On 1/26/24 16:31, Kees Cook wrote:
After commit e3eac9f32ec0 ("wifi: cfg80211: Annotate struct
cfg80211_scan_request with __counted_by"), the compiler may enforce
dynamic array indexing of req->channels to stay below n_channels. As a
result, n_channels needs to be increased _before_ accessing the newly
added array index. Increment it first, then use "i" for the prior index.
Solves this warning in the coming GCC that has __counted_by support:
../drivers/net/wireless/broadcom/brcm80211/brcmfmac/cfg80211.c: In function
'brcmf_internal_escan_add_info':
../drivers/net/wireless/broadcom/brcm80211/brcmfmac/cfg80211.c:3783:46: warning:
operation on 'req->
n_channels' may be undefined [-Wsequence-point]
3783 | req->channels[req->n_channels++] = chan;
| ~~~~~~~~~~~~~~~^~
Fixes: e3eac9f32ec0 ("wifi: cfg80211: Annotate struct cfg80211_scan_request with
__counted_by")
Cc: Arend van Spriel <[email protected]>
Cc: Franky Lin <[email protected]>
Cc: Hante Meuleman <[email protected]>
Cc: Kalle Valo <[email protected]>
Cc: Chi-hsien Lin <[email protected]>
Cc: Ian Lin <[email protected]>
Cc: Johannes Berg <[email protected]>
Cc: Wright Feng <[email protected]>
Cc: Hector Martin <[email protected]>
Cc: [email protected]
Cc: [email protected]
Signed-off-by: Kees Cook <[email protected]>
Reviewed-by: Gustavo A. R. Silva <[email protected]>
Thanks!
--
Gustavo
---
drivers/net/wireless/broadcom/brcm80211/brcmfmac/cfg80211.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/cfg80211.c
b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/cfg80211.c
index 133c5ea6429c..28d6a30cc010 100644
--- a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/cfg80211.c
+++ b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/cfg80211.c
@@ -3779,8 +3779,10 @@ static int brcmf_internal_escan_add_info(struct
cfg80211_scan_request *req,
if (req->channels[i] == chan)
break;
}
- if (i == req->n_channels)
- req->channels[req->n_channels++] = chan;
+ if (i == req->n_channels) {
+ req->n_channels++;
+ req->channels[i] = chan;
+ }
for (i = 0; i < req->n_ssids; i++) {
if (req->ssids[i].ssid_len == ssid_len &&
