diff options
Diffstat (limited to 'fs/notify/fanotify/fanotify_user.c')
| -rw-r--r-- | fs/notify/fanotify/fanotify_user.c | 105 |
1 files changed, 105 insertions, 0 deletions
diff --git a/fs/notify/fanotify/fanotify_user.c b/fs/notify/fanotify/fanotify_user.c index b192ee068a7a..1dadda82cae5 100644 --- a/fs/notify/fanotify/fanotify_user.c +++ b/fs/notify/fanotify/fanotify_user.c @@ -50,6 +50,7 @@ /* configurable via /proc/sys/fs/fanotify/ */ static int fanotify_max_queued_events __read_mostly; +static int perm_group_timeout __read_mostly; #ifdef CONFIG_SYSCTL @@ -85,6 +86,14 @@ static const struct ctl_table fanotify_table[] = { .proc_handler = proc_dointvec_minmax, .extra1 = SYSCTL_ZERO }, + { + .procname = "watchdog_timeout", + .data = &perm_group_timeout, + .maxlen = sizeof(int), + .mode = 0644, + .proc_handler = proc_dointvec_minmax, + .extra1 = SYSCTL_ZERO, + }, }; static void __init fanotify_sysctls_init(void) @@ -95,6 +104,91 @@ static void __init fanotify_sysctls_init(void) #define fanotify_sysctls_init() do { } while (0) #endif /* CONFIG_SYSCTL */ +static LIST_HEAD(perm_group_list); +static DEFINE_SPINLOCK(perm_group_lock); +static void perm_group_watchdog(struct work_struct *work); +static DECLARE_DELAYED_WORK(perm_group_work, perm_group_watchdog); + +static void perm_group_watchdog_schedule(void) +{ + schedule_delayed_work(&perm_group_work, secs_to_jiffies(perm_group_timeout)); +} + +static void perm_group_watchdog(struct work_struct *work) +{ + struct fsnotify_group *group; + struct fanotify_perm_event *event; + struct task_struct *task; + pid_t failed_pid = 0; + + guard(spinlock)(&perm_group_lock); + if (list_empty(&perm_group_list)) + return; + + list_for_each_entry(group, &perm_group_list, + fanotify_data.perm_grp_list) { + /* + * Ok to test without lock, racing with an addition is + * fine, will deal with it next round + */ + if (list_empty(&group->fanotify_data.access_list)) + continue; + + spin_lock(&group->notification_lock); + list_for_each_entry(event, &group->fanotify_data.access_list, + fae.fse.list) { + if (likely(event->watchdog_cnt == 0)) { + event->watchdog_cnt = 1; + } else if (event->watchdog_cnt == 1) { + /* Report on event only once */ + event->watchdog_cnt = 2; + + /* Do not report same pid repeatedly */ + if (event->recv_pid == failed_pid) + continue; + + failed_pid = event->recv_pid; + rcu_read_lock(); + task = find_task_by_pid_ns(event->recv_pid, + &init_pid_ns); + pr_warn_ratelimited( + "PID %u (%s) failed to respond to fanotify queue for more than %d seconds\n", + event->recv_pid, + task ? task->comm : NULL, + perm_group_timeout); + rcu_read_unlock(); + } + } + spin_unlock(&group->notification_lock); + } + perm_group_watchdog_schedule(); +} + +static void fanotify_perm_watchdog_group_remove(struct fsnotify_group *group) +{ + if (!list_empty(&group->fanotify_data.perm_grp_list)) { + /* Perm event watchdog can no longer scan this group. */ + spin_lock(&perm_group_lock); + list_del_init(&group->fanotify_data.perm_grp_list); + spin_unlock(&perm_group_lock); + } +} + +static void fanotify_perm_watchdog_group_add(struct fsnotify_group *group) +{ + if (!perm_group_timeout) + return; + + spin_lock(&perm_group_lock); + if (list_empty(&group->fanotify_data.perm_grp_list)) { + /* Add to perm_group_list for monitoring by watchdog. */ + if (list_empty(&perm_group_list)) + perm_group_watchdog_schedule(); + list_add_tail(&group->fanotify_data.perm_grp_list, &perm_group_list); + } + spin_unlock(&perm_group_lock); +} + /* * All flags that may be specified in parameter event_f_flags of fanotify_init. * @@ -953,6 +1047,7 @@ static ssize_t fanotify_read(struct file *file, char __user *buf, spin_lock(&group->notification_lock); list_add_tail(&event->fse.list, &group->fanotify_data.access_list); + FANOTIFY_PERM(event)->recv_pid = current->pid; spin_unlock(&group->notification_lock); } } @@ -1012,6 +1107,8 @@ static int fanotify_release(struct inode *ignored, struct file *file) */ fsnotify_group_stop_queueing(group); + fanotify_perm_watchdog_group_remove(group); + /* * Process all permission events on access_list and notification queue * and simulate reply from userspace. @@ -1465,6 +1562,10 @@ out: fsnotify_group_unlock(group); fsnotify_put_mark(fsn_mark); + + if (!ret && (mask & FANOTIFY_PERM_EVENTS)) + fanotify_perm_watchdog_group_add(group); + return ret; } @@ -1625,6 +1726,7 @@ SYSCALL_DEFINE2(fanotify_init, unsigned int, flags, unsigned int, event_f_flags) group->fanotify_data.f_flags = event_f_flags; init_waitqueue_head(&group->fanotify_data.access_waitq); INIT_LIST_HEAD(&group->fanotify_data.access_list); + INIT_LIST_HEAD(&group->fanotify_data.perm_grp_list); switch (class) { case FAN_CLASS_NOTIF: group->priority = FSNOTIFY_PRIO_NORMAL; @@ -1999,7 +2101,10 @@ static int do_fanotify_mark(int fanotify_fd, unsigned int flags, __u64 mask, user_ns = path.mnt->mnt_sb->s_user_ns; obj = path.mnt->mnt_sb; } else if (obj_type == FSNOTIFY_OBJ_TYPE_MNTNS) { + ret = -EINVAL; mntns = mnt_ns_from_dentry(path.dentry); + if (!mntns) + goto path_put_and_out; user_ns = mntns->user_ns; obj = mntns; } |