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 C158B33D4E2; Thu, 30 Jul 2026 14:25:36 +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=1785421538; cv=none; b=kQoTK/+V0HLaNVBgl0sxw2soeR5BmDnTiUpkWCmI3z+kpFxU7Qf496O4SdkpTVbfH3MybGD7NozaQ6C92JbRNsBmB6FhuPMRgz4nUTibBMuQxgB2ZnCXVOl+qv9rCfq7/OuwnDIHNv66a5pBU2oTCbp2PmT3SUD0GlXgasWhNJ8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785421538; c=relaxed/simple; bh=5KABwT+BaWsg8mNtwvHsExuDdXWIgrClrYUVnU6Z+ps=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=da3SIuaaWnhcqzdG7wsmg/gTVVxYxReBeb1hyMXh9ADzCwsgze31glgY4bHD2FlDBYBA61KE3S/Ftw0iQRkttlMTP7qt6V85HsXYYbwOlWhGqGqg2Ro9CzdaZk5EewfMgrdVzfNi606Lc8mZG0j8Z6QLtcp+qPMoUBMG3Mz2LQ4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=N9zKrnnF; 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="N9zKrnnF" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 184DF1F000E9; Thu, 30 Jul 2026 14:25:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1785421536; bh=FE+8JIZX3oCN3v6oBi+b31cqRFC+MZ8dIRErjGX3o1A=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=N9zKrnnFfS7TZsvziEWvEdfsxPOr0ebSPyLebaEzL7k4zIBddACQfoJ5XNv1F/M3m S1nf8yIhZX0B3LmMon4130hFRFC3uRgF+j7X5b3Gs7/0gXS4xorHYwmTtBGL/4KKo/ xqBVM7+JxqIV1vOdM9Z5VD18PUI4TBjA7ywjnrgM= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Huihui Huang , Johannes Berg Subject: [PATCH 7.1 138/744] wifi: at76c50x-usb: avoid length underflow in at76_guess_freq() Date: Thu, 30 Jul 2026 16:06:51 +0200 Message-ID: <20260730141447.213858331@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260730141444.267951807@linuxfoundation.org> References: <20260730141444.267951807@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 7.1-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 @@ -1521,13 +1521,16 @@ 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);