asm-generic headers: add arch-specific __strnlen_user calling in uaccess.h

This patch changes the implementation of strnlen_user in include/asm-generic/uaccess.h. Originally, it calls strlen() function directly, which may not correctly handle the access of user space in most mmu-enabled architectures. New __strnlen_user is added for using as an architecture specific function. Signed-off-by: Guan Xuetao <gxt@mprc.pku.edu.cn> Reviewed-by: Arnd Bergmann <arnd@arndb.de>

asm-generic headers: add arch-specific __strnlen_user calling in uaccess.h
This patch changes the implementation of strnlen_user in include/asm-generic/uaccess.h. Originally, it calls strlen() function directly, which may not correctly handle the access of user space in most mmu-enabled architectures. New __strnlen_user is added for using as an architecture specific function. Signed-off-by: Guan Xuetao <gxt@mprc.pku.edu.cn> Reviewed-by: Arnd Bergmann <arnd@arndb.de>
GuanXuetao
1 parent 38f5bf84bd
Showing 1 changed file with 5 additions and 3 deletions Side-by-side Diff
include/asm-generic/uaccess.h
@@ -288,14 +288,16 @@
  *
  * Return 0 on exception, a value greater than N if too long
  */
-#ifndef strnlen_user
+#ifndef __strnlen_user
+#define __strnlen_user strnlen
+#endif
+
 static inline long strnlen_user(const char __user *src, long n)
 {
 	if (!access_ok(VERIFY_READ, src, 1))
 		return 0;
-	return strlen((void * __force)src) + 1;
+	return __strnlen_user(src, n);
 }
-#endif
  
 static inline long strlen_user(const char __user *src)
 {
...	...	@@ -288,14 +288,16 @@
288	288	*
289	289	* Return 0 on exception, a value greater than N if too long
290	290	*/
291		-#ifndef strnlen_user
	291	+#ifndef __strnlen_user
	292	+#define __strnlen_user strnlen
	293	+#endif
	294	+
292	295	static inline long strnlen_user(const char __user *src, long n)
293	296	{
294	297	if (!access_ok(VERIFY_READ, src, 1))
295	298	return 0;
296		- return strlen((void * __force)src) + 1;
	299	+ return __strnlen_user(src, n);
297	300	}
298		-#endif
299	301
300	302	static inline long strlen_user(const char __user *src)
301	303	{