larger stack guard gap, between vmas in kernel-mm and glibc CVE-2017-1000364 CVE-2017-1000365 (aka Stack Clash)
asked 2017-06-29 12:32:21 +0300
This post is a wiki. Anyone with karma >75 is welcome to improve it.
An issue was discovered in the size of the stack guard page on Linux, specifically a 4k stack guard page is not sufficiently large and can be "jumped" over (the stack guard page is bypassed), this affects Linux Kernel versions 4.11.5 and earlier (the stackguard page was introduced in 2010).
The Linux Kernel imposes a size restriction on the arguments and environmental strings passed through RLIMIT_STACK/RLIM_INFINITY (1/4 of the size), but does not take the argument and environment pointers into account, which allows attackers to bypass this limitation. This affects Linux Kernel versions 4.11.5 and earlier. It appears that this feature was introduced in the Linux Kernel version 2.6.23.
Patches upstream |1| |2| have to be backported to 3.4.108 (maybe look at kernel 3.2 backports |1| |2| )...
CVSS v3 Base Score: 9.8 Critical 7.8 High (attack range: local)
|the 2nd part of stack-clash is a glibc vulnerability CVE-2017-1000366 and requires glibc update| <- released in Jämsänjoki 2.1.1 / Kiiminkijoki 2.1.2
The updated kernel/glibc packages for distributions like RHEL have issues (some software packages refuse to start after upgrading the kernel) so a fix for SFOS needs thorough testing and perhaps picking the most compatible fix for the problem. See https://bugzilla.redhat.com/show_bug.cgi?id=1463241 or https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=865311 for details on problematic fixes for the vulnerability.
Maus ( 2017-06-29 19:08:10 +0300 )editnow, jolla should be able to patch....
lpr ( 2017-10-05 15:08:51 +0300 )edit