From patchwork Tue Jan 18 16:06:03 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg KH X-Patchwork-Id: 533232 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 3792AC433F5 for ; Tue, 18 Jan 2022 16:11:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1346362AbiARQL5 (ORCPT ); Tue, 18 Jan 2022 11:11:57 -0500 Received: from dfw.source.kernel.org ([139.178.84.217]:41304 "EHLO dfw.source.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1347225AbiARQKO (ORCPT ); Tue, 18 Jan 2022 11:10:14 -0500 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 8B3F0612E7; Tue, 18 Jan 2022 16:10:13 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5EDE1C00446; Tue, 18 Jan 2022 16:10:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1642522213; bh=s3CsI5MmGWZgzICs6nkaVvUohwmFXDbrC1qDtryJsvw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=WbD5eV5AUvrP/3Z1mCm6i5fw4nv8jLH9zouN4IWX1sXNwiYQ5LC2G5UJBHxRGqg2R DzwMaxsqC/15EHSac4cEYKTuJqX5nKcNiUjPEfEqDTxi7dXc4/pMgW7rAEWEpF5aNK ISFschLWFK09UfrD8G/qQfAsinFPG/umJ2JsOD48= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Qiushi Wu , Kees Cook , Johan Hovold , "Michael S. Tsirkin" Subject: [PATCH 5.15 17/28] firmware: qemu_fw_cfg: fix NULL-pointer deref on duplicate entries Date: Tue, 18 Jan 2022 17:06:03 +0100 Message-Id: <20220118160452.450455334@linuxfoundation.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20220118160451.879092022@linuxfoundation.org> References: <20220118160451.879092022@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Johan Hovold commit d3e305592d69e21e36b76d24ca3c01971a2d09be upstream. Commit fe3c60684377 ("firmware: Fix a reference count leak.") "fixed" a kobject leak in the file registration helper by properly calling kobject_put() for the entry in case registration of the object fails (e.g. due to a name collision). This would however result in a NULL pointer dereference when the release function tries to remove the never added entry from the fw_cfg_entry_cache list. Fix this by moving the list-removal out of the release function. Note that the offending commit was one of the benign looking umn.edu fixes which was reviewed but not reverted. [1][2] [1] https://lore.kernel.org/r/202105051005.49BFABCE@keescook [2] https://lore.kernel.org/all/YIg7ZOZvS3a8LjSv@kroah.com Fixes: fe3c60684377 ("firmware: Fix a reference count leak.") Cc: stable@vger.kernel.org # 5.8 Cc: Qiushi Wu Cc: Kees Cook Cc: Greg Kroah-Hartman Signed-off-by: Johan Hovold Link: https://lore.kernel.org/r/20211201132528.30025-2-johan@kernel.org Signed-off-by: Michael S. Tsirkin Signed-off-by: Greg Kroah-Hartman --- drivers/firmware/qemu_fw_cfg.c | 5 +---- 1 file changed, 1 insertion(+), 4 deletions(-) --- a/drivers/firmware/qemu_fw_cfg.c +++ b/drivers/firmware/qemu_fw_cfg.c @@ -388,9 +388,7 @@ static void fw_cfg_sysfs_cache_cleanup(v struct fw_cfg_sysfs_entry *entry, *next; list_for_each_entry_safe(entry, next, &fw_cfg_entry_cache, list) { - /* will end up invoking fw_cfg_sysfs_cache_delist() - * via each object's release() method (i.e. destructor) - */ + fw_cfg_sysfs_cache_delist(entry); kobject_put(&entry->kobj); } } @@ -448,7 +446,6 @@ static void fw_cfg_sysfs_release_entry(s { struct fw_cfg_sysfs_entry *entry = to_entry(kobj); - fw_cfg_sysfs_cache_delist(entry); kfree(entry); }