From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 78F0CC433DB for ; Mon, 1 Mar 2021 12:33:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3828A64E75 for ; Mon, 1 Mar 2021 12:33:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235040AbhCAMdr (ORCPT ); Mon, 1 Mar 2021 07:33:47 -0500 Received: from mail-m121143.qiye.163.com ([115.236.121.143]:56674 "EHLO mail-m121143.qiye.163.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233519AbhCAMdn (ORCPT ); Mon, 1 Mar 2021 07:33:43 -0500 Received: from vivo-HP-ProDesk-680-G4-PCI-MT.vivo.xyz (unknown [58.250.176.228]) by mail-m121143.qiye.163.com (Hmail) with ESMTPA id 670E2540212; Mon, 1 Mar 2021 20:32:53 +0800 (CST) From: Wang Qing To: Andrew Morton , linux-mm@kvack.org, linux-kernel@vger.kernel.org Cc: Wang Qing Subject: [PATCH] mm: Return -EFAULT if copy_to_user() fails Date: Mon, 1 Mar 2021 20:32:43 +0800 Message-Id: <1614601963-25812-1-git-send-email-wangqing@vivo.com> X-Mailer: git-send-email 2.7.4 X-HM-Spam-Status: e1kfGhgUHx5ZQUtXWQgYFAkeWUFZS1VLWVdZKFlBSE83V1ktWUFJV1kPCR oVCBIfWUFZT0pPSk9JGB1ITk5CVkpNSk9NS0pCTEhNTktVEwETFhoSFyQUDg9ZV1kWGg8SFR0UWU FZT0tIVUpKS0hNSlVLWQY+ X-HM-Sender-Digest: e1kMHhlZQR0aFwgeV1kSHx4VD1lBWUc6Ohw6ASo*LT8LDxAOHkooAgg6 LjBPCwJVSlVKTUpPTUtKQkxIQk1LVTMWGhIXVQwaFRwKEhUcOw0SDRRVGBQWRVlXWRILWUFZTkNV SU5LVUpMTVVJSUNZV1kIAVlBSk5JSTcG X-HM-Tid: 0a77edc6ef41b038kuuu670e2540212 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The copy_to_user() function returns the number of bytes remaining to be copied, but we want to return -EFAULT if the copy doesn't complete. Signed-off-by: Wang Qing --- mm/mempolicy.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/mm/mempolicy.c b/mm/mempolicy.c index ab51132..a116e56 --- a/mm/mempolicy.c +++ b/mm/mempolicy.c @@ -1667,7 +1667,7 @@ COMPAT_SYSCALL_DEFINE5(get_mempolicy, int __user *, policy, if (!err && nmask) { unsigned long copy_size; copy_size = min_t(unsigned long, sizeof(bm), alloc_size); - err = copy_from_user(bm, nm, copy_size); + err = copy_from_user(bm, nm, copy_size) ? -EFAULT : 0; /* ensure entire bitmap is zeroed */ err |= clear_user(nmask, ALIGN(maxnode-1, 8) / 8); err |= compat_put_bitmap(nmask, bm, nr_bits); -- 2.7.4