Critical: kernel

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  

Additional References

Red Hat: CVE-2017-1000364, CVE-2017-1000371

Mitre: CVE-2017-1000364, CVE-2017-1000371