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path: root/include/linux/fanotify.h
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2010-12-15fanotify: split version into version and metadata_lenAlexey Zaytsev
To implement per event type optional headers we are interested in knowing how long the metadata structure is. This patch slits the __u32 version field into a __u8 version and a __u16 metadata_len field (with __u8 left over). This should allow for backwards compat ABI. Signed-off-by: Alexey Zaytsev <alexey.zaytsev@gmail.com> [rewrote descrtion and changed object sizes and ordering - eparis] Signed-off-by: Eric Paris <eparis@redhat.com>
2010-12-07fanotify: Introduce FAN_NOFDLino Sanfilippo
FAN_NOFD is used in fanotify events that do not provide an open file descriptor (like the overflow_event). Signed-off-by: Lino Sanfilippo <LinoSanfilippo@gmx.de> Signed-off-by: Eric Paris <eparis@redhat.com>
2010-12-07fanotify: remove packed from access response messageEric Paris
Since fanotify has decided to be careful about alignment and packing rather than rely on __attribute__((packed)) for multiarch support. Since this attribute isn't doing anything on fanotify_response we just drop it. This does not break API/ABI. Suggested-by: Tvrtko Ursulin <tvrtko.ursulin@sophos.com> Signed-off-by: Eric Paris <eparis@redhat.com>
2010-10-28fanotify: Fix FAN_CLOSE commentsStefan Hajnoczi
The comments for FAN_CLOSE_WRITE and FAN_CLOSE_NOWRITE do not match FS_CLOSE_WRITE and FS_CLOSE_NOWRITE, respectively. WRITE is for writable files while NOWRITE is for non-writable files. Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com> Signed-off-by: Eric Paris <eparis@redhat.com>
2010-10-28fanotify: ignore events on directories unless specifically requestedEric Paris
fanotify has a very limited number of events it sends on directories. The usefulness of these events is yet to be seen and still we send them. This is particularly painful for mount marks where one might receive many of these useless events. As such this patch will drop events on IS_DIR() inodes unless they were explictly requested with FAN_ON_DIR. This means that a mark on a directory without FAN_EVENT_ON_CHILD or FAN_ON_DIR is meaningless and will result in no events ever (although it will still be allowed since detecting it is hard) Signed-off-by: Eric Paris <eparis@redhat.com>
2010-10-28fanotify: allow userspace to override max marksEric Paris
Some fanotify groups, especially those like AV scanners, will need to place lots of marks, particularly ignore marks. Since ignore marks do not pin inodes in cache and are cleared if the inode is removed from core (usually under memory pressure) we expose an interface for listeners, with CAP_SYS_ADMIN, to override the maximum number of marks and be allowed to set and 'unlimited' number of marks. Programs which make use of this feature will be able to OOM a machine. Signed-off-by: Eric Paris <eparis@redhat.com>
2010-10-28fanotify: allow userspace to override max queue depthEric Paris
fanotify has a defualt max queue depth. This patch allows processes which explicitly request it to have an 'unlimited' queue depth. These processes need to be very careful to make sure they cannot fall far enough behind that they OOM the box. Thus this flag is gated on CAP_SYS_ADMIN. Signed-off-by: Eric Paris <eparis@redhat.com>
2010-10-28fsnotify: implement a default maximum queue depthEric Paris
Currently fanotify has no maximum queue depth. Since fanotify is CAP_SYS_ADMIN only this does not pose a normal user DoS issue, but it certianly is possible that an fanotify listener which can't keep up could OOM the box. This patch implements a default 16k depth. This is the same default depth used by inotify, but given fanotify's better queue merging in many situations this queue will contain many additional useful events by comparison. Signed-off-by: Eric Paris <eparis@redhat.com>
2010-10-28fanotify: allow userspace to flush all marksEric Paris
fanotify is supposed to be able to flush all marks. This is mostly useful for the AV community to flush all cached decisions on a security policy change. This functionality has existed in the kernel but wasn't correctly exposed to userspace. Signed-off-by: Eric Paris <eparis@redhat.com>
2010-10-28fanotify: use __aligned_u64 in fanotify userspace metadataEric Paris
Currently the userspace struct exposed by fanotify uses __attribute__((packed)) to make sure that alignment works on multiarch platforms. Since this causes a severe performance penalty on some platforms we are going to switch to using explicit alignment notation on the 64bit values so we don't have to use 'packed' Signed-off-by: Eric Paris <eparis@redhat.com>
2010-10-28fanotify: implement fanotify listener orderingEric Paris
The fanotify listeners needs to be able to specify what types of operations they are going to perform so they can be ordered appropriately between other listeners doing other types of operations. They need this to be able to make sure that things like hierarchichal storage managers will get access to inodes before processes which need the data. This patch defines 3 possible uses which groups must indicate in the fanotify_init() flags. FAN_CLASS_PRE_CONTENT FAN_CLASS_CONTENT FAN_CLASS_NOTIF Groups will receive notification in that order. The order between 2 groups in the same class is undeterministic. FAN_CLASS_PRE_CONTENT is intended to be used by listeners which need access to the inode before they are certain that the inode contains it's final data. A hierarchical storage manager should choose to use this class. FAN_CLASS_CONTENT is intended to be used by listeners which need access to the inode after it contains its intended contents. This would be the appropriate level for an AV solution or document control system. FAN_CLASS_NOTIF is intended for normal async notification about access, much the same as inotify and dnotify. Syncronous permissions events are not permitted at this class. Signed-off-by: Eric Paris <eparis@redhat.com>
2010-08-27fanotify: resize pid and reorder structureTvrtko Ursulin
resize pid and reorder the fanotify_event_metadata so it is naturally aligned and we can work towards dropping the packed attributed Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@sophos.com> Cc: Andreas Dilger <adilger@dilger.ca> Signed-off-by: Eric Paris <eparis@redhat.com>
2010-08-23fanotify: flush outstanding perm requests on group destroyEric Paris
When an fanotify listener is closing it may cause a deadlock between the listener and the original task doing an fs operation. If the original task is waiting for a permissions response it will be holding the srcu lock. The listener cannot clean up and exit until after that srcu lock is syncronized. Thus deadlock. The fix introduced here is to stop accepting new permissions events when a listener is shutting down and to grant permission for all outstanding events. Thus the original task will eventually release the srcu lock and the listener can complete shutdown. Reported-by: Andreas Gruenbacher <agruen@suse.de> Cc: Andreas Gruenbacher <agruen@suse.de> Signed-off-by: Eric Paris <eparis@redhat.com>
2010-07-28fanotify: userspace interface for permission responsesEric Paris
fanotify groups need to respond to events which include permissions types. To do so groups will send a response using write() on the fanotify_fd they have open. Signed-off-by: Eric Paris <eparis@redhat.com>
2010-07-28fanotify: permissions and blockingEric Paris
This is the backend work needed for fanotify to support the new FS_OPEN_PERM and FS_ACCESS_PERM fsnotify events. This is done using the new fsnotify secondary queue. No userspace interface is provided actually respond to or request these events. Signed-off-by: Eric Paris <eparis@redhat.com>
2010-07-28fanotify: clear all fanotify marksEric Paris
fanotify listeners may want to clear all marks. They may want to do this to destroy all of their inode marks which have nothing but ignores. Realistically this is useful for av vendors who update policy and want to clear all of their cached allows. Signed-off-by: Eric Paris <eparis@redhat.com>
2010-07-28fanotify: allow ignored_masks to survive modifyEric Paris
Some users may want to truely ignore an inode even if it has been modified. Say you are wanting a mount which contains a log file and you really don't want any notification about that file. This patch allows the listener to do that. Signed-off-by: Eric Paris <eparis@redhat.com>
2010-07-28fanotify: allow users to set an ignored_maskEric Paris
Change the sys_fanotify_mark() system call so users can set ignored_masks on inodes. Remember, if a user new sets a real mask, and only sets ignored masks, the ignore will never be pinned in memory. Thus ignored_masks can be lost under memory pressure and the user may again get events they previously thought were ignored. Signed-off-by: Eric Paris <eparis@redhat.com>
2010-07-28fanotify: remove fanotify.h declarationsAndreas Gruenbacher
fanotify_mark_validate functions are all needlessly declared in headers as static inlines. Instead just do the checks where they are needed for code readability. Signed-off-by: Andreas Gruenbacher <agruen@suse.de> Signed-off-by: Eric Paris <eparis@redhat.com>
2010-07-28fanotify: rename FAN_MARK_ON_VFSMOUNT to FAN_MARK_MOUNTAndreas Gruenbacher
the term 'vfsmount' isn't sensicle to userspace. instead call is 'mount. Signed-off-by: Andreas Gruenbacher <agruen@suse.de> Signed-off-by: Eric Paris <eparis@redhat.com>
2010-07-28fanotify: hooks the fanotify_mark syscall to the vfsmount codeEric Paris
Create a new fanotify_mark flag which indicates we should attach the mark to the vfsmount holding the object referenced by dfd and pathname rather than the inode itself. Signed-off-by: Eric Paris <eparis@redhat.com>
2010-07-28fanotify: Add pids to eventsAndreas Gruenbacher
Pass the process identifiers of the triggering processes to fanotify listeners: this information is useful for event filtering and logging. Signed-off-by: Andreas Gruenbacher <agruen@suse.de> Signed-off-by: Eric Paris <eparis@redhat.com>
2010-07-28fanotify: send events using readEric Paris
Send events to userspace by reading the file descriptor from fanotify_init(). One will get blocks of data which look like: struct fanotify_event_metadata { __u32 event_len; __u32 vers; __s32 fd; __u64 mask; __s64 pid; __u64 cookie; } __attribute__ ((packed)); Simple code to retrieve and deal with events is below while ((len = read(fan_fd, buf, sizeof(buf))) > 0) { struct fanotify_event_metadata *metadata; metadata = (void *)buf; while(FAN_EVENT_OK(metadata, len)) { [PROCESS HERE!!] if (metadata->fd >= 0 && close(metadata->fd) != 0) goto fail; metadata = FAN_EVENT_NEXT(metadata, len); } } Signed-off-by: Eric Paris <eparis@redhat.com>
2010-07-28fanotify: fanotify_mark syscall implementationEric Paris
NAME fanotify_mark - add, remove, or modify an fanotify mark on a filesystem object SYNOPSIS int fanotify_mark(int fanotify_fd, unsigned int flags, u64 mask, int dfd, const char *pathname) DESCRIPTION fanotify_mark() is used to add remove or modify a mark on a filesystem object. Marks are used to indicate that the fanotify group is interested in events which occur on that object. At this point in time marks may only be added to files and directories. fanotify_fd must be a file descriptor returned by fanotify_init() The flags field must contain exactly one of the following: FAN_MARK_ADD - or the bits in mask and ignored mask into the mark FAN_MARK_REMOVE - bitwise remove the bits in mask and ignored mark from the mark The following values can be OR'd into the flags field: FAN_MARK_DONT_FOLLOW - same meaning as O_NOFOLLOW as described in open(2) FAN_MARK_ONLYDIR - same meaning as O_DIRECTORY as described in open(2) dfd may be any of the following: AT_FDCWD: the object will be lookup up based on pathname similar to open(2) file descriptor of a directory: if pathname is not NULL the object to modify will be lookup up similar to openat(2) file descriptor of the final object: if pathname is NULL the object to modify will be the object referenced by dfd The mask is the bitwise OR of the set of events of interest such as: FAN_ACCESS - object was accessed (read) FAN_MODIFY - object was modified (write) FAN_CLOSE_WRITE - object was writable and was closed FAN_CLOSE_NOWRITE - object was read only and was closed FAN_OPEN - object was opened FAN_EVENT_ON_CHILD - interested in objected that happen to children. Only relavent when the object is a directory FAN_Q_OVERFLOW - event queue overflowed (not implemented) RETURN VALUE On success, this system call returns 0. On error, -1 is returned, and errno is set to indicate the error. ERRORS EINVAL An invalid value was specified in flags. EINVAL An invalid value was specified in mask. EINVAL An invalid value was specified in ignored_mask. EINVAL fanotify_fd is not a file descriptor as returned by fanotify_init() EBADF fanotify_fd is not a valid file descriptor EBADF dfd is not a valid file descriptor and path is NULL. ENOTDIR dfd is not a directory and path is not NULL EACCESS no search permissions on some part of the path ENENT file not found ENOMEM Insufficient kernel memory is available. CONFORMING TO These system calls are Linux-specific. Signed-off-by: Eric Paris <eparis@redhat.com>
2010-07-28fanotify: fanotify_init syscall implementationEric Paris
NAME fanotify_init - initialize an fanotify group SYNOPSIS int fanotify_init(unsigned int flags, unsigned int event_f_flags, int priority); DESCRIPTION fanotify_init() initializes a new fanotify instance and returns a file descriptor associated with the new fanotify event queue. The following values can be OR'd into the flags field: FAN_NONBLOCK Set the O_NONBLOCK file status flag on the new open file description. Using this flag saves extra calls to fcntl(2) to achieve the same result. FAN_CLOEXEC Set the close-on-exec (FD_CLOEXEC) flag on the new file descriptor. See the description of the O_CLOEXEC flag in open(2) for reasons why this may be useful. The event_f_flags argument is unused and must be set to 0 The priority argument is unused and must be set to 0 RETURN VALUE On success, this system call return a new file descriptor. On error, -1 is returned, and errno is set to indicate the error. ERRORS EINVAL An invalid value was specified in flags. EINVAL A non-zero valid was passed in event_f_flags or in priority ENFILE The system limit on the total number of file descriptors has been reached. ENOMEM Insufficient kernel memory is available. CONFORMING TO These system calls are Linux-specific. Signed-off-by: Eric Paris <eparis@redhat.com>
2010-07-28fanotify: fscking all notification systemEric Paris
fanotify is a novel file notification system which bases notification on giving userspace both an event type (open, close, read, write) and an open file descriptor to the object in question. This should address a number of races and problems with other notification systems like inotify and dnotify and should allow the future implementation of blocking or access controlled notification. These are useful for on access scanners or hierachical storage management schemes. This patch just implements the basics of the fsnotify functions. Signed-off-by: Eric Paris <eparis@redhat.com>