From fa94111d94354de76c47fea6e1187d1ee91e23a7 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Mon, 8 Jun 2020 21:35:01 -0700 Subject: [PATCH] x86: use non-set_fs based maccess routines 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. [akpm@linux-foundation.org: coding style fixes] Signed-off-by: Christoph Hellwig Signed-off-by: Andrew Morton Cc: Alexei Starovoitov Cc: Daniel Borkmann Cc: "H. Peter Anvin" Cc: Ingo Molnar Cc: Masami Hiramatsu Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/20200521152301.2587579-20-hch@lst.de Signed-off-by: Linus Torvalds --- 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 d8f283b9a569..35b23b0311f5 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_GET_KERNEL_NOFAULT + +#define __get_kernel_nofault(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 __put_kernel_nofault(dst, src, type, err_label) \ + __put_user_size(*((type *)(src)), (__force type __user *)(dst), \ + sizeof(type), err_label) + #endif /* _ASM_X86_UACCESS_H */