commit 688d3ab29923ba85954581d8b524f903379fae9d
author Shawn Willden <swillden@google.com> Wed Oct 02 11:55:27 2019 -0600
committer Shawn Willden <swillden@google.com> Wed Nov 13 06:30:13 2019 -0700
tree f4280b8beb39c87e651891231bf6e5b74696904b
parent 5f5576fe939f4dd7e90f93b496c19fc64c56bfba

Don't clear kesytore after 5 auth failures.

Keystore's security originally derived from encrypting keys with a key
derived from the user's password.  To avoid making keystore into a
password brute force oracle, keystore cleared itself after five
incorrect presentations.  All of this has been superseded by moving
keystore's security into Keymaster, and by moving password security
into Gatekeeper/Weaver, and further by implmenting the synthetic
password model.

This CL removes the now-useless and occasionally-dangerous keystore
self-destruct.

Test: Manual
Change-Id: Id85c1c39769701bbc0dcfcb76511faf9eeb65496

keystore/user_state.cpp

diff --git a/keystore/user_state.cpp b/keystore/user_state.cpp
index 8d993e2..30dfe3c 100644
--- a/keystore/user_state.cpp
+++ b/keystore/user_state.cpp
@@ -37,7 +37,7 @@
 
 UserState::UserState(uid_t userId)
     : mMasterKeyEntry(".masterkey", "user_" + std::to_string(userId), userId, /* masterkey */ true),
-      mUserId(userId), mState(STATE_UNINITIALIZED), mRetry(MAX_RETRY) {}
+      mUserId(userId), mState(STATE_UNINITIALIZED) {}
 
 bool UserState::operator<(const UserState& rhs) const {
     return getUserId() < rhs.getUserId();
@@ -69,9 +69,6 @@
 
 void UserState::setState(State state) {
     mState = state;
-    if (mState == STATE_NO_ERROR || mState == STATE_UNINITIALIZED) {
-        mRetry = MAX_RETRY;
-    }
 }
 
 void UserState::zeroizeMasterKeysInMemory() {
@@ -208,23 +205,9 @@
         }
         return response;
     }
-    if (mRetry <= 0) {
-        reset();
-        return ResponseCode::UNINITIALIZED;
-    }
-    --mRetry;
-    switch (mRetry) {
-    case 0:
-        return ResponseCode::WRONG_PASSWORD_0;
-    case 1:
-        return ResponseCode::WRONG_PASSWORD_1;
-    case 2:
-        return ResponseCode::WRONG_PASSWORD_2;
-    case 3:
-        return ResponseCode::WRONG_PASSWORD_3;
-    default:
-        return ResponseCode::WRONG_PASSWORD_3;
-    }
+
+    LOG(ERROR) << "Invalid password presented";
+    return ResponseCode::WRONG_PASSWORD_0;
 }
 
 bool UserState::reset() {