From patchwork Thu Mar 26 20:06:34 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Daniel Colascione X-Patchwork-Id: 11460993 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 B5E891668 for ; Thu, 26 Mar 2020 20:06:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 971662078C for ; Thu, 26 Mar 2020 20:06:59 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="lPpmx9yP" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728771AbgCZUG6 (ORCPT ); Thu, 26 Mar 2020 16:06:58 -0400 Received: from mail-vk1-f202.google.com ([209.85.221.202]:44936 "EHLO mail-vk1-f202.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728718AbgCZUGy (ORCPT ); Thu, 26 Mar 2020 16:06:54 -0400 Received: by mail-vk1-f202.google.com with SMTP id k67so2092600vka.11 for ; Thu, 26 Mar 2020 13:06:53 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=Y8Q8F3IH8c2hotjV+QMJ3kSw7Jeojd38t24yU7GezVM=; b=lPpmx9yPrL/MYyExIQJGT42ZfXmoCaxGEUrGYFUYgtzqZErnqz25tEHuBVs6UbKG03 cbq05kXjAStd0QUwzzsPx/m4hLKByFqoRBu0ZMko8DOGfpMbfqphPTAc1n4aoSx+jUiD GUkRqspDcIHkNyB21E+AmXM76aByOoFTLmj5Z68AhLoDMFd2yhNWF9wo2X0u1uuBOqyP yWaZ/1SYoC2exZSC6kN0hyxiU7LLLW36qCYgUEFeqhpAMNQye8oOAMZk5AE/478eAua1 38w9tfa8n6lzqlf4LQ8lmPqLhDyBDGb2agpgeh/LtUoaVTpE4nt/fnX+IkzbBesH8+78 Azyw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=Y8Q8F3IH8c2hotjV+QMJ3kSw7Jeojd38t24yU7GezVM=; b=pVQoFbGJr1t2uEZAk0w9POFIUbVSzFgF9DCo+C1zz8uwrhCa8vlcPRf5+ObylCKSN6 Kz0LngcRYV7fQlyOxmma2xSn7EBTpHbwsh2ZSFlnuhPXj6deI4lzNSYJwTdXYEgI8plq ZJW08PzFbcNA9oLkYAAJR+SufeP1o0LvxcyL5HvST7CGpzSuDMPM0+ZHHqiL7fZh3hg0 dvmLEgYhsmOiJRAyp0xdV7Lfh/Ru7W7QecA8FW9WbEGtqkElwLZs61NPLUiGJB177OU9 mJrC6IghnkQhw6nKTbR8Pq+gE6G6aTnViPGeplqmfIG3Im/rLkhVri10ZIk35osSGdaJ WUPg== X-Gm-Message-State: ANhLgQ2quqVuYndeo3WPoCrv7ImF4psbPDQyrq8SS5kz83UZNlfNHc7W E7NsBziLSXAgVoqakSSccMu4lNGnRo4= X-Google-Smtp-Source: ADFU+vusyX36d2CY3Mx/oaqEexC02/Z3H/IlNDB9bKUbWp7T4L1OJf34Zf2nIPvcXbTAxx7+cBlBgkr2U4g= X-Received: by 2002:ab0:424:: with SMTP id 33mr8765913uav.143.1585253213293; Thu, 26 Mar 2020 13:06:53 -0700 (PDT) Date: Thu, 26 Mar 2020 13:06:34 -0700 In-Reply-To: <20200326200634.222009-1-dancol@google.com> Message-Id: <20200326200634.222009-4-dancol@google.com> Mime-Version: 1.0 References: <20200326181456.132742-1-dancol@google.com> <20200326200634.222009-1-dancol@google.com> X-Mailer: git-send-email 2.25.1.696.g5e7596f4ac-goog Subject: [PATCH v4 3/3] Wire UFFD up to SELinux From: Daniel Colascione To: timmurray@google.com, selinux@vger.kernel.org, linux-security-module@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, kvm@vger.kernel.org, viro@zeniv.linux.org.uk, paul@paul-moore.com, nnk@google.com, sds@tycho.nsa.gov, lokeshgidra@google.com, jmorris@namei.org Cc: Daniel Colascione Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org This change gives userfaultfd file descriptors a real security context, allowing policy to act on them. Signed-off-by: Daniel Colascione --- fs/userfaultfd.c | 30 ++++++++++++++++++++++++++---- 1 file changed, 26 insertions(+), 4 deletions(-) diff --git a/fs/userfaultfd.c b/fs/userfaultfd.c index 37df7c9eedb1..78ff5d898733 100644 --- a/fs/userfaultfd.c +++ b/fs/userfaultfd.c @@ -76,6 +76,8 @@ struct userfaultfd_ctx { bool mmap_changing; /* mm with one ore more vmas attached to this userfaultfd_ctx */ struct mm_struct *mm; + /* The inode that owns this context --- not a strong reference. */ + const struct inode *owner; }; struct userfaultfd_fork_ctx { @@ -1022,8 +1024,10 @@ static int resolve_userfault_fork(struct userfaultfd_ctx *ctx, { 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), + ctx->owner); if (fd < 0) return fd; @@ -1945,6 +1949,7 @@ static void init_once_userfaultfd_ctx(void *mem) SYSCALL_DEFINE1(userfaultfd, int, flags) { + struct file *file; struct userfaultfd_ctx *ctx; int fd; @@ -1974,8 +1979,25 @@ 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)); + file = anon_inode_getfile_secure( + "[userfaultfd]", &userfaultfd_fops, ctx, + O_RDWR | (flags & UFFD_SHARED_FCNTL_FLAGS), + NULL); + if (IS_ERR(file)) { + fd = PTR_ERR(file); + goto out; + } + + fd = get_unused_fd_flags(O_RDONLY | O_CLOEXEC); + if (fd < 0) { + fput(file); + goto out; + } + + ctx->owner = file_inode(file); + fd_install(fd, file); + +out: if (fd < 0) { mmdrop(ctx->mm); kmem_cache_free(userfaultfd_ctx_cachep, ctx);