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 X-Spam-Level: X-Spam-Status: No, score=-19.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_2 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id EB069C64E90 for ; Wed, 2 Dec 2020 12:18:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8DE46221FE for ; Wed, 2 Dec 2020 12:18:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388266AbgLBMSH (ORCPT ); Wed, 2 Dec 2020 07:18:07 -0500 Received: from mail.kernel.org ([198.145.29.99]:49572 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726479AbgLBMSG (ORCPT ); Wed, 2 Dec 2020 07:18:06 -0500 Date: Wed, 2 Dec 2020 13:17:21 +0100 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1606911445; bh=nDpirUT4HzebNKlAZcQZP0UPN73yEY091GDvXLXiKoM=; h=From:To:Cc:Subject:In-Reply-To:References:From; b=saBL5IbI/rQj4VdWnSdQDRmPSP2MFwc7rVl8zznM8X1MRnx3kMIodra8LCR0YkGSU aOHWVq3ZnCJWt8VkS4JTajjvUkYFCyj1lepW0ZmCV3z5+Nmqtrlo8uBAFGhWsyefDt ayWru0XhVgT1XRzbcrfkcRJM9yxTvNGWVMA2XFXE= From: Mauro Carvalho Chehab To: Cengiz Can Cc: "Daniel W . S . Almeida" , linux-media@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] media: vidtv: fix read after free Message-ID: <20201202131721.46ff17fc@coco.lan> In-Reply-To: <20201130092825.28532-1-cengiz@kernel.wtf> References: <20201130092825.28532-1-cengiz@kernel.wtf> X-Mailer: Claws Mail 3.17.8 (GTK+ 2.24.32; x86_64-redhat-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Cengiz, Em Mon, 30 Nov 2020 12:28:26 +0300 Cengiz Can escreveu: > `vidtv_channel_si_destroy` function has a call to > `vidtv_psi_pat_table_destroy` that frees Program Association Table. > > However it is followed by a loop that iterates over the count of Program > Map Tables. This obviously accesses an invalid memory. > > Eliminate this by making a copy of num_pmt before free'ing Program > Association Table and loop on it instead. > > Signed-off-by: Cengiz Can Collin sent me a similar fix. I'm applying his because: - it was sent first; - it uses a better approach: it just moves the vidtv_psi_pat_table_destroy() call to happen after freeing the PMT tables. So, it doesn't need an aux var. Regards, Mauro > --- > drivers/media/test-drivers/vidtv/vidtv_channel.c | 5 ++++- > 1 file changed, 4 insertions(+), 1 deletion(-) > > diff --git a/drivers/media/test-drivers/vidtv/vidtv_channel.c b/drivers/media/test-drivers/vidtv/vidtv_channel.c > index 8ad6c0744d36..4af39a8786a7 100644 > --- a/drivers/media/test-drivers/vidtv/vidtv_channel.c > +++ b/drivers/media/test-drivers/vidtv/vidtv_channel.c > @@ -503,10 +503,13 @@ int vidtv_channel_si_init(struct vidtv_mux *m) > void vidtv_channel_si_destroy(struct vidtv_mux *m) > { > u32 i; > + u16 num_pmt; > + > + num_pmt = m->si.pat->num_pmt; > > vidtv_psi_pat_table_destroy(m->si.pat); > > - for (i = 0; i < m->si.pat->num_pmt; ++i) > + for (i = 0; i < num_pmt; ++i) > vidtv_psi_pmt_table_destroy(m->si.pmt_secs[i]); > > kfree(m->si.pmt_secs); Thanks, Mauro