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 0AC0F39A801; Thu, 30 Jul 2026 15:01:50 +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=1785423711; cv=none; b=E1B5Aitt5ZbhK1KNUNwlJU+VistIsI57rfsaaoMhCQX1lShf66zuNWfcjXmH1Ff3CcD6Q3XPXECoDIgue10PiN7Xhpor2ylQlTBTc9FVcUCZLQiIgkXNyfgAAwMFaYyk3X9lQd/mYK7cCCt7braB4MCukJeV/ZOg80wkoIbMg+g= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785423711; c=relaxed/simple; bh=TNIyYvL9PzZHvENBP0LEh8uxiZ8wL6UVdJCZ5ZGR9OE=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=DwpMIjds0l2NA2TEK3XgUMBc0zvPDkMeUruCuvhcx/A78BW4/YvCzDAqvjs9yCBCFAiI3XT5j+Q1TZeB/oCF1tQlFoQ2eOroshAPq+WAOjO2BScotBSclLkbdMh2sNRo8IVqr6hWcOxX4KcfaUhCe8nRc6x6Ep+w3wX54jOC8e8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=0ixTM+04; 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="0ixTM+04" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 514661F000E9; Thu, 30 Jul 2026 15:01:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1785423709; bh=cVeP9tEkAKoySvlsn1xvWvNVqIeXF1cEt2XjJiv2dKE=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=0ixTM+04M2kW7Ph0ANzhr55GE9szrAyivR1TB6X65XuSAIdYwfSXtpvD7xMdr/ANV Mn8lybuCiTL4/50WP3mAj0QeKdRY30PSGSf0klwju0RZkGvIjgFZQY72RyAfW6tRGr 8YIIeilQWc90m85lhsDmPJuHmWodkkG45o70id1A= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Huihui Huang , Johannes Berg Subject: [PATCH 6.18 140/675] wifi: at76c50x-usb: avoid length underflow in at76_guess_freq() Date: Thu, 30 Jul 2026 16:07:50 +0200 Message-ID: <20260730141448.113189395@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260730141445.110192266@linuxfoundation.org> References: <20260730141445.110192266@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 6.18-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);