CGImageIssueDemo

Core Graphics issue test

What for

It seems that there are a strange crash for iOS 11.2+ about CoreGraphics.framework.

There are already a developer thread talk about this: ERROR_CGDataProvider_BufferIsNotReadable crash . This is just a demo to test the issue.

Issue

From iOS 11.2+ (Up to iOS 11.3.1 now), the CGDataProviderRetainBytePtr method which is called from public API CGDataProviderCopyData, will crash at the internal method ERROR_CGDataProvider_BufferIsNotReadable.

The crash seems that ERROR_CGDataProvider_BufferIsNotReadable is attempting to dereference a NULL pointer. Which cause a EXC_BAD_ACCESS KERN_INVALID_ADDRESS 0x0000000000000000.

Steps to Reproduce

1. Create a CGDataProviderCreateDirect using CGDataProviderCreateDirect, which getBytePointer function callback return NULL buffer.

2. Create a new CGImageRef using the data provider above with valid args.

3. Call CGDataProviderCopyData public API, or implicitlly called from Core Animation during this image rendering in UIImageView