* [PATCH] asm-generic headers: add arch-specific __strnlen_user calling in uaccess.h
@ 2011-01-11 8:07 Guan Xuetao
2011-01-11 15:49 ` Arnd Bergmann
0 siblings, 1 reply; 2+ messages in thread
From: Guan Xuetao @ 2011-01-11 8:07 UTC (permalink / raw)
To: Arnd Bergmann, linux-arch, linux-kernel
From: Guan Xuetao <guanxuetao@mprc.pku.edu.cn>
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 <guanxuetao@mprc.pku.edu.cn>
---
include/asm-generic/uaccess.h | 8 +++++---
1 files changed, 5 insertions(+), 3 deletions(-)
diff --git a/include/asm-generic/uaccess.h b/include/asm-generic/uaccess.h
index b218b85..ac68c99 100644
--- a/include/asm-generic/uaccess.h
+++ b/include/asm-generic/uaccess.h
@@ -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)
{
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH] asm-generic headers: add arch-specific __strnlen_user calling in uaccess.h
2011-01-11 8:07 [PATCH] asm-generic headers: add arch-specific __strnlen_user calling in uaccess.h Guan Xuetao
@ 2011-01-11 15:49 ` Arnd Bergmann
0 siblings, 0 replies; 2+ messages in thread
From: Arnd Bergmann @ 2011-01-11 15:49 UTC (permalink / raw)
To: Guan Xuetao; +Cc: linux-arch, linux-kernel
On Tuesday 11 January 2011, Guan Xuetao wrote:
> diff --git a/include/asm-generic/uaccess.h b/include/asm-generic/uaccess.h
> index b218b85..ac68c99 100644
> --- a/include/asm-generic/uaccess.h
> +++ b/include/asm-generic/uaccess.h
> @@ -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)
Yes, looks good. I believe no architecture currently uses the generic
uaccess.h file directly, so it's not surprising that you find problems
like this in it.
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
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