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16 commits

Author SHA1 Message Date
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
Nikita Ioffe
1c6731c649 fskeyring & userspace reboot: support CE keys
During userspace reboot /data might be unmounted & remounted, meaning
that CE keys stored in fs-level keyring will be lost. In order to be
able to restore them, when installing new key to fs-level keyring, it's
also added to session-level keyring with type "fscrypt-provisioning".

Then when init_user0 is called during userspace reboot, vold will try to
load CE keys from the session-level keyring back into fs-level keyring
for all the users that were unlocked before the reboot.

If for any user vold fails to install the key, init_user0 will fail and
fallback to hard reboot will be triggered.

Test: set a pin pattern
Test: adb shell setprop sys.init.userdata_remount.force_umount 1
Test: adb shell svc power reboot userspace
Test: atest CtsUserspaceRebootHostSideTestCases
Bug: 143970043
Change-Id: I37603dc136c7ededc7b0381e4d730cb0ffd912b4
Merged-In: I37603dc136c7ededc7b0381e4d730cb0ffd912b4
(cherry picked from commit 1ee35cf002)
2020-03-11 11:46:46 +00:00
Paul Crowley
249c2fb4aa Refactor: make makeGen local
No need for KeyUtil to know how to make a KeyGeneration, it's cleaner
if each module handles it separately. Also, create a CryptoOptions
structure to track metadata encryption options, and simplify legacy
cipher/option handling.

Test: Treehugger
Bug: 147814592
Change-Id: I740063882914097329ff72348d0c0855c26c7aab
2020-02-18 12:49:36 -08:00
Paul Crowley
4eac264727 Refactor key generation to handle both normal and metadata encryption.
Bug: 147733587
Test: Treehugger
Change-Id: Iee176037dec2621c84da325c2627f988fcebbc8d
Merged-In: Iee176037dec2621c84da325c2627f988fcebbc8d
2020-02-14 13:59:06 -08:00
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
Paul Crowley
77df7f207d Refactor to use EncryptionPolicy everywhere we used to use raw_ref
Test: Boots, no bad log messages: Cuttlefish with v2 policies, Taimen
Bug: 147733587
Change-Id: Ice4acac3236b6b7d90e60a2f57b46814aa1949f5
2020-01-28 11:17:58 -08:00
Eric Biggers
83a73d7d50 vold: support v2 encryption policies
Add support for setting v2 encryption policies when configured in the
fstab (for internal storage) or in system properties (for adoptable
storage), and for installing and evicting the keys for such policies.

v2 policies support the same encryption modes and flags as v1 policies,
but internally they use a more standard, secure, and flexible KDF.  Due
to this, some future features will be supported by v2 policies only.

Bug: 140500999
Test: Configured a device to use v2 encryption policies (applied the
      needed kernel patches and added
      "fileencryption=aes-256-xts:aes-256-cts:v2" to fstab, and set the
      corresponding system properties for adoptable storage).  Wiped
      userdata, booted device and checked logs to verify that v2
      policies were being used.

      Also enabled virtual SD card and formatted as adoptable storage;
      verified it works and that v2 policies were being used on it.

      Also created, started, and stopped a 2nd user and verified their
      keys were evicted.

      Also verified that the device comes up again after rebooting.

      Also verified that a device using v1 encryption policies continues
      to work, both with and without an updated kernel -- including
      stopping a user so that their keys get evicted.

Change-Id: If64028d8580584b2c33c614cabd5d6b93657f608
2019-10-04 16:04:36 -07:00
Eric Biggers
f3dc4203dd vold: use new ioctls to add/remove fscrypt keys when supported
When the kernel supports the new fscrypt key management ioctls, use them
instead of add_key() and keyctl_unlink().

This will be needed in order to support v2 encryption policies, since v2
encryption policies only support the new ioctls.

The new ioctls have other advantages too.  For example,
FS_IOC_REMOVE_ENCRYPTION_KEY automatically evicts exactly the necessary
kernel objects, so the drop_caches sysctl is no longer needed.  This
makes evicting keys faster and more reliable.
FS_IOC_REMOVE_ENCRYPTION_KEY also detects if any files are still open
and therefore couldn't be "locked", whereas this went undetected before.

Therefore, to start out this patch adds support for using the new ioctls
for v1 encryption policies, i.e. on existing devices.

(Originally based on a patch by Satya Tangirala <satyat@google.com>)

Bug: 140500828
Test: tested that a device using v1 policies continues to work, both
      with and without an updated kernel.  See
      If64028d8580584b2c33c614cabd5d6b93657f608 for more details.
      Also checked via the log that the filesystem-level keyring is in
      fact used when supported.
Change-Id: I296ef78138578a3fd773797ac0cd46af1296b959
2019-09-30 13:11:42 -07:00
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
14c8c0765a clang-format many files.
Test: Format-only changes; treehugger suffices.
Change-Id: I23cde3f0bbcac13bef555d13514e922c79d5ad48
2018-09-18 15:41:22 -07:00
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
Paul Crowley
cd8bfe3d7f Label keys with all the possible FBE prefixes that might apply
We don't know which FS and kernel version is going to want these keys,
so put them in the kernel three times with all three possible prefixes.

Test: Marlin set up before this change successfully boots after it.
Change-Id: I6ccfe0894551ba068de9bf5e23fe4fd1e10e36b1
2017-06-20 10:10:08 -07:00
Paul Crowley
d5759811ff Add support for metadata encryption
Support encrypting metadata in /userdata using the dm-default-key
driver with a key in the /metadata partition.

Bug: 29189559
Test: Angler & Marlin build and boot
Change-Id: I716b117508d4bb4f6a4039293acb848cbc60f67b
2017-04-21 13:40:20 -07:00
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