From patchwork Sat Feb 3 13:40:43 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Zhipeng Lu X-Patchwork-Id: 13544263 Received: from azure-sdnproxy.icoremail.net (azure-sdnproxy.icoremail.net [52.237.72.81]) by smtp.subspace.kernel.org (Postfix) with ESMTP id AF2A05D72E; Sat, 3 Feb 2024 13:41:55 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=52.237.72.81 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1706967723; cv=none; b=AI9F1HPmCaPqPrSv+SQX/nAosHe/hh6V5hu2RQtnNUqidiZuroQBGSnVehDD+WuYi3R1lnLUPjkHNRs4EN5P/tMF3e3lmPYpm36V2qLeBdjBxXwLqHdIqOUStH3LhtP2CZno8yPFwoKd4qOMXSbg1du49VgaWxs3A6Hrt9MHHqE= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1706967723; c=relaxed/simple; bh=EY85asdBeaFg8NPjWqjuEp+edDi5chEflzQvYoOVY6s=; h=From:To:Cc:Subject:Date:Message-Id:MIME-Version; b=AQwiIEltcXuZwkb8OLepI3PLZEQmEy2r9QksH4QXc6XsFqreqsEb3ZVO1H32qJrXLQkaQPZEbl3rsbU592WzabEOgY/gEfWFKtYwEpudYUGdenwkW8/qpfrXyg/xHwTFYsu0puAEYOcwH8oMorQ+6PYq24hwdS/d0I+tbQJinGw= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=zju.edu.cn; spf=pass smtp.mailfrom=zju.edu.cn; arc=none smtp.client-ip=52.237.72.81 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=zju.edu.cn Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=zju.edu.cn Received: from luzhipeng.223.5.5.5 (unknown [39.174.92.167]) by mail-app3 (Coremail) with SMTP id cC_KCgB37TeBQr5l8Ib0AA--.2616S2; Sat, 03 Feb 2024 21:41:22 +0800 (CST) From: Zhipeng Lu To: alexious@zju.edu.cn Cc: Mauro Carvalho Chehab , Laurent Pinchart , Hans Verkuil , Greg Kroah-Hartman , Hyunwoo Kim , Sakari Ailus , Marcel Siegert , linux-media@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH] edia: dvbdev: fix a use-after-free Date: Sat, 3 Feb 2024 21:40:43 +0800 Message-Id: <20240203134046.3120099-1-alexious@zju.edu.cn> X-Mailer: git-send-email 2.34.1 Precedence: bulk X-Mailing-List: linux-media@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-CM-TRANSID: cC_KCgB37TeBQr5l8Ib0AA--.2616S2 X-Coremail-Antispam: 1UD129KBjvJXoWxWF1rWFW5Gr1xKFyfXF4xJFb_yoW5Jw48pF 4DGay5KrWj9rn7Zr4UAw18WF98Gw4Sk3y5ur1fCwnxKFsxJryrtryYyay7Z3W8A3ykA347 tr17X3Wkur45Gr7anT9S1TB71UUUUU7qnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUU9014x267AKxVW8JVW5JwAFc2x0x2IEx4CE42xK8VAvwI8IcIk0 rVWrJVCq3wAFIxvE14AKwVWUJVWUGwA2ocxC64kIII0Yj41l84x0c7CEw4AK67xGY2AK02 1l84ACjcxK6xIIjxv20xvE14v26F1j6w1UM28EF7xvwVC0I7IYx2IY6xkF7I0E14v26r4U JVWxJr1l84ACjcxK6I8E87Iv67AKxVW0oVCq3wA2z4x0Y4vEx4A2jsIEc7CjxVAFwI0_Gc CE3s1le2I262IYc4CY6c8Ij28IcVAaY2xG8wAqx4xG64xvF2IEw4CE5I8CrVC2j2WlYx0E 2Ix0cI8IcVAFwI0_Jr0_Jr4lYx0Ex4A2jsIE14v26r1j6r4UMcvjeVCFs4IE7xkEbVWUJV W8JwACjcxG0xvY0x0EwIxGrwACjI8F5VA0II8E6IAqYI8I648v4I1lFIxGxcIEc7CjxVA2 Y2ka0xkIwI1lc7CjxVAaw2AFwI0_Jw0_GFyl42xK82IYc2Ij64vIr41l4I8I3I0E4IkC6x 0Yz7v_Jr0_Gr1lx2IqxVAqx4xG67AKxVWUJVWUGwC20s026x8GjcxK67AKxVWUGVWUWwC2 zVAF1VAY17CE14v26r1q6r43MIIYrxkI7VAKI48JMIIF0xvE2Ix0cI8IcVAFwI0_Jr0_JF 4lIxAIcVC0I7IYx2IY6xkF7I0E14v26r1j6r4UMIIF0xvE42xK8VAvwI8IcIk0rVWUJVWU CwCI42IY6I8E87Iv67AKxVWUJVW8JwCI42IY6I8E87Iv6xkF7I0E14v26r1j6r4UYxBIda VFxhVjvjDU0xZFpf9x0JUd-B_UUUUU= X-CM-SenderInfo: qrsrjiarszq6lmxovvfxof0/ In dvb_register_device, *pdvbdev is set equal to dvbdev, which is freed in several error-handling paths. However, *pdvbdev is not set to NULL after dvbdev's deallocation, causing use-after-frees in many places, for example, in the following call chain: budget_register |-> dvb_dmxdev_init |-> dvb_register_device |-> dvb_dmxdev_release |-> dvb_unregister_device |-> dvb_remove_device |-> dvb_device_put |-> kref_put When calling dvb_unregister_device, dmxdev->dvbdev (i.e. *pdvbdev in dvb_register_device) could point to memory that had been freed in dvb_register_device. Thereafter, this pointer is transferred to kref_put and triggering a use-after-free. Fixes: b61901024776 ("V4L/DVB (5244): Dvbdev: fix illegal re-usage of fileoperations struct") Signed-off-by: Zhipeng Lu --- drivers/media/dvb-core/dvbdev.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/drivers/media/dvb-core/dvbdev.c b/drivers/media/dvb-core/dvbdev.c index 305bb21d843c..a027b9110793 100644 --- a/drivers/media/dvb-core/dvbdev.c +++ b/drivers/media/dvb-core/dvbdev.c @@ -488,6 +488,7 @@ int dvb_register_device(struct dvb_adapter *adap, struct dvb_device **pdvbdev, dvbdevfops = kmemdup(template->fops, sizeof(*dvbdevfops), GFP_KERNEL); if (!dvbdevfops) { kfree(dvbdev); + *pdvbdev = NULL; mutex_unlock(&dvbdev_register_lock); return -ENOMEM; } @@ -496,6 +497,7 @@ int dvb_register_device(struct dvb_adapter *adap, struct dvb_device **pdvbdev, if (!new_node) { kfree(dvbdevfops); kfree(dvbdev); + *pdvbdev = NULL; mutex_unlock(&dvbdev_register_lock); return -ENOMEM; } @@ -529,6 +531,7 @@ int dvb_register_device(struct dvb_adapter *adap, struct dvb_device **pdvbdev, } list_del(&dvbdev->list_head); kfree(dvbdev); + *pdvbdev = NULL; up_write(&minor_rwsem); mutex_unlock(&dvbdev_register_lock); return -EINVAL; @@ -551,6 +554,7 @@ int dvb_register_device(struct dvb_adapter *adap, struct dvb_device **pdvbdev, dvb_media_device_free(dvbdev); list_del(&dvbdev->list_head); kfree(dvbdev); + *pdvbdev = NULL; mutex_unlock(&dvbdev_register_lock); return ret; } @@ -569,6 +573,7 @@ int dvb_register_device(struct dvb_adapter *adap, struct dvb_device **pdvbdev, dvb_media_device_free(dvbdev); list_del(&dvbdev->list_head); kfree(dvbdev); + *pdvbdev = NULL; mutex_unlock(&dvbdev_register_lock); return PTR_ERR(clsdev); }