From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 30DD7C83003 for ; Wed, 7 Jun 2023 20:54:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235492AbjFGUyZ (ORCPT ); Wed, 7 Jun 2023 16:54:25 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55380 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235493AbjFGUyE (ORCPT ); Wed, 7 Jun 2023 16:54:04 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 69A161FEA for ; Wed, 7 Jun 2023 13:53:59 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 018A1647A5 for ; Wed, 7 Jun 2023 20:53:59 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id DDF79C433D2; Wed, 7 Jun 2023 20:53:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1686171238; bh=Jv2BJFI0ZebNhG+1/BDF6i17mtpfugcBwkQ1hEvE0ZU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=w+E172UEnSxydjzJHXEvKmOcOy5DRBUo0LIDOcveBTNxLcAHrcrQa2DX5b70TxFaJ hMkh6VX8rWAMG2kZo8bPoQRvQz/4blQ1DA89rjBHu/C4q8cWo5yWbPVMmVIOqLwxmF Bj8FPyVwp7ITYaMHB3ZMuOZbUHKd6J+KQ92XmYGw= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Wei Chen , Mauro Carvalho Chehab , Sasha Levin Subject: [PATCH 5.4 40/99] media: dvb-usb-v2: ec168: fix null-ptr-deref in ec168_i2c_xfer() Date: Wed, 7 Jun 2023 22:16:32 +0200 Message-ID: <20230607200901.508857846@linuxfoundation.org> X-Mailer: git-send-email 2.41.0 In-Reply-To: <20230607200900.195572674@linuxfoundation.org> References: <20230607200900.195572674@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Wei Chen [ Upstream commit a6dcefcc08eca1bf4e3d213c97c3cfb75f377935 ] In ec168_i2c_xfer, msg is controlled by user. When msg[i].buf is null and msg[i].len is zero, former checks on msg[i].buf would be passed. If accessing msg[i].buf[0] without sanity check, null pointer deref would happen. We add check on msg[i].len to prevent crash. Similar commit: commit 0ed554fd769a ("media: dvb-usb: az6027: fix null-ptr-deref in az6027_i2c_xfer()") Link: https://lore.kernel.org/linux-media/20230313085853.3252349-1-harperchen1110@gmail.com Signed-off-by: Wei Chen Signed-off-by: Mauro Carvalho Chehab Signed-off-by: Sasha Levin --- drivers/media/usb/dvb-usb-v2/ec168.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/drivers/media/usb/dvb-usb-v2/ec168.c b/drivers/media/usb/dvb-usb-v2/ec168.c index e30305876840f..1191e32407c77 100644 --- a/drivers/media/usb/dvb-usb-v2/ec168.c +++ b/drivers/media/usb/dvb-usb-v2/ec168.c @@ -115,6 +115,10 @@ static int ec168_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg msg[], while (i < num) { if (num > i + 1 && (msg[i+1].flags & I2C_M_RD)) { if (msg[i].addr == ec168_ec100_config.demod_address) { + if (msg[i].len < 1) { + i = -EOPNOTSUPP; + break; + } req.cmd = READ_DEMOD; req.value = 0; req.index = 0xff00 + msg[i].buf[0]; /* reg */ @@ -131,6 +135,10 @@ static int ec168_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg msg[], } } else { if (msg[i].addr == ec168_ec100_config.demod_address) { + if (msg[i].len < 1) { + i = -EOPNOTSUPP; + break; + } req.cmd = WRITE_DEMOD; req.value = msg[i].buf[1]; /* val */ req.index = 0xff00 + msg[i].buf[0]; /* reg */ @@ -139,6 +147,10 @@ static int ec168_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg msg[], ret = ec168_ctrl_msg(d, &req); i += 1; } else { + if (msg[i].len < 1) { + i = -EOPNOTSUPP; + break; + } req.cmd = WRITE_I2C; req.value = msg[i].buf[0]; /* val */ req.index = 0x0100 + msg[i].addr; /* I2C addr */ -- 2.39.2