CVE-2024-43846

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

lib: objagg: Fix general protection fault

The library supports aggregation of objects into other objects only if the parent object does not have a parent itself. That is, nesting is not supported.

Aggregation happens in two cases: Without and with hints, where hints are a pre-computed recommendation on how to aggregate the provided objects.

Nesting is not possible in the first case due to a check that prevents it, but in the second case there is no check because the assumption is that nesting cannot happen when creating objects based on hints. The violation of this assumption leads to various warnings and eventually to a general protection fault [1].

Before fixing the root cause, error out when nesting happens and warn.

[1] general protection fault, probably for non-canonical address 0xdead000000000d90: 0000 [#1] PREEMPT SMP PTI CPU: 1 PID: 1083 Comm: kworker/1:9 Tainted: G W 6.9.0-rc6-custom-gd9b4f1cca7fb #7 Hardware name: Mellanox Technologies Ltd. MSN3700/VMOD0005, BIOS 5.11 01/06/2019 Workqueue: mlxswcore mlxswspacltcamvregionrehashwork RIP: 0010:mlxswspaclerpbfinsert+0x25/0x80 [...] Call Trace: <TASK> mlxswspaclatcamentryadd+0x256/0x3c0 mlxswspacltcamentrycreate+0x5e/0xa0 mlxswspacltcamvchunkmigrateone+0x16b/0x270 mlxswspacltcamvregionrehashwork+0xbe/0x510 processonework+0x151/0x370 workerthread+0x2cb/0x3e0 kthread+0xd0/0x100 retfromfork+0x34/0x50 retfromforkasm+0x1a/0x30 </TASK>