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522249f05c
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
140 lines
4.7 KiB
C
140 lines
4.7 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _LINUX_FANOTIFY_H
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#define _LINUX_FANOTIFY_H
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#include <linux/sysctl.h>
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#include <uapi/linux/fanotify.h>
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#define FAN_GROUP_FLAG(group, flag) \
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((group)->fanotify_data.flags & (flag))
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/*
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* Flags allowed to be passed from/to userspace.
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*
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* We intentionally do not add new bits to the old FAN_ALL_* constants, because
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* they are uapi exposed constants. If there are programs out there using
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* these constant, the programs may break if re-compiled with new uapi headers
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* and then run on an old kernel.
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*/
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/* Group classes where permission events are allowed */
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#define FANOTIFY_PERM_CLASSES (FAN_CLASS_CONTENT | \
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FAN_CLASS_PRE_CONTENT)
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#define FANOTIFY_CLASS_BITS (FAN_CLASS_NOTIF | FANOTIFY_PERM_CLASSES)
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#define FANOTIFY_FID_BITS (FAN_REPORT_DFID_NAME_TARGET)
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#define FANOTIFY_INFO_MODES (FANOTIFY_FID_BITS | FAN_REPORT_PIDFD)
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/*
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* fanotify_init() flags that require CAP_SYS_ADMIN.
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* We do not allow unprivileged groups to request permission events.
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* We do not allow unprivileged groups to get other process pid in events.
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* We do not allow unprivileged groups to use unlimited resources.
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*/
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#define FANOTIFY_ADMIN_INIT_FLAGS (FANOTIFY_PERM_CLASSES | \
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FAN_REPORT_TID | \
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FAN_REPORT_PIDFD | \
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FAN_REPORT_FD_ERROR | \
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FAN_UNLIMITED_QUEUE | \
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FAN_UNLIMITED_MARKS)
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/*
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* fanotify_init() flags that are allowed for user without CAP_SYS_ADMIN.
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* FAN_CLASS_NOTIF is the only class we allow for unprivileged group.
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* We do not allow unprivileged groups to get file descriptors in events,
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* so one of the flags for reporting file handles is required.
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*/
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#define FANOTIFY_USER_INIT_FLAGS (FAN_CLASS_NOTIF | \
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FANOTIFY_FID_BITS | \
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FAN_CLOEXEC | FAN_NONBLOCK)
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#define FANOTIFY_INIT_FLAGS (FANOTIFY_ADMIN_INIT_FLAGS | \
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FANOTIFY_USER_INIT_FLAGS)
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/* Internal group flags */
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#define FANOTIFY_UNPRIV 0x80000000
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#define FANOTIFY_INTERNAL_GROUP_FLAGS (FANOTIFY_UNPRIV)
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#define FANOTIFY_MARK_TYPE_BITS (FAN_MARK_INODE | FAN_MARK_MOUNT | \
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FAN_MARK_FILESYSTEM)
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#define FANOTIFY_MARK_CMD_BITS (FAN_MARK_ADD | FAN_MARK_REMOVE | \
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FAN_MARK_FLUSH)
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#define FANOTIFY_MARK_IGNORE_BITS (FAN_MARK_IGNORED_MASK | \
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FAN_MARK_IGNORE)
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#define FANOTIFY_MARK_FLAGS (FANOTIFY_MARK_TYPE_BITS | \
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FANOTIFY_MARK_CMD_BITS | \
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FANOTIFY_MARK_IGNORE_BITS | \
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FAN_MARK_DONT_FOLLOW | \
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FAN_MARK_ONLYDIR | \
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FAN_MARK_IGNORED_SURV_MODIFY | \
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FAN_MARK_EVICTABLE)
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/*
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* Events that can be reported with data type FSNOTIFY_EVENT_PATH.
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* Note that FAN_MODIFY can also be reported with data type
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* FSNOTIFY_EVENT_INODE.
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*/
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#define FANOTIFY_PATH_EVENTS (FAN_ACCESS | FAN_MODIFY | \
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FAN_CLOSE | FAN_OPEN | FAN_OPEN_EXEC)
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/*
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* Directory entry modification events - reported only to directory
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* where entry is modified and not to a watching parent.
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*/
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#define FANOTIFY_DIRENT_EVENTS (FAN_MOVE | FAN_CREATE | FAN_DELETE | \
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FAN_RENAME)
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/* Events that can be reported with event->fd */
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#define FANOTIFY_FD_EVENTS (FANOTIFY_PATH_EVENTS | FANOTIFY_PERM_EVENTS)
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/* Events that can only be reported with data type FSNOTIFY_EVENT_INODE */
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#define FANOTIFY_INODE_EVENTS (FANOTIFY_DIRENT_EVENTS | \
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FAN_ATTRIB | FAN_MOVE_SELF | FAN_DELETE_SELF)
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/* Events that can only be reported with data type FSNOTIFY_EVENT_ERROR */
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#define FANOTIFY_ERROR_EVENTS (FAN_FS_ERROR)
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/* Events that user can request to be notified on */
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#define FANOTIFY_EVENTS (FANOTIFY_PATH_EVENTS | \
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FANOTIFY_INODE_EVENTS | \
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FANOTIFY_ERROR_EVENTS)
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/* Events that require a permission response from user */
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#define FANOTIFY_PERM_EVENTS (FAN_OPEN_PERM | FAN_ACCESS_PERM | \
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FAN_OPEN_EXEC_PERM)
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/* Extra flags that may be reported with event or control handling of events */
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#define FANOTIFY_EVENT_FLAGS (FAN_EVENT_ON_CHILD | FAN_ONDIR)
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/* Events that may be reported to user */
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#define FANOTIFY_OUTGOING_EVENTS (FANOTIFY_EVENTS | \
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FANOTIFY_PERM_EVENTS | \
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FAN_Q_OVERFLOW | FAN_ONDIR)
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/* Events and flags relevant only for directories */
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#define FANOTIFY_DIRONLY_EVENT_BITS (FANOTIFY_DIRENT_EVENTS | \
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FAN_EVENT_ON_CHILD | FAN_ONDIR)
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#define ALL_FANOTIFY_EVENT_BITS (FANOTIFY_OUTGOING_EVENTS | \
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FANOTIFY_EVENT_FLAGS)
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/* These masks check for invalid bits in permission responses. */
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#define FANOTIFY_RESPONSE_ACCESS (FAN_ALLOW | FAN_DENY)
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#define FANOTIFY_RESPONSE_FLAGS (FAN_AUDIT | FAN_INFO)
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#define FANOTIFY_RESPONSE_VALID_MASK (FANOTIFY_RESPONSE_ACCESS | FANOTIFY_RESPONSE_FLAGS)
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/* Do not use these old uapi constants internally */
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#undef FAN_ALL_CLASS_BITS
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#undef FAN_ALL_INIT_FLAGS
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#undef FAN_ALL_MARK_FLAGS
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#undef FAN_ALL_EVENTS
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#undef FAN_ALL_PERM_EVENTS
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#undef FAN_ALL_OUTGOING_EVENTS
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#endif /* _LINUX_FANOTIFY_H */
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