CVE-2017-12190 Information

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.

CVSS Vector

CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H

Reference

http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=2b04e8f6bbb196cab4b232af0f8d48ff2c7a8058 http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=95d78c28b5a85bacbc29b8dba7c04babb9b0d467 http://seclists.org/oss-sec/2017/q4/52 http://www.kernel.org/pub/linux/kernel/v4.x/ChangeLog-4.13.8 http://www.securityfocus.com/bid/101911 https://access.redhat.com/errata/RHSA-2018:0654 https://access.redhat.com/errata/RHSA-2018:0676 https://access.redhat.com/errata/RHSA-2018:1062 https://access.redhat.com/errata/RHSA-2018:1854 https://access.redhat.com/errata/RHSA-2019:1170 https://access.redhat.com/errata/RHSA-2019:1190 https://bugzilla.redhat.com/show_bug.cgi?id=1495089 https://github.com/torvalds/linux/commit/2b04e8f6bbb196cab4b232af0f8d48ff2c7a8058 https://github.com/torvalds/linux/commit/95d78c28b5a85bacbc29b8dba7c04babb9b0d467 https://lists.debian.org/debian-lts-announce/2017/12/msg00004.html https://support.f5.com/csp/article/K93472064?utm_source=f5support&utm_medium=RSS https://usn.ubuntu.com/3582-1/ https://usn.ubuntu.com/3582-2/ https://usn.ubuntu.com/3583-1/ https://usn.ubuntu.com/3583-2/

Attack Complexity

LOW

Privileges Required

LOW

User Interaction Required

LOW

Scope

NONE

Confidentiality Impact

CHANGED

Integrity Impact

NONE

Availability Impact

NONE

Base Score

HIGH

Base Severity

6.5