From: Dan Carpenter <dan.carpenter@oracle.com>
To: linux-wireless@vger.kernel.org
Subject: [bug report] nl80211/cfg80211: add radar detection command/event
Date: Thu, 20 Dec 2018 14:17:26 +0300 [thread overview]
Message-ID: <20181220111726.GA19146@kadam> (raw)
Hi wireless devs,
The patch 04f39047af2a: "nl80211/cfg80211: add radar detection
command/event" from Feb 8, 2013, leads to the following static
checker warning:
net/wireless/chan.c:250 cfg80211_set_chans_dfs_state()
warn: 'center_freq + bandwidth / 2 - 10' negative user limit promoted to high
net/wireless/chan.c
242 static void cfg80211_set_chans_dfs_state(struct wiphy *wiphy, u32 center_freq,
243 u32 bandwidth,
244 enum nl80211_dfs_state dfs_state)
245 {
246 struct ieee80211_channel *c;
247 u32 freq;
248
249 for (freq = center_freq - bandwidth/2 + 10;
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
250 freq <= center_freq + bandwidth/2 - 10;
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
This isn't really a big issue but center_freq comes from
nla_get_u32(attrs[NL80211_ATTR_WIPHY_FREQ]) in nl80211_parse_chandef().
Smatch is complaining that there is an issue with the math
over/underflowing. It just means that we loop for a long time. It's
not a security problem. Even without the overflow, we could end up
looping for a long time.
Is center_freq capped somewhere that I haven't seen?
251 freq += 20) {
252 c = ieee80211_get_channel(wiphy, freq);
253 if (!c || !(c->flags & IEEE80211_CHAN_RADAR))
254 continue;
255
256 c->dfs_state = dfs_state;
257 c->dfs_state_entered = jiffies;
258 }
259 }
regards,
dan carpenter
next reply other threads:[~2018-12-20 11:18 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-12-20 11:17 Dan Carpenter [this message]
2018-12-20 14:16 ` [bug report] nl80211/cfg80211: add radar detection command/event Johannes Berg
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20181220111726.GA19146@kadam \
--to=dan.carpenter@oracle.com \
--cc=linux-wireless@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).