From: Hans de Goede <hdegoede@xxxxxxxxxx> [ Upstream commit 16e455a465fca91907af0108f3d013150386df30 ] Using brcmfmac with 6.5-rc3 on a brcmfmac43241b4-sdio triggers a backtrace caused by the following field-spanning warning: memcpy: detected field-spanning write (size 120) of single field "¶ms_le->channel_list[0]" at drivers/net/wireless/broadcom/brcm80211/brcmfmac/cfg80211.c:1072 (size 2) The driver still works after this warning. The warning was introduced by the new field-spanning write checks which were enabled recently. Fix this by replacing the channel_list[1] declaration at the end of the struct with a flexible array declaration. Most users of struct brcmf_scan_params_le calculate the size to alloc using the size of the non flex-array part of the struct + needed extra space, so they do not care about sizeof(struct brcmf_scan_params_le). brcmf_notify_escan_complete() however uses the struct on the stack, expecting there to be room for at least 1 entry in the channel-list to store the special -1 abort channel-id. To make this work use an anonymous union with a padding member added + the actual channel_list flexible array. Cc: Kees Cook <keescook@xxxxxxxxxxxx> Signed-off-by: Hans de Goede <hdegoede@xxxxxxxxxx> Reviewed-by: Kees Cook <keescook@xxxxxxxxxxxx> Reviewed-by: Franky Lin <franky.lin@xxxxxxxxxxxx> Signed-off-by: Kalle Valo <kvalo@xxxxxxxxxx> Link: https://lore.kernel.org/r/20230729140500.27892-1-hdegoede@xxxxxxxxxx Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- .../net/wireless/broadcom/brcm80211/brcmfmac/fwil_types.h | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/fwil_types.h b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/fwil_types.h index 05bd636011ec9..58338b6443f8d 100644 --- a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/fwil_types.h +++ b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/fwil_types.h @@ -354,7 +354,12 @@ struct brcmf_scan_params_le { * fixed parameter portion is assumed, otherwise * ssid in the fixed portion is ignored */ - __le16 channel_list[1]; /* list of chanspecs */ + union { + __le16 padding; /* Reserve space for at least 1 entry for abort + * which uses an on stack brcmf_scan_params_le + */ + DECLARE_FLEX_ARRAY(__le16, channel_list); /* chanspecs */ + }; }; struct brcmf_scan_results { -- 2.40.1
