K93472064 : Linux kernel vulnerability CVE-2017-12190

Security Advisory Description

The bio_map_user_iov and bio_unmap_user functions in block/bio.c in the Linux kernel before 4.13.8 do unbalanced refcounting when a SCSI I/O vector has small consecutive buffers belonging to the same page. The bio_add_pc_page function merges them into one, but the page reference is never dropped. This causes a memory leak and possible system lockup (exploitable against the host OS by a guest OS user, if a SCSI disk is passed through to a virtual machine) due to an out-of-memory condition. (CVE-2017-12190)

Impact

A locally authenticated attacker can exploit this vulnerability to trigger an out-of-memory condition to cause a denial of service (DoS) on the affected system.