CVE-2024-47684

/// Technical description

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

tcp: check skb is non-NULL in tcp_rto_delta_us()

We have some machines running stock Ubuntu 20.04.6 which is their 5.4.0-174-generic

kernel that are running ceph and recently hit a null ptr dereference in

tcp_rearm_rto(). Initially hitting it from the TLP path, but then later we also

saw it getting hit from the RACK case as well. Here are examples of the oops

messages we saw in each of those cases:

Jul 26 15:05:02 rx [11061395.780353] BUG: kernel NULL pointer dereference, address: 0000000000000020

Jul 26 15:05:02 rx [11061395.787572] #PF: supervisor read access in kernel mode

Jul 26 15:05:02 rx [11061395.792971] #PF: error_code(0x0000) - not-present page

Jul 26 15:05:02 rx [11061395.798362] PGD 0 P4D 0

Jul 26 15:05:02 rx [11061395.801164] Oops: 0000 [#1] SMP NOPTI

Jul 26 15:05:02 rx [11061395.805091] CPU: 0 PID: 9180 Comm: msgr-worker-1 Tainted: G W 5.4.0-174-generic #193-Ubuntu

Jul 26 15:05:02 rx [11061395.814996]

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References