From patchwork Fri May 11 09:36:45 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alexey Gladkov X-Patchwork-Id: 10393795 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 6254E60236 for ; Fri, 11 May 2018 09:55:23 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 2B5932237D for ; Fri, 11 May 2018 09:55:23 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 1F3BB2843B; Fri, 11 May 2018 09:55:23 +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, DKIM_ADSP_CUSTOM_MED, FREEMAIL_FROM,RCVD_IN_DNSWL_HI autolearn=unavailable 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 93EE02237D for ; Fri, 11 May 2018 09:55:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752362AbeEKJzT (ORCPT ); Fri, 11 May 2018 05:55:19 -0400 Received: from monster.unsafe.ru ([5.9.28.80]:42556 "EHLO mail.unsafe.ru" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751406AbeEKJzS (ORCPT ); Fri, 11 May 2018 05:55:18 -0400 Received: from comp-core-i7-2640m-0182e6 (nat-pool-brq-t.redhat.com [213.175.37.10]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.unsafe.ru (Postfix) with ESMTPSA id 71952C61A9E; Fri, 11 May 2018 09:46:42 +0000 (UTC) Date: Fri, 11 May 2018 11:36:45 +0200 From: Alexey Gladkov To: Kees Cook , Andy Lutomirski , Andrew Morton , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, kernel-hardening@lists.openwall.com, linux-security-module@vger.kernel.org, linux-api@vger.kernel.org Cc: Greg Kroah-Hartman , Alexander Viro , Akinobu Mita , Oleg Nesterov , Jeff Layton , Ingo Molnar , Alexey Dobriyan , "Eric W. Biederman" , Linus Torvalds , aniel Micay , Jonathan Corbet , bfields@fieldses.org, Stephen Rothwell , solar@openwall.com, "Dmitry V. Levin" , Djalal Harouni Subject: [PATCH v5 6/7] proc: flush task dcache entries from all procfs instances Message-ID: <20180511093645.GA1365@comp-core-i7-2640m-0182e6> MIME-Version: 1.0 Content-Disposition: inline Sender: owner-linux-security-module@vger.kernel.org Precedence: bulk List-ID: X-Virus-Scanned: ClamAV using ClamSMTP From: Djalal Harouni This allows to flush dcache entries of a task on multiple procfs mounts per pid namespace. Cc: Kees Cook Cc: Andy Lutomirski Signed-off-by: Djalal Harouni --- fs/proc/base.c | 27 ++++++++++++++++++++++----- fs/proc/inode.c | 9 ++++++++- fs/proc/root.c | 10 ++++++++++ include/linux/pid_namespace.h | 42 ++++++++++++++++++++++++++++++++++++++++++ include/linux/proc_fs.h | 2 ++ 5 files changed, 84 insertions(+), 6 deletions(-) diff --git a/fs/proc/base.c b/fs/proc/base.c index 31baeef..987d702 100644 --- a/fs/proc/base.c +++ b/fs/proc/base.c @@ -3068,7 +3068,8 @@ static const struct inode_operations proc_tgid_base_inode_operations = { .permission = proc_pid_permission, }; -static void proc_flush_task_mnt(struct vfsmount *mnt, pid_t pid, pid_t tgid) +static void proc_flush_task_mnt_root(struct dentry *mnt_root, + pid_t pid, pid_t tgid) { struct dentry *dentry, *leader, *dir; char buf[10 + 1]; @@ -3077,7 +3078,7 @@ static void proc_flush_task_mnt(struct vfsmount *mnt, pid_t pid, pid_t tgid) name.name = buf; name.len = snprintf(buf, sizeof(buf), "%u", pid); /* no ->d_hash() rejects on procfs */ - dentry = d_hash_and_lookup(mnt->mnt_root, &name); + dentry = d_hash_and_lookup(mnt_root, &name); if (dentry) { d_invalidate(dentry); dput(dentry); @@ -3088,7 +3089,7 @@ static void proc_flush_task_mnt(struct vfsmount *mnt, pid_t pid, pid_t tgid) name.name = buf; name.len = snprintf(buf, sizeof(buf), "%u", tgid); - leader = d_hash_and_lookup(mnt->mnt_root, &name); + leader = d_hash_and_lookup(mnt_root, &name); if (!leader) goto out; @@ -3143,14 +3144,30 @@ void proc_flush_task(struct task_struct *task) int i; struct pid *pid, *tgid; struct upid *upid; + struct proc_fs_info *fs_info_entry; + struct pid_namespace *pid_ns; + struct dentry *mnt_root; pid = task_pid(task); tgid = task_tgid(task); for (i = 0; i <= pid->level; i++) { upid = &pid->numbers[i]; - proc_flush_task_mnt(upid->ns->proc_mnt, upid->nr, - tgid->numbers[i].nr); + pid_ns = upid->ns; + + pidns_proc_lock_shared(pid_ns); + list_for_each_entry(fs_info_entry, &pid_ns->procfs_mounts, + pidns_entry) { + if (proc_fs_newinstance(fs_info_entry)) { + mnt_root = fs_info_entry->sb->s_root; + proc_flush_task_mnt_root(mnt_root, upid->nr, + tgid->numbers[i].nr); + } + } + pidns_proc_unlock_shared(pid_ns); + + mnt_root = pid_ns->proc_mnt->mnt_root; + proc_flush_task_mnt_root(mnt_root, upid->nr, tgid->numbers[i].nr); } } diff --git a/fs/proc/inode.c b/fs/proc/inode.c index 985df4b..5e62598 100644 --- a/fs/proc/inode.c +++ b/fs/proc/inode.c @@ -498,10 +498,17 @@ struct inode *proc_get_inode(struct super_block *sb, struct proc_dir_entry *de) int proc_fill_super(struct super_block *s, void *data, int silent) { struct proc_fs_info *fs_info = proc_sb(s); + struct pid_namespace *ns = get_pid_ns(fs_info->pid_ns); struct inode *root_inode; int ret; - get_pid_ns(fs_info->pid_ns); + fs_info->sb = s; + + if (proc_fs_newinstance(fs_info)) { + pidns_proc_lock(ns); + list_add_tail(&fs_info->pidns_entry, &ns->procfs_mounts); + pidns_proc_unlock(ns); + } if (!proc_parse_options(data, fs_info)) return -EINVAL; diff --git a/fs/proc/root.c b/fs/proc/root.c index c5ce241..c72d22c 100644 --- a/fs/proc/root.c +++ b/fs/proc/root.c @@ -249,6 +249,13 @@ static void proc_kill_sb(struct super_block *sb) dput(fs_info->proc_self); if (fs_info->proc_thread_self) dput(fs_info->proc_thread_self); + + if (proc_fs_newinstance(fs_info)) { + pidns_proc_lock(ns); + list_del(&fs_info->pidns_entry); + pidns_proc_unlock(ns); + } + kill_anon_super(sb); put_pid_ns(ns); kfree(fs_info); @@ -357,6 +364,9 @@ int pid_ns_prepare_proc(struct pid_namespace *ns) return PTR_ERR(mnt); ns->proc_mnt = mnt; + init_rwsem(&ns->rw_procfs_mnts); + INIT_LIST_HEAD(&ns->procfs_mounts); + return 0; } diff --git a/include/linux/pid_namespace.h b/include/linux/pid_namespace.h index f91a8bf..767fc96 100644 --- a/include/linux/pid_namespace.h +++ b/include/linux/pid_namespace.h @@ -32,6 +32,8 @@ struct pid_namespace { struct pid_namespace *parent; #ifdef CONFIG_PROC_FS struct vfsmount *proc_mnt; /* Internal proc mounted during each new pidns */ + struct rw_semaphore rw_procfs_mnts; + struct list_head procfs_mounts; /* list of separated procfs mounts */ #endif #ifdef CONFIG_BSD_PROCESS_ACCT struct fs_pin *bacct; @@ -98,4 +100,44 @@ extern struct pid_namespace *task_active_pid_ns(struct task_struct *tsk); void pidhash_init(void); void pid_idr_init(void); +#ifdef CONFIG_PROC_FS +static inline void pidns_proc_lock(struct pid_namespace *pid_ns) +{ + down_write(&pid_ns->rw_procfs_mnts); +} + +static inline void pidns_proc_unlock(struct pid_namespace *pid_ns) +{ + up_write(&pid_ns->rw_procfs_mnts); +} + +static inline void pidns_proc_lock_shared(struct pid_namespace *pid_ns) +{ + down_read(&pid_ns->rw_procfs_mnts); +} + +static inline void pidns_proc_unlock_shared(struct pid_namespace *pid_ns) +{ + up_read(&pid_ns->rw_procfs_mnts); +} +#else /* !CONFIG_PROC_FS */ + +static inline void pidns_proc_lock(struct pid_namespace *pid_ns) +{ +} + +static inline void pidns_proc_unlock(struct pid_namespace *pid_ns) +{ +} + +static inline void pidns_proc_lock_shared(struct pid_namespace *pid_ns) +{ +} + +static inline void pidns_proc_unlock_shared(struct pid_namespace *pid_ns) +{ +} + +#endif /* CONFIG_PROC_FS */ + #endif /* _LINUX_PID_NS_H */ diff --git a/include/linux/proc_fs.h b/include/linux/proc_fs.h index 2d16d0e..70e8b10 100644 --- a/include/linux/proc_fs.h +++ b/include/linux/proc_fs.h @@ -19,7 +19,9 @@ enum { /* definitions for proc mount option limit_pids */ }; struct proc_fs_info { + struct super_block *sb; struct pid_namespace *pid_ns; + struct list_head pidns_entry; /* Node in procfs_mounts of a pidns */ struct dentry *proc_self; /* For /proc/self */ struct dentry *proc_thread_self; /* For /proc/thread-self/ */ bool newinstance; /* Private flag for new separated instances */