From nobody Mon Feb 9 06:01:44 2026 Delivered-To: importer@patchew.org Authentication-Results: mx.zohomail.com; dkim=fail header.i=@intel.com; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=fail(p=none dis=none) header.from=linux.intel.com Return-Path: Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) by mx.zohomail.com with SMTPS id 1640099687528683.1574782533519; Tue, 21 Dec 2021 07:14:47 -0800 (PST) Received: from localhost ([::1]:43080 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1mzgqj-0001MO-QT for importer@patchew.org; Tue, 21 Dec 2021 10:14:45 -0500 Received: from eggs.gnu.org ([209.51.188.92]:45858) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mzgoY-0006zK-60 for qemu-devel@nongnu.org; Tue, 21 Dec 2021 10:12:30 -0500 Received: from mga04.intel.com ([192.55.52.120]:9690) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mzgoV-00088g-S5 for qemu-devel@nongnu.org; Tue, 21 Dec 2021 10:12:29 -0500 Received: from orsmga005.jf.intel.com ([10.7.209.41]) by fmsmga104.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 21 Dec 2021 07:12:26 -0800 Received: from chaop.bj.intel.com ([10.240.192.101]) by orsmga005.jf.intel.com with ESMTP; 21 Dec 2021 07:12:18 -0800 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1640099547; x=1671635547; h=from:to:cc:subject:date:message-id:in-reply-to: references; bh=L6zzX+w0dRm95JSP/7w36iYjjnEIWuQgAZ4mQ5a+0Og=; b=JNZzOxZDn5BOErikjA17Z4f+kVuaFVY+4AjewaNPaE26vdx0bUisUsNc B/c7dGmJ5K2Wn1SoDxS/RdztC7z5017eh2phHbF3kR9uauj/8ICT610mn qKJfRvGhCtF8W7a8FLAVfPC53byrJsBGU5ayV6kVrvH/3ulKcwqEI3gq8 i6IvulFxcoiDo2d1aRBaaWAn6+MGlAci4MTMs1+EOl+MKwmaCoxhRBInr +msFYy0NjbtLBxRVUTNfzLvxrxsoFFtai0QFSaPdVU7VhDZHAiXl0YIne GXemhPlVvv3EupWsJdAkfSAakPc3ATIr3xU0LJVG7uTAXZj+ayqtIlruk g==; X-IronPort-AV: E=McAfee;i="6200,9189,10204"; a="239157579" X-IronPort-AV: E=Sophos;i="5.88,223,1635231600"; d="scan'208";a="239157579" X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.88,223,1635231600"; d="scan'208";a="684688307" From: Chao Peng To: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, qemu-devel@nongnu.org Subject: [PATCH v3 02/15] mm/memfd: Introduce MFD_INACCESSIBLE flag Date: Tue, 21 Dec 2021 23:11:12 +0800 Message-Id: <20211221151125.19446-3-chao.p.peng@linux.intel.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20211221151125.19446-1-chao.p.peng@linux.intel.com> References: <20211221151125.19446-1-chao.p.peng@linux.intel.com> Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Received-SPF: none client-ip=192.55.52.120; envelope-from=chao.p.peng@linux.intel.com; helo=mga04.intel.com X-Spam_score_int: -44 X-Spam_score: -4.5 X-Spam_bar: ---- X-Spam_report: (-4.5 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.203, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_MED=-2.3, RCVD_IN_MSPIKE_H2=-0.001, SPF_HELO_NONE=0.001, SPF_NONE=0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Wanpeng Li , jun.nakajima@intel.com, david@redhat.com, "J . Bruce Fields" , dave.hansen@intel.com, "H . Peter Anvin" , Chao Peng , ak@linux.intel.com, Jonathan Corbet , Joerg Roedel , x86@kernel.org, Hugh Dickins , Ingo Molnar , Borislav Petkov , luto@kernel.org, Thomas Gleixner , Vitaly Kuznetsov , Jim Mattson , Sean Christopherson , susie.li@intel.com, Jeff Layton , john.ji@intel.com, Yu Zhang , Paolo Bonzini , Andrew Morton , "Kirill A . Shutemov" Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail-DKIM: fail (Header signature does not verify) X-ZM-MESSAGEID: 1640099688795100001 Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Introduce a new memfd_create() flag indicating the content of the created memfd is inaccessible from userspace. It does this by force setting F_SEAL_INACCESSIBLE seal when the file is created. It also set F_SEAL_SEAL to prevent future sealing, which means, it can not coexist with MFD_ALLOW_SEALING. Signed-off-by: Chao Peng --- include/uapi/linux/memfd.h | 1 + mm/memfd.c | 12 +++++++++++- 2 files changed, 12 insertions(+), 1 deletion(-) diff --git a/include/uapi/linux/memfd.h b/include/uapi/linux/memfd.h index 7a8a26751c23..48750474b904 100644 --- a/include/uapi/linux/memfd.h +++ b/include/uapi/linux/memfd.h @@ -8,6 +8,7 @@ #define MFD_CLOEXEC 0x0001U #define MFD_ALLOW_SEALING 0x0002U #define MFD_HUGETLB 0x0004U +#define MFD_INACCESSIBLE 0x0008U =20 /* * Huge page size encoding when MFD_HUGETLB is specified, and a huge page diff --git a/mm/memfd.c b/mm/memfd.c index 9f80f162791a..c898a007fb76 100644 --- a/mm/memfd.c +++ b/mm/memfd.c @@ -245,7 +245,8 @@ long memfd_fcntl(struct file *file, unsigned int cmd, u= nsigned long arg) #define MFD_NAME_PREFIX_LEN (sizeof(MFD_NAME_PREFIX) - 1) #define MFD_NAME_MAX_LEN (NAME_MAX - MFD_NAME_PREFIX_LEN) =20 -#define MFD_ALL_FLAGS (MFD_CLOEXEC | MFD_ALLOW_SEALING | MFD_HUGETLB) +#define MFD_ALL_FLAGS (MFD_CLOEXEC | MFD_ALLOW_SEALING | MFD_HUGETLB | \ + MFD_INACCESSIBLE) =20 SYSCALL_DEFINE2(memfd_create, const char __user *, uname, @@ -267,6 +268,10 @@ SYSCALL_DEFINE2(memfd_create, return -EINVAL; } =20 + /* Disallow sealing when MFD_INACCESSIBLE is set. */ + if (flags & MFD_INACCESSIBLE && flags & MFD_ALLOW_SEALING) + return -EINVAL; + /* length includes terminating zero */ len =3D strnlen_user(uname, MFD_NAME_MAX_LEN + 1); if (len <=3D 0) @@ -315,6 +320,11 @@ SYSCALL_DEFINE2(memfd_create, *file_seals &=3D ~F_SEAL_SEAL; } =20 + if (flags & MFD_INACCESSIBLE) { + file_seals =3D memfd_file_seals_ptr(file); + *file_seals &=3D F_SEAL_SEAL | F_SEAL_INACCESSIBLE; + } + fd_install(fd, file); kfree(name); return fd; --=20 2.17.1