kernel/linux.git/fs/fuse/dev.c, branch v5.10.257

fuse: Initialize beyond-EOF page contents before setting uptodate

2024-09-04T11:17:29+00:00

commit 3c0da3d163eb32f1f91891efaade027fa9b245b9 upstream. fuse_notify_store(), unlike fuse_do_readpage(), does not enable page zeroing (because it can be used to change partial page contents). So fuse_notify_store() must be more careful to fully initialize page contents (including parts of the page that are beyond end-of-file) before marking the page uptodate. The current code can leave beyond-EOF page contents uninitialized, which makes these uninitialized page contents visible to userspace via mmap(). This is an information leak, but only affects systems which do not enable init-on-alloc (via CONFIG_INIT_ON_ALLOC_DEFAULT_ON=y or the corresponding kernel command line parameter). Link: https://bugs.chromium.org/p/project-zero/issues/detail?id=2574 Cc: stable@kernel.org Fixes: a1d75f258230 ("fuse: add store request") Signed-off-by: Jann Horn Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman

fuse: fix pipe buffer lifetime for direct_io

2022-03-16T13:16:01+00:00

commit 0c4bcfdecb1ac0967619ee7ff44871d93c08c909 upstream. In FOPEN_DIRECT_IO mode, fuse_file_write_iter() calls fuse_direct_write_iter(), which normally calls fuse_direct_io(), which then imports the write buffer with fuse_get_user_pages(), which uses iov_iter_get_pages() to grab references to userspace pages instead of actually copying memory. On the filesystem device side, these pages can then either be read to userspace (via fuse_dev_read()), or splice()d over into a pipe using fuse_dev_splice_read() as pipe buffers with &nosteal_pipe_buf_ops. This is wrong because after fuse_dev_do_read() unlocks the FUSE request, the userspace filesystem can mark the request as completed, causing write() to return. At that point, the userspace filesystem should no longer have access to the pipe buffer. Fix by copying pages coming from the user address space to new pipe buffers. Reported-by: Jann Horn Fixes: c3021629a0d8 ("fuse: support splice() reading from fuse device") Cc: Signed-off-by: Miklos Szeredi Signed-off-by: Greg Kroah-Hartman

fuse: release pipe buf after last use

2021-12-01T08:19:00+00:00

commit 473441720c8616dfaf4451f9c7ea14f0eb5e5d65 upstream. Checking buf->flags should be done before the pipe_buf_release() is called on the pipe buffer, since releasing the buffer might modify the flags. This is exactly what page_cache_pipe_buf_release() does, and which results in the same VM_BUG_ON_PAGE(PageLRU(page)) that the original patch was trying to fix. Reported-by: Justin Forbes Fixes: 712a951025c0 ("fuse: fix page stealing") Cc: # v2.6.35 Signed-off-by: Miklos Szeredi Signed-off-by: Greg Kroah-Hartman

fuse: fix page stealing

2021-11-18T13:03:40+00:00

commit 712a951025c0667ff00b25afc360f74e639dfabe upstream. It is possible to trigger a crash by splicing anon pipe bufs to the fuse device. The reason for this is that anon_pipe_buf_release() will reuse buf->page if the refcount is 1, but that page might have already been stolen and its flags modified (e.g. PG_lru added). This happens in the unlikely case of fuse_dev_splice_write() getting around to calling pipe_buf_release() after a page has been stolen, added to the page cache and removed from the page cache. Fix by calling pipe_buf_release() right after the page was inserted into the page cache. In this case the page has an elevated refcount so any release function will know that the page isn't reusable. Reported-by: Frank Dinoff Link: https://lore.kernel.org/r/CAAmZXrsGg2xsP1CK+cbuEMumtrqdvD-NKnWzhNcvn71RV3c1yw@mail.gmail.com/ Fixes: dd3bb14f44a6 ("fuse: support splice() writing to fuse device") Cc: # v2.6.35 Signed-off-by: Miklos Szeredi Signed-off-by: Greg Kroah-Hartman

fuse: fix use after free in fuse_read_interrupt()

2021-09-22T10:28:00+00:00

[ Upstream commit e1e71c168813564be0f6ea3d6740a059ca42d177 ] There is a potential race between fuse_read_interrupt() and fuse_request_end(). TASK1 in fuse_read_interrupt(): delete req->intr_entry (while holding fiq->lock) TASK2 in fuse_request_end(): req->intr_entry is empty -> skip fiq->lock wake up TASK3 TASK3 request is freed TASK1 in fuse_read_interrupt(): dereference req->in.h.unique ***BAM*** Fix by always grabbing fiq->lock if the request was ever interrupted (FR_INTERRUPTED set) thereby serializing with concurrent fuse_read_interrupt() calls. FR_INTERRUPTED is set before the request is queued on fiq->interrupts. Dequeing the request is done with list_del_init() but FR_INTERRUPTED is not cleared in this case. Reported-by: lijiazi Signed-off-by: Miklos Szeredi Signed-off-by: Sasha Levin

fuse: reject internal errno

2021-07-14T14:55:47+00:00

commit 49221cf86d18bb66fe95d3338cb33bd4b9880ca5 upstream. Don't allow userspace to report errors that could be kernel-internal. Reported-by: Anatoly Trosinenko Fixes: 334f485df85a ("[PATCH] FUSE - device functions") Cc: # v2.6.14 Signed-off-by: Miklos Szeredi Signed-off-by: Greg Kroah-Hartman

fuse: check connected before queueing on fpq->io

2021-07-14T14:55:47+00:00

commit 80ef08670d4c28a06a3de954bd350368780bcfef upstream. A request could end up on the fpq->io list after fuse_abort_conn() has reset fpq->connected and aborted requests on that list: Thread-1 Thread-2 ======== ======== ->fuse_simple_request() ->shutdown ->__fuse_request_send() ->queue_request() ->fuse_abort_conn() ->fuse_dev_do_read() ->acquire(fpq->lock) ->wait_for(fpq->lock) ->set err to all req's in fpq->io ->release(fpq->lock) ->acquire(fpq->lock) ->add req to fpq->io After the userspace copy is done the request will be ended, but req->out.h.error will remain uninitialized. Also the copy might block despite being already aborted. Fix both issues by not allowing the request to be queued on the fpq->io list after fuse_abort_conn() has processed this list. Reported-by: Pradeep P V K Fixes: fd22d62ed0c3 ("fuse: no fc->lock for iqueue parts") Cc: # v4.2 Signed-off-by: Miklos Szeredi Signed-off-by: Greg Kroah-Hartman

fuse: ignore PG_workingset after stealing

2021-07-14T14:55:47+00:00

commit b89ecd60d38ec042d63bdb376c722a16f92bcb88 upstream. Fix the "fuse: trying to steal weird page" warning. Description from Johannes Weiner: "Think of it as similar to PG_active. It's just another usage/heat indicator of file and anon pages on the reclaim LRU that, unlike PG_active, persists across deactivation and even reclaim (we store it in the page cache / swapper cache tree until the page refaults). So if fuse accepts pages that can legally have PG_active set, PG_workingset is fine too." Reported-by: Thomas Lindroth Fixes: 1899ad18c607 ("mm: workingset: tell cache transitions from workingset thrashing") Cc: # v4.20 Signed-off-by: Miklos Szeredi Signed-off-by: Greg Kroah-Hartman

fuse: split fuse_mount off of fuse_conn

2020-09-18T13:17:41+00:00

We want to allow submounts for the same fuse_conn, but with different superblocks so that each of the submounts has its own device ID. To do so, we need to split all mount-specific information off of fuse_conn into a new fuse_mount structure, so that multiple mounts can share a single fuse_conn. We need to take care only to perform connection-level actions once (i.e. when the fuse_conn and thus the first fuse_mount are established, or when the last fuse_mount and thus the fuse_conn are destroyed). For example, fuse_sb_destroy() must invoke fuse_send_destroy() until the last superblock is released. To do so, we keep track of which fuse_mount is the root mount and perform all fuse_conn-level actions only when this fuse_mount is involved. Signed-off-by: Max Reitz Reviewed-by: Stefan Hajnoczi Signed-off-by: Miklos Szeredi

fuse: drop fuse_conn parameter where possible

2020-09-18T13:17:41+00:00

With the last commit, all functions that handle some existing fuse_req no longer need to be given the associated fuse_conn, because they can get it from the fuse_req object. Signed-off-by: Max Reitz Reviewed-by: Stefan Hajnoczi Signed-off-by: Miklos Szeredi