[PATCH 8/8] staging: wfx: improve robustness of wfx_get_hw_rate()

From: Jerome Pouiller
Date: Fri Oct 09 2020 - 13:13:49 EST


From: Jérôme Pouiller <jerome.pouiller@xxxxxxxxxx>

Smatch complains:

data_tx.c:37 wfx_get_hw_rate() warn: constraint '(struct ieee80211_supported_band)->bitrates' overflow 'band->bitrates' 0 <= abs_rl '0-127' user_rl '' required = '(struct ieee80211_supported_band)->n_bitrates'
23 struct ieee80211_supported_band *band;
24
25 if (rate->idx < 0)
26 return -1;
27 if (rate->flags & IEEE80211_TX_RC_MCS) {
28 if (rate->idx > 7) {
29 WARN(1, "wrong rate->idx value: %d", rate->idx);
30 return -1;
31 }
32 return rate->idx + 14;
33 }
34 // WFx only support 2GHz, else band information should be retrieved
35 // from ieee80211_tx_info
36 band = wdev->hw->wiphy->bands[NL80211_BAND_2GHZ];
37 return band->bitrates[rate->idx].hw_value;

Add a simple check to make Smatch happy.

Reported-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
Signed-off-by: Jérôme Pouiller <jerome.pouiller@xxxxxxxxxx>
---
drivers/staging/wfx/data_tx.c | 4 ++++
1 file changed, 4 insertions(+)

diff --git a/drivers/staging/wfx/data_tx.c b/drivers/staging/wfx/data_tx.c
index 8db0be08daf8..41f6a604a697 100644
--- a/drivers/staging/wfx/data_tx.c
+++ b/drivers/staging/wfx/data_tx.c
@@ -31,6 +31,10 @@ static int wfx_get_hw_rate(struct wfx_dev *wdev,
}
return rate->idx + 14;
}
+ if (rate->idx >= band->n_bitrates) {
+ WARN(1, "wrong rate->idx value: %d", rate->idx);
+ return -1;
+ }
// WFx only support 2GHz, else band information should be retrieved
// from ieee80211_tx_info
band = wdev->hw->wiphy->bands[NL80211_BAND_2GHZ];
--
2.28.0