From patchwork Fri Jan 8 22:22:23 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Lokesh Gidra X-Patchwork-Id: 12007693 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=-26.6 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT,USER_IN_DEF_DKIM_WL autolearn=unavailable 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 D2A13C43331 for ; Fri, 8 Jan 2021 22:24:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A2E5423A74 for ; Fri, 8 Jan 2021 22:24:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726620AbhAHWXz (ORCPT ); Fri, 8 Jan 2021 17:23:55 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44136 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725844AbhAHWXx (ORCPT ); Fri, 8 Jan 2021 17:23:53 -0500 Received: from mail-qv1-xf4a.google.com (mail-qv1-xf4a.google.com [IPv6:2607:f8b0:4864:20::f4a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8C43EC061757 for ; Fri, 8 Jan 2021 14:22:34 -0800 (PST) Received: by mail-qv1-xf4a.google.com with SMTP id t18so9240984qva.6 for ; Fri, 08 Jan 2021 14:22:34 -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=Cge7zJHdUeDRqJYsTUJX6Q9Nj8WIU/VuWZZ/mr14Zmg=; b=v+yhPZ9NrwpjtqFQ7CSlkBzImFQFcSd4kKZnF9rH26V1lt8Qg5cxRh9hRixcXcfRMw 0Lf4CGMVNWArdhaWV7eqSVrmfWNHHTG2GqQUTUsKER8HcbWrgI4EsRu5u2xMbMBOLdZG enbMJD0O3lLJC5+hBXKZ8fQwnsqWrrT2xzKwjSR7ktKRt3ZgfCjPaIhCFd40+Q/Q1AXX duBQJXo4lJu5e1RWyxAFuv8sOpAPa3wlcLbISobyv2qg71lRq319UEt7shp1nVAZunCT B4okVewDiZl6jt55qYk8Q7SKQwfY2JZURmXUoti7gE+lMfdtRPy3fxppwAJ6HgysnKOH 2xPw== 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=Cge7zJHdUeDRqJYsTUJX6Q9Nj8WIU/VuWZZ/mr14Zmg=; b=bmzk9viqEFZnIDoqm7YWaEkGMbqPsnrudEijjiHnpwPFTBXctNjXCHx/tKHkiYDn5D hspdmN/9i58MnI2aEHeQY7m5zvjzemLdEww7GkJkxoX6RKvO2plpQYNQB9bzB+jp0nQj 6yslCJBxio15TgvcAlcx2SezHAwFltbFk/VTn7N3QrU8z4em9VVsaIrl4/CNOpBMeooh XfCp7iFT4bGQcVNx1fWXtjRh48jJDX0upfTmnaJe8U1ax0z3x/65UzKF8RF/kIz7Hxim yWQqMeTXxyA6Pzvr0DSua0PrcrsFjcRbE/uTZunB2XUNxtaREu3Js7dcTmrREI+FMagn TJaA== X-Gm-Message-State: AOAM532Efb9oF4ITJnj2G62bDOHtToWRntZADs21tT5ToIa5KyF5O919 dkT/ph7MbReUqJc8zUcD2RG4WQGSf3rfjs4drw== X-Google-Smtp-Source: ABdhPJxrcozKHrR0xcQ3FM8Iv9GH5ysTauNVEag5mDoPrcF3rxvRgJusdDawbqRfPuHDtVtP8Oko7A7c/uJcaebjSA== 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:a05:6214:13e2:: with SMTP id ch2mr5888288qvb.57.1610144553679; Fri, 08 Jan 2021 14:22:33 -0800 (PST) Date: Fri, 8 Jan 2021 14:22:23 -0800 In-Reply-To: <20210108222223.952458-1-lokeshgidra@google.com> Message-Id: <20210108222223.952458-5-lokeshgidra@google.com> Mime-Version: 1.0 References: <20210108222223.952458-1-lokeshgidra@google.com> X-Mailer: git-send-email 2.30.0.284.gd98b1dd5eaa7-goog Subject: [PATCH v15 4/4] userfaultfd: use secure anon inodes for userfaultfd From: Lokesh Gidra To: Andrea Arcangeli , Alexander Viro , James Morris , Stephen Smalley , Casey Schaufler , Eric Biggers , Paul Moore Cc: "Serge E. Hallyn" , Eric Paris , Lokesh Gidra , Daniel Colascione , Kees Cook , "Eric W. Biederman" , KP Singh , David Howells , Anders Roxell , Sami Tolvanen , Matthew Garrett , Randy Dunlap , "Joel Fernandes (Google)" , YueHaibing , Christian Brauner , Alexei Starovoitov , 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, jeffv@google.com, kernel-team@android.com, linux-mm@kvack.org, Andrew Morton , hch@infradead.org 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 [LG: Remove owner inode from userfaultfd_ctx] [LG: Use anon_inode_getfd_secure() instead of anon_inode_getfile_secure() in userfaultfd syscall] [LG: Use inode of file in userfaultfd_read() in resolve_userfault_fork()] Signed-off-by: Lokesh Gidra Reviewed-by: Eric Biggers --- fs/userfaultfd.c | 19 ++++++++++--------- 1 file changed, 10 insertions(+), 9 deletions(-) diff --git a/fs/userfaultfd.c b/fs/userfaultfd.c index 894cc28142e7..0be8cdd4425a 100644 --- a/fs/userfaultfd.c +++ b/fs/userfaultfd.c @@ -979,14 +979,14 @@ 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; @@ -996,7 +996,7 @@ 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); @@ -1107,7 +1107,7 @@ 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)) { /* @@ -1167,6 +1167,7 @@ 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; @@ -1174,7 +1175,7 @@ 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))) @@ -1999,8 +2000,8 @@ 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);