Currently struct ieee80211_tim_ie defines: u8 virtual_map[1]; Per the guidance in [1] change this to be a flexible array. Per the discussion in [2] wrap the virtual_map in a union with a u8 item in order to preserve the existing expectation that the virtual_map must contain at least one octet (at least when used in a non-S1G PPDU). This means that no driver changes are required. [1] https://docs.kernel.org/process/deprecated.html#zero-length-and-one-element-arrays [2] https://lore.kernel.org/linux-wireless/202308301529.AC90A9EF98@keescook/ Suggested-by: Kees Cook <keescook@xxxxxxxxxxxx> Signed-off-by: Jeff Johnson <quic_jjohnson@xxxxxxxxxxx> --- include/linux/ieee80211.h | 13 ++++++++++--- 1 file changed, 10 insertions(+), 3 deletions(-) diff --git a/include/linux/ieee80211.h b/include/linux/ieee80211.h index bd2f6e19c357..340d7e0f6bf7 100644 --- a/include/linux/ieee80211.h +++ b/include/linux/ieee80211.h @@ -951,17 +951,24 @@ struct ieee80211_wide_bw_chansw_ie { * @dtim_count: DTIM Count * @dtim_period: DTIM Period * @bitmap_ctrl: Bitmap Control + * @required_octet: "Syntatic sugar" to force the struct size to the + * minimum valid size when carried in a non-S1G PPDU * @virtual_map: Partial Virtual Bitmap * * This structure represents the payload of the "TIM element" as - * described in IEEE Std 802.11-2020 section 9.4.2.5. + * described in IEEE Std 802.11-2020 section 9.4.2.5. Note that this + * definition is only applicable when the element is carried in a + * non-S1G PPDU. When the TIM is carried in an S1G PPDU, the Bitmap + * Control and Partial Virtual Bitmap may not be present. */ struct ieee80211_tim_ie { u8 dtim_count; u8 dtim_period; u8 bitmap_ctrl; - /* variable size: 1 - 251 bytes */ - u8 virtual_map[1]; + union { + u8 required_octet; + DECLARE_FLEX_ARRAY(u8, virtual_map); + }; } __packed; /** -- 2.42.0
