diff options
| -rw-r--r-- | fs/notify/fanotify/fanotify.c | 3 | ||||
| -rw-r--r-- | fs/notify/fanotify/fanotify_user.c | 182 | ||||
| -rw-r--r-- | include/linux/fanotify.h | 5 |
3 files changed, 184 insertions, 6 deletions
diff --git a/fs/notify/fanotify/fanotify.c b/fs/notify/fanotify/fanotify.c index 52d0a55..bbcfccd 100644 --- a/fs/notify/fanotify/fanotify.c +++ b/fs/notify/fanotify/fanotify.c @@ -114,6 +114,9 @@ static int fanotify_get_response_from_access(struct fsnotify_group *group, event->response = 0; spin_unlock(&event->lock); + pr_debug("%s: group=%p event=%p about to return ret=%d\n", __func__, + group, event, ret); + return ret; } #endif diff --git a/fs/notify/fanotify/fanotify_user.c b/fs/notify/fanotify/fanotify_user.c index 09d9bdb..87f0be8 100644 --- a/fs/notify/fanotify/fanotify_user.c +++ b/fs/notify/fanotify/fanotify_user.c @@ -18,6 +18,13 @@ extern const struct fsnotify_ops fanotify_fsnotify_ops; static struct kmem_cache *fanotify_mark_cache __read_mostly; +static struct kmem_cache *fanotify_response_event_cache __read_mostly; + +struct fanotify_response_event { + struct list_head list; + __s32 fd; + struct fsnotify_event *event; +}; /* * Get an fsnotify notification event if one exists and is small @@ -110,23 +117,152 @@ static ssize_t fill_event_metadata(struct fsnotify_group *group, return metadata->fd; } +#ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS +static struct fanotify_response_event *dequeue_re(struct fsnotify_group *group, + __s32 fd) +{ + struct fanotify_response_event *re, *return_re = NULL; + + mutex_lock(&group->fanotify_data.access_mutex); + list_for_each_entry(re, &group->fanotify_data.access_list, list) { + if (re->fd != fd) + continue; + + list_del_init(&re->list); + return_re = re; + break; + } + mutex_unlock(&group->fanotify_data.access_mutex); + + pr_debug("%s: found return_re=%p\n", __func__, return_re); + + return return_re; +} + +static int process_access_response(struct fsnotify_group *group, + struct fanotify_response *response_struct) +{ + struct fanotify_response_event *re; + __s32 fd = response_struct->fd; + __u32 response = response_struct->response; + + pr_debug("%s: group=%p fd=%d response=%d\n", __func__, group, + fd, response); + /* + * make sure the response is valid, if invalid we do nothing and either + * userspace can send a valid responce or we will clean it up after the + * timeout + */ + switch (response) { + case FAN_ALLOW: + case FAN_DENY: + break; + default: + return -EINVAL; + } + + if (fd < 0) + return -EINVAL; + + re = dequeue_re(group, fd); + if (!re) + return -ENOENT; + + re->event->response = response; + + wake_up(&group->fanotify_data.access_waitq); + + kmem_cache_free(fanotify_response_event_cache, re); + + return 0; +} + +static int prepare_for_access_response(struct fsnotify_group *group, + struct fsnotify_event *event, + __s32 fd) +{ + struct fanotify_response_event *re; + + if (!(event->mask & FAN_ALL_PERM_EVENTS)) + return 0; + + re = kmem_cache_alloc(fanotify_response_event_cache, GFP_KERNEL); + if (!re) + return -ENOMEM; + + re->event = event; + re->fd = fd; + + mutex_lock(&group->fanotify_data.access_mutex); + list_add_tail(&re->list, &group->fanotify_data.access_list); + mutex_unlock(&group->fanotify_data.access_mutex); + + return 0; +} + +static void remove_access_response(struct fsnotify_group *group, + struct fsnotify_event *event, + __s32 fd) +{ + struct fanotify_response_event *re; + + if (!(event->mask & FAN_ALL_PERM_EVENTS)) + return; + + re = dequeue_re(group, fd); + if (!re) + return; + + BUG_ON(re->event != event); + + kmem_cache_free(fanotify_response_event_cache, re); + + return; +} +#else +static int prepare_for_access_response(struct fsnotify_group *group, + struct fsnotify_event *event, + __s32 fd) +{ + return 0; +} + +static void remove_access_response(struct fsnotify_group *group, + struct fsnotify_event *event, + __s32 fd) +{ + return 0; +} +#endif + static ssize_t copy_event_to_user(struct fsnotify_group *group, struct fsnotify_event *event, char __user *buf) { struct fanotify_event_metadata fanotify_event_metadata; - int ret; + int fd, ret; pr_debug("%s: group=%p event=%p\n", __func__, group, event); - ret = fill_event_metadata(group, &fanotify_event_metadata, event); - if (ret < 0) - return ret; + fd = fill_event_metadata(group, &fanotify_event_metadata, event); + if (fd < 0) + return fd; + + ret = prepare_for_access_response(group, event, fd); + if (ret) + goto out_close_fd; + ret = -EFAULT; if (copy_to_user(buf, &fanotify_event_metadata, FAN_EVENT_METADATA_LEN)) - return -EFAULT; + goto out_kill_access_response; return FAN_EVENT_METADATA_LEN; + +out_kill_access_response: + remove_access_response(group, event, fd); +out_close_fd: + sys_close(fd); + return ret; } /* intofiy userspace file descriptor functions */ @@ -197,6 +333,33 @@ static ssize_t fanotify_read(struct file *file, char __user *buf, return ret; } +static ssize_t fanotify_write(struct file *file, const char __user *buf, size_t count, loff_t *pos) +{ +#ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS + struct fanotify_response response = { .fd = -1, .response = -1 }; + struct fsnotify_group *group; + int ret; + + group = file->private_data; + + if (count > sizeof(response)) + count = sizeof(response); + + pr_debug("%s: group=%p count=%zu\n", __func__, group, count); + + if (copy_from_user(&response, buf, count)) + return -EFAULT; + + ret = process_access_response(group, &response); + if (ret < 0) + count = ret; + + return count; +#else + return -EINVAL; +#endif +} + static int fanotify_release(struct inode *ignored, struct file *file) { struct fsnotify_group *group = file->private_data; @@ -237,6 +400,7 @@ static long fanotify_ioctl(struct file *file, unsigned int cmd, unsigned long ar static const struct file_operations fanotify_fops = { .poll = fanotify_poll, .read = fanotify_read, + .write = fanotify_write, .fasync = NULL, .release = fanotify_release, .unlocked_ioctl = fanotify_ioctl, @@ -470,7 +634,7 @@ SYSCALL_DEFINE3(fanotify_init, unsigned int, flags, unsigned int, event_f_flags, if (flags & ~FAN_ALL_INIT_FLAGS) return -EINVAL; - f_flags = (O_RDONLY | FMODE_NONOTIFY); + f_flags = O_RDWR | FMODE_NONOTIFY; if (flags & FAN_CLOEXEC) f_flags |= O_CLOEXEC; if (flags & FAN_NONBLOCK) @@ -527,7 +691,11 @@ SYSCALL_DEFINE(fanotify_mark)(int fanotify_fd, unsigned int flags, default: return -EINVAL; } +#ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS + if (mask & ~(FAN_ALL_EVENTS | FAN_ALL_PERM_EVENTS | FAN_EVENT_ON_CHILD)) +#else if (mask & ~(FAN_ALL_EVENTS | FAN_EVENT_ON_CHILD)) +#endif return -EINVAL; filp = fget_light(fanotify_fd, &fput_needed); @@ -600,6 +768,8 @@ SYSCALL_ALIAS(sys_fanotify_mark, SyS_fanotify_mark); static int __init fanotify_user_setup(void) { fanotify_mark_cache = KMEM_CACHE(fsnotify_mark, SLAB_PANIC); + fanotify_response_event_cache = KMEM_CACHE(fanotify_response_event, + SLAB_PANIC); return 0; } diff --git a/include/linux/fanotify.h b/include/linux/fanotify.h index 02f8067..f0949a5 100644 --- a/include/linux/fanotify.h +++ b/include/linux/fanotify.h @@ -75,6 +75,11 @@ struct fanotify_event_metadata { __s64 pid; } __attribute__ ((packed)); +struct fanotify_response { + __s32 fd; + __u32 response; +} __attribute__ ((packed)); + /* Legit userspace responses to a _PERM event */ #define FAN_ALLOW 0x01 #define FAN_DENY 0x02 |