Merge branch 'uaccess-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

Pull uaccess fixes from Al Viro:
 "Fixes for broken uaccess primitives - mostly lack of proper zeroing
  in copy_from_user()/get_user()/__get_user(), but for several
  architectures there's more (broken clear_user() on frv and
  strncpy_from_user() on hexagon)"

* 'uaccess-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (28 commits)
  avr32: fix copy_from_user()
  microblaze: fix __get_user()
  microblaze: fix copy_from_user()
  m32r: fix __get_user()
  blackfin: fix copy_from_user()
  sparc32: fix copy_from_user()
  sh: fix copy_from_user()
  sh64: failing __get_user() should zero
  score: fix copy_from_user() and friends
  score: fix __get_user/get_user
  s390: get_user() should zero on failure
  ppc32: fix copy_from_user()
  parisc: fix copy_from_user()
  openrisc: fix copy_from_user()
  nios2: fix __get_user()
  nios2: copy_from_user() should zero the tail of destination
  mn10300: copy_from_user() should zero on access_ok() failure...
  mn10300: failing __get_user() and get_user() should zero
  mips: copy_from_user() must zero the destination on access_ok() failure
  ARC: uaccess: get_user to zero out dest in cause of fault
  ...

26 files changed, 179 insertions, 170 deletions

diff --git a/arch/alpha/include/asm/uaccess.h b/arch/alpha/include/asm/uaccess.h
index c419b43c461d..466e42e96bfa 100644
--- a/arch/alpha/include/asm/uaccess.h
+++ b/arch/alpha/include/asm/uaccess.h
@@ -371,14 +371,6 @@ __copy_tofrom_user_nocheck(void *to, const void *from, long len)
 	return __cu_len;
 }
 
-extern inline long
-__copy_tofrom_user(void *to, const void *from, long len, const void __user *validate)
-{
-	if (__access_ok((unsigned long)validate, len, get_fs()))
-		len = __copy_tofrom_user_nocheck(to, from, len);
-	return len;
-}
-
 #define __copy_to_user(to, from, n)					\
 ({									\
 	__chk_user_ptr(to);						\
@@ -393,17 +385,22 @@ __copy_tofrom_user(void *to, const void *from, long len, const void __user *vali
 #define __copy_to_user_inatomic __copy_to_user
 #define __copy_from_user_inatomic __copy_from_user
 
-
 extern inline long
 copy_to_user(void __user *to, const void *from, long n)
 {
-	return __copy_tofrom_user((__force void *)to, from, n, to);
+	if (likely(__access_ok((unsigned long)to, n, get_fs())))
+		n = __copy_tofrom_user_nocheck((__force void *)to, from, n);
+	return n;
 }
 
 extern inline long
 copy_from_user(void *to, const void __user *from, long n)
 {
-	return __copy_tofrom_user(to, (__force void *)from, n, from);
+	if (likely(__access_ok((unsigned long)from, n, get_fs())))
+		n = __copy_tofrom_user_nocheck(to, (__force void *)from, n);
+	else
+		memset(to, 0, n);
+	return n;
 }
 
 extern void __do_clear_user(void);
diff --git a/arch/arc/include/asm/uaccess.h b/arch/arc/include/asm/uaccess.h
index a78d5670884f..41faf17cd28d 100644
--- a/arch/arc/include/asm/uaccess.h
+++ b/arch/arc/include/asm/uaccess.h
@@ -83,7 +83,10 @@
 	"2:	;nop\n"				\
 	"	.section .fixup, \"ax\"\n"	\
 	"	.align 4\n"			\
-	"3:	mov %0, %3\n"			\
+	"3:	# return -EFAULT\n"		\
+	"	mov %0, %3\n"			\
+	"	# zero out dst ptr\n"		\
+	"	mov %1,  0\n"			\
 	"	j   2b\n"			\
 	"	.previous\n"			\
 	"	.section __ex_table, \"a\"\n"	\
@@ -101,7 +104,11 @@
 	"2:	;nop\n"				\
 	"	.section .fixup, \"ax\"\n"	\
 	"	.align 4\n"			\
-	"3:	mov %0, %3\n"			\
+	"3:	# return -EFAULT\n"		\
+	"	mov %0, %3\n"			\
+	"	# zero out dst ptr\n"		\
+	"	mov %1,  0\n"			\
+	"	mov %R1, 0\n"			\
 	"	j   2b\n"			\
 	"	.previous\n"			\
 	"	.section __ex_table, \"a\"\n"	\
diff --git a/arch/avr32/include/asm/uaccess.h b/arch/avr32/include/asm/uaccess.h
index 68cf638faf48..b1ec1fa06463 100644
--- a/arch/avr32/include/asm/uaccess.h
+++ b/arch/avr32/include/asm/uaccess.h
@@ -74,7 +74,7 @@ extern __kernel_size_t __copy_user(void *to, const void *from,
 
 extern __kernel_size_t copy_to_user(void __user *to, const void *from,
 				    __kernel_size_t n);
-extern __kernel_size_t copy_from_user(void *to, const void __user *from,
+extern __kernel_size_t ___copy_from_user(void *to, const void __user *from,
 				      __kernel_size_t n);
 
 static inline __kernel_size_t __copy_to_user(void __user *to, const void *from,
@@ -88,6 +88,15 @@ static inline __kernel_size_t __copy_from_user(void *to,
 {
 	return __copy_user(to, (const void __force *)from, n);
 }
+static inline __kernel_size_t copy_from_user(void *to,
+					       const void __user *from,
+					       __kernel_size_t n)
+{
+	size_t res = ___copy_from_user(to, from, n);
+	if (unlikely(res))
+		memset(to + (n - res), 0, res);
+	return res;
+}
 
 #define __copy_to_user_inatomic __copy_to_user
 #define __copy_from_user_inatomic __copy_from_user
diff --git a/arch/avr32/kernel/avr32_ksyms.c b/arch/avr32/kernel/avr32_ksyms.c
index d93ead02daed..7c6cf14f0985 100644
--- a/arch/avr32/kernel/avr32_ksyms.c
+++ b/arch/avr32/kernel/avr32_ksyms.c
@@ -36,7 +36,7 @@ EXPORT_SYMBOL(copy_page);
 /*
  * Userspace access stuff.
  */
-EXPORT_SYMBOL(copy_from_user);
+EXPORT_SYMBOL(___copy_from_user);
 EXPORT_SYMBOL(copy_to_user);
 EXPORT_SYMBOL(__copy_user);
 EXPORT_SYMBOL(strncpy_from_user);
diff --git a/arch/avr32/lib/copy_user.S b/arch/avr32/lib/copy_user.S
index ea59c04b07de..96a6de9d578f 100644
--- a/arch/avr32/lib/copy_user.S
+++ b/arch/avr32/lib/copy_user.S
@@ -25,11 +25,11 @@
 	.align	1
 	.global	copy_from_user
 	.type	copy_from_user, @function
-copy_from_user:
+___copy_from_user:
 	branch_if_kernel r8, __copy_user
 	ret_if_privileged r8, r11, r10, r10
 	rjmp	__copy_user
-	.size	copy_from_user, . - copy_from_user
+	.size	___copy_from_user, . - ___copy_from_user
 
 	.global	copy_to_user
 	.type	copy_to_user, @function
diff --git a/arch/blackfin/include/asm/uaccess.h b/arch/blackfin/include/asm/uaccess.h
index 12f5d6851bbc..0a2a70096d8b 100644
--- a/arch/blackfin/include/asm/uaccess.h
+++ b/arch/blackfin/include/asm/uaccess.h
@@ -171,11 +171,12 @@ static inline int bad_user_access_length(void)
 static inline unsigned long __must_check
 copy_from_user(void *to, const void __user *from, unsigned long n)
 {
-	if (access_ok(VERIFY_READ, from, n))
+	if (likely(access_ok(VERIFY_READ, from, n))) {
 		memcpy(to, (const void __force *)from, n);
-	else
-		return n;
-	return 0;
+		return 0;
+	}
+	memset(to, 0, n);
+	return n;
 }
 
 static inline unsigned long __must_check
diff --git a/arch/cris/include/asm/uaccess.h b/arch/cris/include/asm/uaccess.h
index e3530d0f13ee..56c7d5750abd 100644
--- a/arch/cris/include/asm/uaccess.h
+++ b/arch/cris/include/asm/uaccess.h
@@ -194,30 +194,6 @@ extern unsigned long __copy_user(void __user *to, const void *from, unsigned lon
 extern unsigned long __copy_user_zeroing(void *to, const void __user *from, unsigned long n);
 extern unsigned long __do_clear_user(void __user *to, unsigned long n);
 
-static inline unsigned long
-__generic_copy_to_user(void __user *to, const void *from, unsigned long n)
-{
-	if (access_ok(VERIFY_WRITE, to, n))
-		return __copy_user(to, from, n);
-	return n;
-}
-
-static inline unsigned long
-__generic_copy_from_user(void *to, const void __user *from, unsigned long n)
-{
-	if (access_ok(VERIFY_READ, from, n))
-		return __copy_user_zeroing(to, from, n);
-	return n;
-}
-
-static inline unsigned long
-__generic_clear_user(void __user *to, unsigned long n)
-{
-	if (access_ok(VERIFY_WRITE, to, n))
-		return __do_clear_user(to, n);
-	return n;
-}
-
 static inline long
 __strncpy_from_user(char *dst, const char __user *src, long count)
 {
@@ -282,7 +258,7 @@ __constant_copy_from_user(void *to, const void __user *from, unsigned long n)
 	else if (n == 24)
 		__asm_copy_from_user_24(to, from, ret);
 	else
-		ret = __generic_copy_from_user(to, from, n);
+		ret = __copy_user_zeroing(to, from, n);
 
 	return ret;
 }
@@ -333,7 +309,7 @@ __constant_copy_to_user(void __user *to, const void *from, unsigned long n)
 	else if (n == 24)
 		__asm_copy_to_user_24(to, from, ret);
 	else
-		ret = __generic_copy_to_user(to, from, n);
+		ret = __copy_user(to, from, n);
 
 	return ret;
 }
@@ -366,26 +342,43 @@ __constant_clear_user(void __user *to, unsigned long n)
 	else if (n == 24)
 		__asm_clear_24(to, ret);
 	else
-		ret = __generic_clear_user(to, n);
+		ret = __do_clear_user(to, n);
 
 	return ret;
 }
 
 
-#define clear_user(to, n)				\
-	(__builtin_constant_p(n) ?			\
-	 __constant_clear_user(to, n) :			\
-	 __generic_clear_user(to, n))
+static inline size_t clear_user(void __user *to, size_t n)
+{
+	if (unlikely(!access_ok(VERIFY_WRITE, to, n)))
+		return n;
+	if (__builtin_constant_p(n))
+		return __constant_clear_user(to, n);
+	else
+		return __do_clear_user(to, n);
+}
 
-#define copy_from_user(to, from, n)			\
-	(__builtin_constant_p(n) ?			\
-	 __constant_copy_from_user(to, from, n) :	\
-	 __generic_copy_from_user(to, from, n))
+static inline size_t copy_from_user(void *to, const void __user *from, size_t n)
+{
+	if (unlikely(!access_ok(VERIFY_READ, from, n))) {
+		memset(to, 0, n);
+		return n;
+	}
+	if (__builtin_constant_p(n))
+		return __constant_copy_from_user(to, from, n);
+	else
+		return __copy_user_zeroing(to, from, n);
+}
 
-#define copy_to_user(to, from, n)			\
-	(__builtin_constant_p(n) ?			\
-	 __constant_copy_to_user(to, from, n) :		\
-	 __generic_copy_to_user(to, from, n))
+static inline size_t copy_to_user(void __user *to, const void *from, size_t n)
+{
+	if (unlikely(!access_ok(VERIFY_WRITE, to, n)))
+		return n;
+	if (__builtin_constant_p(n))
+		return __constant_copy_to_user(to, from, n);
+	else
+		return __copy_user(to, from, n);
+}
 
 /* We let the __ versions of copy_from/to_user inline, because they're often
  * used in fast paths and have only a small space overhead.
diff --git a/arch/frv/include/asm/uaccess.h b/arch/frv/include/asm/uaccess.h
index 3ac9a59d65d4..87d9e34c5df8 100644
--- a/arch/frv/include/asm/uaccess.h
+++ b/arch/frv/include/asm/uaccess.h
@@ -263,19 +263,25 @@ do {							\
 extern long __memset_user(void *dst, unsigned long count);
 extern long __memcpy_user(void *dst, const void *src, unsigned long count);
 
-#define clear_user(dst,count)			__memset_user(____force(dst), (count))
+#define __clear_user(dst,count)			__memset_user(____force(dst), (count))
 #define __copy_from_user_inatomic(to, from, n)	__memcpy_user((to), ____force(from), (n))
 #define __copy_to_user_inatomic(to, from, n)	__memcpy_user(____force(to), (from), (n))
 
 #else
 
-#define clear_user(dst,count)			(memset(____force(dst), 0, (count)), 0)
+#define __clear_user(dst,count)			(memset(____force(dst), 0, (count)), 0)
 #define __copy_from_user_inatomic(to, from, n)	(memcpy((to), ____force(from), (n)), 0)
 #define __copy_to_user_inatomic(to, from, n)	(memcpy(____force(to), (from), (n)), 0)
 
 #endif
 
-#define __clear_user clear_user
+static inline unsigned long __must_check
+clear_user(void __user *to, unsigned long n)
+{
+	if (likely(__access_ok(to, n)))
+		n = __clear_user(to, n);
+	return n;
+}
 
 static inline unsigned long __must_check
 __copy_to_user(void __user *to, const void *from, unsigned long n)
diff --git a/arch/hexagon/include/asm/uaccess.h b/arch/hexagon/include/asm/uaccess.h
index f000a382bc7f..f61cfb28e9f2 100644
--- a/arch/hexagon/include/asm/uaccess.h
+++ b/arch/hexagon/include/asm/uaccess.h
@@ -103,7 +103,8 @@ static inline long hexagon_strncpy_from_user(char *dst, const char __user *src,
 {
 	long res = __strnlen_user(src, n);
 
-	/* return from strnlen can't be zero -- that would be rubbish. */
+	if (unlikely(!res))
+		return -EFAULT;
 
 	if (res > n) {
 		copy_from_user(dst, src, n);
diff --git a/arch/ia64/include/asm/uaccess.h b/arch/ia64/include/asm/uaccess.h
index 0472927ebb9b..bfe13196f770 100644
--- a/arch/ia64/include/asm/uaccess.h
+++ b/arch/ia64/include/asm/uaccess.h
@@ -269,19 +269,16 @@ __copy_from_user (void *to, const void __user *from, unsigned long count)
 	__cu_len;									\
 })
 
-#define copy_from_user(to, from, n)							\
-({											\
-	void *__cu_to = (to);								\
-	const void __user *__cu_from = (from);						\
-	long __cu_len = (n);								\
-											\
-	__chk_user_ptr(__cu_from);							\
-	if (__access_ok(__cu_from, __cu_len, get_fs())) {				\
-		check_object_size(__cu_to, __cu_len, false);			\
-		__cu_len = __copy_user((__force void __user *) __cu_to, __cu_from, __cu_len);	\
-	}										\
-	__cu_len;									\
-})
+static inline unsigned long
+copy_from_user(void *to, const void __user *from, unsigned long n)
+{
+	check_object_size(to, n, false);
+	if (likely(__access_ok(from, n, get_fs())))
+		n = __copy_user((__force void __user *) to, from, n);
+	else
+		memset(to, 0, n);
+	return n;
+}
 
 #define __copy_in_user(to, from, size)	__copy_user((to), (from), (size))
 
diff --git a/arch/m32r/include/asm/uaccess.h b/arch/m32r/include/asm/uaccess.h
index cac7014daef3..6f8982157a75 100644
--- a/arch/m32r/include/asm/uaccess.h
+++ b/arch/m32r/include/asm/uaccess.h
@@ -219,7 +219,7 @@ extern int fixup_exception(struct pt_regs *regs);
 #define __get_user_nocheck(x, ptr, size)				\
 ({									\
 	long __gu_err = 0;						\
-	unsigned long __gu_val;						\
+	unsigned long __gu_val = 0;					\
 	might_fault();							\
 	__get_user_size(__gu_val, (ptr), (size), __gu_err);		\
 	(x) = (__force __typeof__(*(ptr)))__gu_val;			\
diff --git a/arch/metag/include/asm/uaccess.h b/arch/metag/include/asm/uaccess.h
index 8282cbce7e39..273e61225c27 100644
--- a/arch/metag/include/asm/uaccess.h
+++ b/arch/metag/include/asm/uaccess.h
@@ -204,8 +204,9 @@ extern unsigned long __must_check __copy_user_zeroing(void *to,
 static inline unsigned long
 copy_from_user(void *to, const void __user *from, unsigned long n)
 {
-	if (access_ok(VERIFY_READ, from, n))
+	if (likely(access_ok(VERIFY_READ, from, n)))
 		return __copy_user_zeroing(to, from, n);
+	memset(to, 0, n);
 	return n;
 }
 
diff --git a/arch/microblaze/include/asm/uaccess.h b/arch/microblaze/include/asm/uaccess.h
index 331b0d35f89c..826676778094 100644
--- a/arch/microblaze/include/asm/uaccess.h
+++ b/arch/microblaze/include/asm/uaccess.h
@@ -227,7 +227,7 @@ extern long __user_bad(void);
 
 #define __get_user(x, ptr)						\
 ({									\
-	unsigned long __gu_val;						\
+	unsigned long __gu_val = 0;					\
 	/*unsigned long __gu_ptr = (unsigned long)(ptr);*/		\
 	long __gu_err;							\
 	switch (sizeof(*(ptr))) {					\
@@ -373,10 +373,13 @@ extern long __user_bad(void);
 static inline long copy_from_user(void *to,
 		const void __user *from, unsigned long n)
 {
+	unsigned long res = n;
 	might_fault();
-	if (access_ok(VERIFY_READ, from, n))
-		return __copy_from_user(to, from, n);
-	return n;
+	if (likely(access_ok(VERIFY_READ, from, n)))
+		res = __copy_from_user(to, from, n);
+	if (unlikely(res))
+		memset(to + (n - res), 0, res);
+	return res;
 }
 
 #define __copy_to_user(to, from, n)	\
diff --git a/arch/mips/include/asm/uaccess.h b/arch/mips/include/asm/uaccess.h
index 11b965f98d95..21a2aaba20d5 100644
--- a/arch/mips/include/asm/uaccess.h
+++ b/arch/mips/include/asm/uaccess.h
@@ -14,6 +14,7 @@
 #include <linux/kernel.h>
 #include <linux/errno.h>
 #include <linux/thread_info.h>
+#include <linux/string.h>
 #include <asm/asm-eva.h>
 
 /*
@@ -1170,6 +1171,8 @@ extern size_t __copy_in_user_eva(void *__to, const void *__from, size_t __n);
 			__cu_len = __invoke_copy_from_user(__cu_to,	\
 							   __cu_from,	\
 							   __cu_len);   \
+		} else {						\
+			memset(__cu_to, 0, __cu_len);			\
 		}							\
 	}								\
 	__cu_len;							\
diff --git a/arch/mn10300/include/asm/uaccess.h b/arch/mn10300/include/asm/uaccess.h
index 20f7bf6de384..d012e877a95a 100644
--- a/arch/mn10300/include/asm/uaccess.h
+++ b/arch/mn10300/include/asm/uaccess.h
@@ -166,6 +166,7 @@ struct __large_struct { unsigned long buf[100]; };
 		"2:\n"						\
 		"	.section	.fixup,\"ax\"\n"	\
 		"3:\n\t"					\
+		"	mov		0,%1\n"			\
 		"	mov		%3,%0\n"		\
 		"	jmp		2b\n"			\
 		"	.previous\n"				\
diff --git a/arch/mn10300/lib/usercopy.c b/arch/mn10300/lib/usercopy.c
index 7826e6c364e7..ce8899e5e171 100644
--- a/arch/mn10300/lib/usercopy.c
+++ b/arch/mn10300/lib/usercopy.c
@@ -9,7 +9,7 @@
  * as published by the Free Software Foundation; either version
  * 2 of the Licence, or (at your option) any later version.
  */
-#include <asm/uaccess.h>
+#include <linux/uaccess.h>
 
 unsigned long
 __generic_copy_to_user(void *to, const void *from, unsigned long n)
@@ -24,6 +24,8 @@ __generic_copy_from_user(void *to, const void *from, unsigned long n)
 {
 	if (access_ok(VERIFY_READ, from, n))
 		__copy_user_zeroing(to, from, n);
+	else
+		memset(to, 0, n);
 	return n;
 }
 
diff --git a/arch/nios2/include/asm/uaccess.h b/arch/nios2/include/asm/uaccess.h
index caa51ff85a3c..0ab82324c817 100644
--- a/arch/nios2/include/asm/uaccess.h
+++ b/arch/nios2/include/asm/uaccess.h
@@ -102,9 +102,12 @@ extern long __copy_to_user(void __user *to, const void *from, unsigned long n);
 static inline long copy_from_user(void *to, const void __user *from,
 				unsigned long n)
 {
-	if (!access_ok(VERIFY_READ, from, n))
-		return n;
-	return __copy_from_user(to, from, n);
+	unsigned long res = n;
+	if (access_ok(VERIFY_READ, from, n))
+		res = __copy_from_user(to, from, n);
+	if (unlikely(res))
+		memset(to + (n - res), 0, res);
+	return res;
 }
 
 static inline long copy_to_user(void __user *to, const void *from,
@@ -139,7 +142,7 @@ extern long strnlen_user(const char __user *s, long n);
 
 #define __get_user_unknown(val, size, ptr, err) do {			\
 	err = 0;							\
-	if (copy_from_user(&(val), ptr, size)) {			\
+	if (__copy_from_user(&(val), ptr, size)) {			\
 		err = -EFAULT;						\
 	}								\
 	} while (0)
@@ -166,7 +169,7 @@ do {									\
 	({								\
 	long __gu_err = -EFAULT;					\
 	const __typeof__(*(ptr)) __user *__gu_ptr = (ptr);		\
-	unsigned long __gu_val;						\
+	unsigned long __gu_val = 0;					\
 	__get_user_common(__gu_val, sizeof(*(ptr)), __gu_ptr, __gu_err);\
 	(x) = (__force __typeof__(x))__gu_val;				\
 	__gu_err;							\
diff --git a/arch/openrisc/include/asm/uaccess.h b/arch/openrisc/include/asm/uaccess.h
index a6bd07ca3d6c..cbad29b5a131 100644
--- a/arch/openrisc/include/asm/uaccess.h
+++ b/arch/openrisc/include/asm/uaccess.h
@@ -273,28 +273,20 @@ __copy_tofrom_user(void *to, const void *from, unsigned long size);
 static inline unsigned long
 copy_from_user(void *to, const void *from, unsigned long n)
 {
-	unsigned long over;
-
-	if (access_ok(VERIFY_READ, from, n))
-		return __copy_tofrom_user(to, from, n);
-	if ((unsigned long)from < TASK_SIZE) {
-		over = (unsigned long)from + n - TASK_SIZE;
-		return __copy_tofrom_user(to, from, n - over) + over;
-	}
-	return n;
+	unsigned long res = n;
+
+	if (likely(access_ok(VERIFY_READ, from, n)))
+		n = __copy_tofrom_user(to, from, n);
+	if (unlikely(res))
+		memset(to + (n - res), 0, res);
+	return res;
 }
 
 static inline unsigned long
 copy_to_user(void *to, const void *from, unsigned long n)
 {
-	unsigned long over;
-
-	if (access_ok(VERIFY_WRITE, to, n))
-		return __copy_tofrom_user(to, from, n);
-	if ((unsigned long)to < TASK_SIZE) {
-		over = (unsigned long)to + n - TASK_SIZE;
-		return __copy_tofrom_user(to, from, n - over) + over;
-	}
+	if (likely(access_ok(VERIFY_WRITE, to, n)))
+		n = __copy_tofrom_user(to, from, n);
 	return n;
 }
 
@@ -303,13 +295,8 @@ extern unsigned long __clear_user(void *addr, unsigned long size);
 static inline __must_check unsigned long
 clear_user(void *addr, unsigned long size)
 {
-
-	if (access_ok(VERIFY_WRITE, addr, size))
-		return __clear_user(addr, size);
-	if ((unsigned long)addr < TASK_SIZE) {
-		unsigned long over = (unsigned long)addr + size - TASK_SIZE;
-		return __clear_user(addr, size - over) + over;
-	}
+	if (likely(access_ok(VERIFY_WRITE, addr, size)))
+		size = __clear_user(addr, size);
 	return size;
 }
 
diff --git a/arch/parisc/include/asm/uaccess.h b/arch/parisc/include/asm/uaccess.h
index e9150487e20d..482847865dac 100644
--- a/arch/parisc/include/asm/uaccess.h
+++ b/arch/parisc/include/asm/uaccess.h
@@ -10,6 +10,7 @@
 #include <asm-generic/uaccess-unaligned.h>
 
 #include <linux/bug.h>
+#include <linux/string.h>
 
 #define VERIFY_READ 0
 #define VERIFY_WRITE 1
@@ -221,7 +222,7 @@ static inline unsigned long __must_check copy_from_user(void *to,
                                           unsigned long n)
 {
         int sz = __compiletime_object_size(to);
-        int ret = -EFAULT;
+        unsigned long ret = n;
 
         if (likely(sz == -1 || sz >= n))
                 ret = __copy_from_user(to, from, n);
@@ -230,6 +231,8 @@ static inline unsigned long __must_check copy_from_user(void *to,
 	else
                 __bad_copy_user();
 
+	if (unlikely(ret))
+		memset(to + (n - ret), 0, ret);
         return ret;
 }
 
diff --git a/arch/powerpc/include/asm/uaccess.h b/arch/powerpc/include/asm/uaccess.h
index f1e382498bbb..c266227fdd5b 100644
--- a/arch/powerpc/include/asm/uaccess.h
+++ b/arch/powerpc/include/asm/uaccess.h
@@ -308,36 +308,21 @@ extern unsigned long __copy_tofrom_user(void __user *to,
 static inline unsigned long copy_from_user(void *to,
 		const void __user *from, unsigned long n)
 {
-	unsigned long over;
-
-	if (access_ok(VERIFY_READ, from, n)) {
+	if (likely(access_ok(VERIFY_READ, from, n))) {
 		check_object_size(to, n, false);
 		return __copy_tofrom_user((__force void __user *)to, from, n);
 	}
-	if ((unsigned long)from < TASK_SIZE) {
-		over = (unsigned long)from + n - TASK_SIZE;
-		check_object_size(to, n - over, false);
-		return __copy_tofrom_user((__force void __user *)to, from,
-				n - over) + over;
-	}
+	memset(to, 0, n);
 	return n;
 }
 
 static inline unsigned long copy_to_user(void __user *to,
 		const void *from, unsigned long n)
 {
-	unsigned long over;
-
 	if (access_ok(VERIFY_WRITE, to, n)) {
 		check_object_size(from, n, true);
 		return __copy_tofrom_user(to, (__force void __user *)from, n);
 	}
-	if ((unsigned long)to < TASK_SIZE) {
-		over = (unsigned long)to + n - TASK_SIZE;
-		check_object_size(from, n - over, true);
-		return __copy_tofrom_user(to, (__force void __user *)from,
-				n - over) + over;
-	}
 	return n;
 }
 
@@ -434,10 +419,6 @@ static inline unsigned long clear_user(void __user *addr, unsigned long size)
 	might_fault();
 	if (likely(access_ok(VERIFY_WRITE, addr, size)))
 		return __clear_user(addr, size);
-	if ((unsigned long)addr < TASK_SIZE) {
-		unsigned long over = (unsigned long)addr + size - TASK_SIZE;
-		return __clear_user(addr, size - over) + over;
-	}
 	return size;
 }
 
diff --git a/arch/s390/include/asm/uaccess.h b/arch/s390/include/asm/uaccess.h
index 95aefdba4be2..52d7c8709279 100644
--- a/arch/s390/include/asm/uaccess.h
+++ b/arch/s390/include/asm/uaccess.h
@@ -266,28 +266,28 @@ int __put_user_bad(void) __attribute__((noreturn));
 	__chk_user_ptr(ptr);					\
 	switch (sizeof(*(ptr))) {				\
 	case 1: {						\
-		unsigned char __x;				\
+		unsigned char __x = 0;				\
 		__gu_err = __get_user_fn(&__x, ptr,		\
 					 sizeof(*(ptr)));	\
 		(x) = *(__force __typeof__(*(ptr)) *) &__x;	\
 		break;						\
 	};							\
 	case 2: {						\
-		unsigned short __x;				\
+		unsigned short __x = 0;				\
 		__gu_err = __get_user_fn(&__x, ptr,		\
 					 sizeof(*(ptr)));	\
 		(x) = *(__force __typeof__(*(ptr)) *) &__x;	\
 		break;						\
 	};							\
 	case 4: {						\
-		unsigned int __x;				\
+		unsigned int __x = 0;				\
 		__gu_err = __get_user_fn(&__x, ptr,		\
 					 sizeof(*(ptr)));	\
 		(x) = *(__force __typeof__(*(ptr)) *) &__x;	\
 		break;						\
 	};							\
 	case 8: {						\
-		unsigned long long __x;				\
+		unsigned long long __x = 0;			\
 		__gu_err = __get_user_fn(&__x, ptr,		\
 					 sizeof(*(ptr)));	\
 		(x) = *(__force __typeof__(*(ptr)) *) &__x;	\
diff --git a/arch/score/include/asm/uaccess.h b/arch/score/include/asm/uaccess.h
index 20a3591225cc..01aec8ccde83 100644
--- a/arch/score/include/asm/uaccess.h
+++ b/arch/score/include/asm/uaccess.h
@@ -163,7 +163,7 @@ do {									\
 		__get_user_asm(val, "lw", ptr);				\
 		 break;							\
 	case 8: 							\
-		if ((copy_from_user((void *)&val, ptr, 8)) == 0)	\
+		if (__copy_from_user((void *)&val, ptr, 8) == 0)	\
 			__gu_err = 0;					\
 		else							\
 			__gu_err = -EFAULT;				\
@@ -188,6 +188,8 @@ do {									\
 									\
 	if (likely(access_ok(VERIFY_READ, __gu_ptr, size)))		\
 		__get_user_common((x), size, __gu_ptr);			\
+	else								\
+		(x) = 0;						\
 									\
 	__gu_err;							\
 })
@@ -201,6 +203,7 @@ do {									\
 		"2:\n"							\
 		".section .fixup,\"ax\"\n"				\
 		"3:li	%0, %4\n"					\
+		"li	%1, 0\n"					\
 		"j	2b\n"						\
 		".previous\n"						\
 		".section __ex_table,\"a\"\n"				\
@@ -298,35 +301,34 @@ extern int __copy_tofrom_user(void *to, const void *from, unsigned long len);
 static inline unsigned long
 copy_from_user(void *to, const void *from, unsigned long len)
 {
-	unsigned long over;
+	unsigned long res = len;
 
-	if (access_ok(VERIFY_READ, from, len))
-		return __copy_tofrom_user(to, from, len);
+	if (likely(access_ok(VERIFY_READ, from, len)))
+		res = __copy_tofrom_user(to, from, len);
 
-	if ((unsigned long)from < TASK_SIZE) {
-		over = (unsigned long)from + len - TASK_SIZE;
-		return __copy_tofrom_user(to, from, len - over) + over;
-	}
-	return len;
+	if (unlikely(res))
+		memset(to + (len - res), 0, res);
+
+	return res;
 }
 
 static inline unsigned long
 copy_to_user(void *to, const void *from, unsigned long len)
 {
-	unsigned long over;
-
-	if (access_ok(VERIFY_WRITE, to, len))
-		return __copy_tofrom_user(to, from, len);
+	if (likely(access_ok(VERIFY_WRITE, to, len)))
+		len = __copy_tofrom_user(to, from, len);
 
-	if ((unsigned long)to < TASK_SIZE) {
-		over = (unsigned long)to + len - TASK_SIZE;
-		return __copy_tofrom_user(to, from, len - over) + over;
-	}
 	return len;
 }
 
-#define __copy_from_user(to, from, len)	\
-		__copy_tofrom_user((to), (from), (len))
+static inline unsigned long
+__copy_from_user(void *to, const void *from, unsigned long len)
+{
+	unsigned long left = __copy_tofrom_user(to, from, len);
+	if (unlikely(left))
+		memset(to + (len - left), 0, left);
+	return left;
+}
 
 #define __copy_to_user(to, from, len)		\
 		__copy_tofrom_user((to), (from), (len))
@@ -340,17 +342,17 @@ __copy_to_user_inatomic(void *to, const void *from, unsigned long len)
 static inline unsigned long
 __copy_from_user_inatomic(void *to, const void *from, unsigned long len)
 {
-	return __copy_from_user(to, from, len);
+	return __copy_tofrom_user(to, from, len);
 }
 
-#define __copy_in_user(to, from, len)	__copy_from_user(to, from, len)
+#define __copy_in_user(to, from, len)	__copy_tofrom_user(to, from, len)
 
 static inline unsigned long
 copy_in_user(void *to, const void *from, unsigned long len)
 {
 	if (access_ok(VERIFY_READ, from, len) &&
 		      access_ok(VERFITY_WRITE, to, len))
-		return copy_from_user(to, from, len);
+		return __copy_tofrom_user(to, from, len);
 }
 
 /*
diff --git a/arch/sh/include/asm/uaccess.h b/arch/sh/include/asm/uaccess.h
index a49635c51266..92ade79ac427 100644
--- a/arch/sh/include/asm/uaccess.h
+++ b/arch/sh/include/asm/uaccess.h
@@ -151,7 +151,10 @@ copy_from_user(void *to, const void __user *from, unsigned long n)
 	__kernel_size_t __copy_size = (__kernel_size_t) n;
 
 	if (__copy_size && __access_ok(__copy_from, __copy_size))
-		return __copy_user(to, from, __copy_size);
+		__copy_size = __copy_user(to, from, __copy_size);
+
+	if (unlikely(__copy_size))
+		memset(to + (n - __copy_size), 0, __copy_size);
 
 	return __copy_size;
 }
diff --git a/arch/sh/include/asm/uaccess_64.h b/arch/sh/include/asm/uaccess_64.h
index c01376c76b86..ca5073dd4596 100644
--- a/arch/sh/include/asm/uaccess_64.h
+++ b/arch/sh/include/asm/uaccess_64.h
@@ -24,6 +24,7 @@
 #define __get_user_size(x,ptr,size,retval)			\
 do {								\
 	retval = 0;						\
+	x = 0;							\
 	switch (size) {						\
 	case 1:							\
 		retval = __get_user_asm_b((void *)&x,		\
diff --git a/arch/sparc/include/asm/uaccess_32.h b/arch/sparc/include/asm/uaccess_32.h
index e722c510bb1b..ea55f86d7ccd 100644
--- a/arch/sparc/include/asm/uaccess_32.h
+++ b/arch/sparc/include/asm/uaccess_32.h
@@ -266,8 +266,10 @@ static inline unsigned long copy_from_user(void *to, const void __user *from, un
 	if (n && __access_ok((unsigned long) from, n)) {
 		check_object_size(to, n, false);
 		return __copy_user((__force void __user *) to, from, n);
-	} else
+	} else {
+		memset(to, 0, n);
 		return n;
+	}
 }
 
 static inline unsigned long __copy_from_user(void *to, const void __user *from, unsigned long n)
diff --git a/include/asm-generic/uaccess.h b/include/asm-generic/uaccess.h
index 5dea1fb6979c..6df9b0749671 100644
--- a/include/asm-generic/uaccess.h
+++ b/include/asm-generic/uaccess.h
@@ -231,14 +231,18 @@ extern int __put_user_bad(void) __attribute__((noreturn));
 	might_fault();						\
 	access_ok(VERIFY_READ, __p, sizeof(*ptr)) ?		\
 		__get_user((x), (__typeof__(*(ptr)) *)__p) :	\
-		-EFAULT;					\
+		((x) = (__typeof__(*(ptr)))0,-EFAULT);		\
 })
 
 #ifndef __get_user_fn
 static inline int __get_user_fn(size_t size, const void __user *ptr, void *x)
 {
-	size = __copy_from_user(x, ptr, size);
-	return size ? -EFAULT : size;
+	size_t n = __copy_from_user(x, ptr, size);
+	if (unlikely(n)) {
+		memset(x + (size - n), 0, n);
+		return -EFAULT;
+	}
+	return 0;
 }
 
 #define __get_user_fn(sz, u, k)	__get_user_fn(sz, u, k)
@@ -258,11 +262,13 @@ extern int __get_user_bad(void) __attribute__((noreturn));
 static inline long copy_from_user(void *to,
 		const void __user * from, unsigned long n)
 {
+	unsigned long res = n;
 	might_fault();
-	if (access_ok(VERIFY_READ, from, n))
-		return __copy_from_user(to, from, n);
-	else
-		return n;
+	if (likely(access_ok(VERIFY_READ, from, n)))
+		res = __copy_from_user(to, from, n);
+	if (unlikely(res))
+		memset(to + (n - res), 0, res);
+	return res;
 }
 
 static inline long copy_to_user(void __user *to,