keymaster: Fix callback invocations

Fix a pair of sites where a HIDL callback is being invoked potentially
more than once, or invalid data is being after an error has already been
reported to the caller.

Bug: None
Test: None
Signed-off-by: Garret Kelly <gdk@google.com>
Change-Id: Ifd8e5d8c30705485a9a1ff191a80f1ae9c2d751a

1 files changed, 2 insertions, 0 deletions

diff --git a/hals/keymaster/KeymasterDevice.cpp b/hals/keymaster/KeymasterDevice.cpp
index 61614e9..c312262 100644
--- a/hals/keymaster/KeymasterDevice.cpp
+++ b/hals/keymaster/KeymasterDevice.cpp
@@ -346,6 +346,7 @@ Return<void> KeymasterDevice::getHmacSharingParameters(
 
     if (ec != ErrorCode::OK) {
         _hidl_cb(ec, HmacSharingParameters());
+        return Void();
     }
 
     const std::string & nonce = response.hmac_sharing_params().nonce();
@@ -717,6 +718,7 @@ Return<void> KeymasterDevice::attestKey(
         ::strftime(not_after_str, sizeof(not_after_str),
                    "%y%m%d%H%M%SZ", gmtime(&not_after)) == 0) {
         _hidl_cb(ErrorCode::UNKNOWN_ERROR, hidl_vec<hidl_vec<uint8_t> >{});
+        return Void();
     }
 
     startRequest.mutable_blob()->set_blob(&keyToAttest[0], keyToAttest.size());