From nobody Mon Sep 15 04:18:44 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 342F5C54EBE for ; Mon, 16 Jan 2023 11:59:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230211AbjAPL7O (ORCPT ); Mon, 16 Jan 2023 06:59:14 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41336 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230325AbjAPL7A (ORCPT ); Mon, 16 Jan 2023 06:59:00 -0500 Received: from szxga02-in.huawei.com (szxga02-in.huawei.com [45.249.212.188]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5753A19684 for ; Mon, 16 Jan 2023 03:58:58 -0800 (PST) Received: from dggpemm500014.china.huawei.com (unknown [172.30.72.56]) by szxga02-in.huawei.com (SkyGuard) with ESMTP id 4NwVr24brBzRrlv; Mon, 16 Jan 2023 19:57:06 +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; Mon, 16 Jan 2023 19:58:55 +0800 From: Wupeng Ma To: CC: , , , , Subject: [PATCH v2 1/4] mm/mlock: return EINVAL if len overflows for mlock/munlock Date: Mon, 16 Jan 2023 19:58:10 +0800 Message-ID: <20230116115813.2956935-2-mawupeng1@huawei.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20230116115813.2956935-1-mawupeng1@huawei.com> References: <20230116115813.2956935-1-mawupeng1@huawei.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Originating-IP: [10.175.112.125] X-ClientProxiedBy: dggems703-chm.china.huawei.com (10.3.19.180) 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. Signed-off-by: Ma Wupeng --- mm/mlock.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/mm/mlock.c b/mm/mlock.c index 7032f6dd0ce1..5a4e767feb28 100644 --- a/mm/mlock.c +++ b/mm/mlock.c @@ -569,6 +569,7 @@ static __must_check int do_mlock(unsigned long start, s= ize_t len, vm_flags_t fla unsigned long locked; unsigned long lock_limit; int error =3D -ENOMEM; + size_t old_len =3D len; =20 start =3D untagged_addr(start); =20 @@ -578,6 +579,9 @@ static __must_check int do_mlock(unsigned long start, s= ize_t len, vm_flags_t fla len =3D PAGE_ALIGN(len + (offset_in_page(start))); start &=3D PAGE_MASK; =20 + if (old_len !=3D 0 && len =3D=3D 0) + return -EINVAL; + lock_limit =3D rlimit(RLIMIT_MEMLOCK); lock_limit >>=3D PAGE_SHIFT; locked =3D len >> PAGE_SHIFT; @@ -632,12 +636,16 @@ SYSCALL_DEFINE3(mlock2, unsigned long, start, size_t,= len, int, flags) SYSCALL_DEFINE2(munlock, unsigned long, start, size_t, len) { int ret; + size_t old_len =3D len; =20 start =3D untagged_addr(start); =20 len =3D PAGE_ALIGN(len + (offset_in_page(start))); start &=3D PAGE_MASK; =20 + if (old_len !=3D 0 && len =3D=3D 0) + return -EINVAL; + if (mmap_write_lock_killable(current->mm)) return -EINTR; ret =3D apply_vma_lock_flags(start, len, 0); --=20 2.25.1