Re: [PATCH] wifi: mwifiex: Refactor 1-element array into flexible array in struct mwifiex_ie_types_chan_list_param_set

[Kees Cook]

Apologies -- this patch is incomplete. My "git add" failed me. ;) I'll
send a v2!

-Kees


On Tue, Feb 06, 2024 at 08:35:04AM -0800, Kees Cook wrote:
> struct mwifiex_ie_types_chan_list_param_set::chan_scan_param is treated
> as a flexible array, so convert it into one so that it doesn't trip the
> array bounds sanitizer[1]. The code was already calculating sizes by not
> including the trailing single element, so no sizeof() change are needed.
> 
> Link: https://github.com/KSPP/linux/issues/51 [1]
> Cc: Brian Norris <briannorris@xxxxxxxxxxxx>
> Cc: Kalle Valo <kvalo@xxxxxxxxxx>
> Cc: Dmitry Antipov <dmantipov@xxxxxxxxx>
> Cc: Johannes Berg <johannes.berg@xxxxxxxxx>
> Cc: zuoqilin <zuoqilin@xxxxxxxxxx>
> Cc: Ruan Jinjie <ruanjinjie@xxxxxxxxxx>
> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
> Cc: Christophe JAILLET <christophe.jaillet@xxxxxxxxxx>
> Cc: Gustavo A. R. Silva <gustavoars@xxxxxxxxxx>
> Cc: linux-wireless@xxxxxxxxxxxxxxx
> Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>
> ---
>  drivers/net/wireless/marvell/mwifiex/scan.c | 14 ++++++--------
>  1 file changed, 6 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/net/wireless/marvell/mwifiex/scan.c b/drivers/net/wireless/marvell/mwifiex/scan.c
> index a2ddac363b10..0326b121747c 100644
> --- a/drivers/net/wireless/marvell/mwifiex/scan.c
> +++ b/drivers/net/wireless/marvell/mwifiex/scan.c
> @@ -664,15 +664,14 @@ mwifiex_scan_channel_list(struct mwifiex_private *priv,
>  
>  			/* Copy the current channel TLV to the command being
>  			   prepared */
> -			memcpy(chan_tlv_out->chan_scan_param + tlv_idx,
> +			memcpy(&chan_tlv_out->chan_scan_param[tlv_idx],
>  			       tmp_chan_list,
> -			       sizeof(chan_tlv_out->chan_scan_param));
> +			       sizeof(*chan_tlv_out->chan_scan_param));
>  
>  			/* Increment the TLV header length by the size
>  			   appended */
>  			le16_unaligned_add_cpu(&chan_tlv_out->header.len,
> -					       sizeof(
> -						chan_tlv_out->chan_scan_param));
> +					       sizeof(*chan_tlv_out->chan_scan_param));
>  
>  			/*
>  			 * The tlv buffer length is set to the number of bytes
> @@ -2369,12 +2368,11 @@ int mwifiex_cmd_802_11_bg_scan_config(struct mwifiex_private *priv,
>  		     chan_idx < MWIFIEX_BG_SCAN_CHAN_MAX &&
>  		     bgscan_cfg_in->chan_list[chan_idx].chan_number;
>  		     chan_idx++) {
> -			temp_chan = chan_list_tlv->chan_scan_param + chan_idx;
> +			temp_chan = &chan_list_tlv->chan_scan_param[chan_idx];
>  
>  			/* Increment the TLV header length by size appended */
>  			le16_unaligned_add_cpu(&chan_list_tlv->header.len,
> -					       sizeof(
> -					       chan_list_tlv->chan_scan_param));
> +					       sizeof(*chan_list_tlv->chan_scan_param));
>  
>  			temp_chan->chan_number =
>  				bgscan_cfg_in->chan_list[chan_idx].chan_number;
> @@ -2413,7 +2411,7 @@ int mwifiex_cmd_802_11_bg_scan_config(struct mwifiex_private *priv,
>  							   chan_scan_param);
>  		le16_unaligned_add_cpu(&chan_list_tlv->header.len,
>  				       chan_num *
> -			     sizeof(chan_list_tlv->chan_scan_param[0]));
> +			     sizeof(*chan_list_tlv->chan_scan_param));
>  	}
>  
>  	tlv_pos += (sizeof(chan_list_tlv->header)
> -- 
> 2.34.1
> 

-- 
Kees Cook