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=ham 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 60489C2D0EF for ; Thu, 26 Mar 2020 20:06:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 363292073E for ; Thu, 26 Mar 2020 20:06:56 +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 S1728780AbgCZUGz (ORCPT ); Thu, 26 Mar 2020 16:06:55 -0400 Received: from mail-vk1-f202.google.com ([209.85.221.202]:56923 "EHLO mail-vk1-f202.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728752AbgCZUGy (ORCPT ); Thu, 26 Mar 2020 16:06:54 -0400 Received: by mail-vk1-f202.google.com with SMTP id e186so2546595vkh.23 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=HfJESZfL2C21u6M+rrA0aBT+rcnBZkMQYwnvwytRHirfNBKeftkbGrtZl9BXBOUrJi LDaOAQABV0ct/9mcNP67/NJP1lw5dWjgK0QTpncDD+kUw6AfhRgArrGiWoV5kZk1pwA8 fga+Zi4FqrEJud2ZFR1r7dsh+pJF9NNgZUG3dtAJyAVZbX8TTX64JZ/mZTYZq+NUWecg uQlUwTrVV/EPwXedPC84ACkRzR3aT+AnO3bF7go+S6+SszPb+oMH0Axd4s9PttKOaMp4 okgMYv3NsZsDyKY7pJ5bBJ+RFe38eAcowLSEUeMUcdgAk/hlmEK6NG1w0/pNmFqhChxR EKxg== X-Gm-Message-State: ANhLgQ2VeFP32sCSxCy+gd8CFv65mwaMF2pax0n0vcPopeMpp3ItDTlf D63I8yw+ghC5066DtWG1UIuWlgR2S1w= 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 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); -- 2.25.1.696.g5e7596f4ac-goog