From patchwork Thu Nov 9 16:14:06 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Djalal Harouni X-Patchwork-Id: 10051231 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 63B97603FA for ; Thu, 9 Nov 2017 16:16:40 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 570712A951 for ; Thu, 9 Nov 2017 16:16:40 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 4B7642AF3C; Thu, 9 Nov 2017 16:16:40 +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=-4.1 required=2.0 tests=BAYES_00, DKIM_ADSP_CUSTOM_MED, DKIM_SIGNED, FREEMAIL_FROM, RCVD_IN_DNSWL_MED, T_DKIM_INVALID autolearn=ham version=3.3.1 Received: from mother.openwall.net (mother.openwall.net [195.42.179.200]) by mail.wl.linuxfoundation.org (Postfix) with SMTP id 07DB12AF8F for ; Thu, 9 Nov 2017 16:16:38 +0000 (UTC) Received: (qmail 5914 invoked by uid 550); 9 Nov 2017 16:14:55 -0000 Mailing-List: contact kernel-hardening-help@lists.openwall.com; run by ezmlm Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-ID: Delivered-To: mailing list kernel-hardening@lists.openwall.com Received: (qmail 5730 invoked from network); 9 Nov 2017 16:14:50 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=7vOZSm/oMaepJBTP+vaIhOm4hY2Es6y7hFN19drTims=; b=gMkVZMr9LbIIaj2LyXQ83fr3xpojNQG7knw+B2j9xRwEdVQ5PyplbYuw+j90s2Yq8n ZmBZh/UijAd9dGZ3eLuQ1veOE5UjvV6vW91pp3pfCIZnD73+Az9dNMtyjHVZKjpJBsvY fIls7lCO1TVYUkcGllAUFPFfDOB7QZn9mFH6bCfFKCWZY3gBcqgbDiue0Nqnm7HdBqFR lP+dw6Egb9qXJ7CHa0FUNKkZseK7wcKY1T/31nXs5bgg6Z5mwM/qV3QxKiD1T7FMBol2 xv9uplIh5rOwj++6l6eZPL5ivTL6CNTCw773lBMAuy7eQ1dJqooXXqXj86x6iQN0RRgc PEVg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=7vOZSm/oMaepJBTP+vaIhOm4hY2Es6y7hFN19drTims=; b=LmhMSxSHlJxDbB788w/imA0Lmkv+N8eZ7YyopD59nQHKGRFDnn0MynjWVkwZdqlZRY ld/hipN8qI+5iuIB0zSJ9m+JLvjBkRYJkQtz3ipJccYzwxz7nnPiuJnTV4/oQqS7SZpY h/c3bWyv68oAxY2nRRF7OUux/5iaX5Xrx9aLMEN/9IcOQxn38AHoj7q6tLVKsiGrTJqM dOKQnl/ss9mRfj0WRI/XRyNOGmyt4yL4NX3sAnpeHvJbBEFVi1UwPcVeXZz2XXAWfc5U 2mI8b33hMyq4WqLLbDX+6/SidiI7tRKNO1yGL5wriHKs2KlqEvGRp3L8SgMsisO2gysx z8ug== X-Gm-Message-State: AJaThX4bIduxLBiSfCdJYN6Yi8esZ6t2EVav2QaPNOZUXppv5rxok0D6 9+0y0c0D9TOXnDQz2+m/Bx8= X-Google-Smtp-Source: ABhQp+Su/d6KGmvmaX1KikVXxpaWqj4Aom0nqpffmAWeiLIv2Vqw+cTDqraLle6/ax97lAjU0oB6OQ== X-Received: by 10.80.168.129 with SMTP id k1mr1356779edc.109.1510244079051; Thu, 09 Nov 2017 08:14:39 -0800 (PST) From: Djalal Harouni To: Kees Cook , Alexey Gladkov , 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 , me@tobin.cc, Oleg Nesterov , Jeff Layton , Ingo Molnar , Alexey Dobriyan , ebiederm@xmission.com, Linus Torvalds , Daniel Micay , Jonathan Corbet , bfields@fieldses.org, Stephen Rothwell , solar@openwall.com, Djalal Harouni Date: Thu, 9 Nov 2017 17:14:06 +0100 Message-Id: <1510244046-3256-8-git-send-email-tixxdz@gmail.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1510244046-3256-1-git-send-email-tixxdz@gmail.com> References: <1510244046-3256-1-git-send-email-tixxdz@gmail.com> Subject: [kernel-hardening] [PATCH RFC v3 7/7] proc: flush dcache entries from all procfs instances X-Virus-Scanned: ClamAV using ClamSMTP Flush dcache entries of a task when it terminates. The task may have showed up in multiple procfs mounts per pid namespace, and we need to walk the mounts and invalidate any left entires. Cc: Kees Cook Cc: Greg Kroah-Hartman Cc: Andy Lutomirski Cc: Alexey Gladkov 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 | 49 +++++++++++++++++++++++++++++++++++++++++++ include/linux/proc_fs.h | 2 ++ 5 files changed, 91 insertions(+), 6 deletions(-) diff --git a/fs/proc/base.c b/fs/proc/base.c index 88b92bc..27e52aa 100644 --- a/fs/proc/base.c +++ b/fs/proc/base.c @@ -3034,7 +3034,8 @@ 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[PROC_NUMBUF]; @@ -3043,7 +3044,7 @@ static void proc_flush_task_mnt(struct vfsmount *mnt, pid_t pid, pid_t tgid) name.name = buf; name.len = snprintf(buf, sizeof(buf), "%d", 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); @@ -3054,7 +3055,7 @@ static void proc_flush_task_mnt(struct vfsmount *mnt, pid_t pid, pid_t tgid) name.name = buf; name.len = snprintf(buf, sizeof(buf), "%d", tgid); - leader = d_hash_and_lookup(mnt->mnt_root, &name); + leader = d_hash_and_lookup(mnt_root, &name); if (!leader) goto out; @@ -3109,14 +3110,30 @@ 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 2707d5f..8fcf0d7 100644 --- a/fs/proc/inode.c +++ b/fs/proc/inode.c @@ -484,10 +484,17 @@ 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 5cdff69..5503799 100644 --- a/fs/proc/root.c +++ b/fs/proc/root.c @@ -259,6 +259,13 @@ 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); @@ -374,6 +381,9 @@ 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 66f47f1..9a7a28d 100644 --- a/include/linux/pid_namespace.h +++ b/include/linux/pid_namespace.h @@ -26,6 +26,15 @@ struct pid_namespace { struct pid_namespace *parent; #ifdef CONFIG_PROC_FS struct vfsmount *proc_mnt; /* Internal proc mounted during each new pidns */ + + /* Serialize separated procfs access from super block create/destory */ + struct rw_semaphore rw_procfs_mnts; + + /* + * List of separated procfs mounts, used to invalidate task dentry + * from all the related procfs mounts. + */ + struct list_head procfs_mounts; #endif #ifdef CONFIG_BSD_PROCESS_ACCT struct fs_pin *bacct; @@ -90,4 +99,44 @@ 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 0730f52..e56fbab 100644 --- a/include/linux/proc_fs.h +++ b/include/linux/proc_fs.h @@ -24,7 +24,9 @@ enum { /* definitions for 'pids' mount option */ }; struct proc_fs_info { + struct super_block *sb; struct pid_namespace *pid_ns; + struct list_head pidns_entry; /* Node in procfs_mounts of pidns */ struct dentry *proc_self; /* For /proc/self/ */ struct dentry *proc_thread_self; /* For /proc/thread-self/ */ bool newinstance; /* Flag for new separated instances */