Commit 9844813f authored Jun 14, 2009 by Mike Frysinger Committed by Arnd Bergmann Jun 19, 2009

asm-generic: uaccess: add missing access_ok() check to strnlen_user()



The strnlen_user() function was missing a access_ok() check on the pointer
given.  We've had cases on Blackfin systems where test programs caused
kernel crashes here because userspace passed up a NULL/-1 pointer and the
kernel gladly attempted to run strlen() on it.

Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

parent 0732f877

include/asm-generic/uaccess.h

+2 −0

Original line number	Diff line number	Diff line
		@@ -291,6 +291,8 @@ strncpy_from_user(char dst, const char __user src, long count)
		#ifndef strnlen_user
		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;
		}
		#endif