From patchwork Fri Nov 6 15:56:26 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Lokesh Gidra X-Patchwork-Id: 11887349 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 EA13F1130 for ; Fri, 6 Nov 2020 15:56:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C0AF522202 for ; Fri, 6 Nov 2020 15:56:54 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="RsQT+l1C" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727768AbgKFP4y (ORCPT ); Fri, 6 Nov 2020 10:56:54 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57496 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727754AbgKFP4v (ORCPT ); Fri, 6 Nov 2020 10:56:51 -0500 Received: from mail-pl1-x649.google.com (mail-pl1-x649.google.com [IPv6:2607:f8b0:4864:20::649]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A7EB7C0613CF for ; Fri, 6 Nov 2020 07:56:51 -0800 (PST) Received: by mail-pl1-x649.google.com with SMTP id bb2so1085502plb.8 for ; Fri, 06 Nov 2020 07:56:51 -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=WDkvhhk+gB3QxGd+Be5zd3cestt1bSfFZfMdeZMOFkc=; b=RsQT+l1Cceiubd2ysLWUV8h2As7XbKgBn+u4sFmyjyhXGIMVBe6DeRx88flcGo8KR5 sl4O41xriDhKiN7umZyVgbPP7suEytMVsyPLWoRrN+8dPEx5fGUYYAauV7AcPfwFeILG YfpSyiF/Xb4+rnv8rl3bb8jdRbPq2PTUklekvsdHWSGtsz506hPYmFjiO7wOILQjhLWf pruQuuRngXqqcx2P4k/jVpbn414Xqvkp0FEof2WvYhJioCjk82tStmDHF/kgs65P9Kpq aYf0/rfT57riU5y656ZoKcC9PuV/Mttvwyzwlp1vQzkrxpQaFbp4xYQkbtW5gWN1zL5S mwjw== 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=WDkvhhk+gB3QxGd+Be5zd3cestt1bSfFZfMdeZMOFkc=; b=Yg7Fy78ZbF9+QhdapdBxjMHGb30DS7ro9j9TF07UFwbj5yGbnhjS4MEcOb9PhOKWEX ehm+3cVkQpUmouzvejDuW3bR2ON6IpiHHwUBoFF/Zp++Hvcg17SL7Uq9HDh5d6X7KT90 aj5moOZ+ab0az5fQy8rqE2LPicLdSZzhR7TEQkXIWyziiDqtXLZYvRiKv8qNMlTdIQKp elQNdIXxKxX4FpieNe/X3CkLeDzPaycTPd+8VXNosqfItblQw9KovASLEAO/gXKb5cFy YsPDI91xHZch4LiYEqYPP1PdQbNbPnSXsAMH3PXAVS3HK1/TmYyt6clE6Dn21wLt/TLN xgPA== X-Gm-Message-State: AOAM533Np6+Veijn6JTz/XC0rOldrlH8lJ6DSEYSjU3I/d17+vL0bi/W nnoSE2Y342Q6fF5ZUyilJ7Yg+pWYz1W1L6ez/w== X-Google-Smtp-Source: ABdhPJyr6d4kWf9xCCa5Q5B2Li129pMxIihfl7MrB7NAAAhzq/yphrSlonTBTACs7Hm/3feKqNqDhVnqI0/i8x7rGQ== 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:a17:902:ee85:b029:d6:c43e:2321 with SMTP id a5-20020a170902ee85b02900d6c43e2321mr2200868pld.29.1604678211192; Fri, 06 Nov 2020 07:56:51 -0800 (PST) Date: Fri, 6 Nov 2020 07:56:26 -0800 In-Reply-To: <20201106155626.3395468-1-lokeshgidra@google.com> Message-Id: <20201106155626.3395468-5-lokeshgidra@google.com> Mime-Version: 1.0 References: <20201106155626.3395468-1-lokeshgidra@google.com> X-Mailer: git-send-email 2.29.1.341.ge80a0c044ae-goog Subject: [PATCH v12 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 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, linux-mm@kvack.org, Andrew Morton , hch@infradead.org, Daniel Colascione , Eric Biggers 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 [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 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 000b457ad087..dd78daf06de6 100644 --- a/fs/userfaultfd.c +++ b/fs/userfaultfd.c @@ -972,14 +972,14 @@ 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; @@ -989,7 +989,7 @@ 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); @@ -1100,7 +1100,7 @@ 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)) { /* @@ -1160,6 +1160,7 @@ 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; @@ -1167,7 +1168,7 @@ 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))) @@ -1985,8 +1986,8 @@ 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);