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 70934C7EE2C for ; Thu, 25 May 2023 19:44:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S242057AbjEYTn7 (ORCPT ); Thu, 25 May 2023 15:43:59 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59748 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S241648AbjEYTnx (ORCPT ); Thu, 25 May 2023 15:43:53 -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 7C6FAE7D; Thu, 25 May 2023 12:43:32 -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 5D21264952; Thu, 25 May 2023 18:43:01 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 29A95C433EF; Thu, 25 May 2023 18:43:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1685040180; bh=fupUgCgMyGgQWt8kjawwhx7r2Ri4PBAcQWn15sZhscM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=MI7/6Ui6xQTPTb8YU9svvYi0aSh5wjKoa1GMCwlT25CkA1EeI3JrXT3F8VzFMwnt/ Hy+ClDUU5pGvJgdpyD1uB6yzJ+RXMW4+JfYYts8FKbtTu5kv55PVutWJM3+EhKRInU Pzns+P23iybQynoFNTBy1/oTQ5VJd8eUB4gp6HoNTiapg5YIB6puRFFSy4YLRp5MUA Pqr5AD/3lcRAtLvp88QUetTCL+KxiqL7HHy2Xvf8NNy6tbfNlV+oxxkt9uC9W99KJM CqlSZO5QW4X7PZOrvvMi+pEd5il2DnDkORsP1qjSVYwhrhiUCPAXN+LAqHxSl4yEvH NTQ1NPGk2eFJA== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Wei Chen , Mauro Carvalho Chehab , Sasha Levin , linux-media@vger.kernel.org Subject: [PATCH AUTOSEL 5.4 09/27] media: dvb-usb: digitv: fix null-ptr-deref in digitv_i2c_xfer() Date: Thu, 25 May 2023 14:42:18 -0400 Message-Id: <20230525184238.1943072-9-sashal@kernel.org> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20230525184238.1943072-1-sashal@kernel.org> References: <20230525184238.1943072-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Wei Chen [ Upstream commit 9ded5bd2a49ce3015b7c936743eec0a0e6e11f0c ] In digitv_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. Malicious data finally reach digitv_i2c_xfer. If accessing msg[i].buf[0] without sanity check, null ptr 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/20230313095008.1039689-1-harperchen1110@gmail.com Signed-off-by: Wei Chen Signed-off-by: Mauro Carvalho Chehab Signed-off-by: Sasha Levin --- drivers/media/usb/dvb-usb/digitv.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/drivers/media/usb/dvb-usb/digitv.c b/drivers/media/usb/dvb-usb/digitv.c index 99a39339d45d5..cf5ec8c1f6773 100644 --- a/drivers/media/usb/dvb-usb/digitv.c +++ b/drivers/media/usb/dvb-usb/digitv.c @@ -63,6 +63,10 @@ static int digitv_i2c_xfer(struct i2c_adapter *adap,struct i2c_msg msg[],int num warn("more than 2 i2c messages at a time is not handled yet. TODO."); for (i = 0; i < num; i++) { + if (msg[i].len < 1) { + i = -EOPNOTSUPP; + break; + } /* write/read request */ if (i+1 < num && (msg[i+1].flags & I2C_M_RD)) { if (digitv_ctrl_msg(d, USB_READ_COFDM, msg[i].buf[0], NULL, 0, -- 2.39.2