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1740 lines
43 KiB
1740 lines
43 KiB
/* |
|
* POSIX message queues filesystem for Linux. |
|
* |
|
* Copyright (C) 2003,2004 Krzysztof Benedyczak ([email protected]) |
|
* Michal Wronski ([email protected]) |
|
* |
|
* Spinlocks: Mohamed Abbas ([email protected]) |
|
* Lockless receive & send, fd based notify: |
|
* Manfred Spraul ([email protected]) |
|
* |
|
* Audit: George Wilson ([email protected]) |
|
* |
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* 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> |
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#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> |
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#include <linux/slab.h> |
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#include <linux/sched/wake_q.h> |
|
#include <linux/sched/signal.h> |
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#include <linux/sched/user.h> |
|
|
|
#include <net/sock.h> |
|
#include "util.h" |
|
|
|
struct mqueue_fs_context { |
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struct ipc_namespace *ipc_ns; |
|
}; |
|
|
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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 |
|
|
|
#define STATE_NONE 0 |
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#define STATE_READY 1 |
|
|
|
struct posix_msg_tree_node { |
|
struct rb_node rb_node; |
|
struct list_head msg_list; |
|
int priority; |
|
}; |
|
|
|
/* |
|
* Locking: |
|
* |
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* 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. |
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* |
|
* 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 struct ctl_table_header *mq_sysctl_table; |
|
|
|
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) { |
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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--; |
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info->qsize -= msg->m_ts; |
|
return msg; |
|
} |
|
|
|
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 inode *inode; |
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int ret = -ENOMEM; |
|
|
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inode = new_inode(sb); |
|
if (!inode) |
|
goto err; |
|
|
|
inode->i_ino = get_next_ino(); |
|
inode->i_mode = mode; |
|
inode->i_uid = current_fsuid(); |
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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; |
|
|
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inode->i_fop = &mqueue_file_operations; |
|
inode->i_size = FILENT_SIZE; |
|
/* mqueue specific info */ |
|
info = MQUEUE_I(inode); |
|
spin_lock_init(&info->lock); |
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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, |
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ipc_ns->mq_msg_default); |
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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; |
|
|
|
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 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; |
|
|
|
/* 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);
|
|
|