1 files changed, 77 insertions, 15 deletions

diff --git a/arch/s390/include/asm/uaccess.h b/arch/s390/include/asm/uaccess.h
index e0900ddf91dd..52d7c8709279 100644
--- a/arch/s390/include/asm/uaccess.h
+++ b/arch/s390/include/asm/uaccess.h
@@ -151,8 +151,65 @@ unsigned long __must_check __copy_to_user(void __user *to, const void *from,
 	__rc;							\
 })
 
-#define __put_user_fn(x, ptr, size) __put_get_user_asm(ptr, x, size, 0x810000UL)
-#define __get_user_fn(x, ptr, size) __put_get_user_asm(x, ptr, size, 0x81UL)
+static inline int __put_user_fn(void *x, void __user *ptr, unsigned long size)
+{
+	unsigned long spec = 0x810000UL;
+	int rc;
+
+	switch (size) {
+	case 1:
+		rc = __put_get_user_asm((unsigned char __user *)ptr,
+					(unsigned char *)x,
+					size, spec);
+		break;
+	case 2:
+		rc = __put_get_user_asm((unsigned short __user *)ptr,
+					(unsigned short *)x,
+					size, spec);
+		break;
+	case 4:
+		rc = __put_get_user_asm((unsigned int __user *)ptr,
+					(unsigned int *)x,
+					size, spec);
+		break;
+	case 8:
+		rc = __put_get_user_asm((unsigned long __user *)ptr,
+					(unsigned long *)x,
+					size, spec);
+		break;
+	};
+	return rc;
+}
+
+static inline int __get_user_fn(void *x, const void __user *ptr, unsigned long size)
+{
+	unsigned long spec = 0x81UL;
+	int rc;
+
+	switch (size) {
+	case 1:
+		rc = __put_get_user_asm((unsigned char *)x,
+					(unsigned char __user *)ptr,
+					size, spec);
+		break;
+	case 2:
+		rc = __put_get_user_asm((unsigned short *)x,
+					(unsigned short __user *)ptr,
+					size, spec);
+		break;
+	case 4:
+		rc = __put_get_user_asm((unsigned int *)x,
+					(unsigned int __user *)ptr,
+					size, spec);
+		break;
+	case 8:
+		rc = __put_get_user_asm((unsigned long *)x,
+					(unsigned long __user *)ptr,
+					size, spec);
+		break;
+	};
+	return rc;
+}
 
 #else /* CONFIG_HAVE_MARCH_Z10_FEATURES */
 
@@ -191,7 +248,7 @@ static inline int __get_user_fn(void *x, const void __user *ptr, unsigned long s
 		__put_user_bad();				\
 		break;						\
 	 }							\
-	__pu_err;						\
+	__builtin_expect(__pu_err, 0);				\
 })
 
 #define put_user(x, ptr)					\
@@ -209,28 +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;	\
@@ -240,7 +297,7 @@ int __put_user_bad(void) __attribute__((noreturn));
 		__get_user_bad();				\
 		break;						\
 	}							\
-	__gu_err;						\
+	__builtin_expect(__gu_err, 0);				\
 })
 
 #define get_user(x, ptr)					\
@@ -254,6 +311,14 @@ int __get_user_bad(void) __attribute__((noreturn));
 #define __put_user_unaligned __put_user
 #define __get_user_unaligned __get_user
 
+extern void __compiletime_error("usercopy buffer size is too small")
+__bad_copy_user(void);
+
+static inline void copy_user_overflow(int size, unsigned long count)
+{
+	WARN(1, "Buffer overflow detected (%d < %lu)!\n", size, count);
+}
+
 /**
  * copy_to_user: - Copy a block of data into user space.
  * @to:   Destination address, in user space.
@@ -275,12 +340,6 @@ copy_to_user(void __user *to, const void *from, unsigned long n)
 	return __copy_to_user(to, from, n);
 }
 
-void copy_from_user_overflow(void)
-#ifdef CONFIG_DEBUG_STRICT_USER_COPY_CHECKS
-__compiletime_warning("copy_from_user() buffer size is not provably correct")
-#endif
-;
-
 /**
  * copy_from_user: - Copy a block of data from user space.
  * @to:   Destination address, in kernel space.
@@ -305,7 +364,10 @@ copy_from_user(void *to, const void __user *from, unsigned long n)
 
 	might_fault();
 	if (unlikely(sz != -1 && sz < n)) {
-		copy_from_user_overflow();
+		if (!__builtin_constant_p(n))
+			copy_user_overflow(sz, n);
+		else
+			__bad_copy_user();
 		return n;
 	}
 	return __copy_from_user(to, from, n);