Acquisition of RTNL Before Calling ip[6]mr_free_table() in ipmr,ip6mr
Summary
GSD-2022-1000288: ipmr,ip6mr: acquire RTNL before calling ip[6]mr_free_table() on failure path. Affects Kernel versions >= f243e5a7859a24d10975afb9a1708cac624ba6f1, < 80c529322600dfb1f985b5e3f14c3c6f522ce154. No fix is published. How to fix ↓
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Background
The ipmr and ip6mr packages are part of the Linux Kernel ecosystem. They provide functionality for managing multicast routing tables in IPv4 and IPv6 networks, respectively. These packages are crucial for efficient multicast communication and routing. However, a vulnerability has been discovered in these packages that could potentially lead to security issues.
Vulnerability Detail
The vulnerability arises from a failure path in the ipmr and ip6mr packages, where the RTNL (Routing Netlink) lock is not acquired before calling the ip[6]mr_free_table() function. This can result in a race condition, allowing an attacker to manipulate the routing tables and potentially disrupt multicast communication. The impact and attack plausibility of this vulnerability have not been proven yet.
How To Fix
No fixed version is published for this vulnerability.
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Workaround
As a workaround, users can manually acquire the RTNL lock before calling ip[6]mr_free_table() on the failure path. Here is an example of how to acquire the lock using the rtnl_lock() function:
#include <linux/rtnetlink.h>
void workaround() {
rtnl_lock();
ip[6]mr_free_table();
rtnl_unlock();
}
Conclusion
In conclusion, the ipmr and ip6mr packages in the Linux Kernel are vulnerable to a race condition when calling ip[6]mr_free_table() on the failure path without acquiring the RTNL lock. To mitigate this vulnerability, it is recommended to update the Kernel to version v4.9.302 or later. Alternatively, users can apply the provided workaround by manually acquiring the RTNL lock. For further support on vulnerability remediation, you can contact DevNack.com.
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FAQ
The impact of this vulnerability is not yet proven. However, if successfully exploited, it could allow an attacker to manipulate multicast routing tables and potentially disrupt multicast communication.
You can use the Vulert Playground at Vulert Scanner to check if your system is affected by this vulnerability. Simply upload your package-lock.json file to the playground, and it will alert you in real-time if the vulnerability is detected.
Yes, a fix is available in Linux Kernel version v4.9.302 or later. It is recommended to update your Kernel to mitigate this vulnerability.
Yes, a workaround is available. You can manually acquire the RTNL lock before calling ip[6]mr_free_table() on the failure path. Refer to the 'workaround' section for more details.
For more information about this vulnerability, you can refer to the vulnerability details in the Open Source Vulnerability format. The link to the details is provided in the 'affected' section of the vulnerability report.
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