kernel/git/stable/linux-stable.git/fs/fuse, branch linux-5.12.y

fuse: reject internal errno

2021-07-14T14:59:14+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

2021-07-14T14:59:14+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

2021-07-14T14:59:14+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: Fix infinite loop in sget_fc()

2021-07-14T14:59:14+00:00

commit e4a9ccdd1c03b3dc58214874399d24331ea0a3ab upstream. We don't set the SB_BORN flag on submounts. This is wrong as these superblocks are then considered as partially constructed or dying in the rest of the code and can break some assumptions. One such case is when you have a virtiofs filesystem with submounts and you try to mount it again : virtio_fs_get_tree() tries to obtain a superblock with sget_fc(). The logic in sget_fc() is to loop until it has either found an existing matching superblock with SB_BORN set or to create a brand new one. It is assumed that a superblock without SB_BORN is transient and the loop is restarted. Forgetting to set SB_BORN on submounts hence causes sget_fc() to retry forever. Setting SB_BORN requires special care, i.e. a write barrier for super_cache_count() which can check SB_BORN without taking any lock. We should call vfs_get_tree() to deal with that but this requires to have a proper ->get_tree() implementation for submounts, which is a bigger piece of work. Go for a simple bug fix in the meatime. Fixes: bf109c64040f ("fuse: implement crossmounts") Cc: stable@vger.kernel.org # v5.10+ Signed-off-by: Greg Kurz Reviewed-by: Max Reitz Signed-off-by: Miklos Szeredi Signed-off-by: Greg Kroah-Hartman

fuse: Fix crash if superblock of submount gets killed early

2021-07-14T14:59:14+00:00

commit e3a43f2a95393000778f8f302d48795add2fc4a8 upstream. As soon as fuse_dentry_automount() does up_write(&sb->s_umount), the superblock can theoretically be killed. If this happens before the submount was added to the &fc->mounts list, fuse_mount_remove() later crashes in list_del_init() because it assumes the submount to be already there. Add the submount before dropping sb->s_umount to fix the inconsistency. It is okay to nest fc->killsb under sb->s_umount, we already do this on the ->kill_sb() path. Signed-off-by: Greg Kurz Fixes: bf109c64040f ("fuse: implement crossmounts") Cc: stable@vger.kernel.org # v5.10+ Reviewed-by: Max Reitz Signed-off-by: Miklos Szeredi Signed-off-by: Greg Kroah-Hartman

fuse: Fix crash in fuse_dentry_automount() error path

2021-07-14T14:59:13+00:00

commit d92d88f0568e97c437eeb79d9c9609bd8277406f upstream. If fuse_fill_super_submount() returns an error, the error path triggers a crash: [ 26.206673] BUG: kernel NULL pointer dereference, address: 0000000000000000 [...] [ 26.226362] RIP: 0010:__list_del_entry_valid+0x25/0x90 [...] [ 26.247938] Call Trace: [ 26.248300] fuse_mount_remove+0x2c/0x70 [fuse] [ 26.248892] virtio_kill_sb+0x22/0x160 [virtiofs] [ 26.249487] deactivate_locked_super+0x36/0xa0 [ 26.250077] fuse_dentry_automount+0x178/0x1a0 [fuse] The crash happens because fuse_mount_remove() assumes that the FUSE mount was already added to list under the FUSE connection, but this only done after fuse_fill_super_submount() has returned success. This means that until fuse_fill_super_submount() has returned success, the FUSE mount isn't actually owned by the superblock. We should thus reclaim ownership by clearing sb->s_fs_info, which will skip the call to fuse_mount_remove(), and perform rollback, like virtio_fs_get_tree() already does for the root sb. Fixes: bf109c64040f ("fuse: implement crossmounts") Cc: stable@vger.kernel.org # v5.10+ Signed-off-by: Greg Kurz Reviewed-by: Max Reitz Signed-off-by: Miklos Szeredi Signed-off-by: Greg Kroah-Hartman

cuse: prevent clone

2021-05-19T08:56:16+00:00

[ Upstream commit 8217673d07256b22881127bf50dce874d0e51653 ] For cloned connections cuse_channel_release() will be called more than once, resulting in use after free. Prevent device cloning for CUSE, which does not make sense at this point, and highly unlikely to be used in real life. Signed-off-by: Miklos Szeredi Signed-off-by: Sasha Levin

virtiofs: fix userns

2021-05-19T08:56:16+00:00

[ Upstream commit 0a7419c68a45d2d066b996be5087aa2d07ce80eb ] get_user_ns() is done twice (once in virtio_fs_get_tree() and once in fuse_conn_init()), resulting in a reference leak. Also looks better to use fsc->user_ns (which *should* be the current_user_ns() at this point). Signed-off-by: Miklos Szeredi Signed-off-by: Sasha Levin

fuse: invalidate attrs when page writeback completes

2021-05-19T08:56:15+00:00

[ Upstream commit 3466958beb31a8e9d3a1441a34228ed088b84f3e ] In fuse when a direct/write-through write happens we invalidate attrs because that might have updated mtime/ctime on server and cached mtime/ctime will be stale. What about page writeback path. Looks like we don't invalidate attrs there. To be consistent, invalidate attrs in writeback path as well. Only exception is when writeback_cache is enabled. In that case we strust local mtime/ctime and there is no need to invalidate attrs. Recently users started experiencing failure of xfstests generic/080, geneirc/215 and generic/614 on virtiofs. This happened only newer "stat" utility and not older one. This patch fixes the issue. So what's the root cause of the issue. Here is detailed explanation. generic/080 test does mmap write to a file, closes the file and then checks if mtime has been updated or not. When file is closed, it leads to flushing of dirty pages (and that should update mtime/ctime on server). But we did not explicitly invalidate attrs after writeback finished. Still generic/080 passed so far and reason being that we invalidated atime in fuse_readpages_end(). This is called in fuse_readahead() path and always seems to trigger before mmaped write. So after mmaped write when lstat() is called, it sees that atleast one of the fields being asked for is invalid (atime) and that results in generating GETATTR to server and mtime/ctime also get updated and test passes. But newer /usr/bin/stat seems to have moved to using statx() syscall now (instead of using lstat()). And statx() allows it to query only ctime or mtime (and not rest of the basic stat fields). That means when querying for mtime, fuse_update_get_attr() sees that mtime is not invalid (only atime is invalid). So it does not generate a new GETATTR and fill stat with cached mtime/ctime. And that means updated mtime is not seen by xfstest and tests start failing. Invalidating attrs after writeback completion should solve this problem in a generic manner. Signed-off-by: Vivek Goyal Signed-off-by: Miklos Szeredi Signed-off-by: Sasha Levin

fuse: fix matching of FUSE_DEV_IOC_CLONE command

2021-05-14T08:52:56+00:00

[ Upstream commit 6076f5f341e612152879bfda99f0b76c1953bf0b ] With commit f8425c939663 ("fuse: 32-bit user space ioctl compat for fuse device") the matching constraints for the FUSE_DEV_IOC_CLONE ioctl command are relaxed, limited to the testing of command type and number. As Arnd noticed, this is wrong as it wouldn't ensure the correctness of the data size or direction for the received FUSE device ioctl. Fix by bringing back the comparison of the ioctl received by the FUSE device to the originally generated FUSE_DEV_IOC_CLONE. Fixes: f8425c939663 ("fuse: 32-bit user space ioctl compat for fuse device") Reported-by: Arnd Bergmann Signed-off-by: Alessio Balsini Signed-off-by: Miklos Szeredi Signed-off-by: Sasha Levin