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From: Will Deacon <will@kernel.org>
To: linux-wireless@vger.kernel.org
Cc: nico@semmle.com, Will Deacon <will@kernel.org>,
	stable@vger.kernel.org, Johannes Berg <johannes@sipsolutions.net>,
	Kees Cook <keescook@chromium.org>
Subject: [PATCH 2/2] cfg80211: wext: Reject malformed SSID elements
Date: Fri,  4 Oct 2019 10:51:32 +0100	[thread overview]
Message-ID: <20191004095132.15777-2-will@kernel.org> (raw)
In-Reply-To: <20191004095132.15777-1-will@kernel.org>

Ensure the SSID element is bounds-checked prior to invoking memcpy()
with its length field.

Cc: <stable@vger.kernel.org>
Cc: Johannes Berg <johannes@sipsolutions.net>
Cc: Kees Cook <keescook@chromium.org>
Reported-by: Nicolas Waisman <nico@semmle.com>
Signed-off-by: Will Deacon <will@kernel.org>
---
 net/wireless/wext-sme.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/net/wireless/wext-sme.c b/net/wireless/wext-sme.c
index c67d7a82ab13..3fd2cc7fc36a 100644
--- a/net/wireless/wext-sme.c
+++ b/net/wireless/wext-sme.c
@@ -201,6 +201,7 @@ int cfg80211_mgd_wext_giwessid(struct net_device *dev,
 			       struct iw_request_info *info,
 			       struct iw_point *data, char *ssid)
 {
+	int ret = 0;
 	struct wireless_dev *wdev = dev->ieee80211_ptr;
 
 	/* call only for station! */
@@ -219,7 +220,10 @@ int cfg80211_mgd_wext_giwessid(struct net_device *dev,
 		if (ie) {
 			data->flags = 1;
 			data->length = ie[1];
-			memcpy(ssid, ie + 2, data->length);
+			if (data->length > IW_ESSID_MAX_SIZE)
+				ret = -EINVAL;
+			else
+				memcpy(ssid, ie + 2, data->length);
 		}
 		rcu_read_unlock();
 	} else if (wdev->wext.connect.ssid && wdev->wext.connect.ssid_len) {
@@ -229,7 +233,7 @@ int cfg80211_mgd_wext_giwessid(struct net_device *dev,
 	}
 	wdev_unlock(wdev);
 
-	return 0;
+	return ret;
 }
 
 int cfg80211_mgd_wext_siwap(struct net_device *dev,
-- 
2.23.0.581.g78d2f28ef7-goog


  reply	other threads:[~2019-10-04  9:51 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-10-04  9:51 [PATCH 1/2] mac80211: Reject malformed SSID elements Will Deacon
2019-10-04  9:51 ` Will Deacon [this message]
2019-10-04 15:56   ` [PATCH 2/2] cfg80211: wext: " Kees Cook
2019-10-04 15:55 ` [PATCH 1/2] mac80211: " Kees Cook

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