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![Christian Brauner](/assets/img/avatar_default.png)
Extend some inode methods with an additional user namespace argument. A filesystem that is aware of idmapped mounts will receive the user namespace the mount has been marked with. This can be used for additional permission checking and also to enable filesystems to translate between uids and gids if they need to. We have implemented all relevant helpers in earlier patches. As requested we simply extend the exisiting inode method instead of introducing new ones. This is a little more code churn but it's mostly mechanical and doesnt't leave us with additional inode methods. Link: https://lore.kernel.org/r/20210121131959.646623-25-christian.brauner@ubuntu.com Cc: Christoph Hellwig <hch@lst.de> Cc: David Howells <dhowells@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: linux-fsdevel@vger.kernel.org Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
1736 lines
43 KiB
C
1736 lines
43 KiB
C
/*
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* POSIX message queues filesystem for Linux.
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*
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* Copyright (C) 2003,2004 Krzysztof Benedyczak (golbi@mat.uni.torun.pl)
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* Michal Wronski (michal.wronski@gmail.com)
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*
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* Spinlocks: Mohamed Abbas (abbas.mohamed@intel.com)
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* Lockless receive & send, fd based notify:
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* Manfred Spraul (manfred@colorfullife.com)
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*
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* Audit: George Wilson (ltcgcw@us.ibm.com)
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*
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* This file is released under the GPL.
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*/
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#include <linux/capability.h>
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#include <linux/init.h>
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#include <linux/pagemap.h>
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#include <linux/file.h>
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#include <linux/mount.h>
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#include <linux/fs_context.h>
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#include <linux/namei.h>
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#include <linux/sysctl.h>
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#include <linux/poll.h>
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#include <linux/mqueue.h>
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#include <linux/msg.h>
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#include <linux/skbuff.h>
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#include <linux/vmalloc.h>
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#include <linux/netlink.h>
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#include <linux/syscalls.h>
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#include <linux/audit.h>
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#include <linux/signal.h>
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#include <linux/mutex.h>
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#include <linux/nsproxy.h>
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#include <linux/pid.h>
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#include <linux/ipc_namespace.h>
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#include <linux/user_namespace.h>
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#include <linux/slab.h>
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#include <linux/sched/wake_q.h>
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#include <linux/sched/signal.h>
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#include <linux/sched/user.h>
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#include <net/sock.h>
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#include "util.h"
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struct mqueue_fs_context {
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struct ipc_namespace *ipc_ns;
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};
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#define MQUEUE_MAGIC 0x19800202
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#define DIRENT_SIZE 20
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#define FILENT_SIZE 80
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#define SEND 0
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#define RECV 1
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#define STATE_NONE 0
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#define STATE_READY 1
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struct posix_msg_tree_node {
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struct rb_node rb_node;
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struct list_head msg_list;
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int priority;
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};
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/*
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* Locking:
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*
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* Accesses to a message queue are synchronized by acquiring info->lock.
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*
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* There are two notable exceptions:
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* - The actual wakeup of a sleeping task is performed using the wake_q
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* framework. info->lock is already released when wake_up_q is called.
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* - The exit codepaths after sleeping check ext_wait_queue->state without
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* any locks. If it is STATE_READY, then the syscall is completed without
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* acquiring info->lock.
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*
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* MQ_BARRIER:
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* To achieve proper release/acquire memory barrier pairing, the state is set to
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* STATE_READY with smp_store_release(), and it is read with READ_ONCE followed
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* by smp_acquire__after_ctrl_dep(). In addition, wake_q_add_safe() is used.
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*
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* This prevents the following races:
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*
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* 1) With the simple wake_q_add(), the task could be gone already before
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* the increase of the reference happens
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* Thread A
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* Thread B
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* WRITE_ONCE(wait.state, STATE_NONE);
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* schedule_hrtimeout()
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* wake_q_add(A)
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* if (cmpxchg()) // success
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* ->state = STATE_READY (reordered)
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* <timeout returns>
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* if (wait.state == STATE_READY) return;
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* sysret to user space
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* sys_exit()
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* get_task_struct() // UaF
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*
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* Solution: Use wake_q_add_safe() and perform the get_task_struct() before
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* the smp_store_release() that does ->state = STATE_READY.
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*
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* 2) Without proper _release/_acquire barriers, the woken up task
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* could read stale data
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*
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* Thread A
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* Thread B
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* do_mq_timedreceive
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* WRITE_ONCE(wait.state, STATE_NONE);
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* schedule_hrtimeout()
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* state = STATE_READY;
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* <timeout returns>
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* if (wait.state == STATE_READY) return;
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* msg_ptr = wait.msg; // Access to stale data!
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* receiver->msg = message; (reordered)
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*
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* Solution: use _release and _acquire barriers.
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*
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* 3) There is intentionally no barrier when setting current->state
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* to TASK_INTERRUPTIBLE: spin_unlock(&info->lock) provides the
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* release memory barrier, and the wakeup is triggered when holding
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* info->lock, i.e. spin_lock(&info->lock) provided a pairing
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* acquire memory barrier.
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*/
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struct ext_wait_queue { /* queue of sleeping tasks */
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struct task_struct *task;
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struct list_head list;
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struct msg_msg *msg; /* ptr of loaded message */
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int state; /* one of STATE_* values */
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};
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struct mqueue_inode_info {
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spinlock_t lock;
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struct inode vfs_inode;
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wait_queue_head_t wait_q;
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struct rb_root msg_tree;
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struct rb_node *msg_tree_rightmost;
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struct posix_msg_tree_node *node_cache;
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struct mq_attr attr;
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struct sigevent notify;
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struct pid *notify_owner;
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u32 notify_self_exec_id;
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struct user_namespace *notify_user_ns;
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struct user_struct *user; /* user who created, for accounting */
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struct sock *notify_sock;
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struct sk_buff *notify_cookie;
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/* for tasks waiting for free space and messages, respectively */
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struct ext_wait_queue e_wait_q[2];
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unsigned long qsize; /* size of queue in memory (sum of all msgs) */
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};
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static struct file_system_type mqueue_fs_type;
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static const struct inode_operations mqueue_dir_inode_operations;
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static const struct file_operations mqueue_file_operations;
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static const struct super_operations mqueue_super_ops;
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static const struct fs_context_operations mqueue_fs_context_ops;
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static void remove_notification(struct mqueue_inode_info *info);
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static struct kmem_cache *mqueue_inode_cachep;
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static struct ctl_table_header *mq_sysctl_table;
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static inline struct mqueue_inode_info *MQUEUE_I(struct inode *inode)
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{
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return container_of(inode, struct mqueue_inode_info, vfs_inode);
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}
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/*
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* This routine should be called with the mq_lock held.
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*/
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static inline struct ipc_namespace *__get_ns_from_inode(struct inode *inode)
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{
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return get_ipc_ns(inode->i_sb->s_fs_info);
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}
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static struct ipc_namespace *get_ns_from_inode(struct inode *inode)
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{
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struct ipc_namespace *ns;
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spin_lock(&mq_lock);
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ns = __get_ns_from_inode(inode);
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spin_unlock(&mq_lock);
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return ns;
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}
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/* Auxiliary functions to manipulate messages' list */
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static int msg_insert(struct msg_msg *msg, struct mqueue_inode_info *info)
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{
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struct rb_node **p, *parent = NULL;
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struct posix_msg_tree_node *leaf;
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bool rightmost = true;
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p = &info->msg_tree.rb_node;
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while (*p) {
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parent = *p;
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leaf = rb_entry(parent, struct posix_msg_tree_node, rb_node);
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if (likely(leaf->priority == msg->m_type))
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goto insert_msg;
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else if (msg->m_type < leaf->priority) {
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p = &(*p)->rb_left;
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rightmost = false;
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} else
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p = &(*p)->rb_right;
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}
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if (info->node_cache) {
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leaf = info->node_cache;
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info->node_cache = NULL;
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} else {
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leaf = kmalloc(sizeof(*leaf), GFP_ATOMIC);
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if (!leaf)
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return -ENOMEM;
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INIT_LIST_HEAD(&leaf->msg_list);
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}
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leaf->priority = msg->m_type;
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if (rightmost)
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info->msg_tree_rightmost = &leaf->rb_node;
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rb_link_node(&leaf->rb_node, parent, p);
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rb_insert_color(&leaf->rb_node, &info->msg_tree);
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insert_msg:
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info->attr.mq_curmsgs++;
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info->qsize += msg->m_ts;
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list_add_tail(&msg->m_list, &leaf->msg_list);
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return 0;
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}
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static inline void msg_tree_erase(struct posix_msg_tree_node *leaf,
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struct mqueue_inode_info *info)
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{
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struct rb_node *node = &leaf->rb_node;
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if (info->msg_tree_rightmost == node)
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info->msg_tree_rightmost = rb_prev(node);
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rb_erase(node, &info->msg_tree);
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if (info->node_cache)
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kfree(leaf);
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else
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info->node_cache = leaf;
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}
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static inline struct msg_msg *msg_get(struct mqueue_inode_info *info)
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{
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struct rb_node *parent = NULL;
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struct posix_msg_tree_node *leaf;
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struct msg_msg *msg;
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try_again:
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/*
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* During insert, low priorities go to the left and high to the
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* right. On receive, we want the highest priorities first, so
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* walk all the way to the right.
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*/
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parent = info->msg_tree_rightmost;
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if (!parent) {
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if (info->attr.mq_curmsgs) {
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pr_warn_once("Inconsistency in POSIX message queue, "
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"no tree element, but supposedly messages "
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"should exist!\n");
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info->attr.mq_curmsgs = 0;
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}
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return NULL;
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}
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leaf = rb_entry(parent, struct posix_msg_tree_node, rb_node);
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if (unlikely(list_empty(&leaf->msg_list))) {
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pr_warn_once("Inconsistency in POSIX message queue, "
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"empty leaf node but we haven't implemented "
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"lazy leaf delete!\n");
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msg_tree_erase(leaf, info);
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goto try_again;
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} else {
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msg = list_first_entry(&leaf->msg_list,
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struct msg_msg, m_list);
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list_del(&msg->m_list);
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if (list_empty(&leaf->msg_list)) {
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msg_tree_erase(leaf, info);
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}
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}
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info->attr.mq_curmsgs--;
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info->qsize -= msg->m_ts;
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return msg;
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}
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static struct inode *mqueue_get_inode(struct super_block *sb,
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struct ipc_namespace *ipc_ns, umode_t mode,
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struct mq_attr *attr)
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{
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struct user_struct *u = current_user();
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struct inode *inode;
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int ret = -ENOMEM;
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inode = new_inode(sb);
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if (!inode)
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goto err;
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inode->i_ino = get_next_ino();
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inode->i_mode = mode;
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inode->i_uid = current_fsuid();
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inode->i_gid = current_fsgid();
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inode->i_mtime = inode->i_ctime = inode->i_atime = current_time(inode);
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if (S_ISREG(mode)) {
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struct mqueue_inode_info *info;
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unsigned long mq_bytes, mq_treesize;
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inode->i_fop = &mqueue_file_operations;
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inode->i_size = FILENT_SIZE;
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/* mqueue specific info */
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info = MQUEUE_I(inode);
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spin_lock_init(&info->lock);
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init_waitqueue_head(&info->wait_q);
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INIT_LIST_HEAD(&info->e_wait_q[0].list);
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INIT_LIST_HEAD(&info->e_wait_q[1].list);
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info->notify_owner = NULL;
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info->notify_user_ns = NULL;
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info->qsize = 0;
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info->user = NULL; /* set when all is ok */
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info->msg_tree = RB_ROOT;
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info->msg_tree_rightmost = NULL;
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info->node_cache = NULL;
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memset(&info->attr, 0, sizeof(info->attr));
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info->attr.mq_maxmsg = min(ipc_ns->mq_msg_max,
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ipc_ns->mq_msg_default);
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info->attr.mq_msgsize = min(ipc_ns->mq_msgsize_max,
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ipc_ns->mq_msgsize_default);
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if (attr) {
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info->attr.mq_maxmsg = attr->mq_maxmsg;
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info->attr.mq_msgsize = attr->mq_msgsize;
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}
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/*
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* We used to allocate a static array of pointers and account
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* the size of that array as well as one msg_msg struct per
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* possible message into the queue size. That's no longer
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* accurate as the queue is now an rbtree and will grow and
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* shrink depending on usage patterns. We can, however, still
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* account one msg_msg struct per message, but the nodes are
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* allocated depending on priority usage, and most programs
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* only use one, or a handful, of priorities. However, since
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* this is pinned memory, we need to assume worst case, so
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* that means the min(mq_maxmsg, max_priorities) * struct
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* posix_msg_tree_node.
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*/
|
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ret = -EINVAL;
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if (info->attr.mq_maxmsg <= 0 || info->attr.mq_msgsize <= 0)
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goto out_inode;
|
|
if (capable(CAP_SYS_RESOURCE)) {
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if (info->attr.mq_maxmsg > HARD_MSGMAX ||
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info->attr.mq_msgsize > HARD_MSGSIZEMAX)
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goto out_inode;
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} else {
|
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if (info->attr.mq_maxmsg > ipc_ns->mq_msg_max ||
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info->attr.mq_msgsize > ipc_ns->mq_msgsize_max)
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goto out_inode;
|
|
}
|
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ret = -EOVERFLOW;
|
|
/* check for overflow */
|
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if (info->attr.mq_msgsize > ULONG_MAX/info->attr.mq_maxmsg)
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goto out_inode;
|
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mq_treesize = info->attr.mq_maxmsg * sizeof(struct msg_msg) +
|
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min_t(unsigned int, info->attr.mq_maxmsg, MQ_PRIO_MAX) *
|
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sizeof(struct posix_msg_tree_node);
|
|
mq_bytes = info->attr.mq_maxmsg * info->attr.mq_msgsize;
|
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if (mq_bytes + mq_treesize < mq_bytes)
|
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goto out_inode;
|
|
mq_bytes += mq_treesize;
|
|
spin_lock(&mq_lock);
|
|
if (u->mq_bytes + mq_bytes < u->mq_bytes ||
|
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u->mq_bytes + mq_bytes > rlimit(RLIMIT_MSGQUEUE)) {
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spin_unlock(&mq_lock);
|
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/* mqueue_evict_inode() releases info->messages */
|
|
ret = -EMFILE;
|
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goto out_inode;
|
|
}
|
|
u->mq_bytes += mq_bytes;
|
|
spin_unlock(&mq_lock);
|
|
|
|
/* all is ok */
|
|
info->user = get_uid(u);
|
|
} else if (S_ISDIR(mode)) {
|
|
inc_nlink(inode);
|
|
/* Some things misbehave if size == 0 on a directory */
|
|
inode->i_size = 2 * DIRENT_SIZE;
|
|
inode->i_op = &mqueue_dir_inode_operations;
|
|
inode->i_fop = &simple_dir_operations;
|
|
}
|
|
|
|
return inode;
|
|
out_inode:
|
|
iput(inode);
|
|
err:
|
|
return ERR_PTR(ret);
|
|
}
|
|
|
|
static int mqueue_fill_super(struct super_block *sb, struct fs_context *fc)
|
|
{
|
|
struct inode *inode;
|
|
struct ipc_namespace *ns = sb->s_fs_info;
|
|
|
|
sb->s_iflags |= SB_I_NOEXEC | SB_I_NODEV;
|
|
sb->s_blocksize = PAGE_SIZE;
|
|
sb->s_blocksize_bits = PAGE_SHIFT;
|
|
sb->s_magic = MQUEUE_MAGIC;
|
|
sb->s_op = &mqueue_super_ops;
|
|
|
|
inode = mqueue_get_inode(sb, ns, S_IFDIR | S_ISVTX | S_IRWXUGO, NULL);
|
|
if (IS_ERR(inode))
|
|
return PTR_ERR(inode);
|
|
|
|
sb->s_root = d_make_root(inode);
|
|
if (!sb->s_root)
|
|
return -ENOMEM;
|
|
return 0;
|
|
}
|
|
|
|
static int mqueue_get_tree(struct fs_context *fc)
|
|
{
|
|
struct mqueue_fs_context *ctx = fc->fs_private;
|
|
|
|
return get_tree_keyed(fc, mqueue_fill_super, ctx->ipc_ns);
|
|
}
|
|
|
|
static void mqueue_fs_context_free(struct fs_context *fc)
|
|
{
|
|
struct mqueue_fs_context *ctx = fc->fs_private;
|
|
|
|
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);
|
|
put_user_ns(fc->user_ns);
|
|
fc->user_ns = get_user_ns(ctx->ipc_ns->user_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);
|
|
put_user_ns(fc->user_ns);
|
|
fc->user_ns = get_user_ns(ctx->ipc_ns->user_ns);
|
|
|
|
mnt = fc_mount(fc);
|
|
put_fs_context(fc);
|
|
return mnt;
|
|
}
|
|
|
|
static void init_once(void *foo)
|
|
{
|
|
struct mqueue_inode_info *p = (struct mqueue_inode_info *) foo;
|
|
|
|
inode_init_once(&p->vfs_inode);
|
|
}
|
|
|
|
static struct inode *mqueue_alloc_inode(struct super_block *sb)
|
|
{
|
|
struct mqueue_inode_info *ei;
|
|
|
|
ei = kmem_cache_alloc(mqueue_inode_cachep, GFP_KERNEL);
|
|
if (!ei)
|
|
return NULL;
|
|
return &ei->vfs_inode;
|
|
}
|
|
|
|
static void mqueue_free_inode(struct inode *inode)
|
|
{
|
|
kmem_cache_free(mqueue_inode_cachep, MQUEUE_I(inode));
|
|
}
|
|
|
|
static void mqueue_evict_inode(struct inode *inode)
|
|
{
|
|
struct mqueue_inode_info *info;
|
|
struct user_struct *user;
|
|
struct ipc_namespace *ipc_ns;
|
|
struct msg_msg *msg, *nmsg;
|
|
LIST_HEAD(tmp_msg);
|
|
|
|
clear_inode(inode);
|
|
|
|
if (S_ISDIR(inode->i_mode))
|
|
return;
|
|
|
|
ipc_ns = get_ns_from_inode(inode);
|
|
info = MQUEUE_I(inode);
|
|
spin_lock(&info->lock);
|
|
while ((msg = msg_get(info)) != NULL)
|
|
list_add_tail(&msg->m_list, &tmp_msg);
|
|
kfree(info->node_cache);
|
|
spin_unlock(&info->lock);
|
|
|
|
list_for_each_entry_safe(msg, nmsg, &tmp_msg, m_list) {
|
|
list_del(&msg->m_list);
|
|
free_msg(msg);
|
|
}
|
|
|
|
user = info->user;
|
|
if (user) {
|
|
unsigned long mq_bytes, mq_treesize;
|
|
|
|
/* Total amount of bytes accounted for the mqueue */
|
|
mq_treesize = info->attr.mq_maxmsg * sizeof(struct msg_msg) +
|
|
min_t(unsigned int, info->attr.mq_maxmsg, MQ_PRIO_MAX) *
|
|
sizeof(struct posix_msg_tree_node);
|
|
|
|
mq_bytes = mq_treesize + (info->attr.mq_maxmsg *
|
|
info->attr.mq_msgsize);
|
|
|
|
spin_lock(&mq_lock);
|
|
user->mq_bytes -= mq_bytes;
|
|
/*
|
|
* get_ns_from_inode() ensures that the
|
|
* (ipc_ns = sb->s_fs_info) is either a valid ipc_ns
|
|
* to which we now hold a reference, or it is NULL.
|
|
* We can't put it here under mq_lock, though.
|
|
*/
|
|
if (ipc_ns)
|
|
ipc_ns->mq_queues_count--;
|
|
spin_unlock(&mq_lock);
|
|
free_uid(user);
|
|
}
|
|
if (ipc_ns)
|
|
put_ipc_ns(ipc_ns);
|
|
}
|
|
|
|
static int mqueue_create_attr(struct dentry *dentry, umode_t mode, void *arg)
|
|
{
|
|
struct inode *dir = dentry->d_parent->d_inode;
|
|
struct inode *inode;
|
|
struct mq_attr *attr = arg;
|
|
int error;
|
|
struct ipc_namespace *ipc_ns;
|
|
|
|
spin_lock(&mq_lock);
|
|
ipc_ns = __get_ns_from_inode(dir);
|
|
if (!ipc_ns) {
|
|
error = -EACCES;
|
|
goto out_unlock;
|
|
}
|
|
|
|
if (ipc_ns->mq_queues_count >= ipc_ns->mq_queues_max &&
|
|
!capable(CAP_SYS_RESOURCE)) {
|
|
error = -ENOSPC;
|
|
goto out_unlock;
|
|
}
|
|
ipc_ns->mq_queues_count++;
|
|
spin_unlock(&mq_lock);
|
|
|
|
inode = mqueue_get_inode(dir->i_sb, ipc_ns, mode, attr);
|
|
if (IS_ERR(inode)) {
|
|
error = PTR_ERR(inode);
|
|
spin_lock(&mq_lock);
|
|
ipc_ns->mq_queues_count--;
|
|
goto out_unlock;
|
|
}
|
|
|
|
put_ipc_ns(ipc_ns);
|
|
dir->i_size += DIRENT_SIZE;
|
|
dir->i_ctime = dir->i_mtime = dir->i_atime = current_time(dir);
|
|
|
|
d_instantiate(dentry, inode);
|
|
dget(dentry);
|
|
return 0;
|
|
out_unlock:
|
|
spin_unlock(&mq_lock);
|
|
if (ipc_ns)
|
|
put_ipc_ns(ipc_ns);
|
|
return error;
|
|
}
|
|
|
|
static int mqueue_create(struct user_namespace *mnt_userns, struct inode *dir,
|
|
struct dentry *dentry, umode_t mode, bool excl)
|
|
{
|
|
return mqueue_create_attr(dentry, mode, NULL);
|
|
}
|
|
|
|
static int mqueue_unlink(struct inode *dir, struct dentry *dentry)
|
|
{
|
|
struct inode *inode = d_inode(dentry);
|
|
|
|
dir->i_ctime = dir->i_mtime = dir->i_atime = current_time(dir);
|
|
dir->i_size -= DIRENT_SIZE;
|
|
drop_nlink(inode);
|
|
dput(dentry);
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* This is routine for system read from queue file.
|
|
* To avoid mess with doing here some sort of mq_receive we allow
|
|
* to read only queue size & notification info (the only values
|
|
* that are interesting from user point of view and aren't accessible
|
|
* through std routines)
|
|
*/
|
|
static ssize_t mqueue_read_file(struct file *filp, char __user *u_data,
|
|
size_t count, loff_t *off)
|
|
{
|
|
struct mqueue_inode_info *info = MQUEUE_I(file_inode(filp));
|
|
char buffer[FILENT_SIZE];
|
|
ssize_t ret;
|
|
|
|
spin_lock(&info->lock);
|
|
snprintf(buffer, sizeof(buffer),
|
|
"QSIZE:%-10lu NOTIFY:%-5d SIGNO:%-5d NOTIFY_PID:%-6d\n",
|
|
info->qsize,
|
|
info->notify_owner ? info->notify.sigev_notify : 0,
|
|
(info->notify_owner &&
|
|
info->notify.sigev_notify == SIGEV_SIGNAL) ?
|
|
info->notify.sigev_signo : 0,
|
|
pid_vnr(info->notify_owner));
|
|
spin_unlock(&info->lock);
|
|
buffer[sizeof(buffer)-1] = '\0';
|
|
|
|
ret = simple_read_from_buffer(u_data, count, off, buffer,
|
|
strlen(buffer));
|
|
if (ret <= 0)
|
|
return ret;
|
|
|
|
file_inode(filp)->i_atime = file_inode(filp)->i_ctime = current_time(file_inode(filp));
|
|
return ret;
|
|
}
|
|
|
|
static int mqueue_flush_file(struct file *filp, fl_owner_t id)
|
|
{
|
|
struct mqueue_inode_info *info = MQUEUE_I(file_inode(filp));
|
|
|
|
spin_lock(&info->lock);
|
|
if (task_tgid(current) == info->notify_owner)
|
|
remove_notification(info);
|
|
|
|
spin_unlock(&info->lock);
|
|
return 0;
|
|
}
|
|
|
|
static __poll_t mqueue_poll_file(struct file *filp, struct poll_table_struct *poll_tab)
|
|
{
|
|
struct mqueue_inode_info *info = MQUEUE_I(file_inode(filp));
|
|
__poll_t retval = 0;
|
|
|
|
poll_wait(filp, &info->wait_q, poll_tab);
|
|
|
|
spin_lock(&info->lock);
|
|
if (info->attr.mq_curmsgs)
|
|
retval = EPOLLIN | EPOLLRDNORM;
|
|
|
|
if (info->attr.mq_curmsgs < info->attr.mq_maxmsg)
|
|
retval |= EPOLLOUT | EPOLLWRNORM;
|
|
spin_unlock(&info->lock);
|
|
|
|
return retval;
|
|
}
|
|
|
|
/* Adds current to info->e_wait_q[sr] before element with smaller prio */
|
|
static void wq_add(struct mqueue_inode_info *info, int sr,
|
|
struct ext_wait_queue *ewp)
|
|
{
|
|
struct ext_wait_queue *walk;
|
|
|
|
list_for_each_entry(walk, &info->e_wait_q[sr].list, list) {
|
|
if (walk->task->prio <= current->prio) {
|
|
list_add_tail(&ewp->list, &walk->list);
|
|
return;
|
|
}
|
|
}
|
|
list_add_tail(&ewp->list, &info->e_wait_q[sr].list);
|
|
}
|
|
|
|
/*
|
|
* Puts current task to sleep. Caller must hold queue lock. After return
|
|
* lock isn't held.
|
|
* sr: SEND or RECV
|
|
*/
|
|
static int wq_sleep(struct mqueue_inode_info *info, int sr,
|
|
ktime_t *timeout, struct ext_wait_queue *ewp)
|
|
__releases(&info->lock)
|
|
{
|
|
int retval;
|
|
signed long time;
|
|
|
|
wq_add(info, sr, ewp);
|
|
|
|
for (;;) {
|
|
/* memory barrier not required, we hold info->lock */
|
|
__set_current_state(TASK_INTERRUPTIBLE);
|
|
|
|
spin_unlock(&info->lock);
|
|
time = schedule_hrtimeout_range_clock(timeout, 0,
|
|
HRTIMER_MODE_ABS, CLOCK_REALTIME);
|
|
|
|
if (READ_ONCE(ewp->state) == STATE_READY) {
|
|
/* see MQ_BARRIER for purpose/pairing */
|
|
smp_acquire__after_ctrl_dep();
|
|
retval = 0;
|
|
goto out;
|
|
}
|
|
spin_lock(&info->lock);
|
|
|
|
/* we hold info->lock, so no memory barrier required */
|
|
if (READ_ONCE(ewp->state) == STATE_READY) {
|
|
retval = 0;
|
|
goto out_unlock;
|
|
}
|
|
if (signal_pending(current)) {
|
|
retval = -ERESTARTSYS;
|
|
break;
|
|
}
|
|
if (time == 0) {
|
|
retval = -ETIMEDOUT;
|
|
break;
|
|
}
|
|
}
|
|
list_del(&ewp->list);
|
|
out_unlock:
|
|
spin_unlock(&info->lock);
|
|
out:
|
|
return retval;
|
|
}
|
|
|
|
/*
|
|
* Returns waiting task that should be serviced first or NULL if none exists
|
|
*/
|
|
static struct ext_wait_queue *wq_get_first_waiter(
|
|
struct mqueue_inode_info *info, int sr)
|
|
{
|
|
struct list_head *ptr;
|
|
|
|
ptr = info->e_wait_q[sr].list.prev;
|
|
if (ptr == &info->e_wait_q[sr].list)
|
|
return NULL;
|
|
return list_entry(ptr, struct ext_wait_queue, list);
|
|
}
|
|
|
|
|
|
static inline void set_cookie(struct sk_buff *skb, char code)
|
|
{
|
|
((char *)skb->data)[NOTIFY_COOKIE_LEN-1] = code;
|
|
}
|
|
|
|
/*
|
|
* The next function is only to split too long sys_mq_timedsend
|
|
*/
|
|
static void __do_notify(struct mqueue_inode_info *info)
|
|
{
|
|
/* notification
|
|
* invoked when there is registered process and there isn't process
|
|
* waiting synchronously for message AND state of queue changed from
|
|
* empty to not empty. Here we are sure that no one is waiting
|
|
* synchronously. */
|
|
if (info->notify_owner &&
|
|
info->attr.mq_curmsgs == 1) {
|
|
switch (info->notify.sigev_notify) {
|
|
case SIGEV_NONE:
|
|
break;
|
|
case SIGEV_SIGNAL: {
|
|
struct kernel_siginfo sig_i;
|
|
struct task_struct *task;
|
|
|
|
/* do_mq_notify() accepts sigev_signo == 0, why?? */
|
|
if (!info->notify.sigev_signo)
|
|
break;
|
|
|
|
clear_siginfo(&sig_i);
|
|
sig_i.si_signo = info->notify.sigev_signo;
|
|
sig_i.si_errno = 0;
|
|
sig_i.si_code = SI_MESGQ;
|
|
sig_i.si_value = info->notify.sigev_value;
|
|
rcu_read_lock();
|
|
/* map current pid/uid into info->owner's namespaces */
|
|
sig_i.si_pid = task_tgid_nr_ns(current,
|
|
ns_of_pid(info->notify_owner));
|
|
sig_i.si_uid = from_kuid_munged(info->notify_user_ns,
|
|
current_uid());
|
|
/*
|
|
* We can't use kill_pid_info(), this signal should
|
|
* bypass check_kill_permission(). It is from kernel
|
|
* but si_fromuser() can't know this.
|
|
* We do check the self_exec_id, to avoid sending
|
|
* signals to programs that don't expect them.
|
|
*/
|
|
task = pid_task(info->notify_owner, PIDTYPE_TGID);
|
|
if (task && task->self_exec_id ==
|
|
info->notify_self_exec_id) {
|
|
do_send_sig_info(info->notify.sigev_signo,
|
|
&sig_i, task, PIDTYPE_TGID);
|
|
}
|
|
rcu_read_unlock();
|
|
break;
|
|
}
|
|
case SIGEV_THREAD:
|
|
set_cookie(info->notify_cookie, NOTIFY_WOKENUP);
|
|
netlink_sendskb(info->notify_sock, info->notify_cookie);
|
|
break;
|
|
}
|
|
/* after notification unregisters process */
|
|
put_pid(info->notify_owner);
|
|
put_user_ns(info->notify_user_ns);
|
|
info->notify_owner = NULL;
|
|
info->notify_user_ns = NULL;
|
|
}
|
|
wake_up(&info->wait_q);
|
|
}
|
|
|
|
static int prepare_timeout(const struct __kernel_timespec __user *u_abs_timeout,
|
|
struct timespec64 *ts)
|
|
{
|
|
if (get_timespec64(ts, u_abs_timeout))
|
|
return -EFAULT;
|
|
if (!timespec64_valid(ts))
|
|
return -EINVAL;
|
|
return 0;
|
|
}
|
|
|
|
static void remove_notification(struct mqueue_inode_info *info)
|
|
{
|
|
if (info->notify_owner != NULL &&
|
|
info->notify.sigev_notify == SIGEV_THREAD) {
|
|
set_cookie(info->notify_cookie, NOTIFY_REMOVED);
|
|
netlink_sendskb(info->notify_sock, info->notify_cookie);
|
|
}
|
|
put_pid(info->notify_owner);
|
|
put_user_ns(info->notify_user_ns);
|
|
info->notify_owner = NULL;
|
|
info->notify_user_ns = NULL;
|
|
}
|
|
|
|
static int prepare_open(struct dentry *dentry, int oflag, int ro,
|
|
umode_t mode, struct filename *name,
|
|
struct mq_attr *attr)
|
|
{
|
|
static const int oflag2acc[O_ACCMODE] = { MAY_READ, MAY_WRITE,
|
|
MAY_READ | MAY_WRITE };
|
|
int acc;
|
|
|
|
if (d_really_is_negative(dentry)) {
|
|
if (!(oflag & O_CREAT))
|
|
return -ENOENT;
|
|
if (ro)
|
|
return ro;
|
|
audit_inode_parent_hidden(name, dentry->d_parent);
|
|
return vfs_mkobj(dentry, mode & ~current_umask(),
|
|
mqueue_create_attr, attr);
|
|
}
|
|
/* it already existed */
|
|
audit_inode(name, dentry, 0);
|
|
if ((oflag & (O_CREAT|O_EXCL)) == (O_CREAT|O_EXCL))
|
|
return -EEXIST;
|
|
if ((oflag & O_ACCMODE) == (O_RDWR | O_WRONLY))
|
|
return -EINVAL;
|
|
acc = oflag2acc[oflag & O_ACCMODE];
|
|
return inode_permission(&init_user_ns, d_inode(dentry), acc);
|
|
}
|
|
|
|
static int do_mq_open(const char __user *u_name, int oflag, umode_t mode,
|
|
struct mq_attr *attr)
|
|
{
|
|
struct vfsmount *mnt = current->nsproxy->ipc_ns->mq_mnt;
|
|
struct dentry *root = mnt->mnt_root;
|
|
struct filename *name;
|
|
struct path path;
|
|
int fd, error;
|
|
int ro;
|
|
|
|
audit_mq_open(oflag, mode, attr);
|
|
|
|
if (IS_ERR(name = getname(u_name)))
|
|
return PTR_ERR(name);
|
|
|
|
fd = get_unused_fd_flags(O_CLOEXEC);
|
|
if (fd < 0)
|
|
goto out_putname;
|
|
|
|
ro = mnt_want_write(mnt); /* we'll drop it in any case */
|
|
inode_lock(d_inode(root));
|
|
path.dentry = lookup_one_len(name->name, root, strlen(name->name));
|
|
if (IS_ERR(path.dentry)) {
|
|
error = PTR_ERR(path.dentry);
|
|
goto out_putfd;
|
|
}
|
|
path.mnt = mntget(mnt);
|
|
error = prepare_open(path.dentry, oflag, ro, mode, name, attr);
|
|
if (!error) {
|
|
struct file *file = dentry_open(&path, oflag, current_cred());
|
|
if (!IS_ERR(file))
|
|
fd_install(fd, file);
|
|
else
|
|
error = PTR_ERR(file);
|
|
}
|
|
path_put(&path);
|
|
out_putfd:
|
|
if (error) {
|
|
put_unused_fd(fd);
|
|
fd = error;
|
|
}
|
|
inode_unlock(d_inode(root));
|
|
if (!ro)
|
|
mnt_drop_write(mnt);
|
|
out_putname:
|
|
putname(name);
|
|
return fd;
|
|
}
|
|
|
|
SYSCALL_DEFINE4(mq_open, const char __user *, u_name, int, oflag, umode_t, mode,
|
|
struct mq_attr __user *, u_attr)
|
|
{
|
|
struct mq_attr attr;
|
|
if (u_attr && copy_from_user(&attr, u_attr, sizeof(struct mq_attr)))
|
|
return -EFAULT;
|
|
|
|
return do_mq_open(u_name, oflag, mode, u_attr ? &attr : NULL);
|
|
}
|
|
|
|
SYSCALL_DEFINE1(mq_unlink, const char __user *, u_name)
|
|
{
|
|
int err;
|
|
struct filename *name;
|
|
struct dentry *dentry;
|
|
struct inode *inode = NULL;
|
|
struct ipc_namespace *ipc_ns = current->nsproxy->ipc_ns;
|
|
struct vfsmount *mnt = ipc_ns->mq_mnt;
|
|
|
|
name = getname(u_name);
|
|
if (IS_ERR(name))
|
|
return PTR_ERR(name);
|
|
|
|
audit_inode_parent_hidden(name, mnt->mnt_root);
|
|
err = mnt_want_write(mnt);
|
|
if (err)
|
|
goto out_name;
|
|
inode_lock_nested(d_inode(mnt->mnt_root), I_MUTEX_PARENT);
|
|
dentry = lookup_one_len(name->name, mnt->mnt_root,
|
|
strlen(name->name));
|
|
if (IS_ERR(dentry)) {
|
|
err = PTR_ERR(dentry);
|
|
goto out_unlock;
|
|
}
|
|
|
|
inode = d_inode(dentry);
|
|
if (!inode) {
|
|
err = -ENOENT;
|
|
} else {
|
|
ihold(inode);
|
|
err = vfs_unlink(&init_user_ns, d_inode(dentry->d_parent),
|
|
dentry, NULL);
|
|
}
|
|
dput(dentry);
|
|
|
|
out_unlock:
|
|
inode_unlock(d_inode(mnt->mnt_root));
|
|
if (inode)
|
|
iput(inode);
|
|
mnt_drop_write(mnt);
|
|
out_name:
|
|
putname(name);
|
|
|
|
return err;
|
|
}
|
|
|
|
/* Pipelined send and receive functions.
|
|
*
|
|
* If a receiver finds no waiting message, then it registers itself in the
|
|
* list of waiting receivers. A sender checks that list before adding the new
|
|
* message into the message array. If there is a waiting receiver, then it
|
|
* bypasses the message array and directly hands the message over to the
|
|
* receiver. The receiver accepts the message and returns without grabbing the
|
|
* queue spinlock:
|
|
*
|
|
* - Set pointer to message.
|
|
* - Queue the receiver task for later wakeup (without the info->lock).
|
|
* - Update its state to STATE_READY. Now the receiver can continue.
|
|
* - Wake up the process after the lock is dropped. Should the process wake up
|
|
* before this wakeup (due to a timeout or a signal) it will either see
|
|
* STATE_READY and continue or acquire the lock to check the state again.
|
|
*
|
|
* The same algorithm is used for senders.
|
|
*/
|
|
|
|
static inline void __pipelined_op(struct wake_q_head *wake_q,
|
|
struct mqueue_inode_info *info,
|
|
struct ext_wait_queue *this)
|
|
{
|
|
list_del(&this->list);
|
|
get_task_struct(this->task);
|
|
|
|
/* see MQ_BARRIER for purpose/pairing */
|
|
smp_store_release(&this->state, STATE_READY);
|
|
wake_q_add_safe(wake_q, this->task);
|
|
}
|
|
|
|
/* pipelined_send() - send a message directly to the task waiting in
|
|
* sys_mq_timedreceive() (without inserting message into a queue).
|
|
*/
|
|
static inline void pipelined_send(struct wake_q_head *wake_q,
|
|
struct mqueue_inode_info *info,
|
|
struct msg_msg *message,
|
|
struct ext_wait_queue *receiver)
|
|
{
|
|
receiver->msg = message;
|
|
__pipelined_op(wake_q, info, receiver);
|
|
}
|
|
|
|
/* pipelined_receive() - if there is task waiting in sys_mq_timedsend()
|
|
* gets its message and put to the queue (we have one free place for sure). */
|
|
static inline void pipelined_receive(struct wake_q_head *wake_q,
|
|
struct mqueue_inode_info *info)
|
|
{
|
|
struct ext_wait_queue *sender = wq_get_first_waiter(info, SEND);
|
|
|
|
if (!sender) {
|
|
/* for poll */
|
|
wake_up_interruptible(&info->wait_q);
|
|
return;
|
|
}
|
|
if (msg_insert(sender->msg, info))
|
|
return;
|
|
|
|
__pipelined_op(wake_q, info, sender);
|
|
}
|
|
|
|
static int do_mq_timedsend(mqd_t mqdes, const char __user *u_msg_ptr,
|
|
size_t msg_len, unsigned int msg_prio,
|
|
struct timespec64 *ts)
|
|
{
|
|
struct fd f;
|
|
struct inode *inode;
|
|
struct ext_wait_queue wait;
|
|
struct ext_wait_queue *receiver;
|
|
struct msg_msg *msg_ptr;
|
|
struct mqueue_inode_info *info;
|
|
ktime_t expires, *timeout = NULL;
|
|
struct posix_msg_tree_node *new_leaf = NULL;
|
|
int ret = 0;
|
|
DEFINE_WAKE_Q(wake_q);
|
|
|
|
if (unlikely(msg_prio >= (unsigned long) MQ_PRIO_MAX))
|
|
return -EINVAL;
|
|
|
|
if (ts) {
|
|
expires = timespec64_to_ktime(*ts);
|
|
timeout = &expires;
|
|
}
|
|
|
|
audit_mq_sendrecv(mqdes, msg_len, msg_prio, ts);
|
|
|
|
f = fdget(mqdes);
|
|
if (unlikely(!f.file)) {
|
|
ret = -EBADF;
|
|
goto out;
|
|
}
|
|
|
|
inode = file_inode(f.file);
|
|
if (unlikely(f.file->f_op != &mqueue_file_operations)) {
|
|
ret = -EBADF;
|
|
goto out_fput;
|
|
}
|
|
info = MQUEUE_I(inode);
|
|
audit_file(f.file);
|
|
|
|
if (unlikely(!(f.file->f_mode & FMODE_WRITE))) {
|
|
ret = -EBADF;
|
|
goto out_fput;
|
|
}
|
|
|
|
if (unlikely(msg_len > info->attr.mq_msgsize)) {
|
|
ret = -EMSGSIZE;
|
|
goto out_fput;
|
|
}
|
|
|
|
/* First try to allocate memory, before doing anything with
|
|
* existing queues. */
|
|
msg_ptr = load_msg(u_msg_ptr, msg_len);
|
|
if (IS_ERR(msg_ptr)) {
|
|
ret = PTR_ERR(msg_ptr);
|
|
goto out_fput;
|
|
}
|
|
msg_ptr->m_ts = msg_len;
|
|
msg_ptr->m_type = msg_prio;
|
|
|
|
/*
|
|
* msg_insert really wants us to have a valid, spare node struct so
|
|
* it doesn't have to kmalloc a GFP_ATOMIC allocation, but it will
|
|
* fall back to that if necessary.
|
|
*/
|
|
if (!info->node_cache)
|
|
new_leaf = kmalloc(sizeof(*new_leaf), GFP_KERNEL);
|
|
|
|
spin_lock(&info->lock);
|
|
|
|
if (!info->node_cache && new_leaf) {
|
|
/* Save our speculative allocation into the cache */
|
|
INIT_LIST_HEAD(&new_leaf->msg_list);
|
|
info->node_cache = new_leaf;
|
|
new_leaf = NULL;
|
|
} else {
|
|
kfree(new_leaf);
|
|
}
|
|
|
|
if (info->attr.mq_curmsgs == info->attr.mq_maxmsg) {
|
|
if (f.file->f_flags & O_NONBLOCK) {
|
|
ret = -EAGAIN;
|
|
} else {
|
|
wait.task = current;
|
|
wait.msg = (void *) msg_ptr;
|
|
|
|
/* memory barrier not required, we hold info->lock */
|
|
WRITE_ONCE(wait.state, STATE_NONE);
|
|
ret = wq_sleep(info, SEND, timeout, &wait);
|
|
/*
|
|
* wq_sleep must be called with info->lock held, and
|
|
* returns with the lock released
|
|
*/
|
|
goto out_free;
|
|
}
|
|
} else {
|
|
receiver = wq_get_first_waiter(info, RECV);
|
|
if (receiver) {
|
|
pipelined_send(&wake_q, info, msg_ptr, receiver);
|
|
} else {
|
|
/* adds message to the queue */
|
|
ret = msg_insert(msg_ptr, info);
|
|
if (ret)
|
|
goto out_unlock;
|
|
__do_notify(info);
|
|
}
|
|
inode->i_atime = inode->i_mtime = inode->i_ctime =
|
|
current_time(inode);
|
|
}
|
|
out_unlock:
|
|
spin_unlock(&info->lock);
|
|
wake_up_q(&wake_q);
|
|
out_free:
|
|
if (ret)
|
|
free_msg(msg_ptr);
|
|
out_fput:
|
|
fdput(f);
|
|
out:
|
|
return ret;
|
|
}
|
|
|
|
static int do_mq_timedreceive(mqd_t mqdes, char __user *u_msg_ptr,
|
|
size_t msg_len, unsigned int __user *u_msg_prio,
|
|
struct timespec64 *ts)
|
|
{
|
|
ssize_t ret;
|
|
struct msg_msg *msg_ptr;
|
|
struct fd f;
|
|
struct inode *inode;
|
|
struct mqueue_inode_info *info;
|
|
struct ext_wait_queue wait;
|
|
ktime_t expires, *timeout = NULL;
|
|
struct posix_msg_tree_node *new_leaf = NULL;
|
|
|
|
if (ts) {
|
|
expires = timespec64_to_ktime(*ts);
|
|
timeout = &expires;
|
|
}
|
|
|
|
audit_mq_sendrecv(mqdes, msg_len, 0, ts);
|
|
|
|
f = fdget(mqdes);
|
|
if (unlikely(!f.file)) {
|
|
ret = -EBADF;
|
|
goto out;
|
|
}
|
|
|
|
inode = file_inode(f.file);
|
|
if (unlikely(f.file->f_op != &mqueue_file_operations)) {
|
|
ret = -EBADF;
|
|
goto out_fput;
|
|
}
|
|
info = MQUEUE_I(inode);
|
|
audit_file(f.file);
|
|
|
|
if (unlikely(!(f.file->f_mode & FMODE_READ))) {
|
|
ret = -EBADF;
|
|
goto out_fput;
|
|
}
|
|
|
|
/* checks if buffer is big enough */
|
|
if (unlikely(msg_len < info->attr.mq_msgsize)) {
|
|
ret = -EMSGSIZE;
|
|
goto out_fput;
|
|
}
|
|
|
|
/*
|
|
* msg_insert really wants us to have a valid, spare node struct so
|
|
* it doesn't have to kmalloc a GFP_ATOMIC allocation, but it will
|
|
* fall back to that if necessary.
|
|
*/
|
|
if (!info->node_cache)
|
|
new_leaf = kmalloc(sizeof(*new_leaf), GFP_KERNEL);
|
|
|
|
spin_lock(&info->lock);
|
|
|
|
if (!info->node_cache && new_leaf) {
|
|
/* Save our speculative allocation into the cache */
|
|
INIT_LIST_HEAD(&new_leaf->msg_list);
|
|
info->node_cache = new_leaf;
|
|
} else {
|
|
kfree(new_leaf);
|
|
}
|
|
|
|
if (info->attr.mq_curmsgs == 0) {
|
|
if (f.file->f_flags & O_NONBLOCK) {
|
|
spin_unlock(&info->lock);
|
|
ret = -EAGAIN;
|
|
} else {
|
|
wait.task = current;
|
|
|
|
/* memory barrier not required, we hold info->lock */
|
|
WRITE_ONCE(wait.state, STATE_NONE);
|
|
ret = wq_sleep(info, RECV, timeout, &wait);
|
|
msg_ptr = wait.msg;
|
|
}
|
|
} else {
|
|
DEFINE_WAKE_Q(wake_q);
|
|
|
|
msg_ptr = msg_get(info);
|
|
|
|
inode->i_atime = inode->i_mtime = inode->i_ctime =
|
|
current_time(inode);
|
|
|
|
/* There is now free space in queue. */
|
|
pipelined_receive(&wake_q, info);
|
|
spin_unlock(&info->lock);
|
|
wake_up_q(&wake_q);
|
|
ret = 0;
|
|
}
|
|
if (ret == 0) {
|
|
ret = msg_ptr->m_ts;
|
|
|
|
if ((u_msg_prio && put_user(msg_ptr->m_type, u_msg_prio)) ||
|
|
store_msg(u_msg_ptr, msg_ptr, msg_ptr->m_ts)) {
|
|
ret = -EFAULT;
|
|
}
|
|
free_msg(msg_ptr);
|
|
}
|
|
out_fput:
|
|
fdput(f);
|
|
out:
|
|
return ret;
|
|
}
|
|
|
|
SYSCALL_DEFINE5(mq_timedsend, mqd_t, mqdes, const char __user *, u_msg_ptr,
|
|
size_t, msg_len, unsigned int, msg_prio,
|
|
const struct __kernel_timespec __user *, u_abs_timeout)
|
|
{
|
|
struct timespec64 ts, *p = NULL;
|
|
if (u_abs_timeout) {
|
|
int res = prepare_timeout(u_abs_timeout, &ts);
|
|
if (res)
|
|
return res;
|
|
p = &ts;
|
|
}
|
|
return do_mq_timedsend(mqdes, u_msg_ptr, msg_len, msg_prio, p);
|
|
}
|
|
|
|
SYSCALL_DEFINE5(mq_timedreceive, mqd_t, mqdes, char __user *, u_msg_ptr,
|
|
size_t, msg_len, unsigned int __user *, u_msg_prio,
|
|
const struct __kernel_timespec __user *, u_abs_timeout)
|
|
{
|
|
struct timespec64 ts, *p = NULL;
|
|
if (u_abs_timeout) {
|
|
int res = prepare_timeout(u_abs_timeout, &ts);
|
|
if (res)
|
|
return res;
|
|
p = &ts;
|
|
}
|
|
return do_mq_timedreceive(mqdes, u_msg_ptr, msg_len, u_msg_prio, p);
|
|
}
|
|
|
|
/*
|
|
* Notes: the case when user wants us to deregister (with NULL as pointer)
|
|
* and he isn't currently owner of notification, will be silently discarded.
|
|
* It isn't explicitly defined in the POSIX.
|
|
*/
|
|
static int do_mq_notify(mqd_t mqdes, const struct sigevent *notification)
|
|
{
|
|
int ret;
|
|
struct fd f;
|
|
struct sock *sock;
|
|
struct inode *inode;
|
|
struct mqueue_inode_info *info;
|
|
struct sk_buff *nc;
|
|
|
|
audit_mq_notify(mqdes, notification);
|
|
|
|
nc = NULL;
|
|
sock = NULL;
|
|
if (notification != NULL) {
|
|
if (unlikely(notification->sigev_notify != SIGEV_NONE &&
|
|
notification->sigev_notify != SIGEV_SIGNAL &&
|
|
notification->sigev_notify != SIGEV_THREAD))
|
|
return -EINVAL;
|
|
if (notification->sigev_notify == SIGEV_SIGNAL &&
|
|
!valid_signal(notification->sigev_signo)) {
|
|
return -EINVAL;
|
|
}
|
|
if (notification->sigev_notify == SIGEV_THREAD) {
|
|
long timeo;
|
|
|
|
/* create the notify skb */
|
|
nc = alloc_skb(NOTIFY_COOKIE_LEN, GFP_KERNEL);
|
|
if (!nc)
|
|
return -ENOMEM;
|
|
|
|
if (copy_from_user(nc->data,
|
|
notification->sigev_value.sival_ptr,
|
|
NOTIFY_COOKIE_LEN)) {
|
|
ret = -EFAULT;
|
|
goto free_skb;
|
|
}
|
|
|
|
/* TODO: add a header? */
|
|
skb_put(nc, NOTIFY_COOKIE_LEN);
|
|
/* and attach it to the socket */
|
|
retry:
|
|
f = fdget(notification->sigev_signo);
|
|
if (!f.file) {
|
|
ret = -EBADF;
|
|
goto out;
|
|
}
|
|
sock = netlink_getsockbyfilp(f.file);
|
|
fdput(f);
|
|
if (IS_ERR(sock)) {
|
|
ret = PTR_ERR(sock);
|
|
goto free_skb;
|
|
}
|
|
|
|
timeo = MAX_SCHEDULE_TIMEOUT;
|
|
ret = netlink_attachskb(sock, nc, &timeo, NULL);
|
|
if (ret == 1) {
|
|
sock = NULL;
|
|
goto retry;
|
|
}
|
|
if (ret)
|
|
return ret;
|
|
}
|
|
}
|
|
|
|
f = fdget(mqdes);
|
|
if (!f.file) {
|
|
ret = -EBADF;
|
|
goto out;
|
|
}
|
|
|
|
inode = file_inode(f.file);
|
|
if (unlikely(f.file->f_op != &mqueue_file_operations)) {
|
|
ret = -EBADF;
|
|
goto out_fput;
|
|
}
|
|
info = MQUEUE_I(inode);
|
|
|
|
ret = 0;
|
|
spin_lock(&info->lock);
|
|
if (notification == NULL) {
|
|
if (info->notify_owner == task_tgid(current)) {
|
|
remove_notification(info);
|
|
inode->i_atime = inode->i_ctime = current_time(inode);
|
|
}
|
|
} else if (info->notify_owner != NULL) {
|
|
ret = -EBUSY;
|
|
} else {
|
|
switch (notification->sigev_notify) {
|
|
case SIGEV_NONE:
|
|
info->notify.sigev_notify = SIGEV_NONE;
|
|
break;
|
|
case SIGEV_THREAD:
|
|
info->notify_sock = sock;
|
|
info->notify_cookie = nc;
|
|
sock = NULL;
|
|
nc = NULL;
|
|
info->notify.sigev_notify = SIGEV_THREAD;
|
|
break;
|
|
case SIGEV_SIGNAL:
|
|
info->notify.sigev_signo = notification->sigev_signo;
|
|
info->notify.sigev_value = notification->sigev_value;
|
|
info->notify.sigev_notify = SIGEV_SIGNAL;
|
|
info->notify_self_exec_id = current->self_exec_id;
|
|
break;
|
|
}
|
|
|
|
info->notify_owner = get_pid(task_tgid(current));
|
|
info->notify_user_ns = get_user_ns(current_user_ns());
|
|
inode->i_atime = inode->i_ctime = current_time(inode);
|
|
}
|
|
spin_unlock(&info->lock);
|
|
out_fput:
|
|
fdput(f);
|
|
out:
|
|
if (sock)
|
|
netlink_detachskb(sock, nc);
|
|
else
|
|
free_skb:
|
|
dev_kfree_skb(nc);
|
|
|
|
return ret;
|
|
}
|
|
|
|
SYSCALL_DEFINE2(mq_notify, mqd_t, mqdes,
|
|
const struct sigevent __user *, u_notification)
|
|
{
|
|
struct sigevent n, *p = NULL;
|
|
if (u_notification) {
|
|
if (copy_from_user(&n, u_notification, sizeof(struct sigevent)))
|
|
return -EFAULT;
|
|
p = &n;
|
|
}
|
|
return do_mq_notify(mqdes, p);
|
|
}
|
|
|
|
static int do_mq_getsetattr(int mqdes, struct mq_attr *new, struct mq_attr *old)
|
|
{
|
|
struct fd f;
|
|
struct inode *inode;
|
|
struct mqueue_inode_info *info;
|
|
|
|
if (new && (new->mq_flags & (~O_NONBLOCK)))
|
|
return -EINVAL;
|
|
|
|
f = fdget(mqdes);
|
|
if (!f.file)
|
|
return -EBADF;
|
|
|
|
if (unlikely(f.file->f_op != &mqueue_file_operations)) {
|
|
fdput(f);
|
|
return -EBADF;
|
|
}
|
|
|
|
inode = file_inode(f.file);
|
|
info = MQUEUE_I(inode);
|
|
|
|
spin_lock(&info->lock);
|
|
|
|
if (old) {
|
|
*old = info->attr;
|
|
old->mq_flags = f.file->f_flags & O_NONBLOCK;
|
|
}
|
|
if (new) {
|
|
audit_mq_getsetattr(mqdes, new);
|
|
spin_lock(&f.file->f_lock);
|
|
if (new->mq_flags & O_NONBLOCK)
|
|
f.file->f_flags |= O_NONBLOCK;
|
|
else
|
|
f.file->f_flags &= ~O_NONBLOCK;
|
|
spin_unlock(&f.file->f_lock);
|
|
|
|
inode->i_atime = inode->i_ctime = current_time(inode);
|
|
}
|
|
|
|
spin_unlock(&info->lock);
|
|
fdput(f);
|
|
return 0;
|
|
}
|
|
|
|
SYSCALL_DEFINE3(mq_getsetattr, mqd_t, mqdes,
|
|
const struct mq_attr __user *, u_mqstat,
|
|
struct mq_attr __user *, u_omqstat)
|
|
{
|
|
int ret;
|
|
struct mq_attr mqstat, omqstat;
|
|
struct mq_attr *new = NULL, *old = NULL;
|
|
|
|
if (u_mqstat) {
|
|
new = &mqstat;
|
|
if (copy_from_user(new, u_mqstat, sizeof(struct mq_attr)))
|
|
return -EFAULT;
|
|
}
|
|
if (u_omqstat)
|
|
old = &omqstat;
|
|
|
|
ret = do_mq_getsetattr(mqdes, new, old);
|
|
if (ret || !old)
|
|
return ret;
|
|
|
|
if (copy_to_user(u_omqstat, old, sizeof(struct mq_attr)))
|
|
return -EFAULT;
|
|
return 0;
|
|
}
|
|
|
|
#ifdef CONFIG_COMPAT
|
|
|
|
struct compat_mq_attr {
|
|
compat_long_t mq_flags; /* message queue flags */
|
|
compat_long_t mq_maxmsg; /* maximum number of messages */
|
|
compat_long_t mq_msgsize; /* maximum message size */
|
|
compat_long_t mq_curmsgs; /* number of messages currently queued */
|
|
compat_long_t __reserved[4]; /* ignored for input, zeroed for output */
|
|
};
|
|
|
|
static inline int get_compat_mq_attr(struct mq_attr *attr,
|
|
const struct compat_mq_attr __user *uattr)
|
|
{
|
|
struct compat_mq_attr v;
|
|
|
|
if (copy_from_user(&v, uattr, sizeof(*uattr)))
|
|
return -EFAULT;
|
|
|
|
memset(attr, 0, sizeof(*attr));
|
|
attr->mq_flags = v.mq_flags;
|
|
attr->mq_maxmsg = v.mq_maxmsg;
|
|
attr->mq_msgsize = v.mq_msgsize;
|
|
attr->mq_curmsgs = v.mq_curmsgs;
|
|
return 0;
|
|
}
|
|
|
|
static inline int put_compat_mq_attr(const struct mq_attr *attr,
|
|
struct compat_mq_attr __user *uattr)
|
|
{
|
|
struct compat_mq_attr v;
|
|
|
|
memset(&v, 0, sizeof(v));
|
|
v.mq_flags = attr->mq_flags;
|
|
v.mq_maxmsg = attr->mq_maxmsg;
|
|
v.mq_msgsize = attr->mq_msgsize;
|
|
v.mq_curmsgs = attr->mq_curmsgs;
|
|
if (copy_to_user(uattr, &v, sizeof(*uattr)))
|
|
return -EFAULT;
|
|
return 0;
|
|
}
|
|
|
|
COMPAT_SYSCALL_DEFINE4(mq_open, const char __user *, u_name,
|
|
int, oflag, compat_mode_t, mode,
|
|
struct compat_mq_attr __user *, u_attr)
|
|
{
|
|
struct mq_attr attr, *p = NULL;
|
|
if (u_attr && oflag & O_CREAT) {
|
|
p = &attr;
|
|
if (get_compat_mq_attr(&attr, u_attr))
|
|
return -EFAULT;
|
|
}
|
|
return do_mq_open(u_name, oflag, mode, p);
|
|
}
|
|
|
|
COMPAT_SYSCALL_DEFINE2(mq_notify, mqd_t, mqdes,
|
|
const struct compat_sigevent __user *, u_notification)
|
|
{
|
|
struct sigevent n, *p = NULL;
|
|
if (u_notification) {
|
|
if (get_compat_sigevent(&n, u_notification))
|
|
return -EFAULT;
|
|
if (n.sigev_notify == SIGEV_THREAD)
|
|
n.sigev_value.sival_ptr = compat_ptr(n.sigev_value.sival_int);
|
|
p = &n;
|
|
}
|
|
return do_mq_notify(mqdes, p);
|
|
}
|
|
|
|
COMPAT_SYSCALL_DEFINE3(mq_getsetattr, mqd_t, mqdes,
|
|
const struct compat_mq_attr __user *, u_mqstat,
|
|
struct compat_mq_attr __user *, u_omqstat)
|
|
{
|
|
int ret;
|
|
struct mq_attr mqstat, omqstat;
|
|
struct mq_attr *new = NULL, *old = NULL;
|
|
|
|
if (u_mqstat) {
|
|
new = &mqstat;
|
|
if (get_compat_mq_attr(new, u_mqstat))
|
|
return -EFAULT;
|
|
}
|
|
if (u_omqstat)
|
|
old = &omqstat;
|
|
|
|
ret = do_mq_getsetattr(mqdes, new, old);
|
|
if (ret || !old)
|
|
return ret;
|
|
|
|
if (put_compat_mq_attr(old, u_omqstat))
|
|
return -EFAULT;
|
|
return 0;
|
|
}
|
|
#endif
|
|
|
|
#ifdef CONFIG_COMPAT_32BIT_TIME
|
|
static int compat_prepare_timeout(const struct old_timespec32 __user *p,
|
|
struct timespec64 *ts)
|
|
{
|
|
if (get_old_timespec32(ts, p))
|
|
return -EFAULT;
|
|
if (!timespec64_valid(ts))
|
|
return -EINVAL;
|
|
return 0;
|
|
}
|
|
|
|
SYSCALL_DEFINE5(mq_timedsend_time32, mqd_t, mqdes,
|
|
const char __user *, u_msg_ptr,
|
|
unsigned int, msg_len, unsigned int, msg_prio,
|
|
const struct old_timespec32 __user *, u_abs_timeout)
|
|
{
|
|
struct timespec64 ts, *p = NULL;
|
|
if (u_abs_timeout) {
|
|
int res = compat_prepare_timeout(u_abs_timeout, &ts);
|
|
if (res)
|
|
return res;
|
|
p = &ts;
|
|
}
|
|
return do_mq_timedsend(mqdes, u_msg_ptr, msg_len, msg_prio, p);
|
|
}
|
|
|
|
SYSCALL_DEFINE5(mq_timedreceive_time32, mqd_t, mqdes,
|
|
char __user *, u_msg_ptr,
|
|
unsigned int, msg_len, unsigned int __user *, u_msg_prio,
|
|
const struct old_timespec32 __user *, u_abs_timeout)
|
|
{
|
|
struct timespec64 ts, *p = NULL;
|
|
if (u_abs_timeout) {
|
|
int res = compat_prepare_timeout(u_abs_timeout, &ts);
|
|
if (res)
|
|
return res;
|
|
p = &ts;
|
|
}
|
|
return do_mq_timedreceive(mqdes, u_msg_ptr, msg_len, u_msg_prio, p);
|
|
}
|
|
#endif
|
|
|
|
static const struct inode_operations mqueue_dir_inode_operations = {
|
|
.lookup = simple_lookup,
|
|
.create = mqueue_create,
|
|
.unlink = mqueue_unlink,
|
|
};
|
|
|
|
static const struct file_operations mqueue_file_operations = {
|
|
.flush = mqueue_flush_file,
|
|
.poll = mqueue_poll_file,
|
|
.read = mqueue_read_file,
|
|
.llseek = default_llseek,
|
|
};
|
|
|
|
static const struct super_operations mqueue_super_ops = {
|
|
.alloc_inode = mqueue_alloc_inode,
|
|
.free_inode = mqueue_free_inode,
|
|
.evict_inode = mqueue_evict_inode,
|
|
.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",
|
|
.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;
|
|
ns->mq_msgsize_max = DFLT_MSGSIZEMAX;
|
|
ns->mq_msg_default = DFLT_MSG;
|
|
ns->mq_msgsize_default = DFLT_MSGSIZE;
|
|
|
|
m = mq_create_mount(ns);
|
|
if (IS_ERR(m))
|
|
return PTR_ERR(m);
|
|
ns->mq_mnt = m;
|
|
return 0;
|
|
}
|
|
|
|
void mq_clear_sbinfo(struct ipc_namespace *ns)
|
|
{
|
|
ns->mq_mnt->mnt_sb->s_fs_info = NULL;
|
|
}
|
|
|
|
void mq_put_mnt(struct ipc_namespace *ns)
|
|
{
|
|
kern_unmount(ns->mq_mnt);
|
|
}
|
|
|
|
static int __init init_mqueue_fs(void)
|
|
{
|
|
int error;
|
|
|
|
mqueue_inode_cachep = kmem_cache_create("mqueue_inode_cache",
|
|
sizeof(struct mqueue_inode_info), 0,
|
|
SLAB_HWCACHE_ALIGN|SLAB_ACCOUNT, init_once);
|
|
if (mqueue_inode_cachep == NULL)
|
|
return -ENOMEM;
|
|
|
|
/* ignore failures - they are not fatal */
|
|
mq_sysctl_table = mq_register_sysctl_table();
|
|
|
|
error = register_filesystem(&mqueue_fs_type);
|
|
if (error)
|
|
goto out_sysctl;
|
|
|
|
spin_lock_init(&mq_lock);
|
|
|
|
error = mq_init_ns(&init_ipc_ns);
|
|
if (error)
|
|
goto out_filesystem;
|
|
|
|
return 0;
|
|
|
|
out_filesystem:
|
|
unregister_filesystem(&mqueue_fs_type);
|
|
out_sysctl:
|
|
if (mq_sysctl_table)
|
|
unregister_sysctl_table(mq_sysctl_table);
|
|
kmem_cache_destroy(mqueue_inode_cachep);
|
|
return error;
|
|
}
|
|
|
|
device_initcall(init_mqueue_fs);
|