CVE-2015-8767: Race Condition
From the git commit:
An deadlock condition can occur when sctpaccept() is called by the local software during a heartbeat timeout event after the 4-way handshake. Since sctpassocmigrate() changes both assoc->base.sk and assoc->ep, the bhsocklock in sctpgenerateheartbeatevent() will be taken with the listening socket but released with the new association socket. The result is a deadlock on any future attempts to take the listening socket lock, preventing sctp sockets from working correctly.
The server must be running an service using the sctp protocol to be affected.
Resources:
https://patchwork.ozlabs.org/patch/522411/ https://patchwork.ozlabs.org/patch/522412/
Patch commit notes (net-next.git): https://kernel.googlesource.com/pub/scm/linux/kernel/git/horms/ipvs/+/635682a14427d241bab7bbdeebb48a7d7b91638e
CVE Request: http://seclists.org/oss-sec/2016/q1/66
Other sources
net/sctp/smsideeffect.c in the Linux kernel before 4.3 does not properly manage the relationship between a lock and a socket, which allows local users to cause a denial of service (deadlock) via a crafted sctpaccept call.
— Launchpad
Affected Software
Remediation
Event History
Frequently Asked Questions
What is CVE-2015-8767?
CVE-2015-8767 is a vulnerability in the Linux kernel that allows local users to cause a denial of service (deadlock) via a crafted sctp_accept call.
How severe is CVE-2015-8767?
CVE-2015-8767 has a severity level of medium.
Which software versions are affected by CVE-2015-8767?
The affected software versions include Linux kernel versions before 4.3.
How can I fix CVE-2015-8767?
To fix CVE-2015-8767, update your Linux kernel to version 4.3 or later.
Where can I find more information about CVE-2015-8767?
You can find more information about CVE-2015-8767 on the following references: [Link 1](https://patchwork.ozlabs.org/patch/522411/), [Link 2](https://patchwork.ozlabs.org/patch/522412/), [Link 3](https://kernel.googlesource.com/pub/scm/linux/kernel/git/horms/ipvs/+/635682a14427d241bab7bbdeebb48a7d7b91638e).