Re: [PATCH] x86/fpu/xstate: Clear uninitialized xstate areas in core dump

On 5/7/20 9:49 AM, Yu-cheng Yu wrote:

In a core dump, copy_xstate_to_kernel() copies only enabled user xfeatures to a kernel buffer without touching areas for disabled xfeatures. However, those uninitialized areas may contain random data, which is then written to the core dump file and can be read by a non-privileged user.

Fix it by clearing uninitialized areas.

Do you have a Fixes: tag for this, or some background on where this issue originated that might be helpful for backports?