CVE-2017-2636

Published: 7 March 2017

Race condition in drivers/tty/n_hdlc.c in the Linux kernel through 4.10.1 allows local users to gain privileges or cause a denial of service (double free) by setting the HDLC line discipline.

From the Ubuntu Security Team

Alexander Popov discovered that the N_HDLC line discipline implementation in the Linux kernel contained a double-free vulnerability. A local attacker could use this to cause a denial of service (system crash) or possibly gain administrative privileges.

Notes

Author	Note
jdstrand	android kernels (flo, goldfish, grouper, maguro, mako and manta) are not supported on the Ubuntu Touch 14.10 and earlier preview kernels linux-lts-saucy no longer receives official support linux-lts-quantal no longer receives official support
tyhicks	all of our kernels are affected as CONFIG_N_HDLC=m is set in all releases

Author

Note

jdstrand

android kernels (flo, goldfish, grouper, maguro, mako and manta) are
not supported on the Ubuntu Touch 14.10 and earlier preview kernels
linux-lts-saucy no longer receives official support
linux-lts-quantal no longer receives official support

tyhicks

all of our kernels are affected as CONFIG_N_HDLC=m is set
in all releases

Priority

Cvss 3 Severity Score

7.0

Score breakdown

Status

Package	Release	Status
linux Launchpad, Ubuntu, Debian	upstream	Released (4.11~rc2)
	artful	Not vulnerable (4.10.0-19.21)
	precise	Released (3.2.0-124.167)
	trusty	Released (3.13.0-112.159)
	xenial	Released (4.4.0-66.87)
	yakkety	Released (4.8.0-41.44)
	zesty	Not vulnerable (4.10.0-13.15)
	Patches: Introduced by be10eb7589337e5defbe214dae038a53dd21add8 Fixed by 82f2341c94d270421f383641b7cd670e474db56b
linux-armadaxp Launchpad, Ubuntu, Debian	upstream	Released (4.11~rc2)
	artful	Does not exist
	precise	Released (3.2.0-1685.112)
	trusty	Does not exist
	xenial	Does not exist
	yakkety	Does not exist
	zesty	Does not exist
	This package is not directly supported by the Ubuntu Security Team
linux-aws Launchpad, Ubuntu, Debian	upstream	Released (4.11~rc2)
	artful	Does not exist
	precise	Does not exist
	trusty	Not vulnerable (4.4.0-1002.2)
	xenial	Released (4.4.0-1007.16)
	yakkety	Does not exist
	zesty	Does not exist
linux-azure Launchpad, Ubuntu, Debian	upstream	Released (4.11~rc2)
	artful	Does not exist
	trusty	Not vulnerable (4.15.0-1023.24~14.04.1)
	xenial	Not vulnerable (4.11.0-1009.9)
	yakkety	Does not exist
	zesty	Does not exist
linux-euclid Launchpad, Ubuntu, Debian	upstream	Released (4.11~rc2)
	artful	Does not exist
	trusty	Does not exist
	xenial	Not vulnerable (4.4.0-9019.20)
	zesty	Does not exist
linux-flo Launchpad, Ubuntu, Debian	upstream	Released (4.11~rc2)
	artful	Does not exist
	precise	Does not exist
	trusty	Does not exist (trusty was ignored)
	xenial	Ignored (abandoned)
	yakkety	Ignored (end of life)
	zesty	Does not exist
linux-gcp Launchpad, Ubuntu, Debian	upstream	Released (4.11~rc2)
	artful	Does not exist
	trusty	Does not exist
	xenial	Not vulnerable (4.10.0-1004.4)
	yakkety	Does not exist
	zesty	Does not exist
linux-gke Launchpad, Ubuntu, Debian	upstream	Released (4.11~rc2)
	artful	Does not exist
	precise	Does not exist
	trusty	Does not exist
	xenial	Released (4.4.0-1005.6)
	yakkety	Does not exist
	zesty	Does not exist
linux-goldfish Launchpad, Ubuntu, Debian	upstream	Released (4.11~rc2)
	artful	Does not exist
	precise	Does not exist
	trusty	Does not exist (trusty was ignored)
	xenial	Ignored (abandoned)
	yakkety	Ignored (end of life)
	zesty	Ignored (end of life)
linux-grouper Launchpad, Ubuntu, Debian	upstream	Released (4.11~rc2)
	artful	Does not exist
	precise	Does not exist
	trusty	Does not exist (trusty was ignored)
	xenial	Does not exist
	yakkety	Does not exist
	zesty	Does not exist
linux-hwe Launchpad, Ubuntu, Debian	upstream	Released (4.11~rc2)
	artful	Does not exist
	precise	Does not exist
	trusty	Does not exist
	xenial	Released (4.8.0-41.44~16.04.1)
	yakkety	Does not exist
	zesty	Does not exist
linux-hwe-edge Launchpad, Ubuntu, Debian	upstream	Released (4.11~rc2)
	artful	Does not exist
	precise	Does not exist
	trusty	Does not exist
	xenial	Released (4.8.0-41.44~16.04.1)
	yakkety	Does not exist
	zesty	Does not exist
linux-kvm Launchpad, Ubuntu, Debian	upstream	Released (4.11~rc2)
	artful	Does not exist
	trusty	Does not exist
	xenial	Not vulnerable (4.4.0-1004.9)
	zesty	Does not exist
linux-linaro-omap Launchpad, Ubuntu, Debian	upstream	Released (4.11~rc2)
	artful	Does not exist
	precise	Ignored (end of life)
	trusty	Does not exist
	xenial	Does not exist
	yakkety	Does not exist
	zesty	Does not exist
linux-linaro-shared Launchpad, Ubuntu, Debian	upstream	Released (4.11~rc2)
	artful	Does not exist
	precise	Ignored (end of life)
	trusty	Does not exist
	xenial	Does not exist
	yakkety	Does not exist
	zesty	Does not exist
linux-linaro-vexpress Launchpad, Ubuntu, Debian	upstream	Released (4.11~rc2)
	artful	Does not exist
	precise	Ignored (end of life)
	trusty	Does not exist
	xenial	Does not exist
	yakkety	Does not exist
	zesty	Does not exist
linux-lts-quantal Launchpad, Ubuntu, Debian	upstream	Released (4.11~rc2)
	artful	Does not exist
	precise	Ignored (end of life)
	trusty	Does not exist
	xenial	Does not exist
	yakkety	Does not exist
	zesty	Does not exist
	This package is not directly supported by the Ubuntu Security Team
linux-lts-raring Launchpad, Ubuntu, Debian	upstream	Released (4.11~rc2)
	artful	Does not exist
	precise	Ignored (end of life)
	trusty	Does not exist
	xenial	Does not exist
	yakkety	Does not exist
	zesty	Does not exist
linux-lts-saucy Launchpad, Ubuntu, Debian	upstream	Released (4.11~rc2)
	artful	Does not exist
	precise	Ignored (end of life)
	trusty	Does not exist
	xenial	Does not exist
	yakkety	Does not exist
	zesty	Does not exist
	This package is not directly supported by the Ubuntu Security Team
linux-lts-trusty Launchpad, Ubuntu, Debian	upstream	Released (4.11~rc2)
	artful	Does not exist
	precise	Released (3.13.0-112.159~precise1)
	trusty	Does not exist
	xenial	Does not exist
	yakkety	Does not exist
	zesty	Does not exist
linux-lts-utopic Launchpad, Ubuntu, Debian	upstream	Released (4.11~rc2)
	artful	Does not exist
	precise	Does not exist
	trusty	Does not exist (trusty was ignored [end of standard support])
	xenial	Does not exist
	yakkety	Does not exist
	zesty	Does not exist
linux-lts-vivid Launchpad, Ubuntu, Debian	upstream	Released (4.11~rc2)
	artful	Does not exist
	precise	Does not exist
	trusty	Ignored (end of life, was needed)
	xenial	Does not exist
	yakkety	Does not exist
	zesty	Does not exist
linux-lts-wily Launchpad, Ubuntu, Debian	upstream	Released (4.11~rc2)
	artful	Does not exist
	precise	Does not exist
	trusty	Does not exist (trusty was ignored [end of standard support])
	xenial	Does not exist
	yakkety	Does not exist
	zesty	Does not exist
linux-lts-xenial Launchpad, Ubuntu, Debian	upstream	Released (4.11~rc2)
	artful	Does not exist
	precise	Does not exist
	trusty	Released (4.4.0-66.87~14.04.1)
	xenial	Does not exist
	yakkety	Does not exist
	zesty	Does not exist
linux-maguro Launchpad, Ubuntu, Debian	upstream	Released (4.11~rc2)
	artful	Does not exist
	precise	Does not exist
	trusty	Does not exist (trusty was ignored)
	xenial	Does not exist
	yakkety	Does not exist
	zesty	Does not exist
linux-mako Launchpad, Ubuntu, Debian	upstream	Released (4.11~rc2)
	artful	Does not exist
	precise	Does not exist
	trusty	Does not exist (trusty was ignored)
	xenial	Ignored (abandoned)
	yakkety	Ignored (end of life)
	zesty	Does not exist
linux-manta Launchpad, Ubuntu, Debian	upstream	Released (4.11~rc2)
	artful	Does not exist
	precise	Does not exist
	trusty	Does not exist (trusty was ignored)
	xenial	Does not exist
	yakkety	Does not exist
	zesty	Does not exist
linux-oem Launchpad, Ubuntu, Debian	upstream	Released (4.11~rc2)
	artful	Does not exist
	trusty	Does not exist
	xenial	Not vulnerable (4.13.0-1008.9)
	zesty	Does not exist
linux-qcm-msm Launchpad, Ubuntu, Debian	upstream	Released (4.11~rc2)
	artful	Does not exist
	precise	Ignored (end of life)
	trusty	Does not exist
	xenial	Does not exist
	yakkety	Does not exist
	zesty	Does not exist
linux-raspi2 Launchpad, Ubuntu, Debian	upstream	Released (4.11~rc2)
	artful	Not vulnerable (4.10.0-1004.6)
	precise	Does not exist
	trusty	Does not exist
	xenial	Released (4.4.0-1046.53)
	yakkety	Released (4.8.0-1028.31)
	zesty	Not vulnerable (4.10.0-1001.3)
linux-snapdragon Launchpad, Ubuntu, Debian	upstream	Released (4.11~rc2)
	artful	Not vulnerable (4.4.0-1050.54)
	precise	Does not exist
	trusty	Does not exist
	xenial	Released (4.4.0-1050.54)
	yakkety	Released (4.4.0-1050.54)
	zesty	Not vulnerable (4.4.0-1050.54)
linux-ti-omap4 Launchpad, Ubuntu, Debian	artful	Does not exist
	precise	Released (3.2.0-1502.129)
	trusty	Does not exist
	upstream	Released (4.11~rc2)
	xenial	Does not exist
	yakkety	Does not exist
	zesty	Does not exist

Severity score breakdown

Parameter	Value
Base score	7.0
Attack vector	Local
Attack complexity	High
Privileges required	Low
User interaction	None
Scope	Unchanged
Confidentiality	High
Integrity impact	High
Availability impact	High
Vector	CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H

References

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