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 6DFADC7EE29 for ; Thu, 25 May 2023 18:57:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243220AbjEYS51 (ORCPT ); Thu, 25 May 2023 14:57:27 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45644 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S243288AbjEYSzB (ORCPT ); Thu, 25 May 2023 14:55:01 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C38FF1BDB; Thu, 25 May 2023 11:46:42 -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 AB925649A0; Thu, 25 May 2023 18:44:12 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 67183C433A4; Thu, 25 May 2023 18:44:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1685040252; bh=I2fEuViLv0iCPYHPncitlmI2TWtLE4P2wiIBqFAKqNA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=lgBIRLQMFz9IDiL9KFiqlgdXnlmTeOSrJkeHQdYeyfAE5snrI5NkPfjMIEWJUAfDh xT+XyIoa2x055COBQ8MDFsLaKNRqcZDLCBrqz0WjCLo1vjHE8IJ/6EAc/8CrvuD8sW OwWOK+YCKpScqnnOCG0A62DJVyTnoKilz2cWPmemJUffNJbCl61xg/UD3tpbZCTAPj OyYUl3vPDk7qrHzMufsjuobyqrHiqCDVJs32Vcvt/3MzDBVbIaTwXo57Ktaoc+3BAb GExJ0oYPxNYDO1jQZrhWQX/z/vJD2z7FgmHGIepl0bpMKDGX6BFTy8bQoUvU3jufpt OLJlopFSkt4Lw== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Wei Chen , Mauro Carvalho Chehab , Sasha Levin , crope@iki.fi, linux-media@vger.kernel.org Subject: [PATCH AUTOSEL 4.19 06/27] media: dvb-usb-v2: ec168: fix null-ptr-deref in ec168_i2c_xfer() Date: Thu, 25 May 2023 14:43:32 -0400 Message-Id: <20230525184356.1974216-6-sashal@kernel.org> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20230525184356.1974216-1-sashal@kernel.org> References: <20230525184356.1974216-1-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 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 1db8aeef36553..19605958501e1 100644 --- a/drivers/media/usb/dvb-usb-v2/ec168.c +++ b/drivers/media/usb/dvb-usb-v2/ec168.c @@ -125,6 +125,10 @@ 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 */ @@ -141,6 +145,10 @@ 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 */ @@ -149,6 +157,10 @@ 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