Bug 982779 - Ensure that child->parent IPC blobs are never mysterious, r=baku.

content/base/public/nsDOMFile.h

@@ -34,6 +34,7 @@
 #include "nsWrapperCache.h"
 #include "nsCycleCollectionParticipant.h"
 
+class nsDOMMultipartFile;
 class nsIFile;
 class nsIInputStream;
 class nsIClassInfo;
@@ -42,6 +43,8 @@ class nsDOMFileBase : public nsIDOMFile,
                       public nsIXHRSendable,
                       public nsIMutable
 {
+  friend class nsDOMMultipartFile;
+
 public:
   typedef mozilla::dom::indexedDB::FileInfo FileInfo;
 
@@ -361,8 +364,9 @@ public:
   nsDOMMemoryFile(void *aMemoryBuffer,
                   uint64_t aLength,
                   const nsAString& aName,
-                  const nsAString& aContentType)
+                  const nsAString& aContentType,
-    : nsDOMFile(aName, aContentType, aLength, UINT64_MAX),
+                  uint64_t aLastModifiedDate)
+    : nsDOMFile(aName, aContentType, aLength, aLastModifiedDate),
       mDataOwner(new DataOwner(aMemoryBuffer, aLength))
   {
     NS_ASSERTION(mDataOwner && mDataOwner->mData, "must have data");

content/base/src/nsDOMBlobBuilder.cpp

@@ -27,26 +27,6 @@ NS_IMPL_ISUPPORTS_INHERITED(nsDOMMultipartFile, nsDOMFile,
 NS_IMETHODIMP
 nsDOMMultipartFile::GetSize(uint64_t* aLength)
 {
-  if (mLength == UINT64_MAX) {
-    CheckedUint64 length = 0;
-  
-    uint32_t i;
-    uint32_t len = mBlobs.Length();
-    for (i = 0; i < len; i++) {
-      nsIDOMBlob* blob = mBlobs.ElementAt(i).get();
-      uint64_t l = 0;
-  
-      nsresult rv = blob->GetSize(&l);
-      NS_ENSURE_SUCCESS(rv, rv);
-  
-      length += l;
-    }
-  
-    NS_ENSURE_TRUE(length.isValid(), NS_ERROR_FAILURE);
-
-    mLength = length.value();
-  }
-
   *aLength = mLength;
   return NS_OK;
 }
@@ -214,6 +194,8 @@ nsDOMMultipartFile::InitBlob(JSContext* aCx,
     return ParseBlobArrayArgument(aCx, aArgv[0], nativeEOL, aUnwrapFunc);
   }
 
+  SetLengthAndModifiedDate();
+
   return NS_OK;
 }
 
@@ -279,9 +261,48 @@ nsDOMMultipartFile::ParseBlobArrayArgument(JSContext* aCx, JS::Value& aValue,
   }
 
   mBlobs = blobSet.GetBlobs();
+
+  SetLengthAndModifiedDate();
+
   return NS_OK;
 }
 
+void
+nsDOMMultipartFile::SetLengthAndModifiedDate()
+{
+  MOZ_ASSERT(mLength == UINT64_MAX);
+  MOZ_ASSERT(mLastModificationDate == UINT64_MAX);
+
+  uint64_t totalLength = 0;
+
+  for (uint32_t index = 0, count = mBlobs.Length(); index < count; index++) {
+    nsCOMPtr<nsIDOMBlob>& blob = mBlobs[index];
+
+#ifdef DEBUG
+    {
+      // XXX This is only safe so long as all blob implementations in our tree
+      //     inherit nsDOMFileBase.
+      const auto* blobBase = static_cast<nsDOMFileBase*>(blob.get());
+
+      MOZ_ASSERT(!blobBase->IsSizeUnknown());
+      MOZ_ASSERT(!blobBase->IsDateUnknown());
+    }
+#endif
+
+    uint64_t subBlobLength;
+    MOZ_ALWAYS_TRUE(NS_SUCCEEDED(blob->GetSize(&subBlobLength)));
+
+    MOZ_ASSERT(UINT64_MAX - subBlobLength >= totalLength);
+    totalLength += subBlobLength;
+  }
+
+  mLength = totalLength;
+
+  if (mIsFile) {
+    mLastModificationDate = PR_Now();
+  }
+}
+
 NS_IMETHODIMP
 nsDOMMultipartFile::GetMozFullPathInternal(nsAString &aFilename)
 {
@@ -374,7 +395,18 @@ nsDOMMultipartFile::InitChromeFile(JSContext* aCx,
       file->GetLeafName(mName);
     }
 
-    blob = new nsDOMFileFile(file);
+    nsRefPtr<nsDOMFileFile> domFile = new nsDOMFileFile(file);
+
+    // Pre-cache size.
+    uint64_t unused;
+    rv = domFile->GetSize(&unused);
+    NS_ENSURE_SUCCESS(rv, rv);
+
+    // Pre-cache modified date.
+    rv = domFile->GetMozLastModifiedDate(&unused);
+    NS_ENSURE_SUCCESS(rv, rv);
+
+    blob = domFile.forget();
   }
 
   // XXXkhuey this is terrible
@@ -386,6 +418,8 @@ nsDOMMultipartFile::InitChromeFile(JSContext* aCx,
   blobSet.AppendBlob(blob);
   mBlobs = blobSet.GetBlobs();
 
+  SetLengthAndModifiedDate();
+
   return NS_OK;
 }
 

content/base/src/nsDOMBlobBuilder.h

@@ -32,6 +32,7 @@ public:
       mBlobs(aBlobs),
       mIsFromNsiFile(false)
   {
+    SetLengthAndModifiedDate();
   }
 
   // Create as a blob
@@ -41,6 +42,7 @@ public:
       mBlobs(aBlobs),
       mIsFromNsiFile(false)
   {
+    SetLengthAndModifiedDate();
   }
 
   // Create as a file to be later initialized
@@ -109,6 +111,8 @@ protected:
   nsresult ParseBlobArrayArgument(JSContext* aCx, JS::Value& aValue,
                                   bool aNativeEOL, UnwrapFuncPtr aUnwrapFunc);
 
+  void SetLengthAndModifiedDate();
+
   nsTArray<nsCOMPtr<nsIDOMBlob> > mBlobs;
   bool mIsFromNsiFile;
 };
@@ -170,7 +174,7 @@ protected:
       // and put it on the stack
 
       nsCOMPtr<nsIDOMBlob> blob =
-        new nsDOMMemoryFile(mData, mDataLen, EmptyString(), EmptyString());
+        new nsDOMMemoryFile(mData, mDataLen, EmptyString());
       mBlobs.AppendElement(blob);
       mData = nullptr; // The nsDOMMemoryFile takes ownership of the buffer
       mDataLen = 0;

content/html/content/src/HTMLCanvasElement.cpp

@@ -591,7 +591,7 @@ HTMLCanvasElement::MozGetAsFileImpl(const nsAString& aName,
 
   // The DOMFile takes ownership of the buffer
   nsRefPtr<nsDOMMemoryFile> file =
-    new nsDOMMemoryFile(imgData, (uint32_t)imgSize, aName, type);
+    new nsDOMMemoryFile(imgData, (uint32_t)imgSize, aName, type, PR_Now());
 
   file.forget(aResult);
   return NS_OK;

dom/ipc/Blob.cpp

@@ -1821,10 +1821,15 @@ BlobParent::Create(ContentParent* aManager,
 
   const ChildBlobConstructorParams& blobParams = aParams.blobParams();
 
+  MOZ_ASSERT(blobParams.type() !=
+             ChildBlobConstructorParams::TMysteryBlobConstructorParams);
+
   switch (blobParams.type()) {
+    case ChildBlobConstructorParams::TMysteryBlobConstructorParams:
+      return nullptr;
+
     case ChildBlobConstructorParams::TNormalBlobConstructorParams:
     case ChildBlobConstructorParams::TFileBlobConstructorParams:
-    case ChildBlobConstructorParams::TMysteryBlobConstructorParams:
       return new BlobParent(aManager, aParams);
 
     case ChildBlobConstructorParams::TSlicedBlobConstructorParams: {

dom/ipc/ContentChild.cpp

@@ -876,43 +876,6 @@ ContentChild::GetOrCreateActorForBlob(nsIDOMBlob* aBlob)
     return actor;
   }
 
-  // XXX This is only safe so long as all blob implementations in our tree
-  //     inherit nsDOMFileBase. If that ever changes then this will need to grow
-  //     a real interface or something.
-  const nsDOMFileBase* blob = static_cast<nsDOMFileBase*>(aBlob);
-
-  // We often pass blobs that are multipart but that only contain one sub-blob
-  // (WebActivities does this a bunch). Unwrap to reduce the number of actors
-  // that we have to maintain.
-  const nsTArray<nsCOMPtr<nsIDOMBlob> >* subBlobs = blob->GetSubBlobs();
-  if (subBlobs && subBlobs->Length() == 1) {
-    const nsCOMPtr<nsIDOMBlob>& subBlob = subBlobs->ElementAt(0);
-    MOZ_ASSERT(subBlob);
-
-    // We can only take this shortcut if the multipart and the sub-blob are both
-    // Blob objects or both File objects.
-    nsCOMPtr<nsIDOMFile> multipartBlobAsFile = do_QueryInterface(aBlob);
-    nsCOMPtr<nsIDOMFile> subBlobAsFile = do_QueryInterface(subBlob);
-    if (!multipartBlobAsFile == !subBlobAsFile) {
-      // The wrapping was unnecessary, see if we can simply pass an existing
-      // remote blob.
-      if (nsCOMPtr<nsIRemoteBlob> remoteBlob = do_QueryInterface(subBlob)) {
-        BlobChild* actor =
-          static_cast<BlobChild*>(
-            static_cast<PBlobChild*>(remoteBlob->GetPBlob()));
-        MOZ_ASSERT(actor);
-        return actor;
-      }
-
-      // No need to add a reference here since the original blob must have a
-      // strong reference in the caller and it must also have a strong reference
-      // to this sub-blob.
-      aBlob = subBlob;
-      blob = static_cast<nsDOMFileBase*>(aBlob);
-      subBlobs = blob->GetSubBlobs();
-    }
-  }
-
   // All blobs shared between processes must be immutable.
   nsCOMPtr<nsIMutable> mutableBlob = do_QueryInterface(aBlob);
   if (!mutableBlob || NS_FAILED(mutableBlob->SetMutable(false))) {
@@ -920,56 +883,59 @@ ContentChild::GetOrCreateActorForBlob(nsIDOMBlob* aBlob)
     return nullptr;
   }
 
+#ifdef DEBUG
+  {
+    // XXX This is only safe so long as all blob implementations in our tree
+    //     inherit nsDOMFileBase. If that ever changes then this will need to
+    //     grow a real interface or something.
+    const auto* blob = static_cast<nsDOMFileBase*>(aBlob);
+
+    MOZ_ASSERT(!blob->IsSizeUnknown());
+    MOZ_ASSERT(!blob->IsDateUnknown());
+  }
+#endif
+
   ParentBlobConstructorParams params;
 
-  if (blob->IsSizeUnknown() || blob->IsDateUnknown()) {
+  nsString contentType;
-    // We don't want to call GetSize or GetLastModifiedDate
+  nsresult rv = aBlob->GetType(contentType);
-    // yet since that may stat a file on the main thread
+  NS_ENSURE_SUCCESS(rv, nullptr);
-    // here. Instead we'll learn the size lazily from the
+
-    // other process.
+  uint64_t length;
-    params.blobParams() = MysteryBlobConstructorParams();
+  rv = aBlob->GetSize(&length);
-    params.optionalInputStreamParams() = void_t();
+  NS_ENSURE_SUCCESS(rv, nullptr);
-  }
+
-  else {
+  nsCOMPtr<nsIInputStream> stream;
-    nsString contentType;
+  rv = aBlob->GetInternalStream(getter_AddRefs(stream));
-    nsresult rv = aBlob->GetType(contentType);
+  NS_ENSURE_SUCCESS(rv, nullptr);
+
+  InputStreamParams inputStreamParams;
+  nsTArray<mozilla::ipc::FileDescriptor> fds;
+  SerializeInputStream(stream, inputStreamParams, fds);
+
+  MOZ_ASSERT(fds.IsEmpty());
+
+  params.optionalInputStreamParams() = inputStreamParams;
+
+  nsCOMPtr<nsIDOMFile> file = do_QueryInterface(aBlob);
+  if (file) {
+    FileBlobConstructorParams fileParams;
+
+    rv = file->GetName(fileParams.name());
     NS_ENSURE_SUCCESS(rv, nullptr);
 
-    uint64_t length;
+    rv = file->GetMozLastModifiedDate(&fileParams.modDate());
-    rv = aBlob->GetSize(&length);
     NS_ENSURE_SUCCESS(rv, nullptr);
 
-    nsCOMPtr<nsIInputStream> stream;
+    fileParams.contentType() = contentType;
-    rv = aBlob->GetInternalStream(getter_AddRefs(stream));
+    fileParams.length() = length;
-    NS_ENSURE_SUCCESS(rv, nullptr);
 
-    InputStreamParams inputStreamParams;
+    params.blobParams() = fileParams;
-    nsTArray<mozilla::ipc::FileDescriptor> fds;
+  } else {
-    SerializeInputStream(stream, inputStreamParams, fds);
+    NormalBlobConstructorParams blobParams;
-    MOZ_ASSERT(fds.IsEmpty());
+    blobParams.contentType() = contentType;
-
+    blobParams.length() = length;
-    params.optionalInputStreamParams() = inputStreamParams;
+    params.blobParams() = blobParams;
-
-    nsCOMPtr<nsIDOMFile> file = do_QueryInterface(aBlob);
-    if (file) {
-      FileBlobConstructorParams fileParams;
-
-      rv = file->GetName(fileParams.name());
-      NS_ENSURE_SUCCESS(rv, nullptr);
-
-      rv = file->GetMozLastModifiedDate(&fileParams.modDate());
-      NS_ENSURE_SUCCESS(rv, nullptr);
-
-      fileParams.contentType() = contentType;
-      fileParams.length() = length;
-
-      params.blobParams() = fileParams;
-    } else {
-      NormalBlobConstructorParams blobParams;
-      blobParams.contentType() = contentType;
-      blobParams.length() = length;
-      params.blobParams() = blobParams;
-    }
   }
 
   BlobChild* actor = BlobChild::Create(this, aBlob);

dom/ipc/ContentParent.cpp

@@ -2374,46 +2374,6 @@ ContentParent::GetOrCreateActorForBlob(nsIDOMBlob* aBlob)
     }
   }
 
-  // XXX This is only safe so long as all blob implementations in our tree
-  //     inherit nsDOMFileBase. If that ever changes then this will need to grow
-  //     a real interface or something.
-  const nsDOMFileBase* blob = static_cast<nsDOMFileBase*>(aBlob);
-
-  // We often pass blobs that are multipart but that only contain one sub-blob
-  // (WebActivities does this a bunch). Unwrap to reduce the number of actors
-  // that we have to maintain.
-  const nsTArray<nsCOMPtr<nsIDOMBlob> >* subBlobs = blob->GetSubBlobs();
-  if (subBlobs && subBlobs->Length() == 1) {
-    const nsCOMPtr<nsIDOMBlob>& subBlob = subBlobs->ElementAt(0);
-    MOZ_ASSERT(subBlob);
-
-    // We can only take this shortcut if the multipart and the sub-blob are both
-    // Blob objects or both File objects.
-    nsCOMPtr<nsIDOMFile> multipartBlobAsFile = do_QueryInterface(aBlob);
-    nsCOMPtr<nsIDOMFile> subBlobAsFile = do_QueryInterface(subBlob);
-    if (!multipartBlobAsFile == !subBlobAsFile) {
-      // The wrapping might have been unnecessary, see if we can simply pass an
-      // existing remote blob for this ContentParent.
-      if (nsCOMPtr<nsIRemoteBlob> remoteSubBlob = do_QueryInterface(subBlob)) {
-        BlobParent* actor =
-          static_cast<BlobParent*>(
-            static_cast<PBlobParent*>(remoteSubBlob->GetPBlob()));
-        MOZ_ASSERT(actor);
-
-        if (static_cast<ContentParent*>(actor->Manager()) == this) {
-          return actor;
-        }
-      }
-
-      // No need to add a reference here since the original blob must have a
-      // strong reference in the caller and it must also have a strong reference
-      // to this sub-blob.
-      aBlob = subBlob;
-      blob = static_cast<nsDOMFileBase*>(aBlob);
-      subBlobs = blob->GetSubBlobs();
-    }
-  }
-
   // All blobs shared between processes must be immutable.
   nsCOMPtr<nsIMutable> mutableBlob = do_QueryInterface(aBlob);
   if (!mutableBlob || NS_FAILED(mutableBlob->SetMutable(false))) {
@@ -2421,6 +2381,11 @@ ContentParent::GetOrCreateActorForBlob(nsIDOMBlob* aBlob)
     return nullptr;
   }
 
+  // XXX This is only safe so long as all blob implementations in our tree
+  //     inherit nsDOMFileBase. If that ever changes then this will need to grow
+  //     a real interface or something.
+  const auto* blob = static_cast<nsDOMFileBase*>(aBlob);
+
   ChildBlobConstructorParams params;
 
   if (blob->IsSizeUnknown() || blob->IsDateUnknown()) {