Commit Graph

32 Commits

Author SHA1 Message Date
Eric Paris
3bcf3860a4 fsnotify: store struct file not struct path
Al explains that calling dentry_open() with a mnt/dentry pair is only
garunteed to be safe if they are already used in an open struct file.  To
make sure this is the case don't store and use a struct path in fsnotify,
always use a struct file.

Signed-off-by: Eric Paris <eparis@redhat.com>
2010-07-28 10:18:51 -04:00
Eric Paris
80af258867 fanotify: groups can specify their f_flags for new fd
Currently fanotify fds opened for thier listeners are done with f_flags
equal to O_RDONLY | O_LARGEFILE.  This patch instead takes f_flags from the
fanotify_init syscall and uses those when opening files in the context of
the listener.

Signed-off-by: Eric Paris <eparis@redhat.com>
2010-07-28 10:18:50 -04:00
Tejun Heo
e4e047a220 fsnotify: update gfp/slab.h includes
Implicit slab.h inclusion via percpu.h is about to go away.  Make sure
gfp.h or slab.h is included as necessary.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Eric Paris <eparis@redhat.com>
Signed-off-by: Eric Paris <eparis@redhat.com>
2010-07-28 09:59:03 -04:00
Eric Paris
08ae89380a fanotify: drop the useless priority argument
The priority argument in fanotify is useless.  Kill it.

Signed-off-by: Eric Paris <eparis@redhat.com>
2010-07-28 09:59:03 -04:00
Eric Paris
8860f060e4 fanotify: do not return 0 in a void function
remove_access_response() is supposed to have a void return, but was
returning 0;

Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Eric Paris <eparis@redhat.com>
2010-07-28 09:59:02 -04:00
Eric Paris
b2d879096a fanotify: userspace interface for permission responses
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>
2010-07-28 09:59:02 -04:00
Eric Paris
9e66e4233d fanotify: permissions and blocking
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>
2010-07-28 09:59:02 -04:00
Eric Paris
cb2d429faf fsnotify: add group priorities
This introduces an ordering to fsnotify groups.  With purely asynchronous
notification based "things" implementing fsnotify (inotify, dnotify) ordering
isn't particularly important.  But if people want to use fsnotify for the
basis of sycronous notification or blocking notification ordering becomes
important.

eg. A Hierarchical Storage Management listener would need to get its event
before an AV scanner could get its event (since the HSM would need to
bring the data in for the AV scanner to scan.)  Typically asynchronous notification
would want to run after the AV scanner made any relevant access decisions
so as to not send notification about an event that was denied.

Signed-off-by: Eric Paris <eparis@redhat.com>
2010-07-28 09:59:01 -04:00
Eric Paris
4d92604cc9 fanotify: clear all fanotify marks
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>
2010-07-28 09:59:00 -04:00
Eric Paris
c9778a98e7 fanotify: allow ignored_masks to survive modify
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>
2010-07-28 09:59:00 -04:00
Eric Paris
b9e4e3bd04 fanotify: allow users to set an ignored_mask
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>
2010-07-28 09:59:00 -04:00
Eric Paris
90b1e7a578 fsnotify: allow marks to not pin inodes in core
inotify marks must pin inodes in core.  dnotify doesn't technically need to
since they are closed when the directory is closed.  fanotify also need to
pin inodes in core as it works today.  But the next step is to introduce
the concept of 'ignored masks' which is actually a mask of events for an
inode of no interest.  I claim that these should be liberally sent to the
kernel and should not pin the inode in core.  If the inode is brought back
in the listener will get an event it may have thought excluded, but this is
not a serious situation and one any listener should deal with.

This patch lays the ground work for non-pinning inode marks by using lazy
inode pinning.  We do not pin a mark until it has a non-zero mask entry.  If a
listener new sets a mask we never pin the inode.

Signed-off-by: Eric Paris <eparis@redhat.com>
2010-07-28 09:58:59 -04:00
Andreas Gruenbacher
33d3dfff45 fanotify: remove outgoing function checks in fanotify.h
A number of validity checks on outgoing data are done in static inlines but
are only used in one place.  Instead just do them where they are used for
readability.

Signed-off-by: Andreas Gruenbacher <agruen@suse.de>
Signed-off-by: Eric Paris <eparis@redhat.com>
2010-07-28 09:58:59 -04:00
Andreas Gruenbacher
88380fe66e fanotify: remove fanotify.h declarations
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>
2010-07-28 09:58:59 -04:00
Andreas Gruenbacher
f3640192c0 fanotify: split fanotify_remove_mark
split fanotify_remove_mark into fanotify_remove_inode_mark and
fanotify_remove_vfsmount_mark.

Signed-off-by: Andreas Gruenbacher <agruen@suse.de>
Signed-off-by: Eric Paris <eparis@redhat.com>
2010-07-28 09:58:59 -04:00
Andreas Gruenbacher
eac8e9e80c fanotify: rename FAN_MARK_ON_VFSMOUNT to FAN_MARK_MOUNT
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>
2010-07-28 09:58:59 -04:00
Eric Paris
0ff21db9fc fanotify: hooks the fanotify_mark syscall to the vfsmount code
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>
2010-07-28 09:58:59 -04:00
Andreas Gruenbacher
90dd201d1a fanotify: remove fanotify_add_mark
fanotify_add_mark now does nothing useful anymore, drop it.

Signed-off-by: Andreas Gruenbacher <agruen@suse.de>
Signed-off-by: Eric Paris <eparis@redhat.com>
2010-07-28 09:58:58 -04:00
Andreas Gruenbacher
52202dfbd9 fanotify: do not return pointer from fanotify_add_*_mark
No need to return the mark from fanotify_add_*_mark to fanotify_add_mark

Signed-off-by: Andreas Gruenbacher <agruen@suse.de>
Signed-off-by: Eric Paris <eparis@redhat.com>
2010-07-28 09:58:58 -04:00
Andreas Gruenbacher
912ee3946c fanotify: do not call fanotify_update_object_mask in fanotify_add_mark
Recalculate masks in fanotify_add_mark, don't use
fanotify_update_object_mask.  This gets us one step closers to readable
code.

Signed-off-by: Andreas Gruenbacher <agruen@suse.de>
Signed-off-by: Eric Paris <eparis@redhat.com>
2010-07-28 09:58:58 -04:00
Andreas Gruenbacher
088b09b0ac fanotify: do not call fanotify_update_object_mask in fanotify_remove_mark
Recalculate masks in fanotify_remove_mark, don't use
fanotify_update_object_mask.  This gets us one step closers to readable
code.

Signed-off-by: Andreas Gruenbacher <agruen@suse.de>
Signed-off-by: Eric Paris <eparis@redhat.com>
2010-07-28 09:58:58 -04:00
Andreas Gruenbacher
c6223f4649 fanotify: remove fanotify_update_mark
fanotify_update_mark() doesn't do much useful;  remove it.

Signed-off-by: Andreas Gruenbacher <agruen@suse.de>
Signed-off-by: Eric Paris <eparis@redhat.com>
2010-07-28 09:58:58 -04:00
Eric Paris
88826276dc fanotify: infrastructure to add an remove marks on vfsmounts
infrastructure work to add and remove marks on vfsmounts.  This should get
every set up except wiring the functions to the syscalls.

Signed-off-by: Eric Paris <eparis@redhat.com>
2010-07-28 09:58:57 -04:00
Eric Paris
5444e2981c fsnotify: split generic and inode specific mark code
currently all marking is done by functions in inode-mark.c.  Some of this
is pretty generic and should be instead done in a generic function and we
should only put the inode specific code in inode-mark.c

Signed-off-by: Eric Paris <eparis@redhat.com>
2010-07-28 09:58:57 -04:00
Andreas Gruenbacher
32c3263221 fanotify: Add pids to events
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>
2010-07-28 09:58:56 -04:00
Andreas Gruenbacher
22aa425dec fanotify: create_fd cleanup
Code cleanup which does the fd creation work seperately from the userspace
metadata creation.  It fits better with the other code.

Signed-off-by: Andreas Gruenbacher <agruen@suse.de>
Signed-off-by: Eric Paris <eparis@redhat.com>
2010-07-28 09:58:56 -04:00
Heiko Carstens
9bbfc964b8 fanotify: CONFIG_HAVE_SYSCALL_WRAPPERS for sys_fanotify_mark
Please note that you need the patch below in addition, otherwise the
syscall wrapper stuff won't work on those 32 bit architectures which enable
the wrappers.

When enabled the syscall wrapper defines always take long parameters and then
cast them to whatever is needed. This approach doesn't work for the 32 bit
case where the original syscall takes a long long parameter, since we would
lose the upper 32 bits.
So syscalls with 64 bit arguments are special cases wrt to syscall wrappers
and enp up in the ugliness below (see also sys_fallocate). In addition these
special cased syscall wrappers have the drawback that ftrace syscall tracing
doesn't work on them, since they don't get defined by using the usual macros.

Signed-off-by: Eric Paris <eparis@redhat.com>
2010-07-28 09:58:56 -04:00
Eric Paris
a1014f1023 fanotify: send events using read
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>
2010-07-28 09:58:56 -04:00
Eric Paris
2a3edf8604 fanotify: fanotify_mark syscall implementation
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>
2010-07-28 09:58:56 -04:00
Eric Paris
bbaa4168b2 fanotify: sys_fanotify_mark declartion
This patch simply declares the new sys_fanotify_mark syscall

int fanotify_mark(int fanotify_fd, unsigned int flags, u64_mask,
		  int dfd const char *pathname)

Signed-off-by: Eric Paris <eparis@redhat.com>
2010-07-28 09:58:55 -04:00
Eric Paris
52c923dd07 fanotify: fanotify_init syscall implementation
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>
2010-07-28 09:58:55 -04:00
Eric Paris
11637e4b7d fanotify: fanotify_init syscall declaration
This patch defines a new syscall fanotify_init() of the form:

int sys_fanotify_init(unsigned int flags, unsigned int event_f_flags,
		      unsigned int priority)

This syscall is used to create and fanotify group.  This is very similar to
the inotify_init() syscall.

Signed-off-by: Eric Paris <eparis@redhat.com>
2010-07-28 09:58:55 -04:00