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From: Christoph Hellwig <hch@lst.de>
To: "David S. Miller" <davem@davemloft.net>,
	Jakub Kicinski <kuba@kernel.org>,
	Alexei Starovoitov <ast@kernel.org>,
	Daniel Borkmann <daniel@iogearbox.net>,
	Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>,
	Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>,
	Eric Dumazet <edumazet@google.com>
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 04/26] net: add a new sockptr_t type
Date: Thu, 23 Jul 2020 08:08:46 +0200	[thread overview]
Message-ID: <20200723060908.50081-5-hch@lst.de> (raw)
In-Reply-To: <20200723060908.50081-1-hch@lst.de>

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.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 include/linux/sockptr.h | 104 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 104 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..700856e13ea0c4
--- /dev/null
+++ b/include/linux/sockptr.h
@@ -0,0 +1,104 @@
+/* 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 <linux/slab.h>
+#include <linux/uaccess.h>
+
+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 };
+}
+
+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 */
-- 
2.27.0


  parent reply	other threads:[~2020-07-23  6:13 UTC|newest]

Thread overview: 64+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-07-23  6:08 get rid of the address_space override in setsockopt v2 Christoph Hellwig
2020-07-23  6:08 ` [PATCH 01/26] bpfilter: fix up a sparse annotation Christoph Hellwig
2020-07-23 11:14   ` Luc Van Oostenryck
2020-07-23  6:08 ` [PATCH 02/26] net/bpfilter: split __bpfilter_process_sockopt Christoph Hellwig
2020-07-23  6:08 ` [PATCH 03/26] bpfilter: reject kernel addresses Christoph Hellwig
2020-07-23 14:42   ` David Laight
2020-07-23 14:44     ` 'Christoph Hellwig'
2020-07-23 14:56       ` David Laight
2020-07-23  6:08 ` Christoph Hellwig [this message]
2020-07-23 15:40   ` [PATCH 04/26] net: add a new sockptr_t type Jan Engelhardt
2020-07-23 16:40   ` Eric Dumazet
2020-07-23 16:44     ` Christoph Hellwig
2020-07-23  6:08 ` [PATCH 05/26] net: switch copy_bpf_fprog_from_user to sockptr_t Christoph Hellwig
2020-07-23  6:08 ` [PATCH 06/26] net: switch sock_setbindtodevice " Christoph Hellwig
2020-07-23  6:08 ` [PATCH 07/26] net: switch sock_set_timeout " Christoph Hellwig
2020-07-23  6:08 ` [PATCH 08/26] " Christoph Hellwig
2020-07-23  8:39   ` [MPTCP] " Matthieu Baerts
2020-07-23  6:08 ` [PATCH 09/26] net/xfrm: switch xfrm_user_policy " Christoph Hellwig
2020-07-23  6:08 ` [PATCH 10/26] netfilter: remove the unused user argument to do_update_counters Christoph Hellwig
2020-07-23  6:08 ` [PATCH 11/26] netfilter: switch xt_copy_counters to sockptr_t Christoph Hellwig
2020-07-23  6:08 ` [PATCH 12/26] netfilter: switch nf_setsockopt " Christoph Hellwig
2020-07-27 15:03   ` Jason A. Donenfeld
2020-07-27 15:06     ` Christoph Hellwig
2020-07-27 16:16       ` Jason A. Donenfeld
2020-07-27 16:23         ` Christoph Hellwig
2020-07-28  8:07           ` David Laight
2020-07-28  8:17             ` Jason A. Donenfeld
2020-07-27 16:16     ` Christoph Hellwig
2020-07-27 16:21       ` Jason A. Donenfeld
2020-07-23  6:08 ` [PATCH 13/26] bpfilter: switch bpfilter_ip_set_sockopt " Christoph Hellwig
2020-07-23 11:16   ` David Laight
2020-07-23 11:44     ` 'Christoph Hellwig'
2020-07-23  6:08 ` [PATCH 14/26] net/ipv4: switch ip_mroute_setsockopt " Christoph Hellwig
2020-07-23  6:08 ` [PATCH 15/26] net/ipv4: merge ip_options_get and ip_options_get_from_user Christoph Hellwig
2020-07-23  6:08 ` [PATCH 16/26] net/ipv4: switch do_ip_setsockopt to sockptr_t Christoph Hellwig
2020-07-23  6:08 ` [PATCH 17/26] net/ipv6: switch ip6_mroute_setsockopt " Christoph Hellwig
2020-07-23  6:09 ` [PATCH 18/26] net/ipv6: split up ipv6_flowlabel_opt Christoph Hellwig
2020-07-23  6:09 ` [PATCH 19/26] net/ipv6: switch ipv6_flowlabel_opt to sockptr_t Christoph Hellwig
2020-07-27 12:15   ` Ido Schimmel
2020-07-27 13:00     ` Christoph Hellwig
2020-07-27 13:33       ` Ido Schimmel
2020-07-27 16:15         ` Christoph Hellwig
2020-07-27 18:22           ` Ido Schimmel
2020-07-27 13:24     ` David Laight
2020-07-23  6:09 ` [PATCH 20/26] net/ipv6: factor out a ipv6_set_opt_hdr helper Christoph Hellwig
2020-07-23  6:09 ` [PATCH 21/26] net/ipv6: switch do_ipv6_setsockopt to sockptr_t Christoph Hellwig
2020-07-23  6:09 ` [PATCH 22/26] net/udp: switch udp_lib_setsockopt " Christoph Hellwig
2020-07-23  6:09 ` [PATCH 23/26] net/tcp: switch ->md5_parse " Christoph Hellwig
2020-07-23  6:09 ` [PATCH 24/26] net/tcp: switch do_tcp_setsockopt " Christoph Hellwig
2020-07-23  6:09 ` [PATCH 25/26] net: pass a sockptr_t into ->setsockopt Christoph Hellwig
2020-07-23  8:39   ` [MPTCP] " Matthieu Baerts
2020-08-06 22:21   ` Eric Dumazet
2020-08-07  7:21     ` Christoph Hellwig
2020-08-07  9:18     ` David Laight
2020-08-07 18:29       ` Eric Dumazet
2020-08-08 13:54         ` David Laight
2020-07-23  6:09 ` [PATCH 26/26] net: optimize the sockptr_t for unified kernel/user address spaces Christoph Hellwig
2020-07-24 22:43 ` get rid of the address_space override in setsockopt v2 David Miller
2020-07-26  7:03   ` Christoph Hellwig
2020-07-26  7:08     ` Andreas Schwab
2020-07-26  7:46     ` David Miller
2020-07-27  9:51   ` David Laight
2020-07-27 13:48     ` Al Viro
2020-07-27 14:09       ` David Laight

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