From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 3A8B83E025C; Mon, 17 Aug 2026 14:25:06 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786976707; cv=none; b=fG1k4nGnlpvEdvcY1qOOLH6H+cnuEA+TNa+fmoPW4y5Oe+/95LosvVHrzGrgK4FtMnhMOhGX7jCo7JlTxVxIEWNk8REhJLu8gc19dTyIxlbWm6PGNUcVNObPdnk8akgSnVQbqeMvxhjRIvBKounb9RBf8MOsQhkInWxTuuSpFis= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786976707; c=relaxed/simple; bh=ne6N5thVeIz5yXDQBksXN3QVZjMcbJsgS6q+gCJmi9E=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=W2q4VGquYvioR6FxBoBVwFefQtJcFXMku1Gi+ck00lhea06A+XibqfHyyJajHu5VPBI6FrR2IBXV7zTJ1r7UvfH9kmDbfJrr2bi6SFFO7iH0JvnQIkB/J6tRo68X5N6tTLzRjKBieMOStYkn260NvVPRLbaU6eX6fKtv7DX9jrU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=mVkp88ZK; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="mVkp88ZK" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 625221F000E9; Mon, 17 Aug 2026 14:25:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1786976705; bh=IDg1yIuNez+vp6PJNe+bSfOH+cX9hcUWyBonvo0c7Rs=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=mVkp88ZKglSQ4rbhSG1Pd9vTWpHw3Kk/C0MAwJmY3Ad2v7j74n6flTl0FSra97Uvl Tb0G2jVOn47C7Jn0AZ0VMw1xH/aKc49nO4/OjHOL9fouqFpgMjsqmJMJ15d+zQp3bw yq0ncwSu1A+vSzcoupgTKoeNp6AEE6+9jJK4TPX4= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Huihui Huang , Johannes Berg Subject: [PATCH 5.15 059/456] wifi: at76c50x-usb: avoid length underflow in at76_guess_freq() Date: Mon, 17 Aug 2026 15:27:29 +0200 Message-ID: <20260817132542.353372865@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260817132539.792407575@linuxfoundation.org> References: <20260817132539.792407575@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 5.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Huihui Huang commit 61a799ffd1e5a4fd3702d547828b7ff3d161468e upstream. at76_guess_freq() checks only that the received frame is at least a bare 802.11 header (24 bytes) before subtracting the fixed management-body offset: len -= el_off; For both beacon and probe response frames, el_off is 36. If the frame is shorter than el_off, subtracting it causes the calculated IE length to wrap. The length is eventually passed to cfg80211_find_elem_match() as a very large unsigned value, so the element walk runs beyond the RX skb. This path is reached from at76_rx_tasklet() while scanning. If the device delivers a truncated beacon or probe response, the oversized IE length causes an out-of-bounds read during scanning. Skip the IE lookup if the frame does not reach the variable elements, before subtracting el_off. Fixes: 1264b951463a ("at76c50x-usb: add driver") Cc: stable@vger.kernel.org Assisted-by: Claude:claude-opus-4-8 Signed-off-by: Huihui Huang Link: https://patch.msgid.link/20260715140815.1242033-1-hhhuang@smu.edu.sg Signed-off-by: Johannes Berg Signed-off-by: Greg Kroah-Hartman --- drivers/net/wireless/atmel/at76c50x-usb.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) --- a/drivers/net/wireless/atmel/at76c50x-usb.c +++ b/drivers/net/wireless/atmel/at76c50x-usb.c @@ -1527,13 +1527,16 @@ static inline int at76_guess_freq(struct if (ieee80211_is_probe_resp(hdr->frame_control)) { el_off = offsetof(struct ieee80211_mgmt, u.probe_resp.variable); - el = ((struct ieee80211_mgmt *)hdr)->u.probe_resp.variable; } else if (ieee80211_is_beacon(hdr->frame_control)) { el_off = offsetof(struct ieee80211_mgmt, u.beacon.variable); - el = ((struct ieee80211_mgmt *)hdr)->u.beacon.variable; } else { goto exit; } + + if (len < el_off) + goto exit; + + el = priv->rx_skb->data + el_off; len -= el_off; el = cfg80211_find_ie(WLAN_EID_DS_PARAMS, el, len);