// SPDX-License-Identifier: GPL-2.0
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#include <linux/fanotify.h>
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#include <linux/fdtable.h>
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#include <linux/fsnotify_backend.h>
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#include <linux/init.h>
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#include <linux/jiffies.h>
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#include <linux/kernel.h> /* UINT_MAX */
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#include <linux/mount.h>
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#include <linux/sched.h>
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#include <linux/sched/user.h>
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#include <linux/sched/signal.h>
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#include <linux/types.h>
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#include <linux/wait.h>
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#include <linux/audit.h>
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#include <linux/sched/mm.h>
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#include <linux/statfs.h>
|
|
#include "fanotify.h"
|
|
static bool fanotify_path_equal(struct path *p1, struct path *p2)
|
{
|
return p1->mnt == p2->mnt && p1->dentry == p2->dentry;
|
}
|
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static inline bool fanotify_fsid_equal(__kernel_fsid_t *fsid1,
|
__kernel_fsid_t *fsid2)
|
{
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return fsid1->val[0] == fsid2->val[0] && fsid1->val[1] == fsid2->val[1];
|
}
|
|
static bool fanotify_fh_equal(struct fanotify_fh *fh1,
|
struct fanotify_fh *fh2)
|
{
|
if (fh1->type != fh2->type || fh1->len != fh2->len)
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return false;
|
|
return !fh1->len ||
|
!memcmp(fanotify_fh_buf(fh1), fanotify_fh_buf(fh2), fh1->len);
|
}
|
|
static bool fanotify_fid_event_equal(struct fanotify_fid_event *ffe1,
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struct fanotify_fid_event *ffe2)
|
{
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/* Do not merge fid events without object fh */
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if (!ffe1->object_fh.len)
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return false;
|
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return fanotify_fsid_equal(&ffe1->fsid, &ffe2->fsid) &&
|
fanotify_fh_equal(&ffe1->object_fh, &ffe2->object_fh);
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}
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static bool fanotify_info_equal(struct fanotify_info *info1,
|
struct fanotify_info *info2)
|
{
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if (info1->dir_fh_totlen != info2->dir_fh_totlen ||
|
info1->file_fh_totlen != info2->file_fh_totlen ||
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info1->name_len != info2->name_len)
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return false;
|
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if (info1->dir_fh_totlen &&
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!fanotify_fh_equal(fanotify_info_dir_fh(info1),
|
fanotify_info_dir_fh(info2)))
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return false;
|
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if (info1->file_fh_totlen &&
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!fanotify_fh_equal(fanotify_info_file_fh(info1),
|
fanotify_info_file_fh(info2)))
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return false;
|
|
return !info1->name_len ||
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!memcmp(fanotify_info_name(info1), fanotify_info_name(info2),
|
info1->name_len);
|
}
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static bool fanotify_name_event_equal(struct fanotify_name_event *fne1,
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struct fanotify_name_event *fne2)
|
{
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struct fanotify_info *info1 = &fne1->info;
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struct fanotify_info *info2 = &fne2->info;
|
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/* Do not merge name events without dir fh */
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if (!info1->dir_fh_totlen)
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return false;
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if (!fanotify_fsid_equal(&fne1->fsid, &fne2->fsid))
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return false;
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return fanotify_info_equal(info1, info2);
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}
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static bool fanotify_should_merge(struct fsnotify_event *old_fsn,
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struct fsnotify_event *new_fsn)
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{
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struct fanotify_event *old, *new;
|
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pr_debug("%s: old=%p new=%p\n", __func__, old_fsn, new_fsn);
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old = FANOTIFY_E(old_fsn);
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new = FANOTIFY_E(new_fsn);
|
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if (old_fsn->objectid != new_fsn->objectid ||
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old->type != new->type || old->pid != new->pid)
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return false;
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/*
|
* We want to merge many dirent events in the same dir (i.e.
|
* creates/unlinks/renames), but we do not want to merge dirent
|
* events referring to subdirs with dirent events referring to
|
* non subdirs, otherwise, user won't be able to tell from a
|
* mask FAN_CREATE|FAN_DELETE|FAN_ONDIR if it describes mkdir+
|
* unlink pair or rmdir+create pair of events.
|
*/
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if ((old->mask & FS_ISDIR) != (new->mask & FS_ISDIR))
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return false;
|
|
switch (old->type) {
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case FANOTIFY_EVENT_TYPE_PATH:
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return fanotify_path_equal(fanotify_event_path(old),
|
fanotify_event_path(new));
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case FANOTIFY_EVENT_TYPE_FID:
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return fanotify_fid_event_equal(FANOTIFY_FE(old),
|
FANOTIFY_FE(new));
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case FANOTIFY_EVENT_TYPE_FID_NAME:
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return fanotify_name_event_equal(FANOTIFY_NE(old),
|
FANOTIFY_NE(new));
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default:
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WARN_ON_ONCE(1);
|
}
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return false;
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}
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/* Limit event merges to limit CPU overhead per event */
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#define FANOTIFY_MAX_MERGE_EVENTS 128
|
|
/* and the list better be locked by something too! */
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static int fanotify_merge(struct list_head *list, struct fsnotify_event *event)
|
{
|
struct fsnotify_event *test_event;
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struct fanotify_event *new;
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int i = 0;
|
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pr_debug("%s: list=%p event=%p\n", __func__, list, event);
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new = FANOTIFY_E(event);
|
|
/*
|
* Don't merge a permission event with any other event so that we know
|
* the event structure we have created in fanotify_handle_event() is the
|
* one we should check for permission response.
|
*/
|
if (fanotify_is_perm_event(new->mask))
|
return 0;
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|
list_for_each_entry_reverse(test_event, list, list) {
|
if (++i > FANOTIFY_MAX_MERGE_EVENTS)
|
break;
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if (fanotify_should_merge(test_event, event)) {
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FANOTIFY_E(test_event)->mask |= new->mask;
|
return 1;
|
}
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}
|
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return 0;
|
}
|
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/*
|
* Wait for response to permission event. The function also takes care of
|
* freeing the permission event (or offloads that in case the wait is canceled
|
* by a signal). The function returns 0 in case access got allowed by userspace,
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* -EPERM in case userspace disallowed the access, and -ERESTARTSYS in case
|
* the wait got interrupted by a signal.
|
*/
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static int fanotify_get_response(struct fsnotify_group *group,
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struct fanotify_perm_event *event,
|
struct fsnotify_iter_info *iter_info)
|
{
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int ret;
|
|
pr_debug("%s: group=%p event=%p\n", __func__, group, event);
|
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ret = wait_event_killable(group->fanotify_data.access_waitq,
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event->state == FAN_EVENT_ANSWERED);
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/* Signal pending? */
|
if (ret < 0) {
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spin_lock(&group->notification_lock);
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/* Event reported to userspace and no answer yet? */
|
if (event->state == FAN_EVENT_REPORTED) {
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/* Event will get freed once userspace answers to it */
|
event->state = FAN_EVENT_CANCELED;
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spin_unlock(&group->notification_lock);
|
return ret;
|
}
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/* Event not yet reported? Just remove it. */
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if (event->state == FAN_EVENT_INIT)
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fsnotify_remove_queued_event(group, &event->fae.fse);
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/*
|
* Event may be also answered in case signal delivery raced
|
* with wakeup. In that case we have nothing to do besides
|
* freeing the event and reporting error.
|
*/
|
spin_unlock(&group->notification_lock);
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goto out;
|
}
|
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/* userspace responded, convert to something usable */
|
switch (event->response & ~FAN_AUDIT) {
|
case FAN_ALLOW:
|
ret = 0;
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break;
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case FAN_DENY:
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default:
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ret = -EPERM;
|
}
|
|
/* Check if the response should be audited */
|
if (event->response & FAN_AUDIT)
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audit_fanotify(event->response & ~FAN_AUDIT);
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|
pr_debug("%s: group=%p event=%p about to return ret=%d\n", __func__,
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group, event, ret);
|
out:
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fsnotify_destroy_event(group, &event->fae.fse);
|
|
return ret;
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}
|
|
/*
|
* This function returns a mask for an event that only contains the flags
|
* that have been specifically requested by the user. Flags that may have
|
* been included within the event mask, but have not been explicitly
|
* requested by the user, will not be present in the returned mask.
|
*/
|
static u32 fanotify_group_event_mask(struct fsnotify_group *group,
|
struct fsnotify_iter_info *iter_info,
|
u32 event_mask, const void *data,
|
int data_type, struct inode *dir)
|
{
|
__u32 marks_mask = 0, marks_ignored_mask = 0;
|
__u32 test_mask, user_mask = FANOTIFY_OUTGOING_EVENTS |
|
FANOTIFY_EVENT_FLAGS;
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const struct path *path = fsnotify_data_path(data, data_type);
|
unsigned int fid_mode = FAN_GROUP_FLAG(group, FANOTIFY_FID_BITS);
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struct fsnotify_mark *mark;
|
int type;
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pr_debug("%s: report_mask=%x mask=%x data=%p data_type=%d\n",
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__func__, iter_info->report_mask, event_mask, data, data_type);
|
|
if (!fid_mode) {
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/* Do we have path to open a file descriptor? */
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if (!path)
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return 0;
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/* Path type events are only relevant for files and dirs */
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if (!d_is_reg(path->dentry) && !d_can_lookup(path->dentry))
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return 0;
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} else if (!(fid_mode & FAN_REPORT_FID)) {
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/* Do we have a directory inode to report? */
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if (!dir && !(event_mask & FS_ISDIR))
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return 0;
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}
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fsnotify_foreach_obj_type(type) {
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if (!fsnotify_iter_should_report_type(iter_info, type))
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continue;
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mark = iter_info->marks[type];
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/* Apply ignore mask regardless of ISDIR and ON_CHILD flags */
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marks_ignored_mask |= mark->ignored_mask;
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|
/*
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* If the event is on dir and this mark doesn't care about
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* events on dir, don't send it!
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*/
|
if (event_mask & FS_ISDIR && !(mark->mask & FS_ISDIR))
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continue;
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/*
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* If the event is on a child and this mark is on a parent not
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* watching children, don't send it!
|
*/
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if (type == FSNOTIFY_OBJ_TYPE_PARENT &&
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!(mark->mask & FS_EVENT_ON_CHILD))
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continue;
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marks_mask |= mark->mask;
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}
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test_mask = event_mask & marks_mask & ~marks_ignored_mask;
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/*
|
* For dirent modification events (create/delete/move) that do not carry
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* the child entry name information, we report FAN_ONDIR for mkdir/rmdir
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* so user can differentiate them from creat/unlink.
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*
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* For backward compatibility and consistency, do not report FAN_ONDIR
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* to user in legacy fanotify mode (reporting fd) and report FAN_ONDIR
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* to user in fid mode for all event types.
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*
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* We never report FAN_EVENT_ON_CHILD to user, but we do pass it in to
|
* fanotify_alloc_event() when group is reporting fid as indication
|
* that event happened on child.
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*/
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if (fid_mode) {
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/* Do not report event flags without any event */
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if (!(test_mask & ~FANOTIFY_EVENT_FLAGS))
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return 0;
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} else {
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user_mask &= ~FANOTIFY_EVENT_FLAGS;
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}
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return test_mask & user_mask;
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}
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/*
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* Check size needed to encode fanotify_fh.
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*
|
* Return size of encoded fh without fanotify_fh header.
|
* Return 0 on failure to encode.
|
*/
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static int fanotify_encode_fh_len(struct inode *inode)
|
{
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int dwords = 0;
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if (!inode)
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return 0;
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exportfs_encode_inode_fh(inode, NULL, &dwords, NULL);
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return dwords << 2;
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}
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/*
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* Encode fanotify_fh.
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*
|
* Return total size of encoded fh including fanotify_fh header.
|
* Return 0 on failure to encode.
|
*/
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static int fanotify_encode_fh(struct fanotify_fh *fh, struct inode *inode,
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unsigned int fh_len, gfp_t gfp)
|
{
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int dwords, type = 0;
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char *ext_buf = NULL;
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void *buf = fh->buf;
|
int err;
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fh->type = FILEID_ROOT;
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fh->len = 0;
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fh->flags = 0;
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if (!inode)
|
return 0;
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|
/*
|
* !gpf means preallocated variable size fh, but fh_len could
|
* be zero in that case if encoding fh len failed.
|
*/
|
err = -ENOENT;
|
if (fh_len < 4 || WARN_ON_ONCE(fh_len % 4))
|
goto out_err;
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/* No external buffer in a variable size allocated fh */
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if (gfp && fh_len > FANOTIFY_INLINE_FH_LEN) {
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/* Treat failure to allocate fh as failure to encode fh */
|
err = -ENOMEM;
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ext_buf = kmalloc(fh_len, gfp);
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if (!ext_buf)
|
goto out_err;
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*fanotify_fh_ext_buf_ptr(fh) = ext_buf;
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buf = ext_buf;
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fh->flags |= FANOTIFY_FH_FLAG_EXT_BUF;
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}
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dwords = fh_len >> 2;
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type = exportfs_encode_inode_fh(inode, buf, &dwords, NULL);
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err = -EINVAL;
|
if (!type || type == FILEID_INVALID || fh_len != dwords << 2)
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goto out_err;
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fh->type = type;
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fh->len = fh_len;
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return FANOTIFY_FH_HDR_LEN + fh_len;
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|
out_err:
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pr_warn_ratelimited("fanotify: failed to encode fid (type=%d, len=%d, err=%i)\n",
|
type, fh_len, err);
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kfree(ext_buf);
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*fanotify_fh_ext_buf_ptr(fh) = NULL;
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/* Report the event without a file identifier on encode error */
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fh->type = FILEID_INVALID;
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fh->len = 0;
|
return 0;
|
}
|
|
/*
|
* The inode to use as identifier when reporting fid depends on the event.
|
* Report the modified directory inode on dirent modification events.
|
* Report the "victim" inode otherwise.
|
* For example:
|
* FS_ATTRIB reports the child inode even if reported on a watched parent.
|
* FS_CREATE reports the modified dir inode and not the created inode.
|
*/
|
static struct inode *fanotify_fid_inode(u32 event_mask, const void *data,
|
int data_type, struct inode *dir)
|
{
|
if (event_mask & ALL_FSNOTIFY_DIRENT_EVENTS)
|
return dir;
|
|
return fsnotify_data_inode(data, data_type);
|
}
|
|
/*
|
* The inode to use as identifier when reporting dir fid depends on the event.
|
* Report the modified directory inode on dirent modification events.
|
* Report the "victim" inode if "victim" is a directory.
|
* Report the parent inode if "victim" is not a directory and event is
|
* reported to parent.
|
* Otherwise, do not report dir fid.
|
*/
|
static struct inode *fanotify_dfid_inode(u32 event_mask, const void *data,
|
int data_type, struct inode *dir)
|
{
|
struct inode *inode = fsnotify_data_inode(data, data_type);
|
|
if (event_mask & ALL_FSNOTIFY_DIRENT_EVENTS)
|
return dir;
|
|
if (S_ISDIR(inode->i_mode))
|
return inode;
|
|
return dir;
|
}
|
|
static struct fanotify_event *fanotify_alloc_path_event(const struct path *path,
|
gfp_t gfp)
|
{
|
struct fanotify_path_event *pevent;
|
|
pevent = kmem_cache_alloc(fanotify_path_event_cachep, gfp);
|
if (!pevent)
|
return NULL;
|
|
pevent->fae.type = FANOTIFY_EVENT_TYPE_PATH;
|
pevent->path = *path;
|
path_get(path);
|
|
return &pevent->fae;
|
}
|
|
static struct fanotify_event *fanotify_alloc_perm_event(const struct path *path,
|
gfp_t gfp)
|
{
|
struct fanotify_perm_event *pevent;
|
|
pevent = kmem_cache_alloc(fanotify_perm_event_cachep, gfp);
|
if (!pevent)
|
return NULL;
|
|
pevent->fae.type = FANOTIFY_EVENT_TYPE_PATH_PERM;
|
pevent->response = 0;
|
pevent->state = FAN_EVENT_INIT;
|
pevent->path = *path;
|
path_get(path);
|
|
return &pevent->fae;
|
}
|
|
static struct fanotify_event *fanotify_alloc_fid_event(struct inode *id,
|
__kernel_fsid_t *fsid,
|
gfp_t gfp)
|
{
|
struct fanotify_fid_event *ffe;
|
|
ffe = kmem_cache_alloc(fanotify_fid_event_cachep, gfp);
|
if (!ffe)
|
return NULL;
|
|
ffe->fae.type = FANOTIFY_EVENT_TYPE_FID;
|
ffe->fsid = *fsid;
|
fanotify_encode_fh(&ffe->object_fh, id, fanotify_encode_fh_len(id),
|
gfp);
|
|
return &ffe->fae;
|
}
|
|
static struct fanotify_event *fanotify_alloc_name_event(struct inode *id,
|
__kernel_fsid_t *fsid,
|
const struct qstr *file_name,
|
struct inode *child,
|
gfp_t gfp)
|
{
|
struct fanotify_name_event *fne;
|
struct fanotify_info *info;
|
struct fanotify_fh *dfh, *ffh;
|
unsigned int dir_fh_len = fanotify_encode_fh_len(id);
|
unsigned int child_fh_len = fanotify_encode_fh_len(child);
|
unsigned int size;
|
|
size = sizeof(*fne) + FANOTIFY_FH_HDR_LEN + dir_fh_len;
|
if (child_fh_len)
|
size += FANOTIFY_FH_HDR_LEN + child_fh_len;
|
if (file_name)
|
size += file_name->len + 1;
|
fne = kmalloc(size, gfp);
|
if (!fne)
|
return NULL;
|
|
fne->fae.type = FANOTIFY_EVENT_TYPE_FID_NAME;
|
fne->fsid = *fsid;
|
info = &fne->info;
|
fanotify_info_init(info);
|
dfh = fanotify_info_dir_fh(info);
|
info->dir_fh_totlen = fanotify_encode_fh(dfh, id, dir_fh_len, 0);
|
if (child_fh_len) {
|
ffh = fanotify_info_file_fh(info);
|
info->file_fh_totlen = fanotify_encode_fh(ffh, child, child_fh_len, 0);
|
}
|
if (file_name)
|
fanotify_info_copy_name(info, file_name);
|
|
pr_debug("%s: ino=%lu size=%u dir_fh_len=%u child_fh_len=%u name_len=%u name='%.*s'\n",
|
__func__, id->i_ino, size, dir_fh_len, child_fh_len,
|
info->name_len, info->name_len, fanotify_info_name(info));
|
|
return &fne->fae;
|
}
|
|
static struct fanotify_event *fanotify_alloc_event(struct fsnotify_group *group,
|
u32 mask, const void *data,
|
int data_type, struct inode *dir,
|
const struct qstr *file_name,
|
__kernel_fsid_t *fsid)
|
{
|
struct fanotify_event *event = NULL;
|
gfp_t gfp = GFP_KERNEL_ACCOUNT;
|
struct inode *id = fanotify_fid_inode(mask, data, data_type, dir);
|
struct inode *dirid = fanotify_dfid_inode(mask, data, data_type, dir);
|
const struct path *path = fsnotify_data_path(data, data_type);
|
unsigned int fid_mode = FAN_GROUP_FLAG(group, FANOTIFY_FID_BITS);
|
struct mem_cgroup *old_memcg;
|
struct inode *child = NULL;
|
bool name_event = false;
|
|
if ((fid_mode & FAN_REPORT_DIR_FID) && dirid) {
|
/*
|
* With both flags FAN_REPORT_DIR_FID and FAN_REPORT_FID, we
|
* report the child fid for events reported on a non-dir child
|
* in addition to reporting the parent fid and maybe child name.
|
*/
|
if ((fid_mode & FAN_REPORT_FID) &&
|
id != dirid && !(mask & FAN_ONDIR))
|
child = id;
|
|
id = dirid;
|
|
/*
|
* We record file name only in a group with FAN_REPORT_NAME
|
* and when we have a directory inode to report.
|
*
|
* For directory entry modification event, we record the fid of
|
* the directory and the name of the modified entry.
|
*
|
* For event on non-directory that is reported to parent, we
|
* record the fid of the parent and the name of the child.
|
*
|
* Even if not reporting name, we need a variable length
|
* fanotify_name_event if reporting both parent and child fids.
|
*/
|
if (!(fid_mode & FAN_REPORT_NAME)) {
|
name_event = !!child;
|
file_name = NULL;
|
} else if ((mask & ALL_FSNOTIFY_DIRENT_EVENTS) ||
|
!(mask & FAN_ONDIR)) {
|
name_event = true;
|
}
|
}
|
|
/*
|
* For queues with unlimited length lost events are not expected and
|
* can possibly have security implications. Avoid losing events when
|
* memory is short. For the limited size queues, avoid OOM killer in the
|
* target monitoring memcg as it may have security repercussion.
|
*/
|
if (group->max_events == UINT_MAX)
|
gfp |= __GFP_NOFAIL;
|
else
|
gfp |= __GFP_RETRY_MAYFAIL;
|
|
/* Whoever is interested in the event, pays for the allocation. */
|
old_memcg = set_active_memcg(group->memcg);
|
|
if (fanotify_is_perm_event(mask)) {
|
event = fanotify_alloc_perm_event(path, gfp);
|
} else if (name_event && (file_name || child)) {
|
event = fanotify_alloc_name_event(id, fsid, file_name, child,
|
gfp);
|
} else if (fid_mode) {
|
event = fanotify_alloc_fid_event(id, fsid, gfp);
|
} else {
|
event = fanotify_alloc_path_event(path, gfp);
|
}
|
|
if (!event)
|
goto out;
|
|
/*
|
* Use the victim inode instead of the watching inode as the id for
|
* event queue, so event reported on parent is merged with event
|
* reported on child when both directory and child watches exist.
|
*/
|
fanotify_init_event(event, (unsigned long)id, mask);
|
if (FAN_GROUP_FLAG(group, FAN_REPORT_TID))
|
event->pid = get_pid(task_pid(current));
|
else
|
event->pid = get_pid(task_tgid(current));
|
|
out:
|
set_active_memcg(old_memcg);
|
return event;
|
}
|
|
/*
|
* Get cached fsid of the filesystem containing the object from any connector.
|
* All connectors are supposed to have the same fsid, but we do not verify that
|
* here.
|
*/
|
static __kernel_fsid_t fanotify_get_fsid(struct fsnotify_iter_info *iter_info)
|
{
|
int type;
|
__kernel_fsid_t fsid = {};
|
|
fsnotify_foreach_obj_type(type) {
|
struct fsnotify_mark_connector *conn;
|
|
if (!fsnotify_iter_should_report_type(iter_info, type))
|
continue;
|
|
conn = READ_ONCE(iter_info->marks[type]->connector);
|
/* Mark is just getting destroyed or created? */
|
if (!conn)
|
continue;
|
if (!(conn->flags & FSNOTIFY_CONN_FLAG_HAS_FSID))
|
continue;
|
/* Pairs with smp_wmb() in fsnotify_add_mark_list() */
|
smp_rmb();
|
fsid = conn->fsid;
|
if (WARN_ON_ONCE(!fsid.val[0] && !fsid.val[1]))
|
continue;
|
return fsid;
|
}
|
|
return fsid;
|
}
|
|
static int fanotify_handle_event(struct fsnotify_group *group, u32 mask,
|
const void *data, int data_type,
|
struct inode *dir,
|
const struct qstr *file_name, u32 cookie,
|
struct fsnotify_iter_info *iter_info)
|
{
|
int ret = 0;
|
struct fanotify_event *event;
|
struct fsnotify_event *fsn_event;
|
__kernel_fsid_t fsid = {};
|
|
BUILD_BUG_ON(FAN_ACCESS != FS_ACCESS);
|
BUILD_BUG_ON(FAN_MODIFY != FS_MODIFY);
|
BUILD_BUG_ON(FAN_ATTRIB != FS_ATTRIB);
|
BUILD_BUG_ON(FAN_CLOSE_NOWRITE != FS_CLOSE_NOWRITE);
|
BUILD_BUG_ON(FAN_CLOSE_WRITE != FS_CLOSE_WRITE);
|
BUILD_BUG_ON(FAN_OPEN != FS_OPEN);
|
BUILD_BUG_ON(FAN_MOVED_TO != FS_MOVED_TO);
|
BUILD_BUG_ON(FAN_MOVED_FROM != FS_MOVED_FROM);
|
BUILD_BUG_ON(FAN_CREATE != FS_CREATE);
|
BUILD_BUG_ON(FAN_DELETE != FS_DELETE);
|
BUILD_BUG_ON(FAN_DELETE_SELF != FS_DELETE_SELF);
|
BUILD_BUG_ON(FAN_MOVE_SELF != FS_MOVE_SELF);
|
BUILD_BUG_ON(FAN_EVENT_ON_CHILD != FS_EVENT_ON_CHILD);
|
BUILD_BUG_ON(FAN_Q_OVERFLOW != FS_Q_OVERFLOW);
|
BUILD_BUG_ON(FAN_OPEN_PERM != FS_OPEN_PERM);
|
BUILD_BUG_ON(FAN_ACCESS_PERM != FS_ACCESS_PERM);
|
BUILD_BUG_ON(FAN_ONDIR != FS_ISDIR);
|
BUILD_BUG_ON(FAN_OPEN_EXEC != FS_OPEN_EXEC);
|
BUILD_BUG_ON(FAN_OPEN_EXEC_PERM != FS_OPEN_EXEC_PERM);
|
|
BUILD_BUG_ON(HWEIGHT32(ALL_FANOTIFY_EVENT_BITS) != 19);
|
|
mask = fanotify_group_event_mask(group, iter_info, mask, data,
|
data_type, dir);
|
if (!mask)
|
return 0;
|
|
pr_debug("%s: group=%p mask=%x\n", __func__, group, mask);
|
|
if (fanotify_is_perm_event(mask)) {
|
/*
|
* fsnotify_prepare_user_wait() fails if we race with mark
|
* deletion. Just let the operation pass in that case.
|
*/
|
if (!fsnotify_prepare_user_wait(iter_info))
|
return 0;
|
}
|
|
if (FAN_GROUP_FLAG(group, FANOTIFY_FID_BITS)) {
|
fsid = fanotify_get_fsid(iter_info);
|
/* Racing with mark destruction or creation? */
|
if (!fsid.val[0] && !fsid.val[1])
|
return 0;
|
}
|
|
event = fanotify_alloc_event(group, mask, data, data_type, dir,
|
file_name, &fsid);
|
ret = -ENOMEM;
|
if (unlikely(!event)) {
|
/*
|
* We don't queue overflow events for permission events as
|
* there the access is denied and so no event is in fact lost.
|
*/
|
if (!fanotify_is_perm_event(mask))
|
fsnotify_queue_overflow(group);
|
goto finish;
|
}
|
|
fsn_event = &event->fse;
|
ret = fsnotify_add_event(group, fsn_event, fanotify_merge);
|
if (ret) {
|
/* Permission events shouldn't be merged */
|
BUG_ON(ret == 1 && mask & FANOTIFY_PERM_EVENTS);
|
/* Our event wasn't used in the end. Free it. */
|
fsnotify_destroy_event(group, fsn_event);
|
|
ret = 0;
|
} else if (fanotify_is_perm_event(mask)) {
|
ret = fanotify_get_response(group, FANOTIFY_PERM(event),
|
iter_info);
|
}
|
finish:
|
if (fanotify_is_perm_event(mask))
|
fsnotify_finish_user_wait(iter_info);
|
|
return ret;
|
}
|
|
static void fanotify_free_group_priv(struct fsnotify_group *group)
|
{
|
struct user_struct *user;
|
|
user = group->fanotify_data.user;
|
atomic_dec(&user->fanotify_listeners);
|
free_uid(user);
|
}
|
|
static void fanotify_free_path_event(struct fanotify_event *event)
|
{
|
path_put(fanotify_event_path(event));
|
kmem_cache_free(fanotify_path_event_cachep, FANOTIFY_PE(event));
|
}
|
|
static void fanotify_free_perm_event(struct fanotify_event *event)
|
{
|
path_put(fanotify_event_path(event));
|
kmem_cache_free(fanotify_perm_event_cachep, FANOTIFY_PERM(event));
|
}
|
|
static void fanotify_free_fid_event(struct fanotify_event *event)
|
{
|
struct fanotify_fid_event *ffe = FANOTIFY_FE(event);
|
|
if (fanotify_fh_has_ext_buf(&ffe->object_fh))
|
kfree(fanotify_fh_ext_buf(&ffe->object_fh));
|
kmem_cache_free(fanotify_fid_event_cachep, ffe);
|
}
|
|
static void fanotify_free_name_event(struct fanotify_event *event)
|
{
|
kfree(FANOTIFY_NE(event));
|
}
|
|
static void fanotify_free_event(struct fsnotify_event *fsn_event)
|
{
|
struct fanotify_event *event;
|
|
event = FANOTIFY_E(fsn_event);
|
put_pid(event->pid);
|
switch (event->type) {
|
case FANOTIFY_EVENT_TYPE_PATH:
|
fanotify_free_path_event(event);
|
break;
|
case FANOTIFY_EVENT_TYPE_PATH_PERM:
|
fanotify_free_perm_event(event);
|
break;
|
case FANOTIFY_EVENT_TYPE_FID:
|
fanotify_free_fid_event(event);
|
break;
|
case FANOTIFY_EVENT_TYPE_FID_NAME:
|
fanotify_free_name_event(event);
|
break;
|
case FANOTIFY_EVENT_TYPE_OVERFLOW:
|
kfree(event);
|
break;
|
default:
|
WARN_ON_ONCE(1);
|
}
|
}
|
|
static void fanotify_free_mark(struct fsnotify_mark *fsn_mark)
|
{
|
kmem_cache_free(fanotify_mark_cache, fsn_mark);
|
}
|
|
const struct fsnotify_ops fanotify_fsnotify_ops = {
|
.handle_event = fanotify_handle_event,
|
.free_group_priv = fanotify_free_group_priv,
|
.free_event = fanotify_free_event,
|
.free_mark = fanotify_free_mark,
|
};
|
