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* fuse: fix use after free issue in fuse_dev_do_read()Sahitya Tummala2017-02-231-0/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit 6ba4d2722d06960102c981322035239cd66f7316 upstream. There is a potential race between fuse_dev_do_write() and request_wait_answer() contexts as shown below: TASK 1: __fuse_request_send(): |--spin_lock(&fiq->waitq.lock); |--queue_request(); |--spin_unlock(&fiq->waitq.lock); |--request_wait_answer(): |--if (test_bit(FR_SENT, &req->flags)) <gets pre-empted after it is validated true> TASK 2: fuse_dev_do_write(): |--clears bit FR_SENT, |--request_end(): |--sets bit FR_FINISHED |--spin_lock(&fiq->waitq.lock); |--list_del_init(&req->intr_entry); |--spin_unlock(&fiq->waitq.lock); |--fuse_put_request(); |--queue_interrupt(); <request gets queued to interrupts list> |--wake_up_locked(&fiq->waitq); |--wait_event_freezable(); <as FR_FINISHED is set, it returns and then the caller frees this request> Now, the next fuse_dev_do_read(), see interrupts list is not empty and then calls fuse_read_interrupt() which tries to access the request which is already free'd and gets the below crash: [11432.401266] Unable to handle kernel paging request at virtual address 6b6b6b6b6b6b6b6b ... [11432.418518] Kernel BUG at ffffff80083720e0 [11432.456168] PC is at __list_del_entry+0x6c/0xc4 [11432.463573] LR is at fuse_dev_do_read+0x1ac/0x474 ... [11432.679999] [<ffffff80083720e0>] __list_del_entry+0x6c/0xc4 [11432.687794] [<ffffff80082c65e0>] fuse_dev_do_read+0x1ac/0x474 [11432.693180] [<ffffff80082c6b14>] fuse_dev_read+0x6c/0x78 [11432.699082] [<ffffff80081d5638>] __vfs_read+0xc0/0xe8 [11432.704459] [<ffffff80081d5efc>] vfs_read+0x90/0x108 [11432.709406] [<ffffff80081d67f0>] SyS_read+0x58/0x94 As FR_FINISHED bit is set before deleting the intr_entry with input queue lock in request completion path, do the testing of this flag and queueing atomically with the same lock in queue_interrupt(). Signed-off-by: Sahitya Tummala <stummala@codeaurora.org> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Fixes: fd22d62ed0c3 ("fuse: no fc->lock for iqueue parts") Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* fuse: clear FR_PENDING flag when moving requests out of pending queueTahsin Erdogan2017-01-261-1/+2
| | | | | | | | | | | | | | | | | | | | | | commit a8a86d78d673b1c99fe9b0064739fde9e9774184 upstream. fuse_abort_conn() moves requests from pending list to a temporary list before canceling them. This operation races with request_wait_answer() which also tries to remove the request after it gets a fatal signal. It checks FR_PENDING flag to determine whether the request is still in the pending list. Make fuse_abort_conn() clear FR_PENDING flag so that request_wait_answer() does not remove the request from temporary list. This bug causes an Oops when trying to delete an already deleted list entry in end_requests(). Fixes: ee314a870e40 ("fuse: abort: no fc->lock needed for request ending") Signed-off-by: Tahsin Erdogan <tahsin@google.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* fs/fuse: fix ioctl type confusionJann Horn2015-08-161-1/+9
| | | | | | | | | fuse_dev_ioctl() performed fuse_get_dev() on a user-supplied fd, leading to a type confusion issue. Fix it by checking file->f_op. Signed-off-by: Jann Horn <jann@thejh.net> Acked-by: Miklos Szeredi <miklos@szeredi.hu> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* fuse: separate pqueue for clonesMiklos Szeredi2015-07-011-26/+37
| | | | | | | | Make each fuse device clone refer to a separate processing queue. The only constraint on userspace code is that the request answer must be written to the same device clone as it was read off. Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
* fuse: introduce per-instance fuse_dev structureMiklos Szeredi2015-07-011-28/+42
| | | | | | | | | Allow fuse device clones to refer to be distinguished. This patch just adds the infrastructure by associating a separate "struct fuse_dev" with each clone. Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Reviewed-by: Ashish Samant <ashish.samant@oracle.com>
* fuse: device fd cloneMiklos Szeredi2015-07-011-0/+40
| | | | | | | | | | | | Allow an open fuse device to be "cloned". Userspace can create a clone by: newfd = open("/dev/fuse", O_RDWR) ioctl(newfd, FUSE_DEV_IOC_CLONE, &oldfd); At this point newfd will refer to the same fuse connection as oldfd. Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Reviewed-by: Ashish Samant <ashish.samant@oracle.com>
* fuse: abort: no fc->lock needed for request endingMiklos Szeredi2015-07-011-9/+5
| | | | | | | | In fuse_abort_conn() when all requests are on private lists we no longer need fc->lock protection. Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Reviewed-by: Ashish Samant <ashish.samant@oracle.com>
* fuse: no fc->lock for pqueue partsMiklos Szeredi2015-07-011-14/+2
| | | | | | | | Remove fc->lock protection from processing queue members, now protected by fpq->lock. Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Reviewed-by: Ashish Samant <ashish.samant@oracle.com>
* fuse: no fc->lock in request_end()Miklos Szeredi2015-07-011-7/+8
| | | | | | | | | No longer need to call request_end() with the connection lock held. We still protect the background counters and queue with fc->lock, so acquire it if necessary. Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Reviewed-by: Ashish Samant <ashish.samant@oracle.com>
* fuse: cleanup request_end()Miklos Szeredi2015-07-011-4/+2
| | | | | | | | Now that we atomically test having already done everything we no longer need other protection. Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Reviewed-by: Ashish Samant <ashish.samant@oracle.com>
* fuse: request_end(): do onceMiklos Szeredi2015-07-011-2/+6
| | | | | | | | | | | When the connection is aborted it is possible that request_end() will be called twice. Use atomic test and set to do the actual ending only once. test_and_set_bit() also provides the necessary barrier semantics so no explicit smp_wmb() is necessary. Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Reviewed-by: Ashish Samant <ashish.samant@oracle.com>
* fuse: add req flag for private listMiklos Szeredi2015-07-011-3/+7
| | | | | | | | | | | | When an unlocked request is aborted, it is moved from fpq->io to a private list. Then, after unlocking fpq->lock, the private list is processed and the requests are finished off. To protect the private list, we need to mark the request with a flag, so if in the meantime the request is unlocked the list is not corrupted. Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Reviewed-by: Ashish Samant <ashish.samant@oracle.com>
* fuse: pqueue lockingMiklos Szeredi2015-07-011-2/+17
| | | | | | | | Add a fpq->lock for protecting members of struct fuse_pqueue and FR_LOCKED request flag. Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Reviewed-by: Ashish Samant <ashish.samant@oracle.com>
* fuse: abort: group pqueue accessesMiklos Szeredi2015-07-011-1/+1
| | | | | | | | Rearrange fuse_abort_conn() so that processing queue accesses are grouped together. Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Reviewed-by: Ashish Samant <ashish.samant@oracle.com>
* fuse: cleanup fuse_dev_do_read()Miklos Szeredi2015-07-011-20/+20
| | | | | | | | | - locked list_add() + list_del_init() cancel out - common handling of case when request is ended here in the read phase Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Reviewed-by: Ashish Samant <ashish.samant@oracle.com>
* fuse: move list_del_init() from request_end() into callersMiklos Szeredi2015-07-011-1/+7
| | | | Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
* fuse: duplicate ->connected in pqueueMiklos Szeredi2015-07-011-3/+4
| | | | | | | This will allow checking ->connected just with the processing queue lock. Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Reviewed-by: Ashish Samant <ashish.samant@oracle.com>
* fuse: separate out processing queueMiklos Szeredi2015-07-011-9/+12
| | | | | | | | | This is just two fields: fc->io and fc->processing. This patch just rearranges the fields, no functional change. Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Reviewed-by: Ashish Samant <ashish.samant@oracle.com>
* fuse: simplify request_wait()Miklos Szeredi2015-07-011-25/+5
| | | | | | | | wait_event_interruptible_exclusive_locked() will do everything request_wait() does, so replace it. Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Reviewed-by: Ashish Samant <ashish.samant@oracle.com>
* fuse: no fc->lock for iqueue partsMiklos Szeredi2015-07-011-51/+20
| | | | | | | | Remove fc->lock protection from input queue members, now protected by fiq->waitq.lock. Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Reviewed-by: Ashish Samant <ashish.samant@oracle.com>
* fuse: allow interrupt queuing without fc->lockMiklos Szeredi2015-07-011-3/+9
| | | | | | | | | | | | | | | | | | | | | | | Interrupt is only queued after the request has been sent to userspace. This is either done in request_wait_answer() or fuse_dev_do_read() depending on which state the request is in at the time of the interrupt. If it's not yet sent, then queuing the interrupt is postponed until the request is read. Otherwise (the request has already been read and is waiting for an answer) the interrupt is queued immedidately. We want to call queue_interrupt() without fc->lock protection, in which case there can be a race between the two functions: - neither of them queue the interrupt (thinking the other one has already done it). - both of them queue the interrupt The first one is prevented by adding memory barriers, the second is prevented by checking (under fiq->waitq.lock) if the interrupt has already been queued. Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
* fuse: iqueue lockingMiklos Szeredi2015-07-011-6/+45
| | | | | | | | | | Use fiq->waitq.lock for protecting members of struct fuse_iqueue and FR_PENDING request flag, previously protected by fc->lock. Following patches will remove fc->lock protection from these members. Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Reviewed-by: Ashish Samant <ashish.samant@oracle.com>
* fuse: dev read: split list_moveMiklos Szeredi2015-07-011-1/+2
| | | | | | | Different lists will need different locks. Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Reviewed-by: Ashish Samant <ashish.samant@oracle.com>
* fuse: abort: group iqueue accessesMiklos Szeredi2015-07-011-5/+7
| | | | | | | | Rearrange fuse_abort_conn() so that input queue accesses are grouped together. Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Reviewed-by: Ashish Samant <ashish.samant@oracle.com>
* fuse: duplicate ->connected in iqueueMiklos Szeredi2015-07-011-9/+10
| | | | | | | This will allow checking ->connected just with the input queue lock. Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Reviewed-by: Ashish Samant <ashish.samant@oracle.com>
* fuse: separate out input queueMiklos Szeredi2015-07-011-59/+75
| | | | | | | | | | | | | | | The input queue contains normal requests (fc->pending), forgets (fc->forget_*) and interrupts (fc->interrupts). There's also fc->waitq and fc->fasync for waking up the readers of the fuse device when a request is available. The fc->reqctr is also moved to the input queue (assigned to the request when the request is added to the input queue. This patch just rearranges the fields, no functional change. Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Reviewed-by: Ashish Samant <ashish.samant@oracle.com>
* fuse: req state use flagsMiklos Szeredi2015-07-011-9/+14
| | | | | | | | | Use flags for representing the state in fuse_req. This is needed since req->list will be protected by different locks in different states, hence we'll want the state itself to be split into distinct bits, each protected with the relevant lock in that state. Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
* fuse: simplify req statesMiklos Szeredi2015-07-011-3/+2
| | | | | | | | | FUSE_REQ_INIT is actually the same state as FUSE_REQ_PENDING and FUSE_REQ_READING and FUSE_REQ_WRITING can be merged into a common FUSE_REQ_IO state. Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Reviewed-by: Ashish Samant <ashish.samant@oracle.com>
* fuse: don't hold lock over request_wait_answer()Miklos Szeredi2015-07-011-25/+20
| | | | | | | | | Only hold fc->lock over sections of request_wait_answer() that actually need it. If wait_event_interruptible() returns zero, it means that the request finished. Need to add memory barriers, though, to make sure that all relevant data in the request is synchronized. Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
* fuse: simplify unique ctrMiklos Szeredi2015-07-011-6/+1
| | | | | | | | Since it's a 64bit counter, it's never gonna wrap around. Remove code dealing with that possibility. Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Reviewed-by: Ashish Samant <ashish.samant@oracle.com>
* fuse: rework abortMiklos Szeredi2015-07-011-11/+10
| | | | | | | | | | | Splice fc->pending and fc->processing lists into a common kill list while holding fc->lock. By the time we release fc->lock, pending and processing lists are empty and the io list contains only locked requests. Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Reviewed-by: Ashish Samant <ashish.samant@oracle.com>
* fuse: fold helpers into abortMiklos Szeredi2015-07-011-55/+38
| | | | | | | Fold end_io_requests() and end_queued_requests() into fuse_abort_conn(). Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Reviewed-by: Ashish Samant <ashish.samant@oracle.com>
* fuse: use per req lock for lock/unlock_request()Miklos Szeredi2015-07-011-22/+20
| | | | | | | Reuse req->waitq.lock for protecting FR_ABORTED and FR_LOCKED flags. Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Reviewed-by: Ashish Samant <ashish.samant@oracle.com>
* fuse: req use bitopsMiklos Szeredi2015-07-011-35/+36
| | | | | | | | | | | Finer grained locking will mean there's no single lock to protect modification of bitfileds in fuse_req. So move to using bitops. Can use the non-atomic variants for those which happen while the request definitely has only one reference. Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Reviewed-by: Ashish Samant <ashish.samant@oracle.com>
* fuse: simplify request abortMiklos Szeredi2015-07-011-73/+46
| | | | | | | | | - don't end the request while req->locked is true - make unlock_request() return an error if the connection was aborted Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Reviewed-by: Ashish Samant <ashish.samant@oracle.com>
* fuse: call fuse_abort_conn() in dev releaseMiklos Szeredi2015-07-011-8/+3
| | | | | | | | | | | | | | fuse_abort_conn() does all the work done by fuse_dev_release() and more. "More" consists of: end_io_requests(fc); wake_up_all(&fc->waitq); kill_fasync(&fc->fasync, SIGIO, POLL_IN); All of which should be no-op (WARN_ON's added). Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Reviewed-by: Ashish Samant <ashish.samant@oracle.com>
* fuse: fold fuse_request_send_nowait() into single callerMiklos Szeredi2015-07-011-22/+10
| | | | | | | And the same with fuse_request_send_nowait_locked(). Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Reviewed-by: Ashish Samant <ashish.samant@oracle.com>
* fuse: check conn_error earlierMiklos Szeredi2015-07-011-2/+4
| | | | | | | | | fc->conn_error is set once in FUSE_INIT reply and never cleared. Check it in request allocation, there's no sense in doing all the preparation if sending will surely fail. Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Reviewed-by: Ashish Samant <ashish.samant@oracle.com>
* fuse: account as waiting before queuing for backgroundMiklos Szeredi2015-07-011-4/+8
| | | | | | | | | | Move accounting of fc->num_waiting to the point where the request actually starts waiting. This is earlier than the current queue_request() for background requests, since they might be waiting on the fc->bg_queue before being queued on fc->pending. Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Reviewed-by: Ashish Samant <ashish.samant@oracle.com>
* fuse: reset waitingMiklos Szeredi2015-07-011-1/+3
| | | | | | | Reset req->waiting in fuse_put_request(). This is needed for correct accounting in fc->num_waiting for reserved requests. Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
* fuse: fix background request if not connectedMiklos Szeredi2015-07-011-1/+4
| | | | | | | | | | request_end() expects fc->num_background and fc->active_background to have been incremented, which is not the case in fuse_request_send_nowait() failure path. So instead just call the ->end() callback (which is actually set by all callers). Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Reviewed-by: Ashish Samant <ashish.samant@oracle.com>
* fuse: use iov_iter_get_pages() for non-splice pathAl Viro2015-04-111-24/+17
| | | | | | store reference to iter instead of that to iovec Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* fuse: switch to ->read_iter/->write_iterAl Viro2015-04-111-12/+14
| | | | | | we just change the calling conventions here; more work to follow. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* Merge branch 'iocb' into for-nextAl Viro2015-04-111-1/+0
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| * fs: move struct kiocb to fs.hChristoph Hellwig2015-03-251-1/+0
| | | | | | | | | | | | | | | | struct kiocb now is a generic I/O container, so move it to fs.h. Also do a #include diet for aio.h while we're at it. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* | fuse: explicitly set /dev/fuse file's private_dataTom Van Braeckel2015-03-191-0/+12
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The misc subsystem (which is used for /dev/fuse) initializes private_data to point to the misc device when a driver has registered a custom open file operation, and initializes it to NULL when a custom open file operation has *not* been provided. This subtle quirk is confusing, to the point where kernel code registers *empty* file open operations to have private_data point to the misc device structure. And it leads to bugs, where the addition or removal of a custom open file operation surprisingly changes the initial contents of a file's private_data structure. So to simplify things in the misc subsystem, a patch [1] has been proposed to *always* set the private_data to point to the misc device, instead of only doing this when a custom open file operation has been registered. But before this patch can be applied we need to modify drivers that make the assumption that a misc device file's private_data is initialized to NULL because they didn't register a custom open file operation, so they don't rely on this assumption anymore. FUSE uses private_data to store the fuse_conn and errors out if this is not initialized to NULL at mount time. Hence, we now set a file's private_data to NULL explicitly, to be independent of whatever value the misc subsystem initializes it to by default. [1] https://lkml.org/lkml/2014/12/4/939 Reported-by: Giedrius Statkevicius <giedriuswork@gmail.com> Reported-by: Thierry Reding <thierry.reding@gmail.com> Signed-off-by: Tom Van Braeckel <tomvanbraeckel@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
* | fuse: set stolen page uptodateMiklos Szeredi2015-02-261-2/+2
| | | | | | | | | | | | | | | | | | | | Regular pipe buffers' ->steal method (generic_pipe_buf_steal()) doesn't set PG_uptodate. Don't warn on this condition, just set the uptodate flag. Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Cc: stable@vger.kernel.org
* | fuse: notify: don't move pagesMiklos Szeredi2015-02-261-0/+3
|/ | | | | | | | | fuse_try_move_page() is not prepared for replacing pages that have already been read. Reported-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Cc: stable@vger.kernel.org
* fuse: add memory barrier to INITMiklos Szeredi2015-01-061-2/+13
| | | | | | | | | Theoretically we need to order setting of various fields in fc with fc->initialized. No known bug reports related to this yet. Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
* fuse: fix LOOKUP vs INIT compat handlingMiklos Szeredi2015-01-061-0/+36
| | | | | | | | | | | | | | | | | | | | | | | | | | | Analysis from Marc: "Commit 7078187a795f ("fuse: introduce fuse_simple_request() helper") from the above pull request triggers some EIO errors for me in some tests that rely on fuse Looking at the code changes and a bit of debugging info I think there's a general problem here that fuse_get_req checks and possibly waits for fc->initialized, and this was always called first. But this commit changes the ordering and in many places fc->minor is now possibly used before fuse_get_req, and we can't be sure that fc has been initialized. In my case fuse_lookup_init sets req->out.args[0].size to the wrong size because fc->minor at that point is still 0, leading to the EIO error." Fix by moving the compat adjustments into fuse_simple_request() to after fuse_get_req(). This is also more readable than the original, since now compatibility is handled in a single function instead of cluttering each operation. Reported-by: Marc Dionne <marc.c.dionne@gmail.com> Tested-by: Marc Dionne <marc.c.dionne@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Fixes: 7078187a795f ("fuse: introduce fuse_simple_request() helper")
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