Race Condition Affecting kernel package, versions <0:4.9.38-16.35.amzn1


Severity

Recommended
critical

Based on Amazon Linux security rating.

Threat Intelligence

Exploit Maturity
Mature
EPSS
0.09% (40th percentile)

Do your applications use this vulnerable package?

In a few clicks we can analyze your entire application and see what components are vulnerable in your application, and suggest you quick fixes.

Test your applications

Snyk Learn

Learn about Race Condition vulnerabilities in an interactive lesson.

Start learning
  • Snyk IDSNYK-AMZN201803-KERNEL-1708014
  • published27 Sept 2021
  • disclosed5 Oct 2017

Introduced: 5 Oct 2017

CVE-2017-1000112  (opens in a new tab)
CWE-362  (opens in a new tab)

How to fix?

Upgrade Amazon-Linux:2018.03 kernel to version 0:4.9.38-16.35.amzn1 or higher.
This issue was patched in ALAS-2017-868.

NVD Description

Note: Versions mentioned in the description apply only to the upstream kernel package and not the kernel package as distributed by Amazon-Linux. See How to fix? for Amazon-Linux:2018.03 relevant fixed versions and status.

Linux kernel: Exploitable memory corruption due to UFO to non-UFO path switch. When building a UFO packet with MSG_MORE __ip_append_data() calls ip_ufo_append_data() to append. However in between two send() calls, the append path can be switched from UFO to non-UFO one, which leads to a memory corruption. In case UFO packet lengths exceeds MTU, copy = maxfraglen - skb->len becomes negative on the non-UFO path and the branch to allocate new skb is taken. This triggers fragmentation and computation of fraggap = skb_prev->len - maxfraglen. Fraggap can exceed MTU, causing copy = datalen - transhdrlen - fraggap to become negative. Subsequently skb_copy_and_csum_bits() writes out-of-bounds. A similar issue is present in IPv6 code. The bug was introduced in e89e9cf539a2 ("[IPv4/IPv6]: UFO Scatter-gather approach") on Oct 18 2005.

CVSS Scores

version 3.1