Added serialization to SecureHash.

These will be used to resume hash generation when a download is interrupted and later resumed.

BUG=None.
TEST=SecureHashTest.TestSerialization


Review URL: http://codereview.chromium.org/8588057

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@110842 0039d316-1c4b-4281-b951-d872f2087c98

4 files changed, 149 insertions, 0 deletions

diff --git a/crypto/secure_hash.h b/crypto/secure_hash.h
index 8a0f6ae..4a49380 100644
--- a/crypto/secure_hash.h
+++ b/crypto/secure_hash.h
@@ -9,6 +9,8 @@
 #include "base/basictypes.h"
 #include "crypto/crypto_export.h"
 
+class Pickle;
+
 namespace crypto {
 
 // A wrapper to calculate secure hashes incrementally, allowing to
@@ -25,6 +27,17 @@ class CRYPTO_EXPORT SecureHash {
   virtual void Update(const void* input, size_t len) = 0;
   virtual void Finish(void* output, size_t len) = 0;
 
+  // Serialize the context, so it can be restored at a later time.
+  // |pickle| will contain the serialized data.
+  // Returns whether or not |pickle| was filled.
+  virtual bool Serialize(Pickle* pickle) = 0;
+
+  // Restore the context that was saved earlier.
+  // |data_iterator| allows this to be used as part of a larger pickle.
+  // |pickle| holds the saved data.
+  // Returns success or failure.
+  virtual bool Deserialize(void** data_iterator, Pickle* pickle) = 0;
+
  protected:
   SecureHash() {}
 
diff --git a/crypto/secure_hash_default.cc b/crypto/secure_hash_default.cc
index d85754a..6607dfe 100644
--- a/crypto/secure_hash_default.cc
+++ b/crypto/secure_hash_default.cc
@@ -5,6 +5,7 @@
 #include "crypto/secure_hash.h"
 
 #include "base/logging.h"
+#include "base/pickle.h"
 #include "crypto/third_party/nss/chromium-blapi.h"
 #include "crypto/third_party/nss/chromium-sha256.h"
 
@@ -12,8 +13,12 @@ namespace crypto {
 
 namespace {
 
+const char kSHA256Descriptor[] = "NSS";
+
 class SecureHashSHA256NSS : public SecureHash {
  public:
+  static const int kSecureHashVersion = 1;
+
   SecureHashSHA256NSS() {
     SHA256_Begin(&ctx_);
   }
@@ -30,10 +35,53 @@ class SecureHashSHA256NSS : public SecureHash {
                static_cast<unsigned int>(len));
   }
 
+  virtual bool Serialize(Pickle* pickle);
+  virtual bool Deserialize(void** data_iterator, Pickle* pickle);
+
  private:
   SHA256Context ctx_;
 };
 
+bool SecureHashSHA256NSS::Serialize(Pickle* pickle) {
+  if (!pickle)
+    return false;
+
+  if (!pickle->WriteInt(kSecureHashVersion) ||
+      !pickle->WriteString(kSHA256Descriptor) ||
+      !pickle->WriteBytes(&ctx_, sizeof(ctx_))) {
+    return false;
+  }
+
+  return true;
+}
+
+bool SecureHashSHA256NSS::Deserialize(void** data_iterator, Pickle* pickle) {
+  if (!pickle)
+    return false;
+
+  int version;
+  if (!pickle->ReadInt(data_iterator, &version))
+    return false;
+
+  if (version > kSecureHashVersion)
+    return false;  // We don't know how to deal with this.
+
+  std::string type;
+  if (!pickle->ReadString(data_iterator, &type))
+    return false;
+
+  if (type != kSHA256Descriptor)
+    return false;  // It's the wrong kind.
+
+  const char* data = NULL;
+  if (!pickle->ReadBytes(data_iterator, &data, sizeof(ctx_)))
+    return false;
+
+  memcpy(&ctx_, data, sizeof(ctx_));
+
+  return true;
+}
+
 }  // namespace
 
 SecureHash* SecureHash::Create(Algorithm algorithm) {
diff --git a/crypto/secure_hash_openssl.cc b/crypto/secure_hash_openssl.cc
index 8e2f128..098bf27 100644
--- a/crypto/secure_hash_openssl.cc
+++ b/crypto/secure_hash_openssl.cc
@@ -8,14 +8,19 @@
 
 #include "base/basictypes.h"
 #include "base/logging.h"
+#include "base/pickle.h"
 #include "crypto/openssl_util.h"
 
 namespace crypto {
 
 namespace {
 
+const char kSHA256Descriptor[] = "OpenSSL";
+
 class SecureHashSHA256OpenSSL : public SecureHash {
  public:
+  static const int kSecureHashVersion = 1;
+
   SecureHashSHA256OpenSSL() {
     SHA256_Init(&ctx_);
   }
@@ -34,10 +39,54 @@ class SecureHashSHA256OpenSSL : public SecureHash {
     SHA256_Final(result.safe_buffer(), &ctx_);
   }
 
+  virtual bool Serialize(Pickle* pickle);
+  virtual bool Deserialize(void** data_iterator, Pickle* pickle);
+
  private:
   SHA256_CTX ctx_;
 };
 
+bool SecureHashSHA256OpenSSL::Serialize(Pickle* pickle) {
+  if (!pickle)
+    return false;
+
+  if (!pickle->WriteInt(kSecureHashVersion) ||
+      !pickle->WriteString(kSHA256Descriptor) ||
+      !pickle->WriteBytes(&ctx_, sizeof(ctx_))) {
+    return false;
+  }
+
+  return true;
+}
+
+bool SecureHashSHA256OpenSSL::Deserialize(void** data_iterator,
+                                          Pickle* pickle) {
+  if (!pickle)
+    return false;
+
+  int version;
+  if (!pickle->ReadInt(data_iterator, &version))
+    return false;
+
+  if (version > kSecureHashVersion)
+    return false;  // We don't know how to deal with this.
+
+  std::string type;
+  if (!pickle->ReadString(data_iterator, &type))
+    return false;
+
+  if (type != kSHA256Descriptor)
+    return false;  // It's the wrong kind.
+
+  const char* data = NULL;
+  if (!pickle->ReadBytes(data_iterator, &data, sizeof(ctx_)))
+    return false;
+
+  memcpy(&ctx_, data, sizeof(ctx_));
+
+  return true;
+}
+
 }  // namespace
 
 SecureHash* SecureHash::Create(Algorithm algorithm) {
diff --git a/crypto/secure_hash_unittest.cc b/crypto/secure_hash_unittest.cc
index 6ac9285..2adddfb 100644
--- a/crypto/secure_hash_unittest.cc
+++ b/crypto/secure_hash_unittest.cc
@@ -6,6 +6,7 @@
 
 #include "base/basictypes.h"
 #include "base/memory/scoped_ptr.h"
+#include "base/pickle.h"
 #include "crypto/sha2.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
@@ -32,3 +33,41 @@ TEST(SecureHashTest, TestUpdate) {
   for (size_t i = 0; i < crypto::kSHA256Length; i++)
     EXPECT_EQ(expected3[i], static_cast<int>(output3[i]));
 }
+
+// Save the crypto state mid-stream, and create another instance with the
+// saved state.  Then feed the same data afterwards to both.
+// When done, both should have the same hash value.
+TEST(SecureHashTest, TestSerialization) {
+  std::string input1(10001, 'a');  // 'a' repeated 10001 times
+  std::string input2(10001, 'b');  // 'b' repeated 10001 times
+  std::string input3(10001, 'c');  // 'c' repeated 10001 times
+  std::string input4(10001, 'd');  // 'd' repeated 10001 times
+  std::string input5(10001, 'e');  // 'e' repeated 10001 times
+
+  uint8 output1[crypto::kSHA256Length];
+  uint8 output2[crypto::kSHA256Length];
+
+  scoped_ptr<crypto::SecureHash> ctx1(crypto::SecureHash::Create(
+      crypto::SecureHash::SHA256));
+  scoped_ptr<crypto::SecureHash> ctx2(crypto::SecureHash::Create(
+      crypto::SecureHash::SHA256));
+  Pickle pickle;
+  ctx1->Update(input1.data(), input1.size());
+  ctx1->Update(input2.data(), input2.size());
+  ctx1->Update(input3.data(), input3.size());
+
+  EXPECT_TRUE(ctx1->Serialize(&pickle));
+  ctx1->Update(input4.data(), input4.size());
+  ctx1->Update(input5.data(), input5.size());
+
+  ctx1->Finish(output1, sizeof(output1));
+
+  void* data_iterator = NULL;
+  EXPECT_TRUE(ctx2->Deserialize(&data_iterator, &pickle));
+  ctx2->Update(input4.data(), input4.size());
+  ctx2->Update(input5.data(), input5.size());
+
+  ctx2->Finish(output2, sizeof(output2));
+
+  EXPECT_EQ(0, memcmp(output1, output2, crypto::kSHA256Length));
+}