From patchwork Mon Jul 20 12:47:16 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Christoph Hellwig X-Patchwork-Id: 11673809 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id E336F1392 for ; Mon, 20 Jul 2020 12:52:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id CC67822CF7 for ; Mon, 20 Jul 2020 12:52:08 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="MadyBZx0" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728825AbgGTMsM (ORCPT ); Mon, 20 Jul 2020 08:48:12 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40486 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728074AbgGTMsJ (ORCPT ); Mon, 20 Jul 2020 08:48:09 -0400 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4EED7C061794; Mon, 20 Jul 2020 05:48:09 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=Content-Transfer-Encoding:MIME-Version: References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From:Sender:Reply-To: Content-Type:Content-ID:Content-Description; bh=v9KgsOSWea1bJKFDijg05Yu/Lxnc3rcc50PR6ELHK4E=; b=MadyBZx0Wf8x+2kw7O1nJxOIOd FbU4MH1JyD5v78V7lQ/HRw45yXpPVs9JO/G+kH4DiN1QWFmw0WGQv/S2d22ogQPe/4gqcuswjDMxD UA+RyowobKCKhwuLpSB8o4bKj8XVpqEmqj4r0KjhkUO/Xe3omvaNi1zO6Mu7Ul5xJ63b84wq7p4uE igF3dMEhdDGLmF1UIoeXtgDt60qeorgzwuf6irI/HPydWG6GGi42y2nO3TPoyuU57ddcRPRbw8sYq A124JUfae++O65R5yqh735FbvAIm2bAY6i4tx8g4ymy/GWe+BCXCPTa9ItoQv2rd6m2uecW1hKmJ+ VToa8WXQ==; Received: from [2001:4bb8:105:4a81:2a8f:15b1:2c3:7be7] (helo=localhost) by casper.infradead.org with esmtpsa (Exim 4.92.3 #3 (Red Hat Linux)) id 1jxVCt-0004Wa-Pp; Mon, 20 Jul 2020 12:47:49 +0000 From: Christoph Hellwig To: "David S. Miller" , Jakub Kicinski , Alexei Starovoitov , Daniel Borkmann , Alexey Kuznetsov , Hideaki YOSHIFUJI , Eric Dumazet Cc: linux-crypto@vger.kernel.org, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, bpf@vger.kernel.org, netfilter-devel@vger.kernel.org, coreteam@netfilter.org, linux-sctp@vger.kernel.org, linux-hams@vger.kernel.org, linux-bluetooth@vger.kernel.org, bridge@lists.linux-foundation.org, linux-can@vger.kernel.org, dccp@vger.kernel.org, linux-decnet-user@lists.sourceforge.net, linux-wpan@vger.kernel.org, linux-s390@vger.kernel.org, mptcp@lists.01.org, lvs-devel@vger.kernel.org, rds-devel@oss.oracle.com, linux-afs@lists.infradead.org, tipc-discussion@lists.sourceforge.net, linux-x25@vger.kernel.org Subject: [PATCH 03/24] net: add a new sockptr_t type Date: Mon, 20 Jul 2020 14:47:16 +0200 Message-Id: <20200720124737.118617-4-hch@lst.de> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20200720124737.118617-1-hch@lst.de> References: <20200720124737.118617-1-hch@lst.de> MIME-Version: 1.0 X-SRS-Rewrite: SMTP reverse-path rewritten from by casper.infradead.org. See http://www.infradead.org/rpr.html Sender: linux-wpan-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-wpan@vger.kernel.org Add a uptr_t type that can hold a pointer to either a user or kernel memory region, and simply helpers to copy to and from it. For architectures like x86 that have non-overlapping user and kernel address space it just is a union and uses a TASK_SIZE check to select the proper copy routine. For architectures with overlapping address spaces a flag to indicate the address space is used instead. Signed-off-by: Christoph Hellwig --- include/linux/sockptr.h | 121 ++++++++++++++++++++++++++++++++++++++++ 1 file changed, 121 insertions(+) create mode 100644 include/linux/sockptr.h diff --git a/include/linux/sockptr.h b/include/linux/sockptr.h new file mode 100644 index 00000000000000..e41dfa52555dec --- /dev/null +++ b/include/linux/sockptr.h @@ -0,0 +1,121 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* + * Copyright (c) 2020 Christoph Hellwig. + * + * Support for "universal" pointers that can point to either kernel or userspace + * memory. + */ +#ifndef _LINUX_SOCKPTR_H +#define _LINUX_SOCKPTR_H + +#include +#include + +#ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE +typedef union { + void *kernel; + void __user *user; +} sockptr_t; + +static inline bool sockptr_is_kernel(sockptr_t sockptr) +{ + return (unsigned long)sockptr.kernel >= TASK_SIZE; +} + +static inline sockptr_t KERNEL_SOCKPTR(void *p) +{ + return (sockptr_t) { .kernel = p }; +} +#else /* CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE */ +typedef struct { + union { + void *kernel; + void __user *user; + }; + bool is_kernel : 1; +} sockptr_t; + +static inline bool sockptr_is_kernel(sockptr_t sockptr) +{ + return sockptr.is_kernel; +} + +static inline sockptr_t KERNEL_SOCKPTR(void *p) +{ + return (sockptr_t) { .kernel = p, .is_kernel = true }; +} +#endif /* CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE */ + +static inline sockptr_t USER_SOCKPTR(void __user *p) +{ + return (sockptr_t) { .user = p }; +} + +static inline bool sockptr_is_null(sockptr_t sockptr) +{ + return !sockptr.user && !sockptr.kernel; +} + +static inline int copy_from_sockptr(void *dst, sockptr_t src, size_t size) +{ + if (!sockptr_is_kernel(src)) + return copy_from_user(dst, src.user, size); + memcpy(dst, src.kernel, size); + return 0; +} + +static inline int copy_to_sockptr(sockptr_t dst, const void *src, size_t size) +{ + if (!sockptr_is_kernel(dst)) + return copy_to_user(dst.user, src, size); + memcpy(dst.kernel, src, size); + return 0; +} + +static inline void *memdup_sockptr(sockptr_t src, size_t len) +{ + void *p = kmalloc_track_caller(len, GFP_USER | __GFP_NOWARN); + + if (!p) + return ERR_PTR(-ENOMEM); + if (copy_from_sockptr(p, src, len)) { + kfree(p); + return ERR_PTR(-EFAULT); + } + return p; +} + +static inline void *memdup_sockptr_nul(sockptr_t src, size_t len) +{ + char *p = kmalloc_track_caller(len + 1, GFP_KERNEL); + + if (!p) + return ERR_PTR(-ENOMEM); + if (copy_from_sockptr(p, src, len)) { + kfree(p); + return ERR_PTR(-EFAULT); + } + p[len] = '\0'; + return p; +} + +static inline void sockptr_advance(sockptr_t sockptr, size_t len) +{ + if (sockptr_is_kernel(sockptr)) + sockptr.kernel += len; + else + sockptr.user += len; +} + +static inline long strncpy_from_sockptr(char *dst, sockptr_t src, size_t count) +{ + if (sockptr_is_kernel(src)) { + size_t len = min(strnlen(src.kernel, count - 1) + 1, count); + + memcpy(dst, src.kernel, len); + return len; + } + return strncpy_from_user(dst, src.user, count); +} + +#endif /* _LINUX_SOCKPTR_H */