CVE-2021-47475

In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> comedi: vmk80xx: fix transfer-buffer overflows<br /> <br /> The driver uses endpoint-sized USB transfer buffers but up until<br /> recently had no sanity checks on the sizes.<br /> <br /> Commit e1f13c879a7c ("staging: comedi: check validity of wMaxPacketSize<br /> of usb endpoints found") inadvertently fixed NULL-pointer dereferences<br /> when accessing the transfer buffers in case a malicious device has a<br /> zero wMaxPacketSize.<br /> <br /> Make sure to allocate buffers large enough to handle also the other<br /> accesses that are done without a size check (e.g. byte 18 in<br /> vmk80xx_cnt_insn_read() for the VMK8061_MODEL) to avoid writing beyond<br /> the buffers, for example, when doing descriptor fuzzing.<br /> <br /> The original driver was for a low-speed device with 8-byte buffers.<br /> Support was later added for a device that uses bulk transfers and is<br /> presumably a full-speed device with a maximum 64-byte wMaxPacketSize.