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>
This commit is contained in:
GuanXuetao 2011-01-15 18:08:09 +08:00
parent 38f5bf84bd
commit 7f509a9ef7

View File

@ -288,14 +288,16 @@ strncpy_from_user(char *dst, const char __user *src, long count)
*
* 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)
{