From nobody Sun May 24 18:41:06 2026 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 A14783CA4BD; Fri, 22 May 2026 10:16:48 +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=1779445010; cv=none; b=i+NSHk9eswIa/S0wpaj7cGrXNIrxRvJA6IyaPCZ3fPXu4DK40zDHLT20DgotYDm4RIWq33MgP/wSQpIQqdcrS68ZJ1LRgdtyrDWRDavSUPUjwYyU55Y7ALKJM54FMav4vrzwjI2mcvJZqRu3bs/nOnB+z/FfNfFsEKEgzCGBiig= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779445010; c=relaxed/simple; bh=jEw8zWzbkWDyx7Hq2HAzDO8qXrYVI6p7J67gbnOW2Hg=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=JVW33DC4WKo4tyY+zhq9LYQ2Qt3YSXI3DFkGpK7dGzyDZyJ5OzLiC4fvuVgQWDSuEJquJrDcTD1gydp2KZh+zGfv7uVniOGPT2un9uuFLBh/eheFsGrTcfGdsmdopj6Bv7lAdrNwhhV6cdHhGyYkUJeItelEghcwHhNH6UsWO5Q= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=HE/3prED; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="HE/3prED" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 206691F000E9; Fri, 22 May 2026 10:16:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1779445008; bh=tie9Sx62ugl95zHwccy1jha3P+jxL/pmhS11ZitlbEA=; h=From:To:Cc:Subject:Date; b=HE/3prEDlp7XCDeQtG+5MERxqFl0uJZpWlkIrXWj9B11VRVICq+00xbTgYEYyXHEA GQcwCwaIxUpawmfGGI7ooNuoIeTi7FmHMY4io5qYc7E7Wl0vXOmDbFQ7dfu4fzXa85 CUGlpbUHdF4wIQIXkKln3fWNKnAq/mmSztjnrtn4dZsXah4usGYkdwKo2TKimVhQTd /ozmtHA0wsoelNtS9NUM/rrnxOey9mdXLNfPKa+ToUY7ODWXCnJMukyKOJEuI1QBxq zkDi5LkwgCKEo1siJi/aOcBC2pg5kzBkYPPSqH57RzGfm5jKlAZe5iKy0/TFacezwi yJRTrNDDz/3kg== Received: from johan by xi.lan with local (Exim 4.98.2) (envelope-from ) id 1wQMvt-00000003tAf-3cGO; Fri, 22 May 2026 12:16:45 +0200 From: Johan Hovold To: Johan Hovold Cc: Greg Kroah-Hartman , Zhang Cen , linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org Subject: [PATCH] USB: serial: cypress_m8: fix memory corruption with small endpoint Date: Fri, 22 May 2026 12:16:21 +0200 Message-ID: <20260522101621.927034-1-johan@kernel.org> X-Mailer: git-send-email 2.53.0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Make sure that the interrupt-out endpoint max packet size is at least eight bytes to avoid user-controlled slab corruption or NULL-pointer dereference should a malicious device report a smaller size. Fixes: 3416eaa1f8f8 ("USB: cypress_m8: Packet format is separate from chara= cteristic size") Cc: stable@vger.kernel.org # 2.6.26 Signed-off-by: Johan Hovold Reviewed-by: Greg Kroah-Hartman --- drivers/usb/serial/cypress_m8.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/drivers/usb/serial/cypress_m8.c b/drivers/usb/serial/cypress_m= 8.c index afff1a0f4298..82ba0900b399 100644 --- a/drivers/usb/serial/cypress_m8.c +++ b/drivers/usb/serial/cypress_m8.c @@ -445,6 +445,14 @@ static int cypress_generic_port_probe(struct usb_seria= l_port *port) return -ENODEV; } =20 + /* + * The buffer must be large enough for the one or two-byte header (and + * following data) but assume anything smaller than eight bytes is + * broken. + */ + if (port->interrupt_out_size < 8) + return -EINVAL; + priv =3D kzalloc_obj(struct cypress_private); if (!priv) return -ENOMEM; --=20 2.53.0