Commit 4b2c5a14 authored Sep 08, 2019 by Masashi Honma Committed by Johannes Berg Sep 11, 2019

nl80211: Fix possible Spectre-v1 for CQM RSSI thresholds



commit 1222a160 ("nl80211: Fix possible Spectre-v1 for CQM
RSSI thresholds") was incomplete and requires one more fix to
prevent accessing to rssi_thresholds[n] because user can control
rssi_thresholds[i] values to make i reach to n. For example,
rssi_thresholds = {-400, -300, -200, -100} when last is -34.

Cc: stable@vger.kernel.org
Fixes: 1222a160 ("nl80211: Fix possible Spectre-v1 for CQM RSSI thresholds")
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Masashi Honma <masashi.honma@gmail.com>
Link: https://lore.kernel.org/r/20190908005653.17433-1-masashi.honma@gmail.com


Signed-off-by: Johannes Berg <johannes.berg@intel.com>

parent 06354665

net/wireless/nl80211.c

+3 −1

Original line number	Diff line number	Diff line
		@@ -10805,9 +10805,11 @@ static int cfg80211_cqm_rssi_update(struct cfg80211_registered_device *rdev,
		hyst = wdev->cqm_config->rssi_hyst;
		n = wdev->cqm_config->n_rssi_thresholds;

		for (i = 0; i < n; i++)
		for (i = 0; i < n; i++) {
		i = array_index_nospec(i, n);
		if (last < wdev->cqm_config->rssi_thresholds[i])
		break;
		}

		low_index = i - 1;
		if (low_index >= 0) {

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