CVE-2026-64176: wifi: iwlwifi: mvm: fix driver-set TX rates on old devices

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

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

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

wifi: iwlwifi: mvm: fix driver-set TX rates on old devices

On old devices such as 7265D, rates are still encoded in version 1
format, which doesn't use the CCK/OFDM rate index (0-3/0-7) but
rather their PLCP value (e.g. 10 for 1 Mbps CCK rate.)

While introducing v3 rates, I changed the driver from internally
handling v1 rates and converting to v2, to internally handling v3
and converting to v1 or v2 according to the firmware. I accordingly
changed the code in iwl_mvm_mac80211_idx_to_hwrate() to no longer
have different values for different APIs. This was correct.

However, I later reverted this part of the change, because it was
reported that I had broken beacon rates, causing a FW assert/crash.
This caused TX_CMD rates to be set incorrectly, potentially causing
a warning when reported back from the device as having been used.

Fix this (hopefully correctly now) by handling beacon rates in the
TX_CMD that's embedded in the beacon template command separately.
Restore iwl_mvm_mac80211_idx_to_hwrate() to return only the rate
index, not PLCP value, fixing the real TX_CMD.

The Linux kernel CVE team has assigned CVE-2026-64176 to this issue.


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

	Fixed in 6.18.34 with commit 6fe92651b44fd3cfc8dcfdaad0e82885c384dada
	Fixed in 7.0.11 with commit 6b58a79f2cd98156856eb49e8b55db5facdd7e6d
	Fixed in 7.1 with commit fb84b5cbcaab3ca0f4e961d92a40ed7f3aac483b

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-2026-64176
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/wireless/intel/iwlwifi/mvm/mac-ctxt.c
	drivers/net/wireless/intel/iwlwifi/mvm/utils.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/6fe92651b44fd3cfc8dcfdaad0e82885c384dada
	https://git.kernel.org/stable/c/6b58a79f2cd98156856eb49e8b55db5facdd7e6d
	https://git.kernel.org/stable/c/fb84b5cbcaab3ca0f4e961d92a40ed7f3aac483b