Remove broken and unused support for expiring keys when off-body
Remove IKeystoreMaintenance#onDeviceOffBody(), as it's no longer called.
In addition, remove the code that tried to enforce the AllowWhileOnBody
key parameter. This code was broken during the rewrite of Keystore in
Android 12, and as a result, AllowWhileOnBody has no user-visible
effect. AllowWhileOnBody is *supposed* to cause the key's
authentication timeout, if it has one, to automatically expire when the
device is removed from the user's body. (A better name for it might
have been something like UserAuthenticationExpiresWhenRemovedFromBody.)
Android 11 Keystore implemented this behavior; see
https://android.googlesource.com/platform/system/security/+/refs/heads/android11-release/keystore/auth_token_table.cpp#165
Android 12 Keystore changed AllowWhileOnBody to have no effect.
Apparently due to a misunderstanding, the (incorrect) behavior that was
attempted to be implemented was "The key may be used after
authentication timeout if device is still on-body". But what was
actually implemented was that the Keystore daemon stopped enforcing
authentication timeouts for AllowWhileOnBody keys entirely, except after
a wearable device was removed from the body in which case the timeout is
enforced for any earlier authentications. Yet, this has no user-visible
effect because KeyMint still enforces the authentication timeout as
usual. So, AllowWhileOnBody has really been a no-op since Android 12.
We can always bring this code back, fixed and with tests, if this
feature comes back. But for now there is no reason to keep it around.
Bug: 289849354
Test: atest -p --include-subdirs system/security/keystore2
Test: atest CtsKeystoreTestCases
Change-Id: I4a7b3a90b56dacbb5316e30a30bf3fabc0debe48
diff --git a/keystore2/src/database.rs b/keystore2/src/database.rs
index 2757313..f343cb3 100644
--- a/keystore2/src/database.rs
+++ b/keystore2/src/database.rs
@@ -2864,26 +2864,11 @@
}
/// Find the newest auth token matching the given predicate.
- pub fn find_auth_token_entry<F>(&self, p: F) -> Option<(AuthTokenEntry, BootTime)>
+ pub fn find_auth_token_entry<F>(&self, p: F) -> Option<AuthTokenEntry>
where
F: Fn(&AuthTokenEntry) -> bool,
{
- self.perboot.find_auth_token_entry(p).map(|entry| (entry, self.get_last_off_body()))
- }
-
- /// Insert last_off_body into the metadata table at the initialization of auth token table
- pub fn insert_last_off_body(&self, last_off_body: BootTime) {
- self.perboot.set_last_off_body(last_off_body)
- }
-
- /// Update last_off_body when on_device_off_body is called
- pub fn update_last_off_body(&self, last_off_body: BootTime) {
- self.perboot.set_last_off_body(last_off_body)
- }
-
- /// Get last_off_body time when finding auth tokens
- fn get_last_off_body(&self) -> BootTime {
- self.perboot.get_last_off_body()
+ self.perboot.find_auth_token_entry(p)
}
/// Load descriptor of a key by key id
@@ -5051,23 +5036,6 @@
}
#[test]
- fn test_last_off_body() -> Result<()> {
- let mut db = new_test_db()?;
- db.insert_last_off_body(BootTime::now());
- let tx = db.conn.transaction_with_behavior(TransactionBehavior::Immediate)?;
- tx.commit()?;
- let last_off_body_1 = db.get_last_off_body();
- let one_second = Duration::from_secs(1);
- thread::sleep(one_second);
- db.update_last_off_body(BootTime::now());
- let tx2 = db.conn.transaction_with_behavior(TransactionBehavior::Immediate)?;
- tx2.commit()?;
- let last_off_body_2 = db.get_last_off_body();
- assert!(last_off_body_1 < last_off_body_2);
- Ok(())
- }
-
- #[test]
fn test_unbind_keys_for_user() -> Result<()> {
let mut db = new_test_db()?;
db.unbind_keys_for_user(1, false)?;
@@ -5491,7 +5459,7 @@
// All three entries are in the database
assert_eq!(db.perboot.auth_tokens_len(), 3);
// It selected the most recent timestamp
- assert_eq!(db.find_auth_token_entry(|_| true).unwrap().0.auth_token.mac, b"mac2".to_vec());
+ assert_eq!(db.find_auth_token_entry(|_| true).unwrap().auth_token.mac, b"mac2".to_vec());
Ok(())
}