NetBSD Security Advisory 2019-002: Unprivileged kernel memory overwrite in mq_send(3)
3 May, 2019 by security-officer@netbsd.org | netbsd
-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 NetBSD Security Advisory 2019-002 ================================= Topic: Unprivileged kernel memory overwrite in mq_send(3) Version: NetBSD-current: affected prior to April 16, 2019 NetBSD 8.0: affected NetBSD 7.2: affected NetBSD 7.1.2: affected NetBSD 7.0.2: affected Severity: Local user may overwrite kernel memory Fixed: NetBSD-current: April 16, 2019 NetBSD-8 branch: April 16, 2019 NetBSD-7 branch: April 16, 2019 NetBSD-7-1 branch: April 16, 2019 NetBSD-7-0 branch: April 16, 2019 Please note that NetBSD releases prior to 7.1 are no longer supported. It is recommended that all users upgrade to a supported release. Abstract ======== An unprivileged user can overwrite parts of kernel memory via an unprivileged mq_send(3) system call. Technical Details ================= Insufficient argument validation in the mq_send(3) system call could cause a copyin(9) operation of too much data, overrunning the kernel target memory. Solutions and Workarounds ========================= Update the kernel to a fixed version and reboot. To apply a fixed version from a releng build, fetch a fitting kern-GENERIC.tgz from nyftp.netbsd.org and extract the fixed binaries: cd /var/tmp ftp https://nycdn.NetBSD.org/pub/NetBSD-daily/REL/latest/ARCH/binary/sets/kern-GENERIC.tgz cd / tar xzpf /var/tmp/kern-GENERIC.tgz with the following replacements: REL = the release version you are using ARCH = your system's architecture The following instructions describe how to upgrade your kernel by updating your source tree and rebuilding and installing a new version. For all NetBSD versions, you need to obtain fixed kernel sources, rebuild and install the new kernel, and reboot the system. The fixed source may be obtained from the NetBSD CVS repository. The following instructions briefly summarise how to upgrade your kernel. In these instructions, replace: ARCH with your architecture (from uname -m), and KERNCONF with the name of your kernel configuration file. To update from CVS, re-build, and re-install the kernel: # cd src # cvs update -d -P sys/path/to/file.c # ./build.sh kernel=KERNCONF # mv /netbsd /netbsd.old # cp sys/arch/ARCH/compile/obj/KERNCONF/netbsd /netbsd # shutdown -r now For more information on how to do this, see: http://www.NetBSD.org/docs/guide/en/chap-kernel.html Thanks To ========= Andy Nguyen for discovering and reporting the issue. More Information ================ Advisories may be updated as new information becomes available. The most recent version of this advisory (PGP signed) can be found at http://ftp.NetBSD.org/pub/NetBSD/security/advisories/NetBSD-SA2019-002.txt.asc Information about NetBSD and NetBSD security can be found at http://www.NetBSD.org/ and http://www.NetBSD.org/Security/ . Copyright 2019, The NetBSD Foundation, Inc. All Rights Reserved. Redistribution permitted only in full, unmodified form. $NetBSD: NetBSD-SA2019-002.txt.asc,v 1.1 2019/05/03 01:33:11 christos Exp $ -----BEGIN PGP SIGNATURE----- iQIcBAEBAgAGBQJcy5pIAAoJEAZJc6xMSnBuJdAP/i4i5l3HefvFCUIYdt9YsVCW gxQZ6mS/NAgsFS1tHpSYfBqLiYgSAg/uAu1Yo3snni1zQzKhKsZ+1QPalb+oe4AS X+Vw9BXRWcBXCUBHpJS3vPEeg1pMWbQOpBQ0YxC0YVKVo6InWgovCDvUFdQ8hZzv PGbxU7spVNTUJ5+x8/QQw9rJzAZfTRniymLEuRrmFmmn4xPN6KKmi8zhkRTgWEHO AQl3mDVupSUbBID7pLY3FK7dyzbyAcoKptMow42g54Tgl445MiBos7gpVsIzXeAh 9rKwOceGHrzFYf8dawc7bWquxzZ5qH9udDv9XiGoFRCQUAbyGHnrZ9qNYGKgIf0m 1diFrBsLMroSAWLfI/6b7pCbvgXo1NCvePwomYPk1NoIqyVqPZ4YSmGy85aA1e5R LYSmPHCPEMPxP5YPQq1KsXoFNpCUiu1JXoC6CEh28sUijxStSqcx4q29ZweJKzYy PjBNb6FB+h+jDW3z8OzMDo0sYKZKUMaQStLmzqhvBH++zmYEQsKyL6glxdI5jMXr ibW6uBh4nfo6F6d5ao66Cil3dOu1WBSqCgMa5VgyEjpFlAXrvSXHCAcSZDjfNd/V 11LQJvO73MYXSqf01SJ+UEmZqk/fMa3egOEMfBQZc0BoTMBpOzBkGN+ZYVI2ayNO I00zzgJvkKRcWt2Uyqs9 =id0y -----END PGP SIGNATURE-----