From patchwork Wed Sep 7 13:46:02 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: V4bel X-Patchwork-Id: 603606 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 ED6D6C54EE9 for ; Wed, 7 Sep 2022 13:46:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229728AbiIGNq4 (ORCPT ); Wed, 7 Sep 2022 09:46:56 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45766 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230038AbiIGNqe (ORCPT ); Wed, 7 Sep 2022 09:46:34 -0400 Received: from mail-pg1-x536.google.com (mail-pg1-x536.google.com [IPv6:2607:f8b0:4864:20::536]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DF03EA3D3D for ; Wed, 7 Sep 2022 06:46:07 -0700 (PDT) Received: by mail-pg1-x536.google.com with SMTP id t65so2691013pgt.2 for ; Wed, 07 Sep 2022 06:46:07 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=content-disposition:mime-version:message-id:subject:cc:to:from:date :from:to:cc:subject:date; bh=fvvLgOpiiVxhgiqg0jJEN5rqJRa+7V40kP2JA0R4QjE=; b=pf6WNJNDwap/Pz4C6V9eOqc9fN/2snu95ysWQKf3K9ONTgstVtrkGtQk9LnnBI7Fn0 OlOCola71+/URIghquVvu5zEIl5xf6RM05RnPOjWCzq3uNgIDyT9BOOo+m3CWfjCYWrp rseRx3TOVVLkTiRb9obIsX6DSWwt6VHHHRulAvZBVdFUv/X6JLs4CaJGvMVWPKBrVMTZ 6+1jG1iMoK65JrLSaQNJZJ6j8yrt1OjBFC9bdAhlRzzFbV/8Zmmhbi5BF8U0FoyR6JwZ D0FGt75vAx8+6VByCxFd2oV2JO3mYFrX8lCng2yhRQ/MS1459rfj8zIZtybe43OrLI9u c9Lg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-disposition:mime-version:message-id:subject:cc:to:from:date :x-gm-message-state:from:to:cc:subject:date; bh=fvvLgOpiiVxhgiqg0jJEN5rqJRa+7V40kP2JA0R4QjE=; b=lvOEUgl6spNMspDe0M2mZnKr3ldeM5uqZ8rJMC6fr0ADQjlfiQXgYPDd1sU2/BQwPB oWZr3SCsETv4i4utnXGXnkp+pOOWkJMFlz1JMhcakouQClu5vnPpY+cNwpn+xXHynaOZ C1OjaUI9Q5MEJEGrrxN+1Ds06KrpEO7oxaUWq0UoWmjOTuHOYd0bgxD0MHBuwxyCnoGD X+HhyOsx/MJj4tFe2P8o3wMXEZ2lsdrI/2j7rJDhMUZpaYLht4DDAHSM//GZaBAUl+No qD3PGwmJwp/ayZelw2C4Miays6E7MbSDXk2/AB4tL5FUogB7I8hJfdHtEs2hVlbJ1kaj 89sg== X-Gm-Message-State: ACgBeo1160jJSG49eANH7J/0unWzl+sqh8eS5TagFqsg9hMFEHl/p6+S P0WVN9r0H5ayT5x+C76obYuka2KFCfw= X-Google-Smtp-Source: AA6agR5XwPRHYMz0P5mZxBEJxZaR6BfIdSIfr+0WctMuMLBHZ2M6ZqiHfExbN8Rimv2ChRvQqJpblA== X-Received: by 2002:a63:4b43:0:b0:42a:b42a:d216 with SMTP id k3-20020a634b43000000b0042ab42ad216mr3477116pgl.530.1662558366452; Wed, 07 Sep 2022 06:46:06 -0700 (PDT) Received: from ubuntu ([175.124.254.119]) by smtp.gmail.com with ESMTPSA id p5-20020aa79e85000000b0053826eaa1c7sm12541066pfq.22.2022.09.07.06.46.04 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 07 Sep 2022 06:46:05 -0700 (PDT) Date: Wed, 7 Sep 2022 06:46:02 -0700 From: Hyunwoo Kim To: ardb@kernel.org Cc: linux-efi@vger.kernel.org, imv4bel@gmail.com Subject: [PATCH v3] efi: capsule-loader: Fix use-after-free in efi_capsule_write Message-ID: <20220907134602.GA125834@ubuntu> MIME-Version: 1.0 Content-Disposition: inline Precedence: bulk List-ID: X-Mailing-List: linux-efi@vger.kernel.org A race condition may occur if the user calls close() on another thread during a write() operation on the device node of the efi capsule. This is a race condition that occurs between the efi_capsule_write() and efi_capsule_flush() functions of efi_capsule_fops, which ultimately results in UAF. So I added mutex_lock/unlock to these two functions to avoid race condition. Signed-off-by: Hyunwoo Kim --- drivers/firmware/efi/capsule-loader.c | 12 ++++++++++++ include/linux/efi.h | 1 + 2 files changed, 13 insertions(+) diff --git a/drivers/firmware/efi/capsule-loader.c b/drivers/firmware/efi/capsule-loader.c index 4dde8edd53b6..ca50cb982371 100644 --- a/drivers/firmware/efi/capsule-loader.c +++ b/drivers/firmware/efi/capsule-loader.c @@ -174,6 +174,8 @@ static ssize_t efi_capsule_write(struct file *file, const char __user *buff, void *kbuff = NULL; size_t write_byte; + mutex_lock(&cap_info->write_lock); + if (count == 0) return 0; @@ -233,12 +235,16 @@ static ssize_t efi_capsule_write(struct file *file, const char __user *buff, goto failed; } + mutex_unlock(&cap_info->write_lock); + return write_byte; fail_unmap: kunmap(page); failed: efi_free_all_buff_pages(cap_info); + mutex_unlock(&cap_info->write_lock); + return ret; } @@ -256,12 +262,16 @@ static int efi_capsule_flush(struct file *file, fl_owner_t id) int ret = 0; struct capsule_info *cap_info = file->private_data; + mutex_lock(&cap_info->write_lock); + if (cap_info->index > 0) { pr_err("capsule upload not complete\n"); efi_free_all_buff_pages(cap_info); ret = -ECANCELED; } + mutex_unlock(&cap_info->write_lock); + return ret; } @@ -315,6 +325,8 @@ static int efi_capsule_open(struct inode *inode, struct file *file) return -ENOMEM; } + mutex_init(&cap_info->write_lock); + file->private_data = cap_info; return 0; diff --git a/include/linux/efi.h b/include/linux/efi.h index d2b84c2fec39..f8b92a54d3c9 100644 --- a/include/linux/efi.h +++ b/include/linux/efi.h @@ -204,6 +204,7 @@ struct efi_image_auth { struct capsule_info { efi_capsule_header_t header; efi_capsule_header_t *capsule; + struct mutex write_lock; int reset_type; long index; size_t count;