From 409d02ef6d74f5e91f5ea4c587b2ee1375f106fc Mon Sep 17 00:00:00 2001 From: Heiko Carstens Date: Tue, 5 Jan 2010 14:19:11 +0100 Subject: [PATCH] x86: copy_from_user() should not return -EFAULT Callers of copy_from_user() expect it to return the number of bytes it could not copy. In no case it is supposed to return -EFAULT. In case of a detected buffer overflow just return the requested length. In addition one could think of a memset that would clear the size of the target object. [ hpa: code is not in .32 so not needed for -stable ] Signed-off-by: Heiko Carstens Acked-by: Arjan van de Ven LKML-Reference: <20100105131911.GC5480@osiris.boeblingen.de.ibm.com> Signed-off-by: H. Peter Anvin --- arch/x86/include/asm/uaccess_32.h | 5 ++--- arch/x86/include/asm/uaccess_64.h | 5 ++--- 2 files changed, 4 insertions(+), 6 deletions(-) diff --git a/arch/x86/include/asm/uaccess_32.h b/arch/x86/include/asm/uaccess_32.h index 0c9825e97f3..088d09fb161 100644 --- a/arch/x86/include/asm/uaccess_32.h +++ b/arch/x86/include/asm/uaccess_32.h @@ -205,14 +205,13 @@ static inline unsigned long __must_check copy_from_user(void *to, unsigned long n) { int sz = __compiletime_object_size(to); - int ret = -EFAULT; if (likely(sz == -1 || sz >= n)) - ret = _copy_from_user(to, from, n); + n = _copy_from_user(to, from, n); else copy_from_user_overflow(); - return ret; + return n; } long __must_check strncpy_from_user(char *dst, const char __user *src, diff --git a/arch/x86/include/asm/uaccess_64.h b/arch/x86/include/asm/uaccess_64.h index 46324c6a4f6..535e421498f 100644 --- a/arch/x86/include/asm/uaccess_64.h +++ b/arch/x86/include/asm/uaccess_64.h @@ -30,16 +30,15 @@ static inline unsigned long __must_check copy_from_user(void *to, unsigned long n) { int sz = __compiletime_object_size(to); - int ret = -EFAULT; might_fault(); if (likely(sz == -1 || sz >= n)) - ret = _copy_from_user(to, from, n); + n = _copy_from_user(to, from, n); #ifdef CONFIG_DEBUG_VM else WARN(1, "Buffer overflow detected!\n"); #endif - return ret; + return n; } static __always_inline __must_check -- 2.20.1