CVE-2024-36007

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

mlxsw: spectrum_acl_tcam: Fix warning during rehash

As previously explained, the rehash delayed work migrates filters from

one region to another. This is done by iterating over all chunks (all

the filters with the same priority) in the region and in each chunk

iterating over all the filters.

When the work runs out of credits it stores the current chunk and entry

as markers in the per-work context so that it would know where to resume

the migration from the next time the work is scheduled.

Upon error, the chunk marker is reset to NULL, but without resetting the

entry markers despite being relative to it. This can result in migration

being resumed from an entry that does not belong to the chunk being

migrated. In turn, this will eventually lead to a chunk being iterated

over as if it is an entry. Because of how the two structures happen to

be defined, this does not lead to KASAN splats, but to warnings such as

[1].

Fix by creating a helper that resets all the markers and call it from

all the places the currently only reset the chunk marker. For good

measures also call it when starting a completely new rehash. Add a

warning to avoid future cases.

[1]

WARNING: CPU: 7 PID: 1076 at drivers/net/ethernet/mellanox/mlxsw/core_acl_flex_keys.c:407 mlxsw_afk_encode+0x242/0x2f0

Modules linked in:

CPU: 7 PID: 1076 Comm: kworker/7:24 Tainted: G W 6.9.0-rc3-custom-00880-g29e61d91b77b #29

Hardware name: Mellanox Technologies Ltd. MSN3700/VMOD0005, BIOS 5.11 01/06/2019

Workqueue: mlxsw_core mlxsw_sp_acl_tcam_vregion_rehash_work

RIP: 0010:mlxsw_afk_encode+0x242/0x2f0

[...]

Call Trace:

<TASK>

mlxsw_sp_acl_atcam_entry_add+0xd9/0x3c0

mlxsw_sp_acl_tcam_entry_create+0x5e/0xa0

mlxsw_sp_acl_tcam_vchunk_migrate_all+0x109/0x290

mlxsw_sp_acl_tcam_vregion_rehash_work+0x6c/0x470

process_one_work+0x151/0x370

worker_thread+0x2cb/0x3e0

kthread+0xd0/0x100

ret_from_fork+0x34/0x50

</TASK>