Path: csiph.com!1.us.feeder.erje.net!feeder.erje.net!2.eu.feeder.erje.net!news2.arglkargh.de!news.mixmin.net!aioe.org!bofh.it!news.nic.it!robomod From: Greg Kroah-Hartman Newsgroups: linux.kernel Subject: [PATCH 4.4 101/118] frv: fix clear_user() Date: Thu, 22 Sep 2016 19:40:02 +0200 Message-ID: References: X-Mailer: git-send-email 2.10.0 User-Agent: quilt/0.64 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: robomod@news.nic.it List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Approved: robomod@news.nic.it Lines: 49 Organization: linux.* mail to news gateway X-Original-Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Al Viro X-Original-Date: Thu, 22 Sep 2016 19:30:01 +0200 X-Original-Message-ID: <20160922172943.693062392@linuxfoundation.org> X-Original-References: <20160922172938.643879685@linuxfoundation.org> X-Original-Sender: linux-kernel-owner@vger.kernel.org Xref: csiph.com linux.kernel:1489126 4.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Al Viro commit 3b8767a8f00cc6538ba6b1cf0f88502e2fd2eb90 upstream. It should check access_ok(). Otherwise a bunch of places turn into trivially exploitable rootholes. Signed-off-by: Al Viro Signed-off-by: Greg Kroah-Hartman --- arch/frv/include/asm/uaccess.h | 12 +++++++++--- 1 file changed, 9 insertions(+), 3 deletions(-) --- a/arch/frv/include/asm/uaccess.h +++ b/arch/frv/include/asm/uaccess.h @@ -263,19 +263,25 @@ do { \ extern long __memset_user(void *dst, unsigned long count); extern long __memcpy_user(void *dst, const void *src, unsigned long count); -#define clear_user(dst,count) __memset_user(____force(dst), (count)) +#define __clear_user(dst,count) __memset_user(____force(dst), (count)) #define __copy_from_user_inatomic(to, from, n) __memcpy_user((to), ____force(from), (n)) #define __copy_to_user_inatomic(to, from, n) __memcpy_user(____force(to), (from), (n)) #else -#define clear_user(dst,count) (memset(____force(dst), 0, (count)), 0) +#define __clear_user(dst,count) (memset(____force(dst), 0, (count)), 0) #define __copy_from_user_inatomic(to, from, n) (memcpy((to), ____force(from), (n)), 0) #define __copy_to_user_inatomic(to, from, n) (memcpy(____force(to), (from), (n)), 0) #endif -#define __clear_user clear_user +static inline unsigned long __must_check +clear_user(void __user *to, unsigned long n) +{ + if (likely(__access_ok(to, n))) + n = __clear_user(to, n); + return n; +} static inline unsigned long __must_check __copy_to_user(void __user *to, const void *from, unsigned long n)