From patchwork Fri Oct 28 08:19:26 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Luca Ceresoli X-Patchwork-Id: 13023215 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 9CD5DFA3744 for ; Fri, 28 Oct 2022 08:19:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229958AbiJ1ITt (ORCPT ); Fri, 28 Oct 2022 04:19:49 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60924 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229456AbiJ1ITs (ORCPT ); Fri, 28 Oct 2022 04:19:48 -0400 Received: from relay8-d.mail.gandi.net (relay8-d.mail.gandi.net [IPv6:2001:4b98:dc4:8::228]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DF92E101EA; Fri, 28 Oct 2022 01:19:45 -0700 (PDT) Received: from booty.fritz.box (unknown [77.244.183.192]) (Authenticated sender: luca.ceresoli@bootlin.com) by mail.gandi.net (Postfix) with ESMTPA id 150001BF205; Fri, 28 Oct 2022 08:19:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bootlin.com; s=gm1; t=1666945183; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=vqicJIpaIUCqnWaaaf6uDqbeDvMy142ZJ+vF7cMzObg=; b=bkKIitouTwGX+kxNBk+gZ1C/8NirLVohgyvNA9v481ufDHZiyykNv8jQ58K6hcQ51bJvbY 3OHdlEBwpIcPRdjrBnyMJMUrQjx5M40EJ9MYv+pV0cnBQKEAOrsK64BDE+428sxZpcUIYQ JPt2PgbhHuZSuCnbBtHSDotME8E0JtTBMWXCggE3M1kS4AL6cpMKmccV+F4hBRiHcFNhfC /J89pj8ugT6GSoSmnRrA9QGyYcM76IbCMaMqngzExsY1UX4i0q0E0cgvQM+NYyQ2ssOxWR FI3nHWQUgHDxi8bzHsvF834UmiDzMf5tZzlCDb0WXFmVqMw5mcHc1WQiTe6nJA== From: luca.ceresoli@bootlin.com To: Thierry Reding , Jonathan Hunter , Sowjanya Komatineni , Mauro Carvalho Chehab , Greg Kroah-Hartman , Hans Verkuil Cc: Thomas Petazzoni , Luca Ceresoli , stable@vger.kernel.org, Mauro Carvalho Chehab , linux-media@vger.kernel.org, linux-tegra@vger.kernel.org, linux-staging@lists.linux.dev, linux-kernel@vger.kernel.org Subject: [PATCH] staging: media: tegra-video: fix device_node use after free Date: Fri, 28 Oct 2022 10:19:26 +0200 Message-Id: <20221028081926.2320663-1-luca.ceresoli@bootlin.com> X-Mailer: git-send-email 2.34.1 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org From: Luca Ceresoli At probe time this code path is followed: * tegra_csi_init * tegra_csi_channels_alloc * for_each_child_of_node(node, channel) -- iterates over channels * automatically gets 'channel' * tegra_csi_channel_alloc() * saves into chan->of_node a pointer to the channel OF node * automatically gets and puts 'channel' * now the node saved in chan->of_node has refcount 0, can disappear * tegra_csi_channels_init * iterates over channels * tegra_csi_channel_init -- uses chan->of_node After that, chan->of_node keeps storing the node until the device is removed. of_node_get() the node and of_node_put() it during teardown to avoid any risk. Fixes: 1ebaeb09830f ("media: tegra-video: Add support for external sensor capture") Cc: stable@vger.kernel.org Cc: Sowjanya Komatineni Signed-off-by: Luca Ceresoli --- drivers/staging/media/tegra-video/csi.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/staging/media/tegra-video/csi.c b/drivers/staging/media/tegra-video/csi.c index b26e44adb2be..1b05f620b476 100644 --- a/drivers/staging/media/tegra-video/csi.c +++ b/drivers/staging/media/tegra-video/csi.c @@ -433,7 +433,7 @@ static int tegra_csi_channel_alloc(struct tegra_csi *csi, for (i = 0; i < chan->numgangports; i++) chan->csi_port_nums[i] = port_num + i * CSI_PORTS_PER_BRICK; - chan->of_node = node; + chan->of_node = of_node_get(node); chan->numpads = num_pads; if (num_pads & 0x2) { chan->pads[0].flags = MEDIA_PAD_FL_SINK; @@ -640,6 +640,7 @@ static void tegra_csi_channels_cleanup(struct tegra_csi *csi) media_entity_cleanup(&subdev->entity); } + of_node_put(chan->of_node); list_del(&chan->list); kfree(chan); }