ALAS-2017-845


Amazon Linux AMI Security Advisory: ALAS-2017-845
Advisory Release Date: 2017-06-19 08:58 Pacific
Severity: Critical

Issue Overview:

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 jmp'ed over, this affects Linux Kernel versions 4.11.5 and earlier (the stackguard page was introduced in 2010). (CVE-2017-1000364 )

The offset2lib patch as used by the Linux Kernel contains a vulnerability, if RLIMIT_STACK is set to RLIMIT_INFINITY and 1 Gigabyte of memory is allocated (the maximum under the 1/4 restriction) then the stack will be grown down to 0x80000000, and as the PIE binary is mapped above 0x80000000 the minimum distance between the end of the PIE binary's read-write segment and the start of the stack becomes small enough that the stack guard page can be jumped over by an attacker. This is a different issue than CVE-2017-1000370 and CVE-2017-1000365 . (CVE-2017-1000371 )


Affected Packages:

kernel


Issue Correction:
Run yum update kernel to update your system.

New Packages:
i686:
    kernel-debuginfo-common-i686-4.9.27-14.33.amzn1.i686
    perf-debuginfo-4.9.27-14.33.amzn1.i686
    perf-4.9.27-14.33.amzn1.i686
    kernel-tools-debuginfo-4.9.27-14.33.amzn1.i686
    kernel-debuginfo-4.9.27-14.33.amzn1.i686
    kernel-headers-4.9.27-14.33.amzn1.i686
    kernel-tools-devel-4.9.27-14.33.amzn1.i686
    kernel-tools-4.9.27-14.33.amzn1.i686
    kernel-devel-4.9.27-14.33.amzn1.i686
    kernel-4.9.27-14.33.amzn1.i686

noarch:
    kernel-doc-4.9.27-14.33.amzn1.noarch

src:
    kernel-4.9.27-14.33.amzn1.src

x86_64:
    kernel-4.9.27-14.33.amzn1.x86_64
    kernel-tools-4.9.27-14.33.amzn1.x86_64
    kernel-devel-4.9.27-14.33.amzn1.x86_64
    perf-debuginfo-4.9.27-14.33.amzn1.x86_64
    kernel-debuginfo-4.9.27-14.33.amzn1.x86_64
    kernel-tools-debuginfo-4.9.27-14.33.amzn1.x86_64
    perf-4.9.27-14.33.amzn1.x86_64
    kernel-headers-4.9.27-14.33.amzn1.x86_64
    kernel-debuginfo-common-x86_64-4.9.27-14.33.amzn1.x86_64
    kernel-tools-devel-4.9.27-14.33.amzn1.x86_64