From patchwork Tue Feb 19 16:31:50 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Howells X-Patchwork-Id: 10820255 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 698C714E1 for ; Tue, 19 Feb 2019 16:31:54 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 5051B2CD4B for ; Tue, 19 Feb 2019 16:31:54 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 4C6062CD4F; Tue, 19 Feb 2019 16:31:54 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=2.0 tests=BAYES_00,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 924E22CD11 for ; Tue, 19 Feb 2019 16:31:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729020AbfBSQbx (ORCPT ); Tue, 19 Feb 2019 11:31:53 -0500 Received: from mx1.redhat.com ([209.132.183.28]:49678 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726357AbfBSQbx (ORCPT ); Tue, 19 Feb 2019 11:31:53 -0500 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 5C34080467; Tue, 19 Feb 2019 16:31:52 +0000 (UTC) Received: from warthog.procyon.org.uk (ovpn-121-129.rdu2.redhat.com [10.10.121.129]) by smtp.corp.redhat.com (Postfix) with ESMTP id 0682719C58; Tue, 19 Feb 2019 16:31:50 +0000 (UTC) Organization: Red Hat UK Ltd. 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Registered in England and Wales under Company Registration No. 3798903 Subject: [PATCH 25/43] ipc: Convert mqueue fs to fs_context From: David Howells To: viro@zeniv.linux.org.uk Cc: linux-fsdevel@vger.kernel.org, dhowells@redhat.com, torvalds@linux-foundation.org, ebiederm@xmission.com, linux-security-module@vger.kernel.org Date: Tue, 19 Feb 2019 16:31:50 +0000 Message-ID: <155059391026.12449.668855607210599414.stgit@warthog.procyon.org.uk> In-Reply-To: <155059366914.12449.4669870128936536848.stgit@warthog.procyon.org.uk> References: <155059366914.12449.4669870128936536848.stgit@warthog.procyon.org.uk> User-Agent: StGit/unknown-version MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.28]); Tue, 19 Feb 2019 16:31:52 +0000 (UTC) Sender: owner-linux-security-module@vger.kernel.org Precedence: bulk List-ID: X-Virus-Scanned: ClamAV using ClamSMTP Convert the mqueue filesystem to use the filesystem context stuff. Notes: (1) The relevant ipc namespace is selected in when the context is initialised (and it defaults to the current task's ipc namespace). The caller can override this before calling vfs_get_tree(). (2) Rather than simply calling kern_mount_data(), mq_init_ns() and mq_internal_mount() create a context, adjust it and then do the rest of the mount procedure. (3) The lazy mqueue mounting on creation of a new namespace is retained from a previous patch, but the avoidance of sget() if no superblock yet exists is reverted and the superblock is again keyed on the namespace pointer. Yes, there was a performance gain in not searching the superblock hash, but it's only paid once per ipc namespace - and only if someone uses mqueue within that namespace, so I'm not sure it's worth it, especially as calling sget() allows avoidance of recursion. Signed-off-by: David Howells Signed-off-by: Al Viro --- ipc/mqueue.c | 94 ++++++++++++++++++++++++++++++++++++++++++------------- ipc/namespace.c | 2 + 2 files changed, 73 insertions(+), 23 deletions(-) diff --git a/ipc/mqueue.c b/ipc/mqueue.c index c595bed7bfcb..2a9a8be49f5b 100644 --- a/ipc/mqueue.c +++ b/ipc/mqueue.c @@ -18,6 +18,7 @@ #include #include #include +#include #include #include #include @@ -42,6 +43,10 @@ #include #include "util.h" +struct mqueue_fs_context { + struct ipc_namespace *ipc_ns; +}; + #define MQUEUE_MAGIC 0x19800202 #define DIRENT_SIZE 20 #define FILENT_SIZE 80 @@ -87,9 +92,11 @@ struct mqueue_inode_info { unsigned long qsize; /* size of queue in memory (sum of all msgs) */ }; +static struct file_system_type mqueue_fs_type; static const struct inode_operations mqueue_dir_inode_operations; static const struct file_operations mqueue_file_operations; static const struct super_operations mqueue_super_ops; +static const struct fs_context_operations mqueue_fs_context_ops; static void remove_notification(struct mqueue_inode_info *info); static struct kmem_cache *mqueue_inode_cachep; @@ -322,7 +329,7 @@ static struct inode *mqueue_get_inode(struct super_block *sb, return ERR_PTR(ret); } -static int mqueue_fill_super(struct super_block *sb, void *data, int silent) +static int mqueue_fill_super(struct super_block *sb, struct fs_context *fc) { struct inode *inode; struct ipc_namespace *ns = sb->s_fs_info; @@ -343,18 +350,56 @@ static int mqueue_fill_super(struct super_block *sb, void *data, int silent) return 0; } -static struct dentry *mqueue_mount(struct file_system_type *fs_type, - int flags, const char *dev_name, - void *data) +static int mqueue_get_tree(struct fs_context *fc) { - struct ipc_namespace *ns; - if (flags & SB_KERNMOUNT) { - ns = data; - data = NULL; - } else { - ns = current->nsproxy->ipc_ns; - } - return mount_ns(fs_type, flags, data, ns, ns->user_ns, mqueue_fill_super); + struct mqueue_fs_context *ctx = fc->fs_private; + + put_user_ns(fc->user_ns); + fc->user_ns = get_user_ns(ctx->ipc_ns->user_ns); + fc->s_fs_info = ctx->ipc_ns; + return vfs_get_super(fc, vfs_get_keyed_super, mqueue_fill_super); +} + +static void mqueue_fs_context_free(struct fs_context *fc) +{ + struct mqueue_fs_context *ctx = fc->fs_private; + + if (ctx->ipc_ns) + put_ipc_ns(ctx->ipc_ns); + kfree(ctx); +} + +static int mqueue_init_fs_context(struct fs_context *fc) +{ + struct mqueue_fs_context *ctx; + + ctx = kzalloc(sizeof(struct mqueue_fs_context), GFP_KERNEL); + if (!ctx) + return -ENOMEM; + + ctx->ipc_ns = get_ipc_ns(current->nsproxy->ipc_ns); + fc->fs_private = ctx; + fc->ops = &mqueue_fs_context_ops; + return 0; +} + +static struct vfsmount *mq_create_mount(struct ipc_namespace *ns) +{ + struct mqueue_fs_context *ctx; + struct fs_context *fc; + struct vfsmount *mnt; + + fc = fs_context_for_mount(&mqueue_fs_type, SB_KERNMOUNT); + if (IS_ERR(fc)) + return ERR_CAST(fc); + + ctx = fc->fs_private; + put_ipc_ns(ctx->ipc_ns); + ctx->ipc_ns = get_ipc_ns(ns); + + mnt = fc_mount(fc); + put_fs_context(fc); + return mnt; } static void init_once(void *foo) @@ -1522,15 +1567,22 @@ static const struct super_operations mqueue_super_ops = { .statfs = simple_statfs, }; +static const struct fs_context_operations mqueue_fs_context_ops = { + .free = mqueue_fs_context_free, + .get_tree = mqueue_get_tree, +}; + static struct file_system_type mqueue_fs_type = { - .name = "mqueue", - .mount = mqueue_mount, - .kill_sb = kill_litter_super, - .fs_flags = FS_USERNS_MOUNT, + .name = "mqueue", + .init_fs_context = mqueue_init_fs_context, + .kill_sb = kill_litter_super, + .fs_flags = FS_USERNS_MOUNT, }; int mq_init_ns(struct ipc_namespace *ns) { + struct vfsmount *m; + ns->mq_queues_count = 0; ns->mq_queues_max = DFLT_QUEUESMAX; ns->mq_msg_max = DFLT_MSGMAX; @@ -1538,12 +1590,10 @@ int mq_init_ns(struct ipc_namespace *ns) ns->mq_msg_default = DFLT_MSG; ns->mq_msgsize_default = DFLT_MSGSIZE; - ns->mq_mnt = kern_mount_data(&mqueue_fs_type, ns); - if (IS_ERR(ns->mq_mnt)) { - int err = PTR_ERR(ns->mq_mnt); - ns->mq_mnt = NULL; - return err; - } + m = mq_create_mount(ns); + if (IS_ERR(m)) + return PTR_ERR(m); + ns->mq_mnt = m; return 0; } diff --git a/ipc/namespace.c b/ipc/namespace.c index 21607791d62c..b3ca1476ca51 100644 --- a/ipc/namespace.c +++ b/ipc/namespace.c @@ -42,7 +42,7 @@ static struct ipc_namespace *create_ipc_ns(struct user_namespace *user_ns, goto fail; err = -ENOMEM; - ns = kmalloc(sizeof(struct ipc_namespace), GFP_KERNEL); + ns = kzalloc(sizeof(struct ipc_namespace), GFP_KERNEL); if (ns == NULL) goto fail_dec;