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From: Christoph Hellwig <hch@lst.de>
To: x86@kernel.org, Alexei Starovoitov <ast@kernel.org>,
	Daniel Borkmann <daniel@iogearbox.net>,
	Masami Hiramatsu <mhiramat@kernel.org>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Andrew Morton <akpm@linux-foundation.org>
Cc: linux-parisc@vger.kernel.org, linux-um@lists.infradead.org,
	netdev@vger.kernel.org, bpf@vger.kernel.org, linux-mm@kvack.org,
	linux-kernel@vger.kernel.org
Subject: [PATCH 15/15] x86: use non-set_fs based maccess routines
Date: Wed,  6 May 2020 08:22:23 +0200	[thread overview]
Message-ID: <20200506062223.30032-16-hch@lst.de> (raw)
In-Reply-To: <20200506062223.30032-1-hch@lst.de>

Provide arch_kernel_read and arch_kernel_write routines to implement the
maccess routines without messing with set_fs and without stac/clac that
opens up access to user space.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 arch/x86/include/asm/uaccess.h | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/arch/x86/include/asm/uaccess.h b/arch/x86/include/asm/uaccess.h
index d8f283b9a569c..765e18417b3ba 100644
--- a/arch/x86/include/asm/uaccess.h
+++ b/arch/x86/include/asm/uaccess.h
@@ -523,5 +523,21 @@ do {									\
 	unsafe_copy_loop(__ucu_dst, __ucu_src, __ucu_len, u8, label);	\
 } while (0)
 
+#define HAVE_ARCH_PROBE_KERNEL
+
+#define arch_kernel_read(dst, src, type, err_label)			\
+do {									\
+        int __kr_err;							\
+									\
+	__get_user_size(*((type *)dst), (__force type __user *)src,	\
+			sizeof(type), __kr_err);			\
+        if (unlikely(__kr_err))						\
+		goto err_label;						\
+} while (0)
+
+#define arch_kernel_write(dst, src, type, err_label)			\
+	__put_user_size(*((type *)(src)), (__force type __user *)(dst),	\
+			sizeof(type), err_label)
+
 #endif /* _ASM_X86_UACCESS_H */
 
-- 
2.26.2


  parent reply	other threads:[~2020-05-06  6:23 UTC|newest]

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-05-06  6:22 clean up and streamline probe_kernel_* and friends Christoph Hellwig
2020-05-06  6:22 ` [PATCH 01/15] maccess: unexport probe_kernel_write and probe_user_write Christoph Hellwig
2020-05-06  6:22 ` [PATCH 02/15] maccess: remove various unused weak aliases Christoph Hellwig
2020-05-06  6:22 ` [PATCH 03/15] maccess: remove duplicate kerneldoc commens Christoph Hellwig
2020-05-06  6:22 ` [PATCH 04/15] maccess: clarify kerneldoc comments Christoph Hellwig
2020-05-06  6:22 ` [PATCH 05/15] maccess: update the top of file comment Christoph Hellwig
2020-05-06  6:22 ` [PATCH 06/15] maccess: rename strncpy_from_unsafe_user to strncpy_from_user_unsafe Christoph Hellwig
2020-05-06  6:22 ` [PATCH 07/15] maccess: rename strncpy_from_unsafe_strict to strncpy_from_kernel_unsafe Christoph Hellwig
2020-05-06  6:22 ` [PATCH 08/15] maccess: rename strnlen_unsafe_user to strnlen_user_unsafe Christoph Hellwig
2020-05-06 17:44   ` Linus Torvalds
2020-05-06 17:47     ` Christoph Hellwig
2020-05-06 17:57       ` Linus Torvalds
2020-05-06  6:22 ` [PATCH 09/15] maccess: remove probe_read_common and probe_write_common Christoph Hellwig
2020-05-06  6:22 ` [PATCH 10/15] maccess: unify the probe kernel arch hooks Christoph Hellwig
2020-05-06  6:22 ` [PATCH 11/15] maccess: remove strncpy_from_unsafe Christoph Hellwig
2020-05-11  5:34   ` Masami Hiramatsu
2020-05-06  6:22 ` [PATCH 12/15] maccess: always use strict semantics for probe_kernel_read Christoph Hellwig
2020-05-11  5:05   ` Masami Hiramatsu
2020-05-11  5:27     ` Masami Hiramatsu
2020-05-06  6:22 ` [PATCH 13/15] maccess: move user access routines together Christoph Hellwig
2020-05-06  6:22 ` [PATCH 14/15] maccess: allow architectures to provide kernel probing directly Christoph Hellwig
2020-05-06  6:22 ` Christoph Hellwig [this message]
2020-05-06 17:51   ` [PATCH 15/15] x86: use non-set_fs based maccess routines Linus Torvalds
2020-05-06 18:15     ` Christoph Hellwig
2020-05-06 19:01       ` Linus Torvalds
2020-05-07  5:12         ` Christoph Hellwig

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