CVE-2023-53549

In the Linux kernel, the following vulnerability has been resolved:

netfilter: ipset: Rework long task execution when adding/deleting entries

When adding/deleting large number of elements in one step in ipset, it can take a reasonable amount of time and can result in soft lockup errors. The patch 5f7b51bf09ba (netfilter: ipset: Limit the maximal range of consecutive elements to add/delete) tried to fix it by limiting the max elements to process at all. However it was not enough, it is still possible that we get hung tasks. Lowering the limit is not reasonable, so the approach in this patch is as follows: rely on the method used at resizing sets and save the state when we reach a smaller internal batch limit, unlock/lock and proceed from the saved state. Thus we can avoid long continuous tasks and at the same time removed the limit to add/delete large number of elements in one step.

The nfnl mutex is held during the whole operation which prevents one to issue other ipset commands in parallel.

Weakness

The product does not properly acquire or release a lock on a resource, leading to unexpected resource state changes and behaviors.

Affected Software

Extended Description

Locking is a type of synchronization behavior that ensures that multiple independently-operating processes or threads do not interfere with each other when accessing the same resource. All processes/threads are expected to follow the same steps for locking. If these steps are not followed precisely - or if no locking is done at all - then another process/thread could modify the shared resource in a way that is not visible or predictable to the original process. This can lead to data or memory corruption, denial of service, etc.

Potential Mitigations

Related Attack Patterns

• https://cwe.mitre.org/data/definitions/25.html
• https://cwe.mitre.org/data/definitions/26.html
• https://cwe.mitre.org/data/definitions/27.html

References

• https://git.kernel.org/stable/c/24a828f5a54bdeca0846526860d72b3766c5fe95
• https://git.kernel.org/stable/c/5e29dc36bd5e2166b834ceb19990d9e68a734d7d
• https://git.kernel.org/stable/c/8964cc36ba011dc0e1041131fa2e91fb4c2a811b
• https://git.kernel.org/stable/c/a1e1521b463968b4eca7163f61fb6cc54d008061
• https://git.kernel.org/stable/c/ee756980e491c829ba0495bb420b7224a9ee26b2