From patchwork Wed Sep 7 13:52:30 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: V4bel X-Patchwork-Id: 604051 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 C4F10C38145 for ; Wed, 7 Sep 2022 13:52:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229472AbiIGNwg (ORCPT ); Wed, 7 Sep 2022 09:52:36 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37000 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229477AbiIGNwf (ORCPT ); Wed, 7 Sep 2022 09:52:35 -0400 Received: from mail-pf1-x436.google.com (mail-pf1-x436.google.com [IPv6:2607:f8b0:4864:20::436]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A4DC579630 for ; Wed, 7 Sep 2022 06:52:34 -0700 (PDT) Received: by mail-pf1-x436.google.com with SMTP id z187so14679486pfb.12 for ; Wed, 07 Sep 2022 06:52:34 -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=Os46oyuXrrUnaSHzX2Jq5aIhZgyL8+b3lVhx1qrbkDc=; b=dkB94lF8C5dYlJ5scLm6XqDxQpSdghGmoDw5F1hPc6a8Ry24hdRHklg6DlZNrqVGe/ z81+QDHPXHchZ1FgRJv7oWIzm9mcLhvpQ3Cew3MbmHEghQWaq+9SuipEdZwvNcEZWQHH /LSWgLyOyEnH6NdwqhBDjVv/pqtp+GbtOoAIuMafNfK1ai/w++mXxCo5G0ayRJe4mIdU WzvvV8/ONQ/FolOwzc5SuLjLHzxmUCT5IEp+siyJ/Ld9w/qumi5+m9LtMwXhn3uDd2ZA 5MiBioESBD4S0V/3AMUjIMQLvtxTpUsAccEuw/mHYiQhDNr7Hx8t4hXRRyMkbFBpVolZ XBXg== 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=Os46oyuXrrUnaSHzX2Jq5aIhZgyL8+b3lVhx1qrbkDc=; b=c6sbl04HTW6ZfA1zIhP/gCosnRKL1nZTAtl49i0V6JxxzeVnC+ZnWC/uDjxcVPVAwh b3c3WIsZnLRQBEOfbdwSAdpvrCJeuXaj0MiOTe7eGqBRMel0DJwD+xn+LGvhAQRqeHGo 50qpt4pHq6OjHDzel6JpJXCZQVuxCn3HCDvzqGqjduAhWqaAqYpKbjQck+R9jHiRXxIW 2xeD/7az5nkkILtTvmn1kR/ojQyH2WSM9HSQESaCcsfYqbt5DmESIw84J2u3Gp1wwdjl qSDA4FZ/tVp6bZR0hygOjYBShpKGtE8mT8jd6DW3FNbGQQrHE+kOBrtb/IhTUS9BuXmz zxKw== X-Gm-Message-State: ACgBeo0N+LkeEs4i4jmky6otJP7b13s3OlJK3L6pdMOpZ/+YVGZ3ow47 TwQpUHfiMwIijrBdW0b8K44= X-Google-Smtp-Source: AA6agR4ds+XmuM2Kb5JbF8smadZZAh7m8bZtKJiZs3j1y427pKB9fQNgih3nljL7A0brLglGIyyjiA== X-Received: by 2002:a63:798c:0:b0:42a:4612:c07b with SMTP id u134-20020a63798c000000b0042a4612c07bmr3545736pgc.519.1662558754079; Wed, 07 Sep 2022 06:52:34 -0700 (PDT) Received: from ubuntu ([175.124.254.119]) by smtp.gmail.com with ESMTPSA id p2-20020a17090a680200b001efa9e83927sm12064171pjj.51.2022.09.07.06.52.32 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 07 Sep 2022 06:52:33 -0700 (PDT) Date: Wed, 7 Sep 2022 06:52:30 -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: <20220907135230.GA126279@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;