From patchwork Tue Nov 3 22:00:20 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Lokesh Gidra X-Patchwork-Id: 11879135 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id A10EF139F for ; Tue, 3 Nov 2020 22:01:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7A27A2242A for ; Tue, 3 Nov 2020 22:01:03 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="udaQgtvy" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730673AbgKCWBB (ORCPT ); Tue, 3 Nov 2020 17:01:01 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33240 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730603AbgKCWAz (ORCPT ); Tue, 3 Nov 2020 17:00:55 -0500 Received: from mail-pl1-x64a.google.com (mail-pl1-x64a.google.com [IPv6:2607:f8b0:4864:20::64a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 73A38C061A4E for ; Tue, 3 Nov 2020 14:00:53 -0800 (PST) Received: by mail-pl1-x64a.google.com with SMTP id k6so11425378pls.22 for ; Tue, 03 Nov 2020 14:00:53 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=sender:date:in-reply-to:message-id:mime-version:references:subject :from:to:cc; bh=5MfBywdxMmsLRrplRDwjfeuNu4Dz7M8KwUBLUxZj6xM=; b=udaQgtvyrunQ/CMzN8Xk1IupaOPWUZBksj6LPEJBbqUq0NnJlcBoPovdQ789qBRsN5 SJoma5dEVWU4sz/3ILN2w3Vk4tQD+DjTVUo3ut+k9a+xr5lty4GvEe+phRftibB0Wa/u gJAmkO3kpZHqBgu22n8ZJIGZ+QSxJ8qtc//1EWon96YmBC8zN1K2YIUtTEQ0NOZii1/+ OBtUDZL/qPbNFDV/nko3qMAArLcvK6oyiJxvehGhKW4ezFBdwrmtRYlBCcqKEMQHhaxP MN8n2VC22GpAWN1JERlZLWGzmhVq7rOuyrgD4kSMFO10RFq4rywPvgNYh+R7xhpK6C9A Jq4Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=5MfBywdxMmsLRrplRDwjfeuNu4Dz7M8KwUBLUxZj6xM=; b=LOf8KHnZ3ofekHmZaITqaKw6LNdZosmqTyqyAAOIV5AiFPro2uGNtEqRznJKphiIiT fGNXNusZnN4yqrrUCYl7fnnPidI65tS8+heW/Adz3qblRUxX1i6aK97b03PwgoiYaxRy aL/9Mf/ijNP+pq8eVvX9xO6024E/rP3G0CWGB/qN18s6+ej4rjsCWt8M5+icIJAKzU/j G4eByoHipz9CCoG/hgZ24NIXVTALPTwGOFoc9pBTWUoBphIZqda27yvX0u70GClBqayu yDl2HT0/LJRDfTvUO9nTPJeZxmQPSYAyRGMwEzRKh109ZjTYfilhGi4YOsM+O+PLcY1Z VB8Q== X-Gm-Message-State: AOAM530aZLLsCyS03mO+41bOF4X2w2D4lobxHJ4tHZro+qyTPnh8S211 eezkbJlycJYrRkTcpOVXejTPkcKnEYWmsyVxjw== X-Google-Smtp-Source: ABdhPJyAOAyaXh2xZzoHs7/ZBCmt8D42Q2k0vfbMoTbMpRBhGybVkxXxBcnAzulcfDtjqseSbtRBcpDsBFbYgvG5vQ== Sender: "lokeshgidra via sendgmr" X-Received: from lg.mtv.corp.google.com ([2620:15c:211:202:f693:9fff:fef4:29dd]) (user=lokeshgidra job=sendgmr) by 2002:a17:90a:678a:: with SMTP id o10mr1283056pjj.180.1604440852797; Tue, 03 Nov 2020 14:00:52 -0800 (PST) Date: Tue, 3 Nov 2020 14:00:20 -0800 In-Reply-To: <20201103220020.2399003-1-lokeshgidra@google.com> Message-Id: <20201103220020.2399003-4-lokeshgidra@google.com> Mime-Version: 1.0 References: <20201103220020.2399003-1-lokeshgidra@google.com> X-Mailer: git-send-email 2.29.1.341.ge80a0c044ae-goog Subject: [PATCH v10 3/3] Use secure anon inodes for userfaultfd From: Lokesh Gidra To: Andrea Arcangeli , Alexander Viro , James Morris , Stephen Smalley , Casey Schaufler , Eric Biggers Cc: "Serge E. Hallyn" , Paul Moore , Eric Paris , Lokesh Gidra , Daniel Colascione , Kees Cook , "Eric W. Biederman" , KP Singh , David Howells , Thomas Cedeno , Anders Roxell , Sami Tolvanen , Matthew Garrett , Aaron Goidel , Randy Dunlap , "Joel Fernandes (Google)" , YueHaibing , Christian Brauner , Alexei Starovoitov , Alexey Budankov , Adrian Reber , Aleksa Sarai , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-security-module@vger.kernel.org, selinux@vger.kernel.org, kaleshsingh@google.com, calin@google.com, surenb@google.com, nnk@google.com, jeffv@google.com, kernel-team@android.com, linux-mm@kvack.org, Daniel Colascione Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org From: Daniel Colascione This change gives userfaultfd file descriptors a real security context, allowing policy to act on them. Signed-off-by: Daniel Colascione [Remove owner inode from userfaultfd_ctx] [Use anon_inode_getfd_secure() instead of anon_inode_getfile_secure() in userfaultfd syscall] [Use inode of file in userfaultfd_read() in resolve_userfault_fork()] Signed-off-by: Lokesh Gidra --- fs/userfaultfd.c | 19 ++++++++++--------- 1 file changed, 10 insertions(+), 9 deletions(-) diff --git a/fs/userfaultfd.c b/fs/userfaultfd.c index 0e4a3837da52..918535b49475 100644 --- a/fs/userfaultfd.c +++ b/fs/userfaultfd.c @@ -978,14 +978,14 @@ static __poll_t userfaultfd_poll(struct file *file, poll_table *wait) static const struct file_operations userfaultfd_fops; -static int resolve_userfault_fork(struct userfaultfd_ctx *ctx, - struct userfaultfd_ctx *new, +static int resolve_userfault_fork(struct userfaultfd_ctx *new, + struct inode *inode, struct uffd_msg *msg) { int fd; - fd = anon_inode_getfd("[userfaultfd]", &userfaultfd_fops, new, - O_RDWR | (new->flags & UFFD_SHARED_FCNTL_FLAGS)); + fd = anon_inode_getfd_secure("[userfaultfd]", &userfaultfd_fops, new, + O_RDWR | (new->flags & UFFD_SHARED_FCNTL_FLAGS), inode); if (fd < 0) return fd; @@ -995,7 +995,7 @@ static int resolve_userfault_fork(struct userfaultfd_ctx *ctx, } static ssize_t userfaultfd_ctx_read(struct userfaultfd_ctx *ctx, int no_wait, - struct uffd_msg *msg) + struct uffd_msg *msg, struct inode *inode) { ssize_t ret; DECLARE_WAITQUEUE(wait, current); @@ -1106,7 +1106,7 @@ static ssize_t userfaultfd_ctx_read(struct userfaultfd_ctx *ctx, int no_wait, spin_unlock_irq(&ctx->fd_wqh.lock); if (!ret && msg->event == UFFD_EVENT_FORK) { - ret = resolve_userfault_fork(ctx, fork_nctx, msg); + ret = resolve_userfault_fork(fork_nctx, inode, msg); spin_lock_irq(&ctx->event_wqh.lock); if (!list_empty(&fork_event)) { /* @@ -1166,6 +1166,7 @@ static ssize_t userfaultfd_read(struct file *file, char __user *buf, ssize_t _ret, ret = 0; struct uffd_msg msg; int no_wait = file->f_flags & O_NONBLOCK; + struct inode *inode = file_inode(file); if (ctx->state == UFFD_STATE_WAIT_API) return -EINVAL; @@ -1173,7 +1174,7 @@ static ssize_t userfaultfd_read(struct file *file, char __user *buf, for (;;) { if (count < sizeof(msg)) return ret ? ret : -EINVAL; - _ret = userfaultfd_ctx_read(ctx, no_wait, &msg); + _ret = userfaultfd_ctx_read(ctx, no_wait, &msg, inode); if (_ret < 0) return ret ? ret : _ret; if (copy_to_user((__u64 __user *) buf, &msg, sizeof(msg))) @@ -1995,8 +1996,8 @@ SYSCALL_DEFINE1(userfaultfd, int, flags) /* prevent the mm struct to be freed */ mmgrab(ctx->mm); - fd = anon_inode_getfd("[userfaultfd]", &userfaultfd_fops, ctx, - O_RDWR | (flags & UFFD_SHARED_FCNTL_FLAGS)); + fd = anon_inode_getfd_secure("[userfaultfd]", &userfaultfd_fops, ctx, + O_RDWR | (flags & UFFD_SHARED_FCNTL_FLAGS), NULL); if (fd < 0) { mmdrop(ctx->mm); kmem_cache_free(userfaultfd_ctx_cachep, ctx);