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=-19.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,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 3D3D0C433E4 for ; Mon, 22 Mar 2021 12:38:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1A275619D4 for ; Mon, 22 Mar 2021 12:38:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230497AbhCVMhl (ORCPT ); Mon, 22 Mar 2021 08:37:41 -0400 Received: from mail.kernel.org ([198.145.29.99]:55578 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231793AbhCVMfk (ORCPT ); Mon, 22 Mar 2021 08:35:40 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 80837619A1; Mon, 22 Mar 2021 12:35:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1616416532; bh=icoNX7B9VZNqEuw0GgE5BHG/GHIL246ZzjP7xg2Dui8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=nftoq8HscxRUocVxaW79AFrltO8skC9j1NruYvp0prq2yNeLD0DSCrt5ICqQ7eTjG D/i2NasN/oSLv0BMQ9T5jcQPqznXuBRWR6VUJ8mwriuapSInFCsKCaoAoBXdn8zVpQ tHxd4wmw2/4OxkELX8T7bI0Xxf6LLXNJbpdfzqXU= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, lingshan.zhu@intel.com, Stefano Garzarella , "Michael S. Tsirkin" , Jason Wang Subject: [PATCH 5.10 021/157] vhost-vdpa: fix use-after-free of v->config_ctx Date: Mon, 22 Mar 2021 13:26:18 +0100 Message-Id: <20210322121934.443499174@linuxfoundation.org> X-Mailer: git-send-email 2.31.0 In-Reply-To: <20210322121933.746237845@linuxfoundation.org> References: <20210322121933.746237845@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Stefano Garzarella commit f6bbf0010ba004f5e90c7aefdebc0ee4bd3283b9 upstream. When the 'v->config_ctx' eventfd_ctx reference is released we didn't set it to NULL. So if the same character device (e.g. /dev/vhost-vdpa-0) is re-opened, the 'v->config_ctx' is invalid and calling again vhost_vdpa_config_put() causes use-after-free issues like the following refcount_t underflow: refcount_t: underflow; use-after-free. WARNING: CPU: 2 PID: 872 at lib/refcount.c:28 refcount_warn_saturate+0xae/0xf0 RIP: 0010:refcount_warn_saturate+0xae/0xf0 Call Trace: eventfd_ctx_put+0x5b/0x70 vhost_vdpa_release+0xcd/0x150 [vhost_vdpa] __fput+0x8e/0x240 ____fput+0xe/0x10 task_work_run+0x66/0xa0 exit_to_user_mode_prepare+0x118/0x120 syscall_exit_to_user_mode+0x21/0x50 ? __x64_sys_close+0x12/0x40 do_syscall_64+0x45/0x50 entry_SYSCALL_64_after_hwframe+0x44/0xae Fixes: 776f395004d8 ("vhost_vdpa: Support config interrupt in vdpa") Cc: lingshan.zhu@intel.com Cc: stable@vger.kernel.org Signed-off-by: Stefano Garzarella Link: https://lore.kernel.org/r/20210311135257.109460-2-sgarzare@redhat.com Signed-off-by: Michael S. Tsirkin Reviewed-by: Zhu Lingshan Acked-by: Jason Wang Signed-off-by: Greg Kroah-Hartman --- drivers/vhost/vdpa.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) --- a/drivers/vhost/vdpa.c +++ b/drivers/vhost/vdpa.c @@ -312,8 +312,10 @@ static long vhost_vdpa_get_vring_num(str static void vhost_vdpa_config_put(struct vhost_vdpa *v) { - if (v->config_ctx) + if (v->config_ctx) { eventfd_ctx_put(v->config_ctx); + v->config_ctx = NULL; + } } static long vhost_vdpa_set_config_call(struct vhost_vdpa *v, u32 __user *argp)