From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from zeniv.linux.org.uk (zeniv.linux.org.uk [62.89.141.173]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id AA4E3EC9 for ; Thu, 11 May 2023 04:05:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=linux.org.uk; s=zeniv-20220401; h=Sender:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=es1hAOZEanSpUzrO4i+W99kSmiTSzzhtBMlo8JnwlYU=; b=XiM0jwFnKxFWGJpiCOPcZXBOTf 7Lff2nNv1b4BAaAzu2+8+Z6IL8XztnltccQ/JJuih56T1wL6PGmnGsDk5E0M2IhLX/LK07JbuLSIZ 7MeUi0RBKlVjXfF2dQ49aEOFQTTDRlx51zHwTVQTE5xRu4I0fDcigOhciITUn6bZwgzkWHvP5GDoh 2fdZoKkTwbsFp75btQY8vp64HMyDOb8xRvh6sSFXwAn6is5GoyjejZl85uiLUVi+kd01BW70CUhr5 tVCPkz/2NQ/hoG7jre3wotCKe/XGVrVJE/Z2HuYhiIxeH3PutobfBK7QQ7ocB4hd/asQ7TR+7XP1K n3LuDq7A==; Received: from viro by zeniv.linux.org.uk with local (Exim 4.96 #2 (Red Hat Linux)) id 1pwxYC-001apk-2B; Thu, 11 May 2023 04:05:08 +0000 Date: Thu, 11 May 2023 05:05:08 +0100 From: Al Viro To: Zhangfei Gao Cc: Greg Kroah-Hartman , Arnd Bergmann , Herbert Xu , jean-philippe , Wangzhou , Jonathan Cameron , linux-kernel@vger.kernel.org, linux-crypto@vger.kernel.org, iommu@lists.linux.dev, acc@lists.linaro.org, Weili Qian Subject: Re: [PATCH] uacce: use filep->f_mapping to replace inode->i_mapping Message-ID: <20230511040508.GF3390869@ZenIV> References: <20230511021553.44318-1-zhangfei.gao@linaro.org> Precedence: bulk X-Mailing-List: iommu@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20230511021553.44318-1-zhangfei.gao@linaro.org> Sender: Al Viro On Thu, May 11, 2023 at 10:15:53AM +0800, Zhangfei Gao wrote: > The inode can be different in a container, for example, a docker and host > both open the same uacce parent device, which uses the same uacce struct > but different inode, so uacce->inode is not enough. > > What's worse, when docker stops, the inode will be destroyed as well, > causing use-after-free in uacce_remove. > > So use q->filep->f_mapping to replace uacce->inode->i_mapping. > @@ -574,12 +574,6 @@ void uacce_remove(struct uacce_device *uacce) > > if (!uacce) > return; > - /* > - * unmap remaining mapping from user space, preventing user still > - * access the mmaped area while parent device is already removed > - */ > - if (uacce->inode) > - unmap_mapping_range(uacce->inode->i_mapping, 0, 0, 1); > > /* > * uacce_fops_open() may be running concurrently, even after we remove > @@ -589,6 +583,8 @@ void uacce_remove(struct uacce_device *uacce) > mutex_lock(&uacce->mutex); > /* ensure no open queue remains */ > list_for_each_entry_safe(q, next_q, &uacce->queues, list) { > + struct file *filep = q->private_data; > + > /* > * Taking q->mutex ensures that fops do not use the defunct > * uacce->ops after the queue is disabled. > @@ -597,6 +593,12 @@ void uacce_remove(struct uacce_device *uacce) > uacce_put_queue(q); > mutex_unlock(&q->mutex); > uacce_unbind_queue(q); > + > + /* > + * unmap remaining mapping from user space, preventing user still > + * access the mmaped area while parent device is already removed > + */ > + unmap_mapping_range(filep->f_mapping, 0, 0, 1); IDGI. Going through uacce_queue instead of uacce_device is fine, but why bother with file *or* inode? Just store a reference to struct address_space in your uacce_queue and be done with that... Another problem in that driver is uacce_vma_close(); this if (vma->vm_pgoff < UACCE_MAX_REGION) qfr = q->qfrs[vma->vm_pgoff]; kfree(qfr); can't be right - you have q->qfrs left pointing to freed object. If nothing else, subsequent mmap() will fail with -EEXIST, won't it?