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R. Silva" , Linus Walleij , Jisoo Jang , Hans de Goede , Aloka Dixit , John Keeping , Jeff Johnson , linux-kernel@vger.kernel.org, linux-hardening@vger.kernel.org References: <20240126223150.work.548-kees@kernel.org> From: "Gustavo A. R. Silva" In-Reply-To: <20240126223150.work.548-kees@kernel.org> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-AntiAbuse: This header was added to track abuse, please include it with any abuse report X-AntiAbuse: Primary Hostname - gator4166.hostgator.com X-AntiAbuse: Original Domain - vger.kernel.org X-AntiAbuse: Originator/Caller UID/GID - [47 12] / [47 12] X-AntiAbuse: Sender Address Domain - embeddedor.com X-BWhitelist: no X-Source-IP: 187.162.21.192 X-Source-L: No X-Exim-ID: 1rTm2R-001sE1-0h X-Source: X-Source-Args: X-Source-Dir: X-Source-Sender: 187-162-21-192.static.axtel.net ([192.168.15.10]) [187.162.21.192]:48528 X-Source-Auth: gustavo@embeddedor.com X-Email-Count: 2 X-Org: HG=hgshared;ORG=hostgator; X-Source-Cap: Z3V6aWRpbmU7Z3V6aWRpbmU7Z2F0b3I0MTY2Lmhvc3RnYXRvci5jb20= X-Local-Domain: yes X-CMAE-Envelope: MS4xfCKI4GI0fWTE+jYv2CBnP9NHfXyfanVjBc8UIvYiUzci9CCgcQznJC3r5zqJb3iZaVY4YIbHODiP3agd621OhrpteimXYxE+Q0UFVL8M+ndmvkhbWmE5 8iK97x9hqTDOYGRt70bb/WLFpstU2+M9NBxx9LFaEipP2BIQ8/LBTMcpRu7uhUJnwBkig8AP9U1/sK0rmVNbtBs1/XWkcsN4Cz/8g4oBGdVjhQy6IfQBhokm 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 > Cc: Franky Lin > Cc: Hante Meuleman > Cc: Kalle Valo > Cc: Chi-hsien Lin > Cc: Ian Lin > Cc: Johannes Berg > Cc: Wright Feng > Cc: Hector Martin > Cc: linux-wireless@vger.kernel.org > Cc: brcm80211-dev-list.pdl@broadcom.com > Signed-off-by: Kees Cook Reviewed-by: Gustavo A. R. Silva 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 &&