From nobody Sun Sep 14 01:59:22 2025 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id A7139C636BD for ; Sat, 28 Jan 2023 06:32:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231407AbjA1Gcr (ORCPT ); Sat, 28 Jan 2023 01:32:47 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37892 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229530AbjA1Gcn (ORCPT ); Sat, 28 Jan 2023 01:32:43 -0500 Received: from szxga02-in.huawei.com (szxga02-in.huawei.com [45.249.212.188]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5D1C8166FA for ; Fri, 27 Jan 2023 22:32:41 -0800 (PST) Received: from dggpemm500014.china.huawei.com (unknown [172.30.72.55]) by szxga02-in.huawei.com (SkyGuard) with ESMTP id 4P3l1g6WJNzRrCW; Sat, 28 Jan 2023 14:30:31 +0800 (CST) Received: from localhost.localdomain (10.175.112.125) by dggpemm500014.china.huawei.com (7.185.36.153) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.34; Sat, 28 Jan 2023 14:32:38 +0800 From: Wupeng Ma To: CC: , , , , Subject: [PATCH v3 1/4] mm/mlock: return EINVAL if len overflows for mlock/munlock Date: Sat, 28 Jan 2023 14:32:26 +0800 Message-ID: <20230128063229.989058-2-mawupeng1@huawei.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20230128063229.989058-1-mawupeng1@huawei.com> References: <20230128063229.989058-1-mawupeng1@huawei.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Originating-IP: [10.175.112.125] X-ClientProxiedBy: dggems702-chm.china.huawei.com (10.3.19.179) To dggpemm500014.china.huawei.com (7.185.36.153) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" From: Ma Wupeng While testing mlock, we have a problem if the len of mlock is ULONG_MAX. The return value of mlock is zero. But nothing will be locked since the len in do_mlock overflows to zero due to the following code in mlock: len =3D PAGE_ALIGN(len + (offset_in_page(start))); The same problem happens in munlock. Add new check and return -EINVAL to fix this overflowing scenarios since they are absolutely wrong. Return 0 early to avoid burn a bunch of cpu cycles if len =3D=3D 0. Signed-off-by: Ma Wupeng --- mm/mlock.c | 14 ++++++++++++-- 1 file changed, 12 insertions(+), 2 deletions(-) diff --git a/mm/mlock.c b/mm/mlock.c index 7032f6dd0ce1..eb09968ba27f 100644 --- a/mm/mlock.c +++ b/mm/mlock.c @@ -478,8 +478,6 @@ static int apply_vma_lock_flags(unsigned long start, si= ze_t len, end =3D start + len; if (end < start) return -EINVAL; - if (end =3D=3D start) - return 0; vma =3D mas_walk(&mas); if (!vma) return -ENOMEM; @@ -575,7 +573,13 @@ static __must_check int do_mlock(unsigned long start, = size_t len, vm_flags_t fla if (!can_do_mlock()) return -EPERM; =20 + if (!len) + return 0; + len =3D PAGE_ALIGN(len + (offset_in_page(start))); + if (!len) + return -EINVAL; + start &=3D PAGE_MASK; =20 lock_limit =3D rlimit(RLIMIT_MEMLOCK); @@ -635,7 +639,13 @@ SYSCALL_DEFINE2(munlock, unsigned long, start, size_t,= len) =20 start =3D untagged_addr(start); =20 + if (!len) + return 0; + len =3D PAGE_ALIGN(len + (offset_in_page(start))); + if (!len) + return -EINVAL; + start &=3D PAGE_MASK; =20 if (mmap_write_lock_killable(current->mm)) --=20 2.25.1