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From: Dmitry Antipov <dmantipov@yandex.ru>
To: Johannes Berg <johannes.berg@intel.com>
Cc: linux-wireless@vger.kernel.org,
	lvc-project@linuxtesting.org,
	Dmitry Antipov <dmantipov@yandex.ru>,
	syzbot+253cd2d2491df77c93ac@syzkaller.appspotmail.com
Subject: [PATCH] wifi: wireless: add extra SIOCSIWSCAN data check
Date: Fri, 31 May 2024 06:20:10 +0300
Message-ID: <20240531032010.451295-1-dmantipov@yandex.ru>
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In 'cfg80211_wext_siwscan()', add extra check whether number of
channels passed via 'ioctl(sock, SIOCSIWSCAN, ...)' doesn't exceed
IW_MAX_FREQUENCIES and reject invalid request with -EINVAL otherwise.

Reported-by: syzbot+253cd2d2491df77c93ac@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=253cd2d2491df77c93ac
Signed-off-by: Dmitry Antipov <dmantipov@yandex.ru>
---
 net/wireless/scan.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/net/wireless/scan.c b/net/wireless/scan.c
index 127853877a0a..6d4d3447aecc 100644
--- a/net/wireless/scan.c
+++ b/net/wireless/scan.c
@@ -3400,10 +3400,14 @@ int cfg80211_wext_siwscan(struct net_device *dev,
 	wiphy = &rdev->wiphy;
 
 	/* Determine number of channels, needed to allocate creq */
-	if (wreq && wreq->num_channels)
+	if (wreq && wreq->num_channels) {
+		/* Passed from userspace so should be checked */
+		if (unlikely(wreq->num_channels > IW_MAX_FREQUENCIES))
+			return -EINVAL;
 		n_channels = wreq->num_channels;
-	else
+	} else {
 		n_channels = ieee80211_get_num_supported_channels(wiphy);
+	}
 
 	creq = kzalloc(sizeof(*creq) + sizeof(struct cfg80211_ssid) +
 		       n_channels * sizeof(void *),
-- 
2.45.1