[PATCH v2] wifi: mwifiex: Refactor 1-element array into flexible array in struct mwifiex_ie_types_chan_list_param_set

[Kees Cook <keescook@chromium.org>]

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]. Only once place was using sizeof() on the
whole struct (in 11n.c), so adjust it to follow the calculation pattern
used by scan.c to avoid including the trailing single element.

Link: https://github.com/KSPP/linux/issues/51 [1]
Cc: Brian Norris <briannorris@chromium.org>
Cc: Kalle Valo <kvalo@kernel.org>
Cc: Dmitry Antipov <dmantipov@yandex.ru>
Cc: Johannes Berg <johannes.berg@intel.com>
Cc: zuoqilin <zuoqilin@yulong.com>
Cc: Ruan Jinjie <ruanjinjie@huawei.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Cc: Gustavo A. R. Silva <gustavoars@kernel.org>
Cc: linux-wireless@vger.kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>
---
 drivers/net/wireless/marvell/mwifiex/11n.c  |  8 +++-----
 drivers/net/wireless/marvell/mwifiex/fw.h   |  2 +-
 drivers/net/wireless/marvell/mwifiex/scan.c | 14 ++++++--------
 3 files changed, 10 insertions(+), 14 deletions(-)

diff --git a/drivers/net/wireless/marvell/mwifiex/11n.c b/drivers/net/wireless/marvell/mwifiex/11n.c
index 90e401100898..9ed90da4dfcf 100644
--- a/drivers/net/wireless/marvell/mwifiex/11n.c
+++ b/drivers/net/wireless/marvell/mwifiex/11n.c
@@ -392,12 +392,10 @@ mwifiex_cmd_append_11n_tlv(struct mwifiex_private *priv,
 
 		chan_list =
 			(struct mwifiex_ie_types_chan_list_param_set *) *buffer;
-		memset(chan_list, 0,
-		       sizeof(struct mwifiex_ie_types_chan_list_param_set));
+		memset(chan_list, 0, struct_size(chan_list, chan_scan_param, 1));
 		chan_list->header.type = cpu_to_le16(TLV_TYPE_CHANLIST);
-		chan_list->header.len = cpu_to_le16(
-			sizeof(struct mwifiex_ie_types_chan_list_param_set) -
-			sizeof(struct mwifiex_ie_types_header));
+		chan_list->header.len =
+			cpu_to_le16(sizeof(struct mwifiex_chan_scan_param_set));
 		chan_list->chan_scan_param[0].chan_number =
 			bss_desc->bcn_ht_oper->primary_chan;
 		chan_list->chan_scan_param[0].radio_type =
diff --git a/drivers/net/wireless/marvell/mwifiex/fw.h b/drivers/net/wireless/marvell/mwifiex/fw.h
index 62f3c9a52a1d..3adc447b715f 100644
--- a/drivers/net/wireless/marvell/mwifiex/fw.h
+++ b/drivers/net/wireless/marvell/mwifiex/fw.h
@@ -770,7 +770,7 @@ struct mwifiex_chan_scan_param_set {
 
 struct mwifiex_ie_types_chan_list_param_set {
 	struct mwifiex_ie_types_header header;
-	struct mwifiex_chan_scan_param_set chan_scan_param[1];
+	struct mwifiex_chan_scan_param_set chan_scan_param[];
 } __packed;
 
 struct mwifiex_ie_types_rxba_sync {
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