From patchwork Wed Sep 23 19:33:24 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Lokesh Gidra X-Patchwork-Id: 11795597 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 C4F5B6CA for ; Wed, 23 Sep 2020 19:33:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9DD97221EF for ; Wed, 23 Sep 2020 19:33:53 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="nH3WHumR" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726722AbgIWTdt (ORCPT ); Wed, 23 Sep 2020 15:33:49 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52288 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726699AbgIWTdi (ORCPT ); Wed, 23 Sep 2020 15:33:38 -0400 Received: from mail-yb1-xb49.google.com (mail-yb1-xb49.google.com [IPv6:2607:f8b0:4864:20::b49]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 82E92C0613D2 for ; Wed, 23 Sep 2020 12:33:38 -0700 (PDT) Received: by mail-yb1-xb49.google.com with SMTP id 140so713565ybf.2 for ; Wed, 23 Sep 2020 12:33:38 -0700 (PDT) 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=swVHGWLak0coM49FvQF2sRpuRmO23+ilFsPjskPWrfo=; b=nH3WHumRpUzRWGLnFfE4Y0f4u55tPp8TCdxsGIv9yzrcqaaPRLBQYi7X1GjO3DUXxV 9RZicOipKHiL7iq8FJnTM9gv+z/udNwNkJOq8wgYMGDepOaQsOZMj4zfZn/04Ko0eAJi p1cqU1PXouthpT5pHqn/KsYCG+U387292eLAtB1QsjZi24kgMJYJmHXl9iFMH8YyvUES 6MIhJZuWHEkexHP4Uv+89sQb+DHkP4uaHgobTsg8qlRsjEk+8Gl3ePvc3WZRAaRysMbP Zss4mYo/PWnayb5ga/zUk9lJWxgyLr0PGPTtgbvUuA8i+nRKwFQE+5KunQU+mwhz00sO JcYQ== 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=swVHGWLak0coM49FvQF2sRpuRmO23+ilFsPjskPWrfo=; b=NuxWSMSqEJqDK3j29U7aRVNgMvz/XwpanhIaQvKRh2c4PakJOMZ7c0Wh8Rp7SdlS1e b3hPeDaXGeissSRal/8/l9qrvgYzy6m8GzsPVgsgdQvenguCiLpeQ1teM72e+eEeXcOb UTrwqKZuNN4cEL+WDI2iD03rxGzGnHLMoRYp4+bKzZXoBLoqJPtBEK/8/BTJUTImCsBk cu2w+cyuhgVvpsyKrPb11r1TxgyVkLLsZZzzYBthupg1S7ilY76O5VF1rfIJ3E0ILGWQ tT78Z6Urp3xW7/DvrHHqpLi2jpC9rSdy1bvAnQ2/keZVAa8WTSBD2kynZAvu4dnTJmGr h8fw== X-Gm-Message-State: AOAM5313msKFNtXZ80IxrEYNPAtPEQddUfveGe43obP3vXeZJARL8PXY WqMt0aQixuo9t+DbmAOVmvRx3p5EpZtztw1E6A== X-Google-Smtp-Source: ABdhPJzm2PvnHINhT5inXiwKTqEOdoG1jedWURhHs+f4ExDoJhWV1qBZ2soCa0Dsx4wPp+uGHUd96d5iUkuMl6LnxQ== 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:a25:a48a:: with SMTP id g10mr2305845ybi.197.1600889617651; Wed, 23 Sep 2020 12:33:37 -0700 (PDT) Date: Wed, 23 Sep 2020 12:33:24 -0700 In-Reply-To: <20200923193324.3090160-1-lokeshgidra@google.com> Message-Id: <20200923193324.3090160-4-lokeshgidra@google.com> Mime-Version: 1.0 References: <20200923193324.3090160-1-lokeshgidra@google.com> X-Mailer: git-send-email 2.28.0.681.g6f77f65b4e-goog Subject: [PATCH v9 3/3] Wire UFFD up to SELinux From: Lokesh Gidra To: 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, Daniel Colascione Precedence: bulk List-ID: X-Mailing-List: selinux@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);