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 E2987C77B7A for ; Thu, 25 May 2023 19:20:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243344AbjEYTUX (ORCPT ); Thu, 25 May 2023 15:20:23 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35178 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S243720AbjEYTUA (ORCPT ); Thu, 25 May 2023 15:20:00 -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 DCD382D56; Thu, 25 May 2023 12:15:19 -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 8BD3C60B9B; Thu, 25 May 2023 18:45:37 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5BCEFC433D2; Thu, 25 May 2023 18:45:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1685040337; bh=9n0Rm0CdUXYPz3XVJ4+U1z4/EFHPAc62x10WzMiWaSY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=EOojpvxPMU0945X56Bx2wXwtn/+VhdSkevKqzgvbV2V/ugHDlYUHLsTuXOS9mM+pf BQUlBuU43+74mGM9omFcV3tNzsFHN2bDBmKmK5sfTapvHNd29Bk5oY5iFAHs/TrsUB 9BR0F1NqtqXeT6w1RsyRwMhgbkNRwL42eVHWDpNCZhm2oniaSd6LeZk0Wvt5BwXZuQ QNbRb8lCINenm23CGjAZSekdRNO9Zz5z3hukRNiosBXa/2GhKlL1WR6kOSySbRKqMB A9gkd1oEbaW1M1R8WgbooHOWRsY9HDg9FAahbd3YGbf3AaAtfYTFq+82mO+9uZ/Icv TaiFLRp/67OUg== 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 4.14 07/20] media: dvb-usb: digitv: fix null-ptr-deref in digitv_i2c_xfer() Date: Thu, 25 May 2023 14:45:03 -0400 Message-Id: <20230525184520.2004878-7-sashal@kernel.org> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20230525184520.2004878-1-sashal@kernel.org> References: <20230525184520.2004878-1-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 20d33f0544ed2..0e2cffa946f69 100644 --- a/drivers/media/usb/dvb-usb/digitv.c +++ b/drivers/media/usb/dvb-usb/digitv.c @@ -66,6 +66,10 @@ 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