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=-15.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT 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 6924BC4338F for ; Thu, 19 Aug 2021 14:13:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 510BE61156 for ; Thu, 19 Aug 2021 14:13:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S240503AbhHSONr (ORCPT ); Thu, 19 Aug 2021 10:13:47 -0400 Received: from mail-m973.mail.163.com ([123.126.97.3]:34022 "EHLO mail-m973.mail.163.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238495AbhHSONq (ORCPT ); Thu, 19 Aug 2021 10:13:46 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=163.com; s=s110527; h=From:Subject:Date:Message-Id:MIME-Version; bh=LqhkW OTtdIT7p2npUf1GtbNwZzGn75JEoosgJAVBjO0=; b=NenUaFqr/zbzisGFetMoL EC+Udbx66+LcnM4UenfvlsABZsc+RC1w9c2fNlBFRXjaN73UnpCCAKASDeoPKLc+ kLFcDzjaEp62OFYNjc5lVIa94WchJ1BagOC7Jqnt9xbKc5akaU1RFZvJjF1ll15r 48yF4N37pCvF+7HKyviiFk= Received: from localhost.localdomain (unknown [111.201.47.26]) by smtp3 (Coremail) with SMTP id G9xpCgC3GbDjZh5h4bjzDA--.1787S4; Thu, 19 Aug 2021 22:13:01 +0800 (CST) From: Wentao_Liang To: dongchun.zhu@mediatek.com Cc: mchehab@kernel.org, linux-media@vger.kernel.org, linux-kernel@vger.kernel.org, Wentao_Liang Subject: [PATCH] drivers:media:i2c:ov02a10.c: fix a potential use-after-put bug Date: Thu, 19 Aug 2021 22:12:49 +0800 Message-Id: <20210819141249.257945-1-Wentao_Liang_g@163.com> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-CM-TRANSID: G9xpCgC3GbDjZh5h4bjzDA--.1787S4 X-Coremail-Antispam: 1Uf129KBjvJXoW7WF13Zw4UWrWUJrW5Xr4xJFb_yoW8ArWUpa 97A3y5Cry8Wr48ZFy8AFn8ArZIkw1fGrWfJrW3u3sF93WDJFs2yry5KFyYvrZ5CryrZayf Xr4rta47ZF4DCw7anT9S1TB71UUUUUUqnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDUYxBIdaVFxhVjvjDU0xZFpf9x07bUBMNUUUUU= X-Originating-IP: [111.201.47.26] X-CM-SenderInfo: xzhq3t5rboxtpqjbwqqrwthudrp/xtbB3Q3zL2BHKE8HjgAAsF Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org In line 825 (#1), "fwnode_handle_put(ep);" drops the reference to ep and may cause ep to be released. However, ep is subsequently used in lines 831 (#3) by "ret = fwnode_property_read_u32(ep, "ovti,mipi-clock- voltage", &clk_volt);". This may result in an use-after-put bug. It can be fixed by removing "fwnode_handle_put(ep);" in line 825 (#1) and call it respectively before the function returns (line 827, #2) and after ep has been used again (line 831, #3). 806 static int ov02a10_check_hwcfg(struct device *dev, struct ov02a10 *ov02a10) 807 { ... 825 fwnode_handle_put(ep); //#1 Memory can be released. 826 if (ret) 827 return ret; //#2 One of the branch ways ends here. // Function returns. ... 830 ret = fwnode_property_read_u32(ep, "ovti,mipi-clock-voltage", 831 &clk_volt); //#3 Use of memory after it may be freed. ... 853 return ret; 854 } Signed-off-by: Wentao_Liang --- drivers/media/i2c/ov02a10.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/drivers/media/i2c/ov02a10.c b/drivers/media/i2c/ov02a10.c index a3ce5500d355..1066a17e9cf8 100644 --- a/drivers/media/i2c/ov02a10.c +++ b/drivers/media/i2c/ov02a10.c @@ -822,13 +822,15 @@ static int ov02a10_check_hwcfg(struct device *dev, struct ov02a10 *ov02a10) return -ENXIO; ret = v4l2_fwnode_endpoint_alloc_parse(ep, &bus_cfg); - fwnode_handle_put(ep); - if (ret) + if (ret) { + fwnode_handle_put(ep); return ret; + } /* Optional indication of MIPI clock voltage unit */ ret = fwnode_property_read_u32(ep, "ovti,mipi-clock-voltage", &clk_volt); + fwnode_handle_put(ep); if (!ret) ov02a10->mipi_clock_voltage = clk_volt; -- 2.25.1