From: Dan Carpenter <dan.carpenter@oracle.com>
To: masashi.honma@gmail.com
Cc: linux-wireless@vger.kernel.org
Subject: [bug report] nl80211: Fix possible Spectre-v1 for CQM RSSI thresholds
Date: Sat, 7 Sep 2019 16:02:34 +0300 [thread overview]
Message-ID: <20190907130234.GA32057@mwanda> (raw)
Hello Masashi Honma,
The patch 1222a1601488: "nl80211: Fix possible Spectre-v1 for CQM
RSSI thresholds" from Sep 25, 2018, leads to the following static
checker warning:
net/wireless/nl80211.c:10820 cfg80211_cqm_rssi_update()
warn: disabling speculation after use: 'i'
net/wireless/nl80211.c
10804 last = wdev->cqm_config->last_rssi_event_value;
10805 hyst = wdev->cqm_config->rssi_hyst;
10806 n = wdev->cqm_config->n_rssi_thresholds;
10807
10808 for (i = 0; i < n; i++)
10809 if (last < wdev->cqm_config->rssi_thresholds[i])
^^^^^^^^^^^^^^^^^^
We've already used "i" as an index.
10810 break;
10811
10812 low_index = i - 1;
10813 if (low_index >= 0) {
10814 low_index = array_index_nospec(low_index, n);
^^^^^^^^^^^^^^^^^^
10815 low = wdev->cqm_config->rssi_thresholds[low_index] - hyst;
10816 } else {
10817 low = S32_MIN;
10818 }
10819 if (i < n) {
10820 i = array_index_nospec(i, n);
^^^^^^^^^^^^^^^^^^
So this seems like closing the barn door after the horses have left.
10821 high = wdev->cqm_config->rssi_thresholds[i] + hyst - 1;
10822 } else {
10823 high = S32_MAX;
10824 }
regards,
dan carpenter
next reply other threads:[~2019-09-07 13:04 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-09-07 13:02 Dan Carpenter [this message]
2019-09-08 0:55 ` [bug report] nl80211: Fix possible Spectre-v1 for CQM RSSI thresholds Masashi Honma
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