Subject: CVE-2024-36007: mlxsw: spectrum_acl_tcam: Fix warning during rehash

From: Greg Kroah-Hartman <[email-masked]>

Description
===========

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>

The Linux kernel CVE team has assigned CVE-2024-36007 to this issue.

Affected and fixed versions
===========================

	Issue introduced in 5.1 with commit 6f9579d4e302 and fixed in 5.4.275 with commit 0b8863185502
	Issue introduced in 5.1 with commit 6f9579d4e302 and fixed in 5.10.216 with commit 1d76bd2a0034
	Issue introduced in 5.1 with commit 6f9579d4e302 and fixed in 5.15.158 with commit 039992b6d2df
	Issue introduced in 5.1 with commit 6f9579d4e302 and fixed in 6.1.90 with commit 751d35285810
	Issue introduced in 5.1 with commit 6f9579d4e302 and fixed in 6.6.30 with commit e890456051fe
	Issue introduced in 5.1 with commit 6f9579d4e302 and fixed in 6.8.9 with commit 17e9e0bbae65
	Issue introduced in 5.1 with commit 6f9579d4e302 and fixed in 6.9 with commit 743edc8547a9

Please see https://www.kernel.org for a full list of currently supported
kernel versions by the kernel community.

Unaffected versions might change over time as fixes are backported to
older supported kernel versions.  The official CVE entry at
	https://cve.org/CVERecord/?id=CVE-2024-36007
will be updated if fixes are backported, please check that for the most
up to date information about this issue.

Affected files
==============

The file(s) affected by this issue are:
	drivers/net/ethernet/mellanox/mlxsw/spectrum_acl_tcam.c

Mitigation
==========

The Linux kernel CVE team recommends that you update to the latest
stable kernel version for this, and many other bugfixes.  Individual
changes are never tested alone, but rather are part of a larger kernel
release.  Cherry-picking individual commits is not recommended or
supported by the Linux kernel community at all.  If however, updating to
the latest release is impossible, the individual changes to resolve this
issue can be found at these commits:
	https://git.kernel.org/stable/c/0b88631855026b55cad901ac28d081e0f358e596
	https://git.kernel.org/stable/c/1d76bd2a0034d0d08045c1c6adf2235d88982952
	https://git.kernel.org/stable/c/039992b6d2df097c65f480dcf269de3d2656f573
	https://git.kernel.org/stable/c/751d352858108314efd33dddd5a9a2b6bf7d6916
	https://git.kernel.org/stable/c/e890456051fe8c57944b911defb3e6de91315861
	https://git.kernel.org/stable/c/17e9e0bbae652b9b2049e51699e93dfa60b2988d
	https://git.kernel.org/stable/c/743edc8547a92b6192aa1f1b6bb78233fa21dc9b