a user data checkpoint is pending.  This isn't a huge
issue as the key will just get upgraded again, but this should be fixed.

[ebiggers@ - cleaned up slightly from satyat@'s original change]

Bug: 190398249
Change-Id: Ic6c5b4468d07ab335368e3d373916145d096af01
2021-06-08 15:57:31 -07:00
Satya Tangirala
6b98fb6122 Remove unused constants and cleanup KeyStorage.cpp
Now that the salt and hardware auth token related code has been removed,
we can remove the associated (and now unused) constants.

Also cleanup some comments and remove includes related to hardware auth
token support.

Bug: 181910578
Test: Cuttlefish boots.
Change-Id: I3733d5c6bbf6989adc165c554ee53faa2484f4b6
2021-05-12 13:05:35 -07:00
Satya Tangirala
e13617100d Remove HardwareAuthToken support from vold::Keymaster
HardwareAuthTokens are no longer used by vold since Android P. So remove
the auth token parameter from vold. This patch doesn't remove the token
from IVold.aidl, and the methods in VoldNativeService.cpp return an
error if a non-empty auth token is passed to them.

Bug: 181910578
Test: cuttlefish and bramble boot with patch
Change-Id: I1a9f54e10f9efdda9973906afd0a5de5a699ada5
2021-04-07 02:05:35 -07:00
Eric Biggers
3345a2a98c Sync parent directory in storeKeyAtomically()
When an FBE or metadata encryption key is created, it's important that
it be persisted to disk right away; otherwise the device may fail to
boot after an unclean shutdown.  storeKey() has the needed fsync()s.
However, storeKeyAtomically() doesn't, as it doesn't fsync() the parent
directory of key_path after it renames tmp_path to it.

Two callers do fsync() the parent directory themselves, but others
don't.  E.g., the metadata encryption key doesn't get properly synced.

Therefore, add the needed fsync() to storeKeyAtomically() so that it
gets done for everyone.

Also remove the now-unneeded fsync()s from the two callers that did it
themselves.

Change-Id: I342ebd94f0a3d2bf3a7a443c35b6bda0f12e1ab2
2021-02-16 16:05:38 -08:00
Eric Biggers
bd138dd08a Move pathExists() to Utils.cpp
This is useful as a general utility function.

Change-Id: Id43fc106dc6c544c6e4ce65f10c7d4246b99e54a
2021-02-16 16:05:38 -08:00
Seth Moore
5a43d61e66 Add support for binding storage encryption to a seed
With this change, vold exposes an API that may be used to bind key
storage encryption keys to a given seed value. The seed value passed to
vold must be consistent across reboots, or key storage keys will not be
derived consistently. The seed is expected to be set very early in boot,
prior to the use of any key storage encryption keys.

This feature is intended to be used for embedded applications such as
in autos, where the seed may be provided by some other component of the
system. In such systems, there is a default user that is automatically
signed in without a PIN or other credentials. By binding the file
encryption to a platform-provided seed, the default user's data gains
additional protection against removal of the Android embedded device
from the integrated system.

Bug: 157501579
Test: Set seed at startup via init.rc. Seed changes fail as expected.
Change-Id: I9b048ec5e045b84c45883724ace2356d4ef6244d
2021-01-26 21:30:19 +00:00
Eric Biggers
f74373b177 KeyStorage: rework key upgrade handling
Remove the error-prone 'keepOld' parameter, and instead make begin()
(renamed to BeginKeymasterOp()) do all the key upgrade handling.

Don't handle /data and /metadata differently anymore.  Previously, when
a checkpoint is active, key blob files were replaced on /data
immediately; only the actual Keymaster key deletion was delayed until
checkpoint commit.  But it's easier to just delay the key blob file
replacement too, as we have to implement that for /metadata anyway.

Also be more vigilant about deleting any leftover upgraded keys.

Test: Tested on bramble using an OTA rvc-d1-release => master.  In OTA
      success case, verified via logcat that the keys were upgraded and
      then were committed after the boot succeeded.  In OTA failure
      case, verified that the device still boots -- i.e., the old keys
      weren't lost.  Verified that in either case, no
      keymaster_key_blob_upgraded files were left over.  Finally, also
      tried 'pm create-user' and 'pm remove-user' and verified via
      logcat that the Keymaster keys still get deleted.
Change-Id: Ic9c3e63e0bcae0c608fc79050ca4a1676b3852ee
2020-11-05 19:58:26 -08:00
Eric Biggers
c493903732 KeyUtil: don't use keepOld=true for system DE and volume keys
Commit 77df7f207d / http://aosp/1217657 ("Refactor to use
EncryptionPolicy everywhere we used to use raw_ref") unintentionally
made fscrypt_initialize_systemwide_keys() start specifying keepOld=true
(via default parameter value) when retrieving the system DE key, and
likewise for read_or_create_volkey() and volume keys.

As a result, if the associated Keymaster key needs to be upgraded, the
upgraded key blob gets written to "keymaster_key_blob_upgraded", but it
doesn't replace the original "keymaster_key_blob", nor is the original
key deleted from Keymaster.  This happens at every boot, eventually
resulting in the RPMB partition in Keymaster becoming full.

Only the metadata encryption key ever needs keepOld=true, since it's the
only key that isn't stored in /data, and the purpose of keepOld=true is
to allow a key that isn't stored in /data to be committed or rolled back
when a userdata checkpoint is committed or rolled back.

So, fix this bug by removing the default value of keepOld, and
specifying false everywhere except the metadata encryption key.

Note that when an affected device gets this fix, it will finally upgrade
its system DE key correctly.  However, this fix doesn't free up space in
Keymaster that was consumed by this bug.

Test: On bramble:
  - Flashed rvc-d1-dev build, with wiping userdata
  - Flashed a newer build, without wiping userdata
  - Log expectedly shows key upgrades:
        $ adb logcat | grep 'Upgrading key'
        D vold    : Upgrading key: /metadata/vold/metadata_encryption/key
        D vold    : Upgrading key: /data/unencrypted/key
        D vold    : Upgrading key: /data/misc/vold/user_keys/de/0
        D vold    : Upgrading key: /data/misc/vold/user_keys/ce/0/current
  - Rebooted
  - Log unexpectedly shows the system DE key being upgraded again:
        $ adb logcat | grep 'Upgrading key'
        D vold    : Upgrading key: /data/unencrypted/key
  - "keymaster_key_blob_upgraded" unexpectedly still exists:
        $ adb shell find /data /metadata -name keymaster_key_blob_upgraded
        /data/unencrypted/key/keymaster_key_blob_upgraded
  - Applied this fix and flashed, without wiping userdata
  - Log shows system DE key being upgraded (expected because due to the
    bug, the upgraded key didn't replace the original one before)
        $ adb logcat | grep 'Upgrading key'
        D vold    : Upgrading key: /data/unencrypted/key
  - "keymaster_key_blob_upgraded" expectedly no longer exists
        $ adb shell find /data /metadata -name keymaster_key_blob_upgraded
  - Rebooted
  - Log expectedly doesn't show any more key upgrades
        $ adb logcat | grep 'Upgrading key'
Bug: 171944521
Bug: 172019387
Change-Id: I42d3f5fbe32cb2ec229f4b614cfb271412a3ed29
2020-10-30 14:53:43 -07:00
Barani Muthukumaran
3dfb094cb2 vold: Support Storage keys for FBE
To prevent keys from being compromised if an attacker
acquires read access to kernel memory, some inline
encryption hardware supports protecting the keys in
hardware without software having access to or the
ability to set the plaintext keys.  Instead, software
only sees "wrapped keys", which may differ on every boot.

'wrappedkey_v0' fileencryption flag is used to denote
that the device supports inline encryption hardware that
supports this feature. On such devices keymaster is used
to generate keys with STORAGE_KEY tag and export a
per-boot ephemerally wrapped storage key to install it in
the kernel.

The wrapped key framework in the linux kernel ensures the
wrapped key is provided to the inline encryption hardware
where it is unwrapped and the file contents key is derived
to encrypt contents without revealing the plaintext key in
the clear.

Test: FBE validation with Fscrypt v2 + inline crypt + wrapped
key changes kernel.

Bug: 147733587

Change-Id: I1f0de61b56534ec1df9baef075acb74bacd00758
2020-02-12 14:26:26 -08:00
Greg Kaiser
8ae16db72a vold: Pass std::string by const reference
In a couple places, we change to pass a std::string argument
instead of by copy.

Test: TreeHugger
Change-Id: Ib179299a2322fcbab4e6d192051218823ad66a36
2018-12-20 10:38:31 -08:00
Daniel Rosenberg
690d6de5bf Add Support for metadata key with rollback
This adds the ability to upgrade a key and retain the
old one for rollback purposes. We delete the old key
if we boot successfully and delete the new key if we
do not.

Test: Enable checkpointing and test rolling back
      between two versions
Bug: 111020314

Change-Id: I19f31a1ac06a811c0644fc956e61b5ca84e7241a
2018-12-14 14:55:28 -08:00
Paul Crowley
26a53888a4 When we forget a volume, forget per-volume key
Protect all per-volume-per-user keys with a per-volume key, which is
forgotten when the volume is forgotten. This means that the user's key
is securely lost even when their storage is encrypted at forgetting
time.

Bug: 25861755
Test: create a volume, forget it, check logs and filesystem.
Change-Id: I8df77bc91bbfa2258e082ddd54d6160dbf39b378
2017-10-26 12:19:09 -07:00
Pavel Grafov
e2e2d308df Zero memory used for encryuption keys.
std::vector with custom zeroing allocator is used instead of
std::string for data that can contain encryption keys.

Bug: 64201177
Test: manually created a managed profile, changed it's credentials
Test: manually upgraded a phone with profile from O to MR1.
Change-Id: Ic31877049f69eba9f8ea64fd99acaaca5a01d3dd
2017-08-10 17:31:03 +01:00
Rubin Xu
2436e27717 Add secdiscard command for secure deletion of files
This is used by LockSettingsService to delete sensitive credential files.

Bug: 34600579
Test: manual - change device lock under synthetic password, verify
      old data on disk is erased.

Change-Id: I5e11b559ad8818bd2ad2b321d67d21477aab7555
2017-05-16 12:44:02 +01:00
Paul Crowley
f71ace310e Refactor to lay the groundwork for metadata encryption
Bug: 26778031
Test: Angler, Marlin build and boot
Change-Id: Ic136dfe6195a650f7db76d3489f36da6a1929dc5
2017-04-21 10:47:17 -07:00
Paul Crowley
6ab2cabd19 Support keys with a secret but no token, which are handled not using
Keymaster but in-process crypto.

Bug: 33384925
Test: manual for now: patch KeyAuthentication.usesKeymaster() to always return true;
      flash a FBE device, add a device PIN, reboot and verify PIN can unlock FBE.
      Then clear device PIN, reboot and verify FBE is unlocked automatically.
      In both cases, check there is no keymaster_key_blob in
      /data/misc/vold/user_keys/ce/0/current/
      Unit tests to be added.
Change-Id: Ia94e2b39d60bfd98c7a8347a5ba043eeab6928c5
2017-02-13 23:37:31 +00:00
Paul Crowley
df528a7011 Run clang-format over ext4crypt related code
The formatting here is inconsistent with Android house style; use
clang-format to bring it back into line.

Change-Id: Id1fe6ff54e9b668ca88c3fc021ae0a5bdd1327eb
2016-03-09 09:34:13 -08:00
Paul Crowley
a051eb7a22 Use pointers not references for out arguments
Google/Android C++ style requires that arguments passed in for writing
should be pointers, not references, so that it's visible in the caller
that they'll be written to.

Bug: 27566014
Change-Id: I5cd55906cc4b2f61c8b97b223786be0b3ce28862
2016-03-09 09:32:02 -08:00
Paul Crowley
0572080814 Password security for FBE disk encryption keys
Added a new call change_user_key which changes the way that disk
encryption keys are protected; a key can now be protected with a
combination of an auth token and a secret which is a hashed password.
Both of these are passed to unlock_user_key.

This change introduces a security bug, b/26948053, which must be fixed
before we ship.

Bug: 22950892
Change-Id: Iac1e45bb6f86f2af5c472c70a0fe3228b02115bf
2016-02-08 20:03:57 +00:00
Paul Crowley
13ffd8ef7a Improvements to the key storage module
The key storage module didn't comply with Android coding standards
and had room for improvemnet in a few other ways, so have cleaned up.

Change-Id: I260ccff316423169cf887e538113b5ea400892f2
2016-01-27 15:54:35 +00:00
Paul Crowley
1ef255816c Use a keymaster-based key storage module
Instead of writing raw keys, encrypt the keys with keymaster. This
paves the way to protecting them with auth tokens and passwords later.
In addition, fold in the hash of a 16k file into their encryption, to
ensure secure deletion works properly.

Now even C++ier!

Bug: 22502684
Bug: 22950892
Change-Id: If70f139e342373533c42d5a298444b8438428322
2016-01-26 18:24:03 +00:00