commit 8d5b2539464a0e198de24b01cc72d681cb302211
author Paul Crowley <paulcrowley@google.com> Fri Mar 19 10:53:07 2021 -0700
committer Paul Crowley <paulcrowley@google.com> Wed Mar 24 14:40:14 2021 -0700
tree 258d1a80737d8b2fe298480609b164f2fc590236
parent 7a65839abae7d6f425735b83602573e43824152a

Encrypt keys even when device locked

Use ECDH public-key encryption to encrypt unlockedDeviceRequired keys
even when the device is locked.

Bug: 163866361
Test: keystore2_test
Test: atest android.keystore.cts.CipherTest#testEmptyPlaintextEncryptsAndDecryptsWhenUnlockedRequired
Change-Id: Idbb3e02972aba021d97c5284c300d3b5e97756ae

keystore2/src/database.rs

diff --git a/keystore2/src/database.rs b/keystore2/src/database.rs
index 3d9cffe..7e260fe 100644
--- a/keystore2/src/database.rs
+++ b/keystore2/src/database.rs
@@ -112,6 +112,8 @@
         /// Vector representing the raw public key so results from the server can be matched
         /// to the right entry
         AttestationRawPubKey(Vec<u8>) with accessor attestation_raw_pub_key,
+        /// SEC1 public key for ECDH encryption
+        Sec1PublicKey(Vec<u8>) with accessor sec1_public_key,
         //  --- ADD NEW META DATA FIELDS HERE ---
         // For backwards compatibility add new entries only to
         // end of this list and above this comment.
@@ -182,6 +184,8 @@
         AeadTag(Vec<u8>) with accessor aead_tag,
         /// The uuid of the owning KeyMint instance.
         KmUuid(Uuid) with accessor km_uuid,
+        /// If the key is ECDH encrypted, this is the ephemeral public key
+        PublicKey(Vec<u8>) with accessor public_key,
         //  --- ADD NEW META DATA FIELDS HERE ---
         // For backwards compatibility add new entries only to
         // end of this list and above this comment.
@@ -1153,6 +1157,7 @@
         key_type: &SuperKeyType,
         blob: &[u8],
         blob_metadata: &BlobMetaData,
+        key_metadata: &KeyMetaData,
     ) -> Result<KeyEntry> {
         self.with_transaction(TransactionBehavior::Immediate, |tx| {
             let key_id = Self::insert_with_retry(|id| {
@@ -1173,6 +1178,8 @@
             })
             .context("Failed to insert into keyentry table.")?;
 
+            key_metadata.store_in_db(key_id, tx).context("KeyMetaData::store_in_db failed")?;
+
             Self::set_blob_internal(
                 &tx,
                 key_id,
@@ -4899,13 +4906,24 @@
 
         let (encrypted_super_key, metadata) =
             SuperKeyManager::encrypt_with_password(&super_key, &pw)?;
-        db.store_super_key(1, &USER_SUPER_KEY, &encrypted_super_key, &metadata)?;
+        db.store_super_key(
+            1,
+            &USER_SUPER_KEY,
+            &encrypted_super_key,
+            &metadata,
+            &KeyMetaData::new(),
+        )?;
 
         //check if super key exists
         assert!(db.key_exists(Domain::APP, 1, &USER_SUPER_KEY.alias, KeyType::Super)?);
 
         let (_, key_entry) = db.load_super_key(&USER_SUPER_KEY, 1)?.unwrap();
-        let loaded_super_key = SuperKeyManager::extract_super_key_from_key_entry(key_entry, &pw)?;
+        let loaded_super_key = SuperKeyManager::extract_super_key_from_key_entry(
+            USER_SUPER_KEY.algorithm,
+            key_entry,
+            &pw,
+            None,
+        )?;
 
         let decrypted_secret_bytes =
             loaded_super_key.aes_gcm_decrypt(&encrypted_secret, &iv, &tag)?;