2020-10-09 19:54:11

by Jérôme Pouiller

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

From: Jérôme Pouiller <[email protected]>

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 <[email protected]>
Signed-off-by: Jérôme Pouiller <[email protected]>
---
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

2020-10-16 02:04:59

by Nathan Chancellor

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

On Fri, Oct 09, 2020 at 07:13:07PM +0200, Jerome Pouiller wrote:
> From: J?r?me Pouiller <[email protected]>
>
> 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 <[email protected]>
> Signed-off-by: J?r?me Pouiller <[email protected]>
> ---
> 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
>

This now causes a clang warning:

drivers/staging/wfx/data_tx.c:34:19: warning: variable 'band' is uninitialized when used here [-Wuninitialized]
if (rate->idx >= band->n_bitrates) {
^~~~
drivers/staging/wfx/data_tx.c:23:39: note: initialize the variable 'band' to silence this warning
struct ieee80211_supported_band *band;
^
= NULL
1 warning generated.

Cheers,
Nathan