[PATCH v3 0/4] wifi: add opt-in FIPS exception for iwlwifi

[Jose Ignacio Tornos Martinez <jtornosm@redhat.com>]

Commits 5241526dede9 ("wifi: mac80211: don't send keys
to driver when fips_enabled") and 0636800c8ee1 ("wifi:
iwlwifi: disable certain features for fips_enabled")
disabled WiFi functionality under FIPS mode because
Intel firmware autonomously sends some management
frames without FIPS-validated integrity protection.

While this is technically correct, it leaves
FIPS-required environments with no WiFi connectivity
at all, since WPA3-SAE mandates MFP and without
MFP_CAPABLE the client cannot even associate.

This series introduces an opt-in fips_exception=<bitmap>
kernel boot parameter that allows administrators who
understand the firmware limitation to explicitly choose
connectivity over strict compliance. No keys are
installed in firmware; mac80211 handles all data
encryption/decryption in software using FIPS-approved
algorithms. The default behavior remains exactly as the
original commits implemented.

This is a provisional v3 to show the current working
state and continue the conversation from [1]. Changes
and pending items are based on Johannes's very helpful
guidance.

With fips=1 fips_exception=1 on Intel AX211, this
series enables:
- MFP (802.11w) with software crypto in mac80211
- RX AMPDU aggregation
- Bidirectional data with no keys in firmware

Known limitation:
- No TX A-MPDU aggregation. Firmware sends ADDBA
  unprotected, AP drops it (MFP). Host-driven ADDBA
  from mac80211 can work at the protocol level but
  TLC does not aggregate. Details in [1].

Pending for later versions:
- IGTK/BIGTK offload to firmware
- 6 GHz / EHT dependencies
- TX aggregation (if possible)

Test setup:
  AP: WPA2-PSK ieee80211w=2, channel 52 80MHz HE
  STA: Intel AX211, fips=1 fips_exception=1
  RX: ~450 Mbps (iperf3)
  TX: ~26 Mbps (iperf3, no A-MPDU)

[1] https://lore.kernel.org/all/20261009064326.43891-1-jtornosm@redhat.com/

v3: Address comments from Johannes:
    - Drop PTK/GTK offload to firmware, software-only
      crypto
    - Drop A-MSDU size restoration
    - Drop set_rekey_offload
    Per patch:
    - 1/4: same as v2 1/5 but fips_allows() renamed to
      fips_allows_exception() with more suitable semantics
    - 2/4: v2 2/5 (key gate), v2 3/5 (feature restore)
      and v2 4/5 (SW_MGMT_TX) dropped, replaced by only
      enabling MFP_CAPABLE
    - 3/4: new, RX AMPDU and A-MSDU fixes for SW crypto
      path
    - 4/4: same as v2 5/5
v2: https://lore.kernel.org/all/20260930120829.383408-1-jtornosm@redhat.com/

Jose Ignacio Tornos Martinez (4):
  crypto: fips: add fips_exception kernel boot parameter
    and fips_allows_exception() helper
  wifi: iwlwifi: enable MFP_CAPABLE in FIPS mode
  wifi: iwlwifi: fix RX AMPDU and A-MSDU in FIPS mode
  wifi: iwlwifi: reduce encryption error message to
    debug level in FIPS mode