From mboxrd@z Thu Jan 1 00:00:00 1970 From: Yoshinori Sato Subject: [PATCH v5] asm-generic: {get,put}_user ptr argument evaluate only 1 time Date: Fri, 24 Jul 2015 02:55:20 +0900 Message-ID: <1437674120-10746-1-git-send-email-ysato@users.sourceforge.jp> References: <1437023722-7432-1-git-send-email-ysato@users.sourceforge.jp> Return-path: Received: from mail2.asahi-net.or.jp ([202.224.39.198]:63603 "EHLO mail2.asahi-net.or.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752721AbbGWRzZ (ORCPT ); Thu, 23 Jul 2015 13:55:25 -0400 In-Reply-To: <1437023722-7432-1-git-send-email-ysato@users.sourceforge.jp> Sender: linux-arch-owner@vger.kernel.org List-ID: To: Arnd Bergmann Cc: Yoshinori Sato , linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org Current implemantation ptr argument evaluate 2 times. It'll be an unexpected result. Changes v5: Remove unnecessary const. Changes v4: Temporary pointer type change to const void* Changes v3: Some build error fix. Changes v2: Argument x protect. Signed-off-by: Yoshinori Sato --- include/asm-generic/uaccess.h | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) diff --git a/include/asm-generic/uaccess.h b/include/asm-generic/uaccess.h index 72d8803..1bfa602 100644 --- a/include/asm-generic/uaccess.h +++ b/include/asm-generic/uaccess.h @@ -163,9 +163,10 @@ static inline __must_check long __copy_to_user(void __user *to, #define put_user(x, ptr) \ ({ \ + void *__p = (ptr); \ might_fault(); \ - access_ok(VERIFY_WRITE, ptr, sizeof(*ptr)) ? \ - __put_user(x, ptr) : \ + access_ok(VERIFY_WRITE, __p, sizeof(*ptr)) ? \ + __put_user((x), ((__typeof__(*(ptr)) *)__p)) : \ -EFAULT; \ }) @@ -225,9 +226,10 @@ extern int __put_user_bad(void) __attribute__((noreturn)); #define get_user(x, ptr) \ ({ \ + const void *__p = (ptr); \ might_fault(); \ - access_ok(VERIFY_READ, ptr, sizeof(*ptr)) ? \ - __get_user(x, ptr) : \ + access_ok(VERIFY_READ, __p, sizeof(*ptr)) ? \ + __get_user((x), (__typeof__(*(ptr)) *)__p) : \ -EFAULT; \ }) -- 2.1.4