Linux Still Working To Disable RNDIS Drivers In 2024

Back in January 2023 was an attempt to disable kernel drivers for Microsoft's RNDIS protocol. The Remote Network Driver Interface Specification (RNDIS) is home to security concerns for this protocol built atop USB for virtual Ethernet functionality. Later in the year the effort to disable RNDIS on Linux was tried again without going mainline. In recent days it looks like there will be a fresh attempt at getting the RNDIS driver support disabled.

Greg Kroah-Hartman in recent days revived his "rndis-removal" branch as part of the USB subsystem Git tree. Though at this stage it's not the actual "removal" of RNDIS but just the Kconfig changes to prevent the drivers from being easily compiled. Once that gets to the mainline Linux kernel, some months down the road after that if there are no issues raised, the actual stripping of the RNDIS drivers from the Linux kernel could then happen.

The patch description on the change continues to read:

"The Microsoft RNDIS protocol is, as designed, insecure and vulnerable on any system that uses it with untrusted hosts or devices. Because the protocol is impossible to make secure, just disable all rndis drivers to prevent anyone from using them again.

Windows only needed this for XP and newer systems, Windows systems older than that can use the normal USB class protocols instead, which do not have these problems.

Android has had this disabled for many years so there should not be any real systems that still need this."

Given the timing we'll see if this rndis-removal code is submitted for the upcoming Linux v6.9 kernel merge window for trying to get this aging code out of the kernel.