[lvc-project] [PATCH v2 2/2] wifi: ath12k: annotate channel of struct ath12k_wmi_scan_chan_list_arg with __counted_by

[Dmitry Antipov]

According to 'ath12k_reg_update_chan_list()', annotate flexible
array member 'channel' of 'struct ath12k_wmi_scan_chan_list_arg'
with '__counted_by()' attribute to improve runtime bounds checking
when CONFIG_UBSAN_BOUNDS is enabled. Compile tested only.

Signed-off-by: Dmitry Antipov <dmantipov at yandex.ru>
---
v2: fix typo and add related comment in ath12k_reg_update_chan_list()
---
 drivers/net/wireless/ath/ath12k/reg.c | 3 +++
 drivers/net/wireless/ath/ath12k/wmi.h | 2 +-
 2 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/net/wireless/ath/ath12k/reg.c b/drivers/net/wireless/ath/ath12k/reg.c
index 439d61f284d8..dbd6f0570498 100644
--- a/drivers/net/wireless/ath/ath12k/reg.c
+++ b/drivers/net/wireless/ath/ath12k/reg.c
@@ -131,6 +131,9 @@ int ath12k_reg_update_chan_list(struct ath12k *ar)
 		return -ENOMEM;
 
 	arg->pdev_id = ar->pdev->pdev_id;
+	/* Note nallchans should be set before populating channel[],
+	 * otherwise __counted_by() might raise false positives.
+	 */
 	arg->nallchans = num_channels;
 
 	ch = arg->channel;
diff --git a/drivers/net/wireless/ath/ath12k/wmi.h b/drivers/net/wireless/ath/ath12k/wmi.h
index 6a913f9b8315..02b3d722a23b 100644
--- a/drivers/net/wireless/ath/ath12k/wmi.h
+++ b/drivers/net/wireless/ath/ath12k/wmi.h
@@ -3746,7 +3746,7 @@ struct wmi_stop_scan_cmd {
 struct ath12k_wmi_scan_chan_list_arg {
 	u32 pdev_id;
 	u16 nallchans;
-	struct ath12k_wmi_channel_arg channel[];
+	struct ath12k_wmi_channel_arg channel[] __counted_by(nallchans);
 };
 
 struct wmi_scan_chan_list_cmd {
-- 
2.47.0