Reland "update_engine: Deprecate major version 1"

This reverts commit fac20229289cf4d4373fffe83037d44b780eabd0.

Reason for revert: <Since the stepping stone on M72 we can revert this now>

Original change's description:
> Revert "update_engine: Deprecate major version 1"
> 
> This partially reverts commit 55c75417e22d5026971276997924a345d9973bbc.
> 
> It turns out that we forgot a scenario when we deprecated major version
> 1. We use update_engine in lab tests (specifically
> autoupdate_EndToEndTests on stable channel) to update a DUT to an
> old (very old) versions using actual update payloads so we can test that
> they can get updated to newer versions. However, deprecating major
> version 1 in the update_engine caused trouble because we no longer can
> update from a newer version to a version before M72 (to prepare the
> device for update test). We need to put this feature back until we find
> a better solution for it.
> 
> On this CL, we only support major version 1 in the client and only for
> test (non-official) images. We don't even bother adding paygen support
> for it.
> 
> This CL should be reverted once we figured out what to do with
> provisioning the autoupdate end to end tests.
> 
> BUG=chromium:1043428
> TEST=FEATURES=test emerge-reef update_engine
> TEST=cros deployed it, then cros flash using an m71 payload, it succeeded.
> 
> Change-Id: I1fecbe3ae845b2e419f0999adc53e4732b1f7696
> Reviewed-on: https://chromium-review.googlesource.com/c/aosp/platform/system/update_engine/+/2013884
> Reviewed-by: Tianjie Xu <xunchang@google.com>
> Reviewed-by: Sen Jiang <senj@chromium.org>
> Tested-by: Amin Hassani <ahassani@chromium.org>
> Commit-Queue: Amin Hassani <ahassani@chromium.org>

TBR=dhaddock@chromium.org,senj@chromium.org,ahassani@chromium.org,xunchang@google.com,kimjae@chromium.org

# Not skipping CQ checks because original CL landed > 1 day ago.

Bug: chromium:1043428
Change-Id: I011537d4c982fa8f8d6548adddd14d966106ba44
Reviewed-on: https://chromium-review.googlesource.com/c/aosp/platform/system/update_engine/+/2096032
Reviewed-by: Amin Hassani <ahassani@chromium.org>
Commit-Queue: Amin Hassani <ahassani@chromium.org>
Tested-by: Amin Hassani <ahassani@chromium.org>
diff --git a/payload_consumer/payload_metadata.cc b/payload_consumer/payload_metadata.cc
index 69ccb46..b83001a 100644
--- a/payload_consumer/payload_metadata.cc
+++ b/payload_consumer/payload_metadata.cc
@@ -20,7 +20,6 @@
 
 #include <brillo/data_encoding.h>
 
-#include "update_engine/common/hardware_interface.h"
 #include "update_engine/common/hash_calculator.h"
 #include "update_engine/common/utils.h"
 #include "update_engine/payload_consumer/payload_constants.h"
@@ -37,36 +36,18 @@
 const uint64_t PayloadMetadata::kDeltaManifestSizeSize = 8;
 const uint64_t PayloadMetadata::kDeltaMetadataSignatureSizeSize = 4;
 
-bool PayloadMetadata::GetMetadataSignatureSizeOffset(
-    uint64_t* out_offset) const {
-  if (GetMajorVersion() == kBrilloMajorPayloadVersion) {
-    *out_offset = kDeltaManifestSizeOffset + kDeltaManifestSizeSize;
-    return true;
-  }
-  return false;
+uint64_t PayloadMetadata::GetMetadataSignatureSizeOffset() const {
+  return kDeltaManifestSizeOffset + kDeltaManifestSizeSize;
 }
 
-bool PayloadMetadata::GetManifestOffset(uint64_t* out_offset) const {
-  // Actual manifest begins right after the manifest size field or
-  // metadata signature size field if major version >= 2.
-  if (major_payload_version_ == kChromeOSMajorPayloadVersion) {
-    *out_offset = kDeltaManifestSizeOffset + kDeltaManifestSizeSize;
-    return true;
-  }
-  if (major_payload_version_ == kBrilloMajorPayloadVersion) {
-    *out_offset = kDeltaManifestSizeOffset + kDeltaManifestSizeSize +
-                  kDeltaMetadataSignatureSizeSize;
-    return true;
-  }
-  LOG(ERROR) << "Unknown major payload version: " << major_payload_version_;
-  return false;
+uint64_t PayloadMetadata::GetManifestOffset() const {
+  // Actual manifest begins right after the metadata signature size field.
+  return kDeltaManifestSizeOffset + kDeltaManifestSizeSize +
+         kDeltaMetadataSignatureSizeSize;
 }
 
 MetadataParseResult PayloadMetadata::ParsePayloadHeader(
-    const brillo::Blob& payload,
-    HardwareInterface* hardware,
-    ErrorCode* error) {
-  uint64_t manifest_offset;
+    const brillo::Blob& payload, ErrorCode* error) {
   // Ensure we have data to cover the major payload version.
   if (payload.size() < kDeltaManifestSizeOffset)
     return MetadataParseResult::kInsufficientData;
@@ -78,6 +59,11 @@
     return MetadataParseResult::kError;
   }
 
+  uint64_t manifest_offset = GetManifestOffset();
+  // Check again with the manifest offset.
+  if (payload.size() < manifest_offset)
+    return MetadataParseResult::kInsufficientData;
+
   // Extract the payload version from the metadata.
   static_assert(sizeof(major_payload_version_) == kDeltaVersionSize,
                 "Major payload version size mismatch");
@@ -87,26 +73,14 @@
   // Switch big endian to host.
   major_payload_version_ = be64toh(major_payload_version_);
 
-  // We only want to test major version 1 for test images.
-  if (major_payload_version_ == kChromeOSMajorPayloadVersion
-          ? hardware != nullptr && hardware->IsOfficialBuild()
-          : major_payload_version_ < kMinSupportedMajorPayloadVersion ||
-                major_payload_version_ > kMaxSupportedMajorPayloadVersion) {
+  if (major_payload_version_ < kMinSupportedMajorPayloadVersion ||
+      major_payload_version_ > kMaxSupportedMajorPayloadVersion) {
     LOG(ERROR) << "Bad payload format -- unsupported payload version: "
                << major_payload_version_;
     *error = ErrorCode::kUnsupportedMajorPayloadVersion;
     return MetadataParseResult::kError;
   }
 
-  // Get the manifest offset now that we have payload version.
-  if (!GetManifestOffset(&manifest_offset)) {
-    *error = ErrorCode::kUnsupportedMajorPayloadVersion;
-    return MetadataParseResult::kError;
-  }
-  // Check again with the manifest offset.
-  if (payload.size() < manifest_offset)
-    return MetadataParseResult::kInsufficientData;
-
   // Next, parse the manifest size.
   static_assert(sizeof(manifest_size_) == kDeltaManifestSizeSize,
                 "manifest_size size mismatch");
@@ -123,43 +97,33 @@
     return MetadataParseResult::kError;
   }
 
-  if (GetMajorVersion() == kBrilloMajorPayloadVersion) {
-    // Parse the metadata signature size.
-    static_assert(
-        sizeof(metadata_signature_size_) == kDeltaMetadataSignatureSizeSize,
-        "metadata_signature_size size mismatch");
-    uint64_t metadata_signature_size_offset;
-    if (!GetMetadataSignatureSizeOffset(&metadata_signature_size_offset)) {
-      *error = ErrorCode::kError;
-      return MetadataParseResult::kError;
-    }
-    memcpy(&metadata_signature_size_,
-           &payload[metadata_signature_size_offset],
-           kDeltaMetadataSignatureSizeSize);
-    metadata_signature_size_ = be32toh(metadata_signature_size_);
+  // Parse the metadata signature size.
+  static_assert(
+      sizeof(metadata_signature_size_) == kDeltaMetadataSignatureSizeSize,
+      "metadata_signature_size size mismatch");
+  uint64_t metadata_signature_size_offset = GetMetadataSignatureSizeOffset();
+  memcpy(&metadata_signature_size_,
+         &payload[metadata_signature_size_offset],
+         kDeltaMetadataSignatureSizeSize);
+  metadata_signature_size_ = be32toh(metadata_signature_size_);
 
-    if (metadata_size_ + metadata_signature_size_ < metadata_size_) {
-      // Overflow detected.
-      LOG(ERROR) << "Overflow detected on metadata and signature size.";
-      *error = ErrorCode::kDownloadInvalidMetadataSize;
-      return MetadataParseResult::kError;
-    }
+  if (metadata_size_ + metadata_signature_size_ < metadata_size_) {
+    // Overflow detected.
+    LOG(ERROR) << "Overflow detected on metadata and signature size.";
+    *error = ErrorCode::kDownloadInvalidMetadataSize;
+    return MetadataParseResult::kError;
   }
   return MetadataParseResult::kSuccess;
 }
 
-bool PayloadMetadata::ParsePayloadHeader(const brillo::Blob& payload,
-                                         HardwareInterface* hardware) {
+bool PayloadMetadata::ParsePayloadHeader(const brillo::Blob& payload) {
   ErrorCode error;
-  return ParsePayloadHeader(payload, hardware, &error) ==
-         MetadataParseResult::kSuccess;
+  return ParsePayloadHeader(payload, &error) == MetadataParseResult::kSuccess;
 }
 
 bool PayloadMetadata::GetManifest(const brillo::Blob& payload,
                                   DeltaArchiveManifest* out_manifest) const {
-  uint64_t manifest_offset;
-  if (!GetManifestOffset(&manifest_offset))
-    return false;
+  uint64_t manifest_offset = GetManifestOffset();
   CHECK_GE(payload.size(), manifest_offset + manifest_size_);
   return out_manifest->ParseFromArray(&payload[manifest_offset],
                                       manifest_size_);
@@ -181,7 +145,7 @@
                  << metadata_signature;
       return ErrorCode::kDownloadMetadataSignatureError;
     }
-  } else if (major_payload_version_ == kBrilloMajorPayloadVersion) {
+  } else {
     metadata_signature_protobuf_blob.assign(
         payload.begin() + metadata_size_,
         payload.begin() + metadata_size_ + metadata_signature_size_);
@@ -242,7 +206,7 @@
   brillo::Blob payload;
   TEST_AND_RETURN_FALSE(
       utils::ReadFileChunk(payload_path, 0, kMaxPayloadHeaderSize, &payload));
-  TEST_AND_RETURN_FALSE(ParsePayloadHeader(payload, nullptr));
+  TEST_AND_RETURN_FALSE(ParsePayloadHeader(payload));
 
   if (manifest != nullptr) {
     TEST_AND_RETURN_FALSE(
@@ -253,8 +217,7 @@
     TEST_AND_RETURN_FALSE(GetManifest(payload, manifest));
   }
 
-  if (metadata_signatures != nullptr &&
-      GetMajorVersion() >= kBrilloMajorPayloadVersion) {
+  if (metadata_signatures != nullptr) {
     payload.clear();
     TEST_AND_RETURN_FALSE(utils::ReadFileChunk(
         payload_path, GetMetadataSize(), GetMetadataSignatureSize(), &payload));