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Commit 5234ad46 authored by Tao Bao's avatar Tao Bao
Browse files

applypatch: Add backup_source parameter to PatchPartition. 

And set it to false when installing recovery image via applypatch. We
only need to back up the source partition when doing in-place update
(e.g. when updating a given partition under recovery). When installing
recovery image via applypatch, we won't touch the source partition (i.e.
/boot).

Removing the backup step also allows dropping the dac_override_allowed
permission. Previously it was needed due to the access to /cache.
Because applypatch runs as root:root, while /cache is owned by
system:cache with 0770.

Bug: 68319577
Test: Invoke the code that installs recovery image; check that recovery
      is installed successfully without denials.
Test: recovery_unit_test passes on taimen.
Change-Id: I549a770b511762189d6672a2835b6e403d695919
parent 71c35b9f

applypatch/applypatch.cpp

+9 −7
Original line number Diff line number Diff line
@@ -47,7 +47,7 @@ 
using namespace std::string_literals;



static bool GenerateTarget(const Partition& target, const FileContents& source_file,

                           const Value& patch, const Value* bonus_data);

                           const Value& patch, const Value* bonus_data, bool backup_source);



bool LoadFileContents(const std::string& filename, FileContents* file) {

  // No longer allow loading contents from eMMC partitions.
@@ -266,7 +266,7 @@ int ShowLicenses() { 
}



bool PatchPartition(const Partition& target, const Partition& source, const Value& patch,

                    const Value* bonus) {

                    const Value* bonus, bool backup_source) {

  LOG(INFO) << "Patching " << target.name;



  // We try to load and check against the target hash first.
@@ -280,7 +280,7 @@ bool PatchPartition(const Partition& target, const Partition& source, const Valu 


  FileContents source_file;

  if (ReadPartitionToBuffer(source, &source_file, true)) {

    return GenerateTarget(target, source_file, patch, bonus);

    return GenerateTarget(target, source_file, patch, bonus, backup_source);

  }



  LOG(ERROR) << "Failed to find any match";
@@ -326,7 +326,7 @@ bool FlashPartition(const Partition& partition, const std::string& source_filena 
}



static bool GenerateTarget(const Partition& target, const FileContents& source_file,

                           const Value& patch, const Value* bonus_data) {

                           const Value& patch, const Value* bonus_data, bool backup_source) {

  uint8_t expected_sha1[SHA_DIGEST_LENGTH];

  if (ParseSha1(target.hash, expected_sha1) != 0) {

    LOG(ERROR) << "Failed to parse target hash \"" << target.hash << "\"";
@@ -351,11 +351,11 @@ static bool GenerateTarget(const Partition& target, const FileContents& source_f 
  }



  // We write the original source to cache, in case the partition write is interrupted.

  if (!CheckAndFreeSpaceOnCache(source_file.data.size())) {

  if (backup_source && !CheckAndFreeSpaceOnCache(source_file.data.size())) {

    LOG(ERROR) << "Not enough free space on /cache";

    return false;

  }

  if (!SaveFileContents(Paths::Get().cache_temp_source(), &source_file)) {

  if (backup_source && !SaveFileContents(Paths::Get().cache_temp_source(), &source_file)) {

    LOG(ERROR) << "Failed to back up source file";

    return false;

  }
@@ -415,7 +415,9 @@ static bool GenerateTarget(const Partition& target, const FileContents& source_f 
  }



  // Delete the backup copy of the source.

  if (backup_source) {

    unlink(Paths::Get().cache_temp_source().c_str());

  }



  // Success!

  return true;

applypatch/applypatch_modes.cpp

+1 −1
Original line number Diff line number Diff line
@@ -87,7 +87,7 @@ static int PatchMode(const std::string& target_emmc, const std::string& source_e 
    bonus = std::make_unique<Value>(Value::Type::BLOB, std::move(bonus_contents));

  }



  return PatchPartition(target, source, patch, bonus.get()) ? 0 : 1;

  return PatchPartition(target, source, patch, bonus.get(), false) ? 0 : 1;

}



static void Usage() {

applypatch/include/applypatch/applypatch.h

+4 −3
Original line number Diff line number Diff line
@@ -73,10 +73,11 @@ std::ostream& operator<<(std::ostream& os, const Partition& partition); 
// the 'target' Partition. While patching, it will backup the data on the source partition to

// /cache, so that the patching could be resumed on interruption even if both of the source and

// target partitions refer to the same device. The function is idempotent if called multiple times.

// An optional arg 'bonus' can be provided, if the patch was generated with a bonus output.

// Returns the patching result.

// 'bonus' can be provided if the patch was generated with a bonus output, or nullptr.

// 'backup_source' indicates whether the source partition should be backed up prior to the update

// (e.g. when doing in-place update). Returns the patching result.

bool PatchPartition(const Partition& target, const Partition& source, const Value& patch,

                    const Value* bonus);

                    const Value* bonus, bool backup_source);



// Returns whether the contents of the eMMC target or the cached file match the embedded hash.

// It will look for the backup on /cache if the given partition doesn't match the checksum.

tests/unit/applypatch_test.cpp

+2 −2
Original line number Diff line number Diff line
@@ -141,7 +141,7 @@ TEST_F(ApplyPatchTest, PatchPartition) { 
  ASSERT_TRUE(LoadFileContents(from_testdata_base("bonus.file"), &bonus_fc));

  Value bonus(Value::Type::BLOB, std::string(bonus_fc.data.cbegin(), bonus_fc.data.cend()));



  ASSERT_TRUE(PatchPartition(target_partition, source_partition, patch, &bonus));

  ASSERT_TRUE(PatchPartition(target_partition, source_partition, patch, &bonus, false));

}



// Tests patching an eMMC target without a separate bonus file (i.e. recovery-from-boot patch has
@@ -151,7 +151,7 @@ TEST_F(ApplyPatchTest, PatchPartitionWithoutBonusFile) { 
  ASSERT_TRUE(LoadFileContents(from_testdata_base("recovery-from-boot-with-bonus.p"), &patch_fc));

  Value patch(Value::Type::BLOB, std::string(patch_fc.data.cbegin(), patch_fc.data.cend()));



  ASSERT_TRUE(PatchPartition(target_partition, source_partition, patch, nullptr));

  ASSERT_TRUE(PatchPartition(target_partition, source_partition, patch, nullptr, false));

}



class FreeCacheTest : public ::testing::Test {

updater/install.cpp

+1 −1
Original line number Diff line number Diff line
@@ -271,7 +271,7 @@ Value* PatchPartitionFn(const char* name, State* state, 
    return StringValue("");

  }



  bool result = PatchPartition(target, source, *values[0], nullptr);

  bool result = PatchPartition(target, source, *values[0], nullptr, true);

  return StringValue(result ? "t" : "");

}