nagai/kernel
3
0
Fork 0
forked from mirrors/linux
Code Pull requests Activity
kernel/include/linux/fanotify.h
Amir Goldstein 522249f05c fanotify: allow reporting errors on failure to open fd 
When working in "fd mode", fanotify_read() needs to open an fd
from a dentry to report event->fd to userspace.

Opening an fd from dentry can fail for several reasons.
For example, when tasks are gone and we try to open their
/proc files or we try to open a WRONLY file like in sysfs
or when trying to open a file that was deleted on the
remote network server.

Add a new flag FAN_REPORT_FD_ERROR for fanotify_init().
For a group with FAN_REPORT_FD_ERROR, we will send the
event with the error instead of the open fd, otherwise
userspace may not get the error at all.

For an overflow event, we report -EBADF to avoid confusing FAN_NOFD
with -EPERM.  Similarly for pidfd open errors we report either -ESRCH
or the open error instead of FAN_NOPIDFD and FAN_EPIDFD.

In any case, userspace will not know which file failed to
open, so add a debug print for further investigation.

Reported-by: Krishna Vivek Vitta <kvitta@microsoft.com>
Link: https://lore.kernel.org/linux-fsdevel/SI2P153MB07182F3424619EDDD1F393EED46D2@SI2P153MB0718.APCP153.PROD.OUTLOOK.COM/
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Link: https://patch.msgid.link/20241003142922.111539-1-amir73il@gmail.com
2024-10-16 17:43:05 +02:00

139 lines
4.7 KiB
C
Raw Blame History

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _LINUX_FANOTIFY_H
#define _LINUX_FANOTIFY_H
#include <linux/sysctl.h>
#include <uapi/linux/fanotify.h>
#define FAN_GROUP_FLAG(group, flag) \
((group)->fanotify_data.flags & (flag))
/*
* Flags allowed to be passed from/to userspace.
*
* We intentionally do not add new bits to the old FAN_ALL_* constants, because
* they are uapi exposed constants. If there are programs out there using
* these constant, the programs may break if re-compiled with new uapi headers
* and then run on an old kernel.
*/
/* Group classes where permission events are allowed */
#define FANOTIFY_PERM_CLASSES (FAN_CLASS_CONTENT | \
FAN_CLASS_PRE_CONTENT)
#define FANOTIFY_CLASS_BITS (FAN_CLASS_NOTIF | FANOTIFY_PERM_CLASSES)
#define FANOTIFY_FID_BITS (FAN_REPORT_DFID_NAME_TARGET)
#define FANOTIFY_INFO_MODES (FANOTIFY_FID_BITS | FAN_REPORT_PIDFD)
/*
* fanotify_init() flags that require CAP_SYS_ADMIN.
* We do not allow unprivileged groups to request permission events.
* We do not allow unprivileged groups to get other process pid in events.
* We do not allow unprivileged groups to use unlimited resources.
*/
#define FANOTIFY_ADMIN_INIT_FLAGS (FANOTIFY_PERM_CLASSES | \
FAN_REPORT_TID | \
FAN_REPORT_PIDFD | \
FAN_REPORT_FD_ERROR | \
FAN_UNLIMITED_QUEUE | \
FAN_UNLIMITED_MARKS)
/*
* fanotify_init() flags that are allowed for user without CAP_SYS_ADMIN.
* FAN_CLASS_NOTIF is the only class we allow for unprivileged group.
* We do not allow unprivileged groups to get file descriptors in events,
* so one of the flags for reporting file handles is required.
*/
#define FANOTIFY_USER_INIT_FLAGS (FAN_CLASS_NOTIF | \
FANOTIFY_FID_BITS | \
FAN_CLOEXEC | FAN_NONBLOCK)
#define FANOTIFY_INIT_FLAGS (FANOTIFY_ADMIN_INIT_FLAGS | \
FANOTIFY_USER_INIT_FLAGS)
/* Internal group flags */
#define FANOTIFY_UNPRIV 0x80000000
#define FANOTIFY_INTERNAL_GROUP_FLAGS (FANOTIFY_UNPRIV)
#define FANOTIFY_MARK_TYPE_BITS (FAN_MARK_INODE | FAN_MARK_MOUNT | \
FAN_MARK_FILESYSTEM)
#define FANOTIFY_MARK_CMD_BITS (FAN_MARK_ADD | FAN_MARK_REMOVE | \
FAN_MARK_FLUSH)
#define FANOTIFY_MARK_IGNORE_BITS (FAN_MARK_IGNORED_MASK | \
FAN_MARK_IGNORE)
#define FANOTIFY_MARK_FLAGS (FANOTIFY_MARK_TYPE_BITS | \
FANOTIFY_MARK_CMD_BITS | \
FANOTIFY_MARK_IGNORE_BITS | \
FAN_MARK_DONT_FOLLOW | \
FAN_MARK_ONLYDIR | \
FAN_MARK_IGNORED_SURV_MODIFY | \
FAN_MARK_EVICTABLE)
/*
* Events that can be reported with data type FSNOTIFY_EVENT_PATH.
* Note that FAN_MODIFY can also be reported with data type
* FSNOTIFY_EVENT_INODE.
*/
#define FANOTIFY_PATH_EVENTS (FAN_ACCESS | FAN_MODIFY | \
FAN_CLOSE | FAN_OPEN | FAN_OPEN_EXEC)
/*
* Directory entry modification events - reported only to directory
* where entry is modified and not to a watching parent.
*/
#define FANOTIFY_DIRENT_EVENTS (FAN_MOVE | FAN_CREATE | FAN_DELETE | \
FAN_RENAME)
/* Events that can be reported with event->fd */
#define FANOTIFY_FD_EVENTS (FANOTIFY_PATH_EVENTS | FANOTIFY_PERM_EVENTS)
/* Events that can only be reported with data type FSNOTIFY_EVENT_INODE */
#define FANOTIFY_INODE_EVENTS (FANOTIFY_DIRENT_EVENTS | \
FAN_ATTRIB | FAN_MOVE_SELF | FAN_DELETE_SELF)
/* Events that can only be reported with data type FSNOTIFY_EVENT_ERROR */
#define FANOTIFY_ERROR_EVENTS (FAN_FS_ERROR)
/* Events that user can request to be notified on */
#define FANOTIFY_EVENTS (FANOTIFY_PATH_EVENTS | \
FANOTIFY_INODE_EVENTS | \
FANOTIFY_ERROR_EVENTS)
/* Events that require a permission response from user */
#define FANOTIFY_PERM_EVENTS (FAN_OPEN_PERM | FAN_ACCESS_PERM | \
FAN_OPEN_EXEC_PERM)
/* Extra flags that may be reported with event or control handling of events */
#define FANOTIFY_EVENT_FLAGS (FAN_EVENT_ON_CHILD | FAN_ONDIR)
/* Events that may be reported to user */
#define FANOTIFY_OUTGOING_EVENTS (FANOTIFY_EVENTS | \
FANOTIFY_PERM_EVENTS | \
FAN_Q_OVERFLOW | FAN_ONDIR)
/* Events and flags relevant only for directories */
#define FANOTIFY_DIRONLY_EVENT_BITS (FANOTIFY_DIRENT_EVENTS | \
FAN_EVENT_ON_CHILD | FAN_ONDIR)
#define ALL_FANOTIFY_EVENT_BITS (FANOTIFY_OUTGOING_EVENTS | \
FANOTIFY_EVENT_FLAGS)
/* These masks check for invalid bits in permission responses. */
#define FANOTIFY_RESPONSE_ACCESS (FAN_ALLOW | FAN_DENY)
#define FANOTIFY_RESPONSE_FLAGS (FAN_AUDIT | FAN_INFO)
#define FANOTIFY_RESPONSE_VALID_MASK (FANOTIFY_RESPONSE_ACCESS | FANOTIFY_RESPONSE_FLAGS)
/* Do not use these old uapi constants internally */
#undef FAN_ALL_CLASS_BITS
#undef FAN_ALL_INIT_FLAGS
#undef FAN_ALL_MARK_FLAGS
#undef FAN_ALL_EVENTS
#undef FAN_ALL_PERM_EVENTS
#undef FAN_ALL_OUTGOING_EVENTS
#endif /* _LINUX_FANOTIFY_H */
View git blame Copy permalink