commit a35896c0ab209488b347672e9c917355b3fd8f51
author Sen Jiang <senj@google.com> Wed May 25 11:08:41 2016 -0700
committer Sen Jiang <senj@google.com> Mon Jun 06 23:54:17 2016 +0000
tree 6514e5569b04b71ec3ef77cc596a4060d25f9abf
parent 192a86a7e3b5ec90d7860f817100be6a43ca1daa

Only verify the source partition which target hash mismatch.

There's no need to go back to the first partition when target partition
hash failed, those partitions already passed target hash verification.
We should directly go ahead and verify the source partition corresponding
to the current partition which target hash doesn't match, and that should
be the only source partition we verify.

Test: ./update_engine_unittests
Bug: None

Change-Id: I6754d329d62fbed214e2b01568b290a60ad746ac

payload_consumer/filesystem_verifier_action.cc

diff --git a/payload_consumer/filesystem_verifier_action.cc b/payload_consumer/filesystem_verifier_action.cc
index 4b476db..5156f96 100644
--- a/payload_consumer/filesystem_verifier_action.cc
+++ b/payload_consumer/filesystem_verifier_action.cc
@@ -91,18 +91,7 @@
 
 void FilesystemVerifierAction::StartPartitionHashing() {
   if (partition_index_ == install_plan_.partitions.size()) {
-    switch (verifier_step_) {
-      case VerifierStep::kVerifySourceHash:
-        // The action will skip kVerifySourceHash step if target partition hash
-        // matches, if we are in this step, it means target hash does not match,
-        // and now that the source hash matches, we should set the error code to
-        // reflect the error in target partition.
-        Cleanup(ErrorCode::kNewRootfsVerificationError);
-        break;
-      case VerifierStep::kVerifyTargetHash:
-        Cleanup(ErrorCode::kSuccess);
-        break;
-    }
+    Cleanup(ErrorCode::kSuccess);
     return;
   }
   InstallPlan::Partition& partition =
@@ -224,7 +213,6 @@
         // switch to kVerifySourceHash step to check if it's because the source
         // partition does not match either.
         verifier_step_ = VerifierStep::kVerifySourceHash;
-        partition_index_ = 0;
       } else {
         partition_index_++;
       }
@@ -256,8 +244,13 @@
                   << "run: .../src/scripts/sha256_partitions.sh .../file.bin";
         return Cleanup(ErrorCode::kDownloadStateInitializationError);
       }
-      partition_index_++;
-      break;
+      // The action will skip kVerifySourceHash step if target partition hash
+      // matches, if we are in this step, it means target hash does not match,
+      // and now that the source partition hash matches, we should set the error
+      // code to reflect the error in target partition.
+      // We only need to verify the source partition which the target hash does
+      // not match, the rest of the partitions don't matter.
+      return Cleanup(ErrorCode::kNewRootfsVerificationError);
   }
   // Start hashing the next partition, if any.
   hasher_.reset();