| /* |
| * POSIX message queues filesystem for Linux. |
| * |
| * Copyright (C) 2003,2004 Krzysztof Benedyczak (golbi@mat.uni.torun.pl) |
| * Michal Wronski (michal.wronski@gmail.com) |
| * |
| * Spinlocks: Mohamed Abbas (abbas.mohamed@intel.com) |
| * Lockless receive & send, fd based notify: |
| * Manfred Spraul (manfred@colorfullife.com) |
| * |
| * Audit: George Wilson (ltcgcw@us.ibm.com) |
| * |
| * This file is released under the GPL. |
| */ |
| |
| #include <linux/capability.h> |
| #include <linux/init.h> |
| #include <linux/pagemap.h> |
| #include <linux/file.h> |
| #include <linux/mount.h> |
| #include <linux/fs_context.h> |
| #include <linux/namei.h> |
| #include <linux/sysctl.h> |
| #include <linux/poll.h> |
| #include <linux/mqueue.h> |
| #include <linux/msg.h> |
| #include <linux/skbuff.h> |
| #include <linux/vmalloc.h> |
| #include <linux/netlink.h> |
| #include <linux/syscalls.h> |
| #include <linux/audit.h> |
| #include <linux/signal.h> |
| #include <linux/mutex.h> |
| #include <linux/nsproxy.h> |
| #include <linux/pid.h> |
| #include <linux/ipc_namespace.h> |
| #include <linux/user_namespace.h> |
| #include <linux/slab.h> |
| #include <linux/sched/wake_q.h> |
| #include <linux/sched/signal.h> |
| #include <linux/sched/user.h> |
| |
| #include <net/sock.h> |
| #include "util.h" |
| |
| struct mqueue_fs_context { |
| struct ipc_namespace *ipc_ns; |
| bool newns; /* Set if newly created ipc namespace */ |
| }; |
| |
| #define MQUEUE_MAGIC 0x19800202 |
| #define DIRENT_SIZE 20 |
| #define FILENT_SIZE 80 |
| |
| #define SEND 0 |
| #define RECV 1 |
| |
| #define STATE_NONE 0 |
| #define STATE_READY 1 |
| |
| struct posix_msg_tree_node { |
| struct rb_node rb_node; |
| struct list_head msg_list; |
| int priority; |
| }; |
| |
| /* |
| * Locking: |
| * |
| * Accesses to a message queue are synchronized by acquiring info->lock. |
| * |
| * There are two notable exceptions: |
| * - The actual wakeup of a sleeping task is performed using the wake_q |
| * framework. info->lock is already released when wake_up_q is called. |
| * - The exit codepaths after sleeping check ext_wait_queue->state without |
| * any locks. If it is STATE_READY, then the syscall is completed without |
| * acquiring info->lock. |
| * |
| * MQ_BARRIER: |
| * To achieve proper release/acquire memory barrier pairing, the state is set to |
| * STATE_READY with smp_store_release(), and it is read with READ_ONCE followed |
| * by smp_acquire__after_ctrl_dep(). In addition, wake_q_add_safe() is used. |
| * |
| * This prevents the following races: |
| * |
| * 1) With the simple wake_q_add(), the task could be gone already before |
| * the increase of the reference happens |
| * Thread A |
| * Thread B |
| * WRITE_ONCE(wait.state, STATE_NONE); |
| * schedule_hrtimeout() |
| * wake_q_add(A) |
| * if (cmpxchg()) // success |
| * ->state = STATE_READY (reordered) |
| * <timeout returns> |
| * if (wait.state == STATE_READY) return; |
| * sysret to user space |
| * sys_exit() |
| * get_task_struct() // UaF |
| * |
| * Solution: Use wake_q_add_safe() and perform the get_task_struct() before |
| * the smp_store_release() that does ->state = STATE_READY. |
| * |
| * 2) Without proper _release/_acquire barriers, the woken up task |
| * could read stale data |
| * |
| * Thread A |
| * Thread B |
| * do_mq_timedreceive |
| * WRITE_ONCE(wait.state, STATE_NONE); |
| * schedule_hrtimeout() |
| * state = STATE_READY; |
| * <timeout returns> |
| * if (wait.state == STATE_READY) return; |
| * msg_ptr = wait.msg; // Access to stale data! |
| * receiver->msg = message; (reordered) |
| * |
| * Solution: use _release and _acquire barriers. |
| * |
| * 3) There is intentionally no barrier when setting current->state |
| * to TASK_INTERRUPTIBLE: spin_unlock(&info->lock) provides the |
| * release memory barrier, and the wakeup is triggered when holding |
| * info->lock, i.e. spin_lock(&info->lock) provided a pairing |
| * acquire memory barrier. |
| */ |
| |
| struct ext_wait_queue { /* queue of sleeping tasks */ |
| struct task_struct *task; |
| struct list_head list; |
| struct msg_msg *msg; /* ptr of loaded message */ |
| int state; /* one of STATE_* values */ |
| }; |
| |
| struct mqueue_inode_info { |
| spinlock_t lock; |
| struct inode vfs_inode; |
| wait_queue_head_t wait_q; |
| |
| struct rb_root msg_tree; |
| struct rb_node *msg_tree_rightmost; |
| struct posix_msg_tree_node *node_cache; |
| struct mq_attr attr; |
| |
| struct sigevent notify; |
| struct pid *notify_owner; |
| u32 notify_self_exec_id; |
| struct user_namespace *notify_user_ns; |
| struct ucounts *ucounts; /* user who created, for accounting */ |
| struct sock *notify_sock; |
| struct sk_buff *notify_cookie; |
| |
| /* for tasks waiting for free space and messages, respectively */ |
| struct ext_wait_queue e_wait_q[2]; |
| |
| 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; |
| |
| static inline struct mqueue_inode_info *MQUEUE_I(struct inode *inode) |
| { |
| return container_of(inode, struct mqueue_inode_info, vfs_inode); |
| } |
| |
| /* |
| * This routine should be called with the mq_lock held. |
| */ |
| static inline struct ipc_namespace *__get_ns_from_inode(struct inode *inode) |
| { |
| return get_ipc_ns(inode->i_sb->s_fs_info); |
| } |
| |
| static struct ipc_namespace *get_ns_from_inode(struct inode *inode) |
| { |
| struct ipc_namespace *ns; |
| |
| spin_lock(&mq_lock); |
| ns = __get_ns_from_inode(inode); |
| spin_unlock(&mq_lock); |
| return ns; |
| } |
| |
| /* Auxiliary functions to manipulate messages' list */ |
| static int msg_insert(struct msg_msg *msg, struct mqueue_inode_info *info) |
| { |
| struct rb_node **p, *parent = NULL; |
| struct posix_msg_tree_node *leaf; |
| bool rightmost = true; |
| |
| p = &info->msg_tree.rb_node; |
| while (*p) { |
| parent = *p; |
| leaf = rb_entry(parent, struct posix_msg_tree_node, rb_node); |
| |
| if (likely(leaf->priority == msg->m_type)) |
| goto insert_msg; |
| else if (msg->m_type < leaf->priority) { |
| p = &(*p)->rb_left; |
| rightmost = false; |
| } else |
| p = &(*p)->rb_right; |
| } |
| if (info->node_cache) { |
| leaf = info->node_cache; |
| info->node_cache = NULL; |
| } else { |
| leaf = kmalloc(sizeof(*leaf), GFP_ATOMIC); |
| if (!leaf) |
| return -ENOMEM; |
| INIT_LIST_HEAD(&leaf->msg_list); |
| } |
| leaf->priority = msg->m_type; |
| |
| if (rightmost) |
| info->msg_tree_rightmost = &leaf->rb_node; |
| |
| rb_link_node(&leaf->rb_node, parent, p); |
| rb_insert_color(&leaf->rb_node, &info->msg_tree); |
| insert_msg: |
| info->attr.mq_curmsgs++; |
| info->qsize += msg->m_ts; |
| list_add_tail(&msg->m_list, &leaf->msg_list); |
| return 0; |
| } |
| |
| static inline void msg_tree_erase(struct posix_msg_tree_node *leaf, |
| struct mqueue_inode_info *info) |
| { |
| struct rb_node *node = &leaf->rb_node; |
| |
| if (info->msg_tree_rightmost == node) |
| info->msg_tree_rightmost = rb_prev(node); |
| |
| rb_erase(node, &info->msg_tree); |
| if (info->node_cache) |
| kfree(leaf); |
| else |
| info->node_cache = leaf; |
| } |
| |
| static inline struct msg_msg *msg_get(struct mqueue_inode_info *info) |
| { |
| struct rb_node *parent = NULL; |
| struct posix_msg_tree_node *leaf; |
| struct msg_msg *msg; |
| |
| try_again: |
| /* |
| * During insert, low priorities go to the left and high to the |
| * right. On receive, we want the highest priorities first, so |
| * walk all the way to the right. |
| */ |
| parent = info->msg_tree_rightmost; |
| if (!parent) { |
| if (info->attr.mq_curmsgs) { |
| pr_warn_once("Inconsistency in POSIX message queue, " |
| "no tree element, but supposedly messages " |
| "should exist!\n"); |
| info->attr.mq_curmsgs = 0; |
| } |
| return NULL; |
| } |
| leaf = rb_entry(parent, struct posix_msg_tree_node, rb_node); |
| if (unlikely(list_empty(&leaf->msg_list))) { |
| pr_warn_once("Inconsistency in POSIX message queue, " |
| "empty leaf node but we haven't implemented " |
| "lazy leaf delete!\n"); |
| msg_tree_erase(leaf, info); |
| goto try_again; |
| } else { |
| msg = list_first_entry(&leaf->msg_list, |
| struct msg_msg, m_list); |
| list_del(&msg->m_list); |
| if (list_empty(&leaf->msg_list)) { |
| msg_tree_erase(leaf, info); |
| } |
| } |
| info->attr.mq_curmsgs--; |
| info->qsize -= msg->m_ts; |
| return msg; |
| } |
| |
| static struct inode *mqueue_get_inode(struct super_block *sb, |
| struct ipc_namespace *ipc_ns, umode_t mode, |
| struct mq_attr *attr) |
| { |
| struct inode *inode; |
| int ret = -ENOMEM; |
| |
| inode = new_inode(sb); |
| if (!inode) |
| goto err; |
| |
| inode->i_ino = get_next_ino(); |
| inode->i_mode = mode; |
| inode->i_uid = current_fsuid(); |
| inode->i_gid = current_fsgid(); |
| inode->i_mtime = inode->i_ctime = inode->i_atime = current_time(inode); |
| |
| if (S_ISREG(mode)) { |
| struct mqueue_inode_info *info; |
| unsigned long mq_bytes, mq_treesize; |
| |
| inode->i_fop = &mqueue_file_operations; |
| inode->i_size = FILENT_SIZE; |
| /* mqueue specific info */ |
| info = MQUEUE_I(inode); |
| spin_lock_init(&info->lock); |
| init_waitqueue_head(&info->wait_q); |
| INIT_LIST_HEAD(&info->e_wait_q[0].list); |
| INIT_LIST_HEAD(&info->e_wait_q[1].list); |
| info->notify_owner = NULL; |
| info->notify_user_ns = NULL; |
| info->qsize = 0; |
| info->ucounts = NULL; /* set when all is ok */ |
| info->msg_tree = RB_ROOT; |
| info->msg_tree_rightmost = NULL; |
| info->node_cache = NULL; |
| memset(&info->attr, 0, sizeof(info->attr)); |
| info->attr.mq_maxmsg = min(ipc_ns->mq_msg_max, |
| ipc_ns->mq_msg_default); |
| info->attr.mq_msgsize = min(ipc_ns->mq_msgsize_max, |
| ipc_ns->mq_msgsize_default); |
| if (attr) { |
| info->attr.mq_maxmsg = attr->mq_maxmsg; |
| info->attr.mq_msgsize = attr->mq_msgsize; |
| } |
| /* |
| * We used to allocate a static array of pointers and account |
| * the size of that array as well as one msg_msg struct per |
| * possible message into the queue size. That's no longer |
| * accurate as the queue is now an rbtree and will grow and |
| * shrink depending on usage patterns. We can, however, still |
| * account one msg_msg struct per message, but the nodes are |
| * allocated depending on priority usage, and most programs |
| * only use one, or a handful, of priorities. However, since |
| * this is pinned memory, we need to assume worst case, so |
| * that means the min(mq_maxmsg, max_priorities) * struct |
| * posix_msg_tree_node. |
| */ |
| |
| ret = -EINVAL; |
| if (info->attr.mq_maxmsg <= 0 || info->attr.mq_msgsize <= 0) |
| goto out_inode; |
| if (capable(CAP_SYS_RESOURCE)) { |
| if (info->attr.mq_maxmsg > HARD_MSGMAX || |
| info->attr.mq_msgsize > HARD_MSGSIZEMAX) |
| goto out_inode; |
| } else { |
| if (info->attr.mq_maxmsg > ipc_ns->mq_msg_max || |
| info->attr.mq_msgsize > ipc_ns->mq_msgsize_max) |
| goto out_inode; |
| } |
| ret = -EOVERFLOW; |
| /* check for overflow */ |
| if (info->attr.mq_msgsize > ULONG_MAX/info->attr.mq_maxmsg) |
| goto out_inode; |
| 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 = info->attr.mq_maxmsg * info->attr.mq_msgsize; |
| if (mq_bytes + mq_treesize < mq_bytes) |
| goto out_inode; |
| mq_bytes += mq_treesize; |
| info->ucounts = get_ucounts(current_ucounts()); |
| if (info->ucounts) { |
| long msgqueue; |
| |
| spin_lock(&mq_lock); |
| msgqueue = inc_rlimit_ucounts(info->ucounts, UCOUNT_RLIMIT_MSGQUEUE, mq_bytes); |
| if (msgqueue == LONG_MAX || msgqueue > rlimit(RLIMIT_MSGQUEUE)) { |
| dec_rlimit_ucounts(info->ucounts, UCOUNT_RLIMIT_MSGQUEUE, mq_bytes); |
| spin_unlock(&mq_lock); |
| put_ucounts(info->ucounts); |
| info->ucounts = NULL; |
| /* mqueue_evict_inode() releases info->messages */ |
| ret = -EMFILE; |
| goto out_inode; |
| } |
| spin_unlock(&mq_lock); |
| } |
| } 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; |
| |
| /* |
| * With a newly created ipc namespace, we don't need to do a search |
| * for an ipc namespace match, but we still need to set s_fs_info. |
| */ |
| if (ctx->newns) { |
| fc->s_fs_info = ctx->ipc_ns; |
| return get_tree_nodev(fc, mqueue_fill_super); |
| } |
| 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; |
| } |
| |
| /* |
| * mq_init_ns() is currently the only caller of mq_create_mount(). |
| * So the ns parameter is always a newly created ipc namespace. |
| */ |
| 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; |
| ctx->newns = true; |
| 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 = alloc_inode_sb(sb, 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 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); |
| } |
| |
| if (info->ucounts) { |
| 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); |
| dec_rlimit_ucounts(info->ucounts, UCOUNT_RLIMIT_MSGQUEUE, 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); |
| put_ucounts(info->ucounts); |
| info->ucounts = NULL; |
| } |
| 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) |
| { |
| struct task_struct *task; |
| |
| list_del(&this->list); |
| task = get_task_struct(this->task); |
| |
| /* see MQ_BARRIER for purpose/pairing */ |
| smp_store_release(&this->state, STATE_READY); |
| wake_q_add_safe(wake_q, 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; |
| |
| if (!setup_mq_sysctls(&init_ipc_ns)) { |
| pr_warn("sysctl registration failed\n"); |
| return -ENOMEM; |
| } |
| |
| 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: |
| kmem_cache_destroy(mqueue_inode_cachep); |
| return error; |
| } |
| |
| device_initcall(init_mqueue_fs); |