AU: detect failure when using public key verification

delta_performer.h

 // Copyright (c) 2010 The Chromium OS Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CHROMEOS_PLATFORM_UPDATE_ENGINE_DELTA_PERFORMER_H__
 #define CHROMEOS_PLATFORM_UPDATE_ENGINE_DELTA_PERFORMER_H__
 
 #include <inttypes.h>
 
 #include <vector>
@@ skipping 49 matching lines @@
   // Closes both 'path' given to Open() and the kernel path.
   int Close();
 
   // Verifies the downloaded payload against the signed hash included in the
   // payload as well as against the update check hash and size and returns true
   // on success, false on failure. This method should be called after closing
   // the stream. Note this method skips the signed hash check if the public key
   // is unavailable; it returns false if the public key is available but the
   // delta payload doesn't include a signature. If |public_key_path| is an empty
   // string, uses the default public key path.
+  // If the signature check fails, *signature_failed will be set to true (if
+  // it's non-NULL); this will not cause the method to fail.
   bool VerifyPayload(const std::string& public_key_path,
                      const std::string& update_check_response_hash,
-                     const uint64_t update_check_response_size);
+                     const uint64_t update_check_response_size,
+                     bool* signature_failed);
 
   // Reads from the update manifest the expected sizes and hashes of the target
   // kernel and rootfs partitions. These values can be used for applied update
   // hash verification. This method must be called after the update manifest has
   // been parsed (e.g., after closing the stream). Returns true on success, and
   // false on failure (e.g., when the values are not present in the update
   // manifest).
   bool GetNewPartitionInfo(uint64_t* kernel_size,
                            std::vector<char>* kernel_hash,
                            uint64_t* rootfs_size,
@@ skipping 141 matching lines @@
   // verification.
   std::vector<char> current_kernel_hash_;
   std::vector<char> current_rootfs_hash_;
 
   DISALLOW_COPY_AND_ASSIGN(DeltaPerformer);
 };
 
 }  // namespace chromeos_update_engine
 
 #endif  // CHROMEOS_PLATFORM_UPDATE_ENGINE_DELTA_PERFORMER_H__