From mboxrd@z Thu Jan 1 00:00:00 1970 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=-17.4 required=3.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,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 33FAEC43331 for ; Wed, 1 Apr 2020 21:39:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 05A91206E9 for ; Wed, 1 Apr 2020 21:39:26 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="FeWGGGhw" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1733275AbgDAVjY (ORCPT ); Wed, 1 Apr 2020 17:39:24 -0400 Received: from mail-pf1-f202.google.com ([209.85.210.202]:50787 "EHLO mail-pf1-f202.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1733220AbgDAVjW (ORCPT ); Wed, 1 Apr 2020 17:39:22 -0400 Received: by mail-pf1-f202.google.com with SMTP id e18so879593pfl.17 for ; Wed, 01 Apr 2020 14:39:21 -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=DdrdrRerOMvkv7vzgvI3ttukeUZ2OpdhnLu+un2eV2s=; b=FeWGGGhwmXwPYJI7fgk1nXVyU38RCP6BF6eOwbkfauA5Lh/S0K7Nc0SIi0FDfzLZf/ bBZtA01Z+mycAmiPQF6sdgjk5IWYb+EIHKaBqeFr9fpHlHKvNDviHMxgwnRIyxJ2QR+m FhGsIQS2Qu6FM71Bw7dEx5OsIbtQDambyY4fI9IepQU+Cs0Psa6YkBsLcX8FD8WIcBtp vBLKQP3cpYILo3x9L44bcB2+wn09ds8LLHXl7JYuY3kZHmAMRAlkc7Jl2jKOzPh1N4mo qnZvGI1i19BxSMYD89r0zKAZ5tBFZPiVCrcqrSEvreR+Eu5kKl7jbxfQkEj6DqoueZO0 AaSw== 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=DdrdrRerOMvkv7vzgvI3ttukeUZ2OpdhnLu+un2eV2s=; b=a8f9WqW/ZESuNvE2UNIFjrtu+DR1DlR3k0aIJnE8UbZPChNOQB8RTAXRbMfuMTgwqa wXtMgujBrB30Ver9GJfTp7WO4DHtLUXN8NjUy95Mzhh6cro7fYYMPCMkw6a8aA5nHNOB 6+LH+fBizH8LNSrTbZqCekE1o5maVJbjVt3sHiboMbcwFQ2dfUJU0OgeA7vcp8lERrGl 1Fn8U2k/zrGS6wGZ3Y0O1OldJ5BhEWqBAsGukq+UQDIIDyvXbEZih8f9oO4tCBv8jNZU g9xalcXg4sSWkgTuzBtrX/qrt/9J26ya1TZ6db1b1DTeXIazXA6yXqXubCtlkZfybaEn VpfA== X-Gm-Message-State: AGi0PuYFlAez0tLUl8mFajLy+EyVXMcV+8N+M/dltadgTRX5eoMKm5mM 65BL3Z81ZKb1ZDQk67vBICZdw5YfvCE= X-Google-Smtp-Source: APiQypJjIzb/5kmrh3RqCS3HOgTi/GT8cY+ji3kV8XKRQ+4eFtBDnifNrAYKZFtkDdm/KNfMZ+0y3mX+CAA= X-Received: by 2002:a17:90a:2147:: with SMTP id a65mr41318pje.176.1585777160964; Wed, 01 Apr 2020 14:39:20 -0700 (PDT) Date: Wed, 1 Apr 2020 14:39:03 -0700 In-Reply-To: <20200401213903.182112-1-dancol@google.com> Message-Id: <20200401213903.182112-4-dancol@google.com> Mime-Version: 1.0 References: <20200326200634.222009-1-dancol@google.com> <20200401213903.182112-1-dancol@google.com> X-Mailer: git-send-email 2.26.0.rc2.310.g2932bb562d-goog Subject: [PATCH v5 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 Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@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); -- 2.26.0.rc2.310.g2932bb562d-goog