KeyMint HAL: clarify spec text
- Make clear that CERTIFICATE_NOT_{BEFORE,AFTER} must be specified for
generating/importing asymmetric keys.
- Fix enforcement level of Tag::UNLOCKED_DEVICE_REQUIRED.
- Fix reference to exportKey() for Tag::STORAGE_KEY to mention
convertStorageKeyToEphemeral instead.
- Mark Tag::CONFIRMATION_TOKEN as deprecated.
Test: none, comment change
Bug: 188672564
Change-Id: I68727b024f6b6743403941763aefca64e3eb091a
diff --git a/security/keymint/aidl/android/hardware/security/keymint/IKeyMintDevice.aidl b/security/keymint/aidl/android/hardware/security/keymint/IKeyMintDevice.aidl
index 88b2a26..1849723 100644
--- a/security/keymint/aidl/android/hardware/security/keymint/IKeyMintDevice.aidl
+++ b/security/keymint/aidl/android/hardware/security/keymint/IKeyMintDevice.aidl
@@ -275,6 +275,10 @@
* must return ErrorCode::INVALID_ARGUMENT. The values 3 and 65537 must be supported. It is
* recommended to support all prime values up to 2^64.
*
+ * o Tag::CERTIFICATE_NOT_BEFORE and Tag::CERTIFICATE_NOT_AFTER specify the valid date range for
+ * the returned X.509 certificate holding the public key. If omitted, generateKey must return
+ * ErrorCode::MISSING_NOT_BEFORE or ErrorCode::MISSING_NOT_AFTER.
+ *
* The following parameters are not necessary to generate a usable RSA key, but generateKey must
* not return an error if they are omitted:
*
@@ -295,6 +299,10 @@
* Tag::EC_CURVE must be provided to generate an ECDSA key. If it is not provided, generateKey
* must return ErrorCode::UNSUPPORTED_KEY_SIZE. TEE IKeyMintDevice implementations must support
* all curves. StrongBox implementations must support P_256.
+
+ * Tag::CERTIFICATE_NOT_BEFORE and Tag::CERTIFICATE_NOT_AFTER must be provided to specify the
+ * valid date range for the returned X.509 certificate holding the public key. If omitted,
+ * generateKey must return ErrorCode::MISSING_NOT_BEFORE or ErrorCode::MISSING_NOT_AFTER.
*
* == AES Keys ==
*
diff --git a/security/keymint/aidl/android/hardware/security/keymint/Tag.aidl b/security/keymint/aidl/android/hardware/security/keymint/Tag.aidl
index 972ce2e..e8ff14f 100644
--- a/security/keymint/aidl/android/hardware/security/keymint/Tag.aidl
+++ b/security/keymint/aidl/android/hardware/security/keymint/Tag.aidl
@@ -477,12 +477,12 @@
/**
* Tag::TRUSTED_CONFIRMATION_REQUIRED is only applicable to keys with KeyPurpose SIGN, and
- * specifies that this key must not be usable unless the user provides confirmation of the data
- * to be signed. Confirmation is proven to keyMint via an approval token. See
- * CONFIRMATION_TOKEN, as well as the ConfirmationUI HAL.
+ * specifies that this key must not be usable unless the user provides confirmation of the data
+ * to be signed. Confirmation is proven to keyMint via an approval token. See the authToken
+ * parameter of begin(), as well as the ConfirmationUI HAL.
*
* If an attempt to use a key with this tag does not have a cryptographically valid
- * CONFIRMATION_TOKEN provided to finish() or if the data provided to update()/finish() does not
+ * token provided to finish() or if the data provided to update()/finish() does not
* match the data described in the token, keyMint must return NO_USER_CONFIRMATION.
*
* Must be hardware-enforced.
@@ -491,9 +491,11 @@
/**
* Tag::UNLOCKED_DEVICE_REQUIRED specifies that the key may only be used when the device is
- * unlocked.
+ * unlocked, as reported to KeyMint via authToken operation parameter and the
+ * IKeyMintDevice::deviceLocked() method
*
- * Must be software-enforced.
+ * Must be hardware-enforced (but is also keystore-enforced on a per-user basis: see the
+ * deviceLocked() documentation).
*/
UNLOCKED_DEVICE_REQUIRED = TagType.BOOL | 509,
@@ -864,8 +866,9 @@
*
* STORAGE_KEY is used to denote that a key generated or imported is a key used for storage
* encryption. Keys of this type can either be generated or imported or secure imported using
- * keyMint. exportKey() can be used to re-wrap storage key with a per-boot ephemeral key
- * wrapped key once the key characteristics are enforced.
+ * keyMint. The convertStorageKeyToEphemeral() method of IKeyMintDevice can be used to re-wrap
+ * storage key with a per-boot ephemeral key wrapped key once the key characteristics are
+ * enforced.
*
* Keys with this tag cannot be used for any operation within keyMint.
* ErrorCode::INVALID_OPERATION is returned when a key with Tag::STORAGE_KEY is provided to
@@ -914,11 +917,10 @@
RESET_SINCE_ID_ROTATION = TagType.BOOL | 1004,
/**
- * Tag::CONFIRMATION_TOKEN is used to deliver a cryptographic token proving that the user
- * confirmed a signing request. The content is a full-length HMAC-SHA256 value. See the
- * ConfirmationUI HAL for details of token computation.
+ * OBSOLETE: Do not use. See the authToken parameter for IKeyMintDevice::begin and for
+ * IKeyMintOperation methods instead.
*
- * Must never appear in KeyCharacteristics.
+ * TODO(b/191738660): Delete when keystore1 is deleted.
*/
CONFIRMATION_TOKEN = TagType.BYTES | 1005,
