From acedbbd0c426db7ee7418e87e2afacd0b243fd19 Mon Sep 17 00:00:00 2001
From: Sebastian Messmer <messmer@cryfs.org>
Date: Thu, 23 Jun 2016 21:20:36 -0700
Subject: [PATCH] Fix EncryptedBlock::resize() and add test cases for it

---
 .../encrypted/EncryptedBlock.h                |  3 +
 test/blockstore/testutils/BlockStoreTest.h    | 66 ++++++++++++++++++-
 2 files changed, 68 insertions(+), 1 deletion(-)

diff --git a/src/blockstore/implementations/encrypted/EncryptedBlock.h b/src/blockstore/implementations/encrypted/EncryptedBlock.h
index 6abfe396..47632a1e 100644
--- a/src/blockstore/implementations/encrypted/EncryptedBlock.h
+++ b/src/blockstore/implementations/encrypted/EncryptedBlock.h
@@ -187,6 +187,9 @@ template<class Cipher>
 void EncryptedBlock<Cipher>::_encryptToBaseBlock() {
   if (_dataChanged) {
     cpputils::Data encrypted = Cipher::encrypt((byte*)_plaintextWithHeader.data(), _plaintextWithHeader.size(), _encKey);
+    if (_baseBlock->size() != sizeof(FORMAT_VERSION_HEADER) + encrypted.size()) {
+      _baseBlock->resize(sizeof(FORMAT_VERSION_HEADER) + encrypted.size());
+    }
     _baseBlock->write(&FORMAT_VERSION_HEADER, 0, sizeof(FORMAT_VERSION_HEADER));
     _baseBlock->write(encrypted.data(), sizeof(FORMAT_VERSION_HEADER), encrypted.size());
     _dataChanged = false;
diff --git a/test/blockstore/testutils/BlockStoreTest.h b/test/blockstore/testutils/BlockStoreTest.h
index 830cb3f2..a5ce6899 100644
--- a/test/blockstore/testutils/BlockStoreTest.h
+++ b/test/blockstore/testutils/BlockStoreTest.h
@@ -111,6 +111,62 @@ TYPED_TEST_P(BlockStoreTest, CanRemoveModifiedBlock) {
     EXPECT_EQ(0u, blockStore->numBlocks());
 }
 
+TYPED_TEST_P(BlockStoreTest, Resize_Larger_FromZero) {
+  auto blockStore = this->fixture.createBlockStore();
+  auto block = blockStore->create(cpputils::Data(0));
+  block->resize(10);
+  EXPECT_EQ(10u, block->size());
+}
+
+TYPED_TEST_P(BlockStoreTest, Resize_Larger_FromZero_BlockIsStillUsable) {
+  auto blockStore = this->fixture.createBlockStore();
+  auto block = blockStore->create(cpputils::Data(0));
+  block->resize(10);
+  this->TestBlockIsUsable(std::move(block), blockStore.get());
+}
+
+TYPED_TEST_P(BlockStoreTest, Resize_Larger) {
+  auto blockStore = this->fixture.createBlockStore();
+  auto block = blockStore->create(cpputils::Data(10));
+  block->resize(20);
+  EXPECT_EQ(20u, block->size());
+}
+
+TYPED_TEST_P(BlockStoreTest, Resize_Larger_BlockIsStillUsable) {
+  auto blockStore = this->fixture.createBlockStore();
+  auto block = blockStore->create(cpputils::Data(10));
+  block->resize(20);
+  this->TestBlockIsUsable(std::move(block), blockStore.get());
+}
+
+TYPED_TEST_P(BlockStoreTest, Resize_Smaller) {
+  auto blockStore = this->fixture.createBlockStore();
+  auto block = blockStore->create(cpputils::Data(10));
+  block->resize(5);
+  EXPECT_EQ(5u, block->size());
+}
+
+TYPED_TEST_P(BlockStoreTest, Resize_Smaller_BlockIsStillUsable) {
+  auto blockStore = this->fixture.createBlockStore();
+  auto block = blockStore->create(cpputils::Data(10));
+  block->resize(5);
+  this->TestBlockIsUsable(std::move(block), blockStore.get());
+}
+
+TYPED_TEST_P(BlockStoreTest, Resize_Smaller_ToZero) {
+  auto blockStore = this->fixture.createBlockStore();
+  auto block = blockStore->create(cpputils::Data(10));
+  block->resize(0);
+  EXPECT_EQ(0u, block->size());
+}
+
+TYPED_TEST_P(BlockStoreTest, Resize_Smaller_ToZero_BlockIsStillUsable) {
+  auto blockStore = this->fixture.createBlockStore();
+  auto block = blockStore->create(cpputils::Data(10));
+  block->resize(0);
+  this->TestBlockIsUsable(std::move(block), blockStore.get());
+}
+
 #include "BlockStoreTest_Size.h"
 #include "BlockStoreTest_Data.h"
 
@@ -141,7 +197,15 @@ REGISTER_TYPED_TEST_CASE_P(BlockStoreTest,
     WriteAndReadImmediately,
     WriteAndReadAfterLoading,
     OverwriteAndRead,
-    CanRemoveModifiedBlock
+    CanRemoveModifiedBlock,
+    Resize_Larger_FromZero,
+    Resize_Larger_FromZero_BlockIsStillUsable,
+    Resize_Larger,
+    Resize_Larger_BlockIsStillUsable,
+    Resize_Smaller,
+    Resize_Smaller_BlockIsStillUsable,
+    Resize_Smaller_ToZero,
+    Resize_Smaller_ToZero_BlockIsStillUsable
 );