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* fanotify: fix -EOVERFLOW with large files on 64-bitWill Woods2014-05-061-0/+2
| | | | | | | | | | | | | | | | | | | | | | | On 64-bit systems, O_LARGEFILE is automatically added to flags inside the open() syscall (also openat(), blkdev_open(), etc). Userspace therefore defines O_LARGEFILE to be 0 - you can use it, but it's a no-op. Everything should be O_LARGEFILE by default. But: when fanotify does create_fd() it uses dentry_open(), which skips all that. And userspace can't set O_LARGEFILE in fanotify_init() because it's defined to 0. So if fanotify gets an event regarding a large file, the read() will just fail with -EOVERFLOW. This patch adds O_LARGEFILE to fanotify_init()'s event_f_flags on 64-bit systems, using the same test as open()/openat()/etc. Addresses https://bugzilla.redhat.com/show_bug.cgi?id=696821 Signed-off-by: Will Woods <wwoods@redhat.com> Acked-by: Eric Paris <eparis@redhat.com> Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* fanotify: move unrelated handling from copy_event_to_user()Jan Kara2014-04-031-21/+19
| | | | | | | | | | | | | | | | Move code moving event structure to access_list from copy_event_to_user() to fanotify_read() where it is more logical (so that we can immediately see in the main loop that we either move the event to a different list or free it). Also move special error handling for permission events from copy_event_to_user() to the main loop to have it in one place with error handling for normal events. This makes copy_event_to_user() really only copy the event to user without any side effects. Signed-off-by: Jan Kara <jack@suse.cz> Cc: Eric Paris <eparis@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* fanotify: reorganize loop in fanotify_read()Jan Kara2014-04-031-22/+24
| | | | | | | | | | | | | Swap the error / "read ok" branches in the main loop of fanotify_read(). We will grow the "read ok" part in the next patch and this makes the indentation easier. Also it is more common to have error conditions inside an 'if' instead of the fast path. Signed-off-by: Jan Kara <jack@suse.cz> Cc: Eric Paris <eparis@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* fanotify: convert access_mutex to spinlockJan Kara2014-04-031-7/+7
| | | | | | | | | | | access_mutex is used only to guard operations on access_list. There's no need for sleeping within this lock so just make a spinlock out of it. Signed-off-by: Jan Kara <jack@suse.cz> Cc: Eric Paris <eparis@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* fanotify: use fanotify event structure for permission response processingJan Kara2014-04-031-79/+44
| | | | | | | | | | | | | | | | | | | | | | Currently, fanotify creates new structure to track the fact that permission event has been reported to userspace and someone is waiting for a response to it. As event structures are now completely in the hands of each notification framework, we can use the event structure for this tracking instead of allocating a new structure. Since this makes the event structures for normal events and permission events even more different and the structures have different lifetime rules, we split them into two separate structures (where permission event structure contains the structure for a normal event). This makes normal events 8 bytes smaller and the code a tad bit cleaner. [akpm@linux-foundation.org: fix build] Signed-off-by: Jan Kara <jack@suse.cz> Cc: Eric Paris <eparis@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Wu Fengguang <fengguang.wu@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* fanotify: remove useless bypass_perm checkJan Kara2014-04-031-8/+0
| | | | | | | | | | | | | | | | The prepare_for_access_response() function checks whether group->fanotify_data.bypass_perm is set. However this test can never be true because prepare_for_access_response() is called only from fanotify_read() which means fanotify group is alive with an active fd while bypass_perm is set from fanotify_release() when all file descriptors pointing to the group are closed and the group is going away. Signed-off-by: Jan Kara <jack@suse.cz> Cc: Eric Paris <eparis@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* fsnotify: Allocate overflow events with proper typeJan Kara2014-02-251-0/+13
| | | | | | | | | | | | | Commit 7053aee26a35 "fsnotify: do not share events between notification groups" used overflow event statically allocated in a group with the size of the generic notification event. This causes problems because some code looks at type specific parts of event structure and gets confused by a random data it sees there and causes crashes. Fix the problem by allocating overflow event with type corresponding to the group type so code cannot get confused. Signed-off-by: Jan Kara <jack@suse.cz>
* fanotify: Fix use after free for permission eventsJan Kara2014-01-291-1/+6
| | | | | | | | | | | | | Currently struct fanotify_event_info has been destroyed immediately after reporting its contents to userspace. However that is wrong for permission events because those need to stay around until userspace provides response which is filled back in fanotify_event_info. So change to code to free permission events only after we have got the response from userspace. Reported-and-tested-by: Jiri Kosina <jkosina@suse.cz> Reported-and-tested-by: Dave Jones <davej@fedoraproject.org> Signed-off-by: Jan Kara <jack@suse.cz>
* compat: fix sys_fanotify_markHeiko Carstens2014-01-271-2/+2
| | | | | | | | | | | | | | | | | | | | | | | Commit 91c2e0bcae72 ("unify compat fanotify_mark(2), switch to COMPAT_SYSCALL_DEFINE") added a new unified compat fanotify_mark syscall to be used by all architectures. Unfortunately the unified version merges the split mask parameter in a wrong way: the lower and higher word got swapped. This was discovered with glibc's tst-fanotify test case. Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Reported-by: Andreas Krebbel <krebbel@linux.vnet.ibm.com> Cc: "James E.J. Bottomley" <jejb@parisc-linux.org> Acked-by: "David S. Miller" <davem@davemloft.net> Acked-by: Al Viro <viro@ZenIV.linux.org.uk> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: <stable@vger.kernel.org> [3.10+] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* fsnotify: do not share events between notification groupsJan Kara2014-01-211-21/+20
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently fsnotify framework creates one event structure for each notification event and links this event into all interested notification groups. This is done so that we save memory when several notification groups are interested in the event. However the need for event structure shared between inotify & fanotify bloats the event structure so the result is often higher memory consumption. Another problem is that fsnotify framework keeps path references with outstanding events so that fanotify can return open file descriptors with its events. This has the undesirable effect that filesystem cannot be unmounted while there are outstanding events - a regression for inotify compared to a situation before it was converted to fsnotify framework. For fanotify this problem is hard to avoid and users of fanotify should kind of expect this behavior when they ask for file descriptors from notified files. This patch changes fsnotify and its users to create separate event structure for each group. This allows for much simpler code (~400 lines removed by this patch) and also smaller event structures. For example on 64-bit system original struct fsnotify_event consumes 120 bytes, plus additional space for file name, additional 24 bytes for second and each subsequent group linking the event, and additional 32 bytes for each inotify group for private data. After the conversion inotify event consumes 48 bytes plus space for file name which is considerably less memory unless file names are long and there are several groups interested in the events (both of which are uncommon). Fanotify event fits in 56 bytes after the conversion (fanotify doesn't care about file names so its events don't have to have it allocated). A win unless there are four or more fanotify groups interested in the event. The conversion also solves the problem with unmount when only inotify is used as we don't have to grab path references for inotify events. [hughd@google.com: fanotify: fix corruption preventing startup] Signed-off-by: Jan Kara <jack@suse.cz> Reviewed-by: Christoph Hellwig <hch@lst.de> Cc: Eric Paris <eparis@parisplace.org> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* fanotify: put duplicate code for adding vfsmount/inode marks into an own ↵Lino Sanfilippo2013-07-091-36/+35
| | | | | | | | | | | | | | function The code under the groups mark_mutex in fanotify_add_inode_mark() and fanotify_add_vfsmount_mark() is almost identical. So put it into a seperate function. Signed-off-by: Lino Sanfilippo <LinoSanfilippo@gmx.de> Cc: Eric Paris <eparis@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* fanotify: fix races when adding/removing marksLino Sanfilippo2013-07-091-12/+37
| | | | | | | | | | | | | | | | | | | | | | | | | For both adding an event to an existing mark and destroying a mark we first have to find it via fsnotify_find_[inode|vfsmount]_mark(). But getting the mark and adding an event (or destroying it) is not done atomically. This opens a race where a thread is about to destroy a mark while another thread still finds the same mark and adds an event to its mask although it will be destroyed. Another race exists concerning the excess of a groups number of marks limit: When a mark is added the number of group marks is checked against the max number of marks per group and increased afterwards. Since check and increment is also not done atomically, this may result in 2 or more processes passing the check at the same time and increasing the number of group marks above the allowed limit. With this patch both races are avoided by doing the concerning operations with the groups mark mutex locked. Signed-off-by: Lino Sanfilippo <LinoSanfilippo@gmx.de> Cc: Eric Paris <eparis@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* fanotify: info leak in copy_event_to_user()Dan Carpenter2013-07-091-0/+1
| | | | | | | | | | | The ->reserved field isn't cleared so we leak one byte of stack information to userspace. Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Cc: Eric Paris <eparis@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* fanotify: quit wanking with FASYNC in ->release()Al Viro2013-06-291-3/+0
| | | | | | | | | ... especially since there's no way to get that sucker on the list fsnotify_fasync() works with - the only thing adding to it is fsnotify_fasync() itself and it's never called for fanotify files while they are opened. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* unify compat fanotify_mark(2), switch to COMPAT_SYSCALL_DEFINEAl Viro2013-05-091-0/+17
| | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* teach SYSCALL_DEFINE<n> how to deal with long long/unsigned long longAl Viro2013-03-031-14/+3
| | | | | | | ... and convert a bunch of SYSCALL_DEFINE ones to SYSCALL_DEFINE<n>, killing the boilerplate crap around them. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* new helper: file_inode(file)Al Viro2013-02-221-1/+1
| | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* Merge branch 'for-next' of git://git.infradead.org/users/eparis/notifyLinus Torvalds2012-12-201-12/+25
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Pull filesystem notification updates from Eric Paris: "This pull mostly is about locking changes in the fsnotify system. By switching the group lock from a spin_lock() to a mutex() we can now hold the lock across things like iput(). This fixes a problem involving unmounting a fs and having inodes be busy, first pointed out by FAT, but reproducible with tmpfs. This also restores signal driven I/O for inotify, which has been broken since about 2.6.32." Ugh. I *hate* the timing of this. It was rebased after the merge window opened, and then left to sit with the pull request coming the day before the merge window closes. That's just crap. But apparently the patches themselves have been around for over a year, just gathering dust, so now it's suddenly critical. Fixed up semantic conflict in fs/notify/fdinfo.c as per Stephen Rothwell's fixes from -next. * 'for-next' of git://git.infradead.org/users/eparis/notify: inotify: automatically restart syscalls inotify: dont skip removal of watch descriptor if creation of ignored event failed fanotify: dont merge permission events fsnotify: make fasync generic for both inotify and fanotify fsnotify: change locking order fsnotify: dont put marks on temporary list when clearing marks by group fsnotify: introduce locked versions of fsnotify_add_mark() and fsnotify_remove_mark() fsnotify: pass group to fsnotify_destroy_mark() fsnotify: use a mutex instead of a spinlock to protect a groups mark list fanotify: add an extra flag to mark_remove_from_mask that indicates wheather a mark should be destroyed fsnotify: take groups mark_lock before mark lock fsnotify: use reference counting for groups fsnotify: introduce fsnotify_get_group() inotify, fanotify: replace fsnotify_put_group() with fsnotify_destroy_group()
| * fsnotify: make fasync generic for both inotify and fanotifyEric Paris2012-12-111-0/+4
| | | | | | | | | | | | | | | | inotify is supposed to support async signal notification when information is available on the inotify fd. This patch moves that support to generic fsnotify functions so it can be used by all notification mechanisms. Signed-off-by: Eric Paris <eparis@redhat.com>
| * fsnotify: pass group to fsnotify_destroy_mark()Lino Sanfilippo2012-12-111-2/+2
| | | | | | | | | | | | | | | | In fsnotify_destroy_mark() dont get the group from the passed mark anymore, but pass the group itself as an additional parameter to the function. Signed-off-by: Lino Sanfilippo <LinoSanfilippo@gmx.de> Signed-off-by: Eric Paris <eparis@redhat.com>
| * fanotify: add an extra flag to mark_remove_from_mask that indicates wheather ↵Lino Sanfilippo2012-12-111-5/+14
| | | | | | | | | | | | | | | | | | | | | | | | a mark should be destroyed This patch adds an extra flag to mark_remove_from_mask() to inform the caller if the mark should be destroyed. With this we dont destroy the mark implicitly in the function itself any more but let the caller handle it. Signed-off-by: Lino Sanfilippo <LinoSanfilippo@gmx.de> Signed-off-by: Eric Paris <eparis@redhat.com>
| * inotify, fanotify: replace fsnotify_put_group() with fsnotify_destroy_group()Lino Sanfilippo2012-12-111-7/+7
| | | | | | | | | | | | | | | | | | | | | | Currently in fsnotify_put_group() the ref count of a group is decremented and if it becomes 0 fsnotify_destroy_group() is called. Since a groups ref count is only at group creation set to 1 and never increased after that a call to fsnotify_put_group() always results in a call to fsnotify_destroy_group(). With this patch fsnotify_destroy_group() is called directly. Signed-off-by: Lino Sanfilippo <LinoSanfilippo@gmx.de> Signed-off-by: Eric Paris <eparis@redhat.com>
* | fs, notify: add procfs fdinfo helperCyrill Gorcunov2012-12-171-0/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This allow us to print out fsnotify details such as watchee inode, device, mask and optionally a file handle. For inotify objects if kernel compiled with exportfs support the output will be | pos: 0 | flags: 02000000 | inotify wd:3 ino:9e7e sdev:800013 mask:800afce ignored_mask:0 fhandle-bytes:8 fhandle-type:1 f_handle:7e9e0000640d1b6d | inotify wd:2 ino:a111 sdev:800013 mask:800afce ignored_mask:0 fhandle-bytes:8 fhandle-type:1 f_handle:11a1000020542153 | inotify wd:1 ino:6b149 sdev:800013 mask:800afce ignored_mask:0 fhandle-bytes:8 fhandle-type:1 f_handle:49b1060023552153 If kernel compiled without exportfs support, the file handle won't be provided but inode and device only. | pos: 0 | flags: 02000000 | inotify wd:3 ino:9e7e sdev:800013 mask:800afce ignored_mask:0 | inotify wd:2 ino:a111 sdev:800013 mask:800afce ignored_mask:0 | inotify wd:1 ino:6b149 sdev:800013 mask:800afce ignored_mask:0 For fanotify the output is like | pos: 0 | flags: 04002 | fanotify flags:10 event-flags:0 | fanotify mnt_id:12 mask:3b ignored_mask:0 | fanotify ino:50205 sdev:800013 mask:3b ignored_mask:40000000 fhandle-bytes:8 fhandle-type:1 f_handle:05020500fb1d47e7 To minimize impact on general fsnotify code the new functionality is gathered in fs/notify/fdinfo.c file. Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org> Acked-by: Pavel Emelyanov <xemul@parallels.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Andrey Vagin <avagin@openvz.org> Cc: Al Viro <viro@ZenIV.linux.org.uk> Cc: Alexey Dobriyan <adobriyan@gmail.com> Cc: James Bottomley <jbottomley@parallels.com> Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com> Cc: Alexey Dobriyan <adobriyan@gmail.com> Cc: Matthew Helsley <matt.helsley@gmail.com> Cc: "J. Bruce Fields" <bfields@fieldses.org> Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com> Cc: Tvrtko Ursulin <tvrtko.ursulin@onelan.co.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | fanotify: fix FAN_Q_OVERFLOW case of fanotify_read()Al Viro2012-11-181-1/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | If the FAN_Q_OVERFLOW bit set in event->mask, the fanotify event metadata will not contain a valid file descriptor, but copy_event_to_user() didn't check for that, and unconditionally does a fd_install() on the file descriptor. Which in turn will cause a BUG_ON() in __fd_install(). Introduced by commit 352e3b249284 ("fanotify: sanitize failure exits in copy_event_to_user()") Mea culpa - missed that path ;-/ Reported-by: Alex Shi <lkml.alex@gmail.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | switch simple cases of fget_light to fdgetAl Viro2012-09-261-15/+13
| | | | | | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* | fanotify: sanitize failure exits in copy_event_to_user()Al Viro2012-09-261-39/+20
|/ | | | | | | | | | * do copy_to_user() before prepare_for_access_response(); that kills the need in remove_access_response(). * don't do fd_install() until we are past the last possible failure exit. Don't use sys_close() on cleanup side - just put_unused_fd() and fput(). Less racy that way... Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* switch dentry_open() to struct path, make it grab references itselfAl Viro2012-07-231-6/+2
| | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* vfs: move fsnotify junk to struct mountAl Viro2012-01-031-2/+4
| | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* Fix common misspellingsLucas De Marchi2011-03-311-1/+1
| | | | | | Fixes generated by 'codespell' and manually reviewed. Signed-off-by: Lucas De Marchi <lucas.demarchi@profusion.mobi>
* Remove one to many n's in a wordJustin P. Mattock2011-03-011-1/+1
| | | | | Signed-off-by: Justin P. Mattock <justinmattock@gmail.com> Signed-off-by: Jiri Kosina <jkosina@suse.cz>
* fanotify: fill in the metadata_len field on struct fanotify_event_metadataEric Paris2010-12-151-2/+4
| | | | | | | | | The fanotify_event_metadata now has a field which is supposed to indicate the length of the metadata portion of the event. Fill in that field as well. Based-in-part-on-patch-by: Alexey Zaytsev <alexey.zaytsev@gmail.com> Signed-off-by: Eric Paris <eparis@redhat.com>
* fanotify: Dont try to open a file descriptor for the overflow eventLino Sanfilippo2010-12-071-4/+13
| | | | | | | | We should not try to open a file descriptor for the overflow event since this will always fail. Signed-off-by: Lino Sanfilippo <LinoSanfilippo@gmx.de> Signed-off-by: Eric Paris <eparis@redhat.com>
* fanotify: do not leak user reference on allocation failureEric Paris2010-12-071-1/+3
| | | | | | | | | If fanotify_init is unable to allocate a new fsnotify group it will return but will not drop its reference on the associated user struct. Drop that reference on error. Reported-by: Vegard Nossum <vegard.nossum@gmail.com> Signed-off-by: Eric Paris <eparis@redhat.com>
* fanotify: on group destroy allow all waiters to bypass permission checkLino Sanfilippo2010-12-071-2/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When fanotify_release() is called, there may still be processes waiting for access permission. Currently only processes for which an event has already been queued into the groups access list will be woken up. Processes for which no event has been queued will continue to sleep and thus cause a deadlock when fsnotify_put_group() is called. Furthermore there is a race allowing further processes to be waiting on the access wait queue after wake_up (if they arrive before clear_marks_by_group() is called). This patch corrects this by setting a flag to inform processes that the group is about to be destroyed and thus not to wait for access permission. [additional changelog from eparis] Lets think about the 4 relevant code paths from the PoV of the 'operator' 'listener' 'responder' and 'closer'. Where operator is the process doing an action (like open/read) which could require permission. Listener is the task (or in this case thread) slated with reading from the fanotify file descriptor. The 'responder' is the thread responsible for responding to access requests. 'Closer' is the thread attempting to close the fanotify file descriptor. The 'operator' is going to end up in: fanotify_handle_event() get_response_from_access() (THIS BLOCKS WAITING ON USERSPACE) The 'listener' interesting code path fanotify_read() copy_event_to_user() prepare_for_access_response() (THIS CREATES AN fanotify_response_event) The 'responder' code path: fanotify_write() process_access_response() (REMOVE A fanotify_response_event, SET RESPONSE, WAKE UP 'operator') The 'closer': fanotify_release() (SUPPOSED TO CLEAN UP THE REST OF THIS MESS) What we have today is that in the closer we remove all of the fanotify_response_events and set a bit so no more response events are ever created in prepare_for_access_response(). The bug is that we never wake all of the operators up and tell them to move along. You fix that in fanotify_get_response_from_access(). You also fix other operators which haven't gotten there yet. So I agree that's a good fix. [/additional changelog from eparis] [remove additional changes to minimize patch size] [move initialization so it was inside CONFIG_FANOTIFY_PERMISSION] Signed-off-by: Lino Sanfilippo <LinoSanfilippo@gmx.de> Signed-off-by: Eric Paris <eparis@redhat.com>
* fanotify: Dont allow a mask of 0 if setting or removing a markLino Sanfilippo2010-12-071-1/+3
| | | | | | | | | | | In mark_remove_from_mask() we destroy marks that have their event mask cleared. Thus we should not allow the creation of those marks in the first place. With this patch we check if the mask given from user is 0 in case of FAN_MARK_ADD. If so we return an error. Same for FAN_MARK_REMOVE since this does not have any effect. Signed-off-by: Lino Sanfilippo <LinoSanfilippo@gmx.de> Signed-off-by: Eric Paris <eparis@redhat.com>
* fanotify: correct broken ref counting in case adding a mark failedLino Sanfilippo2010-12-071-17/+14
| | | | | | | | | | | | | | | | | If adding a mount or inode mark failed fanotify_free_mark() is called explicitly. But at this time the mark has already been put into the destroy list of the fsnotify_mark kernel thread. If the thread is too slow it will try to decrease the reference of a mark, that has already been freed by fanotify_free_mark(). (If its fast enough it will only decrease the marks ref counter from 2 to 1 - note that the counter has been increased to 2 in add_mark() - which has practically no effect.) This patch fixes the ref counting by not calling free_mark() explicitly, but decreasing the ref counter and rely on the fsnotify_mark thread to cleanup in case adding the mark has failed. Signed-off-by: Lino Sanfilippo <LinoSanfilippo@gmx.de> Signed-off-by: Eric Paris <eparis@redhat.com>
* fanotify: deny permissions when no event was sentEric Paris2010-12-071-4/+12
| | | | | | | | | If no event was sent to userspace we cannot expect userspace to respond to permissions requests. Today such requests just hang forever. This patch will deny any permissions event which was unable to be sent to userspace. Reported-by: Tvrtko Ursulin <tvrtko.ursulin@sophos.com> Signed-off-by: Eric Paris <eparis@redhat.com>
* make fanotify_read() restartable across signalsLino Sanfilippo2010-10-301-1/+1
| | | | | | | In fanotify_read() return -ERESTARTSYS instead of -EINTR to make read() restartable across signals (BSD semantic). Signed-off-by: Eric Paris <eparis@redhat.com>
* fs/notify/fanotify/fanotify_user.c: fix warningsAndrew Morton2010-10-281-3/+2
| | | | | | | | | | | | fs/notify/fanotify/fanotify_user.c: In function 'fanotify_release': fs/notify/fanotify/fanotify_user.c:375: warning: unused variable 'lre' fs/notify/fanotify/fanotify_user.c:375: warning: unused variable 're' this is really ugly. Cc: Eric Paris <eparis@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Eric Paris <eparis@redhat.com>
* fanotify: do not recalculate the mask if the ignored mask changedEric Paris2010-10-281-3/+3
| | | | | | | | If fanotify sets a new bit in the ignored mask it will cause the generic fsnotify layer to recalculate the real mask. This is stupid since we didn't change that part. Signed-off-by: Eric Paris <eparis@redhat.com>
* fanotify: ignore events on directories unless specifically requestedEric Paris2010-10-281-0/+12
| | | | | | | | | | | | | | 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>
* fanotify: limit number of listeners per userEric Paris2010-10-281-0/+11
| | | | | | | | fanotify currently has no limit on the number of listeners a given user can have open. This patch limits the total number of listeners per user to 128. This is the same as the inotify default limit. Signed-off-by: Eric Paris <eparis@redhat.com>
* fanotify: allow userspace to override max marksEric Paris2010-10-281-1/+8
| | | | | | | | | | | | 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>
* fanotify: limit the number of marks in a single fanotify groupEric Paris2010-10-281-0/+9
| | | | | | | | | | There is currently no limit on the number of marks a given fanotify group can have. Since fanotify is gated on CAP_SYS_ADMIN this was not seen as a serious DoS threat. This patch implements a default of 8192, the same as inotify to work towards removing the CAP_SYS_ADMIN gating and eliminating the default DoS'able status. Signed-off-by: Eric Paris <eparis@redhat.com>
* fanotify: allow userspace to override max queue depthEric Paris2010-10-281-1/+8
| | | | | | | | | 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>
* fsnotify: implement a default maximum queue depthEric Paris2010-10-281-0/+4
| | | | | | | | | | | | 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>
* fanotify: ignore fanotify ignore marks if open writersEric Paris2010-10-281-0/+10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | fanotify will clear ignore marks if a task changes the contents of an inode. The problem is with the races around when userspace finishes checking a file and when that result is actually attached to the inode. This race was described as such: Consider the following scenario with hostile processes A and B, and victim process C: 1. Process A opens new file for writing. File check request is generated. 2. File check is performed in userspace. Check result is "file has no malware". 3. The "permit" response is delivered to kernel space. 4. File ignored mark set. 5. Process A writes dummy bytes to the file. File ignored flags are cleared. 6. Process B opens the same file for reading. File check request is generated. 7. File check is performed in userspace. Check result is "file has no malware". 8. Process A writes malware bytes to the file. There is no cached response yet. 9. The "permit" response is delivered to kernel space and is cached in fanotify. 10. File ignored mark set. 11. Now any process C will be permitted to open the malware file. There is a race between steps 8 and 10 While fanotify makes no strong guarantees about systems with hostile processes there is no reason we cannot harden against this race. We do that by simply ignoring any ignore marks if the inode has open writers (aka i_writecount > 0). (We actually do not ignore ignore marks if the FAN_MARK_SURV_MODIFY flag is set) Reported-by: Vasily Novikov <vasily.novikov@kaspersky.com> Signed-off-by: Eric Paris <eparis@redhat.com>
* fanotify: implement fanotify listener orderingEric Paris2010-10-281-1/+24
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* llseek: automatically add .llseek fopArnd Bergmann2010-10-151-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | All file_operations should get a .llseek operation so we can make nonseekable_open the default for future file operations without a .llseek pointer. The three cases that we can automatically detect are no_llseek, seq_lseek and default_llseek. For cases where we can we can automatically prove that the file offset is always ignored, we use noop_llseek, which maintains the current behavior of not returning an error from a seek. New drivers should normally not use noop_llseek but instead use no_llseek and call nonseekable_open at open time. Existing drivers can be converted to do the same when the maintainer knows for certain that no user code relies on calling seek on the device file. The generated code is often incorrectly indented and right now contains comments that clarify for each added line why a specific variant was chosen. In the version that gets submitted upstream, the comments will be gone and I will manually fix the indentation, because there does not seem to be a way to do that using coccinelle. Some amount of new code is currently sitting in linux-next that should get the same modifications, which I will do at the end of the merge window. Many thanks to Julia Lawall for helping me learn to write a semantic patch that does all this. ===== begin semantic patch ===== // This adds an llseek= method to all file operations, // as a preparation for making no_llseek the default. // // The rules are // - use no_llseek explicitly if we do nonseekable_open // - use seq_lseek for sequential files // - use default_llseek if we know we access f_pos // - use noop_llseek if we know we don't access f_pos, // but we still want to allow users to call lseek // @ open1 exists @ identifier nested_open; @@ nested_open(...) { <+... nonseekable_open(...) ...+> } @ open exists@ identifier open_f; identifier i, f; identifier open1.nested_open; @@ int open_f(struct inode *i, struct file *f) { <+... ( nonseekable_open(...) | nested_open(...) ) ...+> } @ read disable optional_qualifier exists @ identifier read_f; identifier f, p, s, off; type ssize_t, size_t, loff_t; expression E; identifier func; @@ ssize_t read_f(struct file *f, char *p, size_t s, loff_t *off) { <+... ( *off = E | *off += E | func(..., off, ...) | E = *off ) ...+> } @ read_no_fpos disable optional_qualifier exists @ identifier read_f; identifier f, p, s, off; type ssize_t, size_t, loff_t; @@ ssize_t read_f(struct file *f, char *p, size_t s, loff_t *off) { ... when != off } @ write @ identifier write_f; identifier f, p, s, off; type ssize_t, size_t, loff_t; expression E; identifier func; @@ ssize_t write_f(struct file *f, const char *p, size_t s, loff_t *off) { <+... ( *off = E | *off += E | func(..., off, ...) | E = *off ) ...+> } @ write_no_fpos @ identifier write_f; identifier f, p, s, off; type ssize_t, size_t, loff_t; @@ ssize_t write_f(struct file *f, const char *p, size_t s, loff_t *off) { ... when != off } @ fops0 @ identifier fops; @@ struct file_operations fops = { ... }; @ has_llseek depends on fops0 @ identifier fops0.fops; identifier llseek_f; @@ struct file_operations fops = { ... .llseek = llseek_f, ... }; @ has_read depends on fops0 @ identifier fops0.fops; identifier read_f; @@ struct file_operations fops = { ... .read = read_f, ... }; @ has_write depends on fops0 @ identifier fops0.fops; identifier write_f; @@ struct file_operations fops = { ... .write = write_f, ... }; @ has_open depends on fops0 @ identifier fops0.fops; identifier open_f; @@ struct file_operations fops = { ... .open = open_f, ... }; // use no_llseek if we call nonseekable_open //////////////////////////////////////////// @ nonseekable1 depends on !has_llseek && has_open @ identifier fops0.fops; identifier nso ~= "nonseekable_open"; @@ struct file_operations fops = { ... .open = nso, ... +.llseek = no_llseek, /* nonseekable */ }; @ nonseekable2 depends on !has_llseek @ identifier fops0.fops; identifier open.open_f; @@ struct file_operations fops = { ... .open = open_f, ... +.llseek = no_llseek, /* open uses nonseekable */ }; // use seq_lseek for sequential files ///////////////////////////////////// @ seq depends on !has_llseek @ identifier fops0.fops; identifier sr ~= "seq_read"; @@ struct file_operations fops = { ... .read = sr, ... +.llseek = seq_lseek, /* we have seq_read */ }; // use default_llseek if there is a readdir /////////////////////////////////////////// @ fops1 depends on !has_llseek && !nonseekable1 && !nonseekable2 && !seq @ identifier fops0.fops; identifier readdir_e; @@ // any other fop is used that changes pos struct file_operations fops = { ... .readdir = readdir_e, ... +.llseek = default_llseek, /* readdir is present */ }; // use default_llseek if at least one of read/write touches f_pos ///////////////////////////////////////////////////////////////// @ fops2 depends on !fops1 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @ identifier fops0.fops; identifier read.read_f; @@ // read fops use offset struct file_operations fops = { ... .read = read_f, ... +.llseek = default_llseek, /* read accesses f_pos */ }; @ fops3 depends on !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @ identifier fops0.fops; identifier write.write_f; @@ // write fops use offset struct file_operations fops = { ... .write = write_f, ... + .llseek = default_llseek, /* write accesses f_pos */ }; // Use noop_llseek if neither read nor write accesses f_pos /////////////////////////////////////////////////////////// @ fops4 depends on !fops1 && !fops2 && !fops3 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @ identifier fops0.fops; identifier read_no_fpos.read_f; identifier write_no_fpos.write_f; @@ // write fops use offset struct file_operations fops = { ... .write = write_f, .read = read_f, ... +.llseek = noop_llseek, /* read and write both use no f_pos */ }; @ depends on has_write && !has_read && !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @ identifier fops0.fops; identifier write_no_fpos.write_f; @@ struct file_operations fops = { ... .write = write_f, ... +.llseek = noop_llseek, /* write uses no f_pos */ }; @ depends on has_read && !has_write && !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @ identifier fops0.fops; identifier read_no_fpos.read_f; @@ struct file_operations fops = { ... .read = read_f, ... +.llseek = noop_llseek, /* read uses no f_pos */ }; @ depends on !has_read && !has_write && !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @ identifier fops0.fops; @@ struct file_operations fops = { ... +.llseek = noop_llseek, /* no read or write fn */ }; ===== End semantic patch ===== Signed-off-by: Arnd Bergmann <arnd@arndb.de> Cc: Julia Lawall <julia@diku.dk> Cc: Christoph Hellwig <hch@infradead.org>
* fanotify: Return EPERM when a process is not privilegedAndreas Gruenbacher2010-08-271-1/+1
| | | | | | | | The appropriate error code when privileged operations are denied is EPERM, not EACCES. Signed-off-by: Andreas Gruenbacher <agruen@suse.de> Signed-off-by: Eric Paris <paris@paris.rdu.redhat.com>
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