fuse_get_user_pages() allocates the temporary pages[] array used by
iov_iter_extract_pages() with the open-coded kzalloc(n * sizeof(*p),
...) form. max_pages is derived from the inbound iov_iter and is not
bounded at compile time, so the multiplication can overflow on
sufficiently large iter counts; the resulting too-small allocation
would then be written past by iov_iter_extract_pages().
Switch to kcalloc(), which carries the same zero-on-allocation
semantics and adds the standard size_mul overflow check. No
functional change for non-overflow inputs.
Signed-off-by: William Theesfeld <william@theesfeld.net>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
FUSE backing files only need a stable snapshot of the current credentials
for later backing-file I/O. prepare_creds() allocates a mutable copy and
can fail, but this code never modifies or commits the result.
Use get_current_cred() instead and store it as a const pointer. This
matches the rest of the backing-file helpers and avoids an unnecessary
allocation and failure path.
Signed-off-by: GuoHan Zhao <zhaoguohan@kylinos.cn>
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Acked-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
- Bernd and Joanne are maintainers for fuse-uring
- Amir is maintainer for passthrough
- mailing list is now officially <fuse-devel@lists.linux.dev>
- change status of fuse-core to be "Supported"
Reviewed-by: Bernd Schubert <bernd@bsbernd.com>
Reviewed-by: Joanne Koong <joannelkoong@gmail.com>
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
In fuse_dev_do_read(), there is already logic that ensures the buffer is
a minimum of at least FUSE_MIN_READ_BUFFER (8k) bytes.
This makes the buffer size checks for interrupt and forget requests
redundant as sizeof(struct fuse_in_header) + sizeof(struct
fuse_interrupt_in) and sizeof(struct fuse_in_header) + sizeof(struct
fuse_forget_in) are both less than FUSE_MIN_READ_BUFFER.
We can get rid of these checks.
Signed-off-by: Joanne Koong <joannelkoong@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
kzalloc_obj with __GFP_NOFAIL is documented to never return failure,
and checking for NULL is redundant (__GFP_NOFAIL in gfp_types.h).
Signed-off-by: Li Wang <liwang@kylinos.cn>
Reviewed-by: Joanne Koong <joannelkoong@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
When the contents of a directory is modified, some of its attributes may
also change, so they need to be invalidated. But this isn't the case
for every attribute. For instance, unlinking or creating a file doesn't
change the uid/gid of its parent directory.
This can cause unnecessary FUSE_GETATTRs to be sent to user-space. For
example, fuse_permission() checks if mode, uid, and gid are valid and
will issue a FUSE_GETATTR if they're not, which results in an extra
FUSE_GETATTR request for every FUSE_UNLINK when removing files in the
same directory.
Signed-off-by: Konrad Sztyber <ksztyber@nvidia.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
In fuse_create_open(), err is initialized to -ENOMEM immediately before
the fuse_alloc_forget() NULL check. If forget allocation fails,
it branches to out_err with that value. If it succeeds, it falls through
without modifying err, so err is still -ENOMEM at the point where
fuse_file_alloc() is called. The second err = -ENOMEM before
fuse_file_alloc() therefore is redundant.
Signed-off-by: Li Wang <liwang@kylinos.cn>
Reviewed-by: Joanne Koong <joannelkoong@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Convert many comments to kernel-doc format to eliminate around 20
kernel-doc warnings like these:
Warning: fs/fuse/fuse_i.h:374 This comment starts with '/**', but isn't a kernel-doc comment. Refer to Documentation/doc-guide/kernel-doc.rst
* A Fuse connection.
Warning: fs/fuse/fuse_i.h:817 This comment starts with '/**', but isn't a kernel-doc comment. Refer to Documentation/doc-guide/kernel-doc.rst
* Get a filled in inode
Warning: fs/fuse/fuse_i.h:859 This comment starts with '/**', but isn't a kernel-doc comment. Refer to Documentation/doc-guide/kernel-doc.rst
* Send RELEASE or RELEASEDIR request
and more like this.
Also add struct member and function parameter descriptions to avoid
these warnings:
Warning: fs/fuse/fuse_i.h:1071 struct member 'epoch_work' not described in 'fuse_conn'
Warning: fs/fuse/fuse_i.h:1071 struct member 'rcu' not described in 'fuse_conn'
Warning: fs/fuse/fuse_i.h:1423 function parameter 'fc' not described in 'fuse_reverse_inval_inode'
Warning: fs/fuse/fuse_i.h:1423 function parameter 'nodeid' not described in 'fuse_reverse_inval_inode'
Warning: fs/fuse/fuse_i.h:1423 function parameter 'offset' not described in 'fuse_reverse_inval_inode'
Warning: fs/fuse/fuse_i.h:1423 function parameter 'len' not described in 'fuse_reverse_inval_inode'
Warning: fs/fuse/fuse_i.h:1436 function parameter 'fc' not described in 'fuse_reverse_inval_entry'
Warning: fs/fuse/fuse_i.h:1436 function parameter 'parent_nodeid' not described in 'fuse_reverse_inval_entry'
Warning: fs/fuse/fuse_i.h:1436 function parameter 'child_nodeid' not described in 'fuse_reverse_inval_entry'
Warning: fs/fuse/fuse_i.h:1436 function parameter 'name' not described in 'fuse_reverse_inval_entry'
Warning: fs/fuse/fuse_i.h:1436 function parameter 'flags' not described in 'fuse_reverse_inval_entry'
Convert struct fuse_file, struct fuse_submount_lookup, struct fuse_inode,
and struct fuse_conn to kernel-doc.
Convert these to plain comments:
Warning: fs/fuse/fuse_i.h:1423 expecting prototype for File(). Prototype was for fuse_reverse_inval_inode() instead
Warning: fs/fuse/fuse_i.h:1436 expecting prototype for File(). Prototype was for fuse_reverse_inval_entry() instead
Change some "/**" to "/*" since they are not kernel-doc comments.
The changes above fix most kernel-doc warnings in this file but
these warnings are not fixed and still remain:
Warning: fs/fuse/fuse_i.h:1428 No description found for return value of 'fuse_fill_super_common'
Warning: fs/fuse/fuse_i.h:1455 No description found for return value of 'fuse_ctl_add_conn'
Binary build output is the same before and after these changes.
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Change some "/**" to "/*" since they are not kernel-doc comments:
Warning: fs/fuse/fuse_dev_i.h:25 This comment starts with '/**', but isn't a kernel-doc comment. Refer to Documentation/doc-guide/kernel-doc.rst
* Request flags
Warning: fs/fuse/fuse_dev_i.h:58 This comment starts with '/**', but isn't a kernel-doc comment. Refer to Documentation/doc-guide/kernel-doc.rst
* A request to the client
Warning: fs/fuse/fuse_dev_i.h:117 This comment starts with '/**', but isn't a kernel-doc comment. Refer to Documentation/doc-guide/kernel-doc.rst
* Input queue callbacks
Warning: fs/fuse/fuse_dev_i.h:289 This comment starts with '/**', but isn't a kernel-doc comment. Refer to Documentation/doc-guide/kernel-doc.rst
* Fuse device instance
and more like this.
Convert enum fuse_req_flag to kernel-doc format.
Convert struct fuse_req, struct fuse_iqueue_ops, and struct fuse_dev
to kernel-doc format.
These warnings remain:
Warning: fs/fuse/fuse_dev_i.h:115 struct member 'ring_entry' not described in 'fuse_req'
Warning: fs/fuse/fuse_dev_i.h:115 struct member 'ring_queue' not described in 'fuse_req'
Binary build output is the same before and after these changes.
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Use regular C comment syntax for a non-kernel-doc comment to avoid
a kernel-doc warning:
Warning: fs/fuse/dev_uring_i.h:104 This comment starts with '/**', but
isn't a kernel-doc comment.
* Describes if uring is for communication and holds alls the data needed
Binary build output is the same before and after this change.
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Don't need to check if the new device file is already initialized, since
fuse_dev_install_with_pq() will do that anyway.
Make fuse_dev_install_with_pq() return a boolean value indicating success so
that fuse_dev_ioctl_clone() can return an error in case of failure.
Move aborting the connection (setting fc->connected to zero) to
fuse_dev_install(), because it is not needed when the clone ioctl fails.
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Prior to this patchset, fuse_dev (containing fuse_pqueue) was allocated on
mount. But now fuse_dev is allocated when opening /dev/fuse, even though
the queues are not needed at that time.
Delay allocation of the pqueue (4k worth of list_head) just before mounting
or cloning a device.
Various distributions (e.g. Debian/Fedora) configure /dev/fuse as world
writable, so the pqueue allocation should be deferred to a privileged
operation (mount) to prevent unprivileged userspace from consuming pinned
kernel memory.
[Li Wang: fix kernel NULL pointer dereference in fuse_uring_add_to_pq()]
[Fix race in fuse_dev_release()]
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Move a couple of function declarations from fuse_i.h to dev.h and
fuse_dev_i.h.
Add fuse_conn_get_id() helper that retrieves the connection ID (s_dev) from
fuse_conn.
With the exception of cuse.c, virtio_fs.c and trace.c source files now
either include fuse_i.h or fuse_dev_i/dev_uring_i.h but not both.
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
In normal use ioctl(FUSE_DEV_IOC_SYNC_INIT) comes before the mount() or
fsconfig() syscalls, they are executed strictly serially.
If ioctl and mount are performed in parallel, the behavior is
nondeterministic. Removing the mutex does not change this.
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Set minor, max_write and max_pages in the fuse_chan. These match the same
fields in fuse_conn but are needed in both layers.
[Dongyang Jin: Pointers should use NULL instead of explicit '0']
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Create a new source file: req.c and add the request sending entry
functions:
__fuse_simple_request()
fuse_simple_background()
fuse_simple_notify_reply()
Introduce transport layer sending functions that are called by the
respective fs layer function:
fuse_chan_send()
fuse_chan_send_bg()
fuse_chan_send_notify_reply()
Move calculation of request header fields uid, gid and pid from
fuse_get_req() and fuse_force_creads() to a new helper: fuse_fill_creds().
These fileds are now passed to the transport layer via struct fuse_args.
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Only used by FUSE_INIT and CUSE_INIT, these can store the relevant pointer
in their structs derived from fuse_args.
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
- rename fuse_abort_conn() to fuse_chan_abort(), pass fuse_chan pointer
instead of fuse_conn
- pass an abort_with_err argument that tells fuse_dev_(read|write) to
return with ECONNABORTED instead of ENODEV
- move fc->aborted to fch->abort_with_err
- rename fuse_wait_aborted() to fuse_chan_wait_aborted()
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Add helpers (get and set functions mainly) that cleanly separate the
layers.
Remove #include "fuse_dev_i.h" from:
- inode.c
- file.c
- control.c
Remove #include "dev_uring_i.h" from inode.c.
[Li Wang: drop redundant initializer in process_init_limits()]
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
And document which members they protect.
end_polls() is called with both, outer fch->lock is probably unnecessary,
but doesn't hurt for now.
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Move the 'fiq' member from fuse_conn to fuse_chan.
Move iqueue related structure definitions and function declarations from
"fuse_i.h" to "fuse_dev_i.h".
Add a fuse_dev_chan_new() helper, that returns a fuse_chan initialized with
the fuse_dev_fiq_ops.
Add a fuse_chan_release() function, that calls fiq->ops->release().
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
The goal is to separate transport layer stuff out from struct fuse_conn,
leaving just the filesystem related members.
Add a new object referenced from fuse_conn. This patch just implements the
allocation and freeing of this object.
Following patches will move transport related members from fuse_conn to
fuse_chan.
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
This marks the first step in cleanly separating the transport layer from
the filesystem layer.
Add "dev.h", which will contain the interface definition for the transport
layer.
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
When a background request completes via the io_uring path, the
background queue gets flushed to dispatch pending background requests,
but this is done before the connection-level background counters
(fc->num_background, fc->active_background) are properly accounted,
which may reduce effective queue depth to one.
The connection-level counters are decremented in fuse_request_end(), but
flush_bg_queue() flushes the /dev/fuse path queue (fc->bg_queue), not
the io_uring per-queue bg one, which means pending uring background
requests on the queue are never dispatched in this path.
Fix this by accounting the connection-level background counters first
before flushing the queue's background queue. Since
fuse_request_bg_finish() clears FR_BACKGROUND, fuse_request_end() will
skip the background cleanup branch entirely, which avoids any
double-decrements; it will call the wake_up(&req->waitq) branch but this
is effectively a no-op as background requests have no waiters on
req->waitq.
Reviewed-by: Bernd Schubert <bernd@bsbernd.com>
Fixes: 857b0263f3 ("fuse: Allow to queue bg requests through io-uring")
Cc: stable@vger.kernel.org
Signed-off-by: Joanne Koong <joannelkoong@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
If device_add() succeeds during CUSE initialization but a subsequent
step (cdev_alloc() or cdev_add()) fails, the error path calls
put_device() without first calling device_del(). This leaks the
devtmpfs entry created by device_add(), leaving a stale /dev/<name>
node that persists until reboot.
Since the cuse_conn is never linked into cuse_conntbl on the failure
path, cuse_channel_release() sees cc->dev == NULL and skips
device_unregister(), so no other code path cleans up the node.
This has several consequences:
- The device name is permanently poisoned: any subsequent attempt to
create a CUSE device with the same name hits the stale sysfs entry,
device_add() fails, and the new device is aborted.
- The collision manifests as ENODEV returned to userspace with no
dmesg diagnostic, making it very difficult to debug.
- The failure is self-perpetuating: once a name is leaked, all future
attempts with that name fail identically.
Fix this by introducing an err_dev label that calls device_del() to
undo device_add() before falling through to err_unlock. The existing
err_unlock path from a device_add() failure correctly skips device_del()
since the device was never added.
Testing instructions can be found at the lore link below.
Link: https://lore.kernel.org/all/20260408-wip-cuse-leak-fix-v1-0-1c028d575e97@redhat.com/
Signed-off-by: Alberto Ruiz <aruiz@redhat.com>
Fixes: 151060ac13 ("CUSE: implement CUSE - Character device in Userspace")
Cc: stable@vger.kernel.org
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Revert the fuse part of commit c9ba789dad ("VFS: introduce
start_creating_noperm() and start_removing_noperm()").
Commit c9ba789dad ("VFS: introduce start_creating_noperm() and
start_removing_noperm()") caused a regression in FUSE_NOTIFY_INVAL_ENTRY,
which failed to invalidate negative dentries.
This manifests in the filesystem returning -ENOENT for operations on an
existing file.
Fixing it properly while still keeping the start_removing* infrastructure
would add much additional complexity.
Instead revert to the original simple implementation.
The start_removing* infrastructure is needed in VFS to abstract the
filesystem locking. However filesystem code can still safely use the raw
locking primitives without affacting other filesystems.
This is part two of the revert.
Reported-by: Артем Лабазов <123321artyom@gmail.com>
Closes: https://lore.kernel.org/all/CAFbF8N7++zopZuEcsKRxBV_sgOGCbzCY0hOyMw1SiGAtuzGhyQ@mail.gmail.com/
Fixes: c9ba789dad ("VFS: introduce start_creating_noperm() and start_removing_noperm()")
Cc: stable@vger.kernel.org # 6.19
Cc: NeilBrown <neilb@ownmail.net>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
This reverts commit cab0123751.
Commit c9ba789dad ("VFS: introduce start_creating_noperm() and
start_removing_noperm()") caused a regression in FUSE_NOTIFY_INVAL_ENTRY,
which failed to invalidate negative dentries.
This manifests in the filesystem returning -ENOENT for operations on an
existing file.
Fixing it properly while still keeping the start_removing* infrastructure
would add much additional complexity.
Instead revert to the original simple implementation.
The start_removing* infrastructure is needed in VFS to abstract the
filesystem locking. However filesystem code can still safely use the raw
locking primitives without affacting other filesystems.
This is part one of the revert.
Reported-by: Артем Лабазов <123321artyom@gmail.com>
Closes: https://lore.kernel.org/all/CAFbF8N7++zopZuEcsKRxBV_sgOGCbzCY0hOyMw1SiGAtuzGhyQ@mail.gmail.com/
Fixes: c9ba789dad ("VFS: introduce start_creating_noperm() and start_removing_noperm()")
Cc: stable@vger.kernel.org # 6.19
Cc: NeilBrown <neilb@ownmail.net>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
FUSE_NOTIFY_PRUNE validates the nodeid payload length with:
size - sizeof(outarg) != outarg.count * sizeof(u64)
On 32-bit kernels, size_t is also 32 bits, so the daemon-controlled
count multiplication can wrap. A prune notification with count
0x20000000 and no nodeid payload passes the check, enters the copy
loop, and asks the device copy path to read nodeids that are not
present in the userspace write buffer. In QEMU this reaches the
fuse_copy_fill() BUG_ON(!err) path.
Validate the payload length with array_size() instead. That accepts
exactly the same valid messages, but avoids wrapping arithmetic before
the copy loop consumes the count.
Assisted-by: Codex:gpt-5.5-cyber-preview
Fixes: 3f29d59e92 ("fuse: add prune notification")
Cc: stable@vger.kernel.org
Signed-off-by: Samuel Moelius <sam.moelius@trailofbits.com>
Reviewed-by: Joanne Koong <joannelkoong@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
If a copy into the userspace ring buffer fails, a request will be
terminated and fuse_uring_req_end() will set ent->fuse_req to NULL but
it will leave the entry on ent_w_req_queue in FRRS_FUSE_REQ state. This
can lead to a NULL deref if the request expiration logic scans
ent_w_req_queue in the window before the entry is moved off it.
Fix this by taking the entry off ent_w_req_queue and changing its state
from FRRS_FUSE_REQ to FRRS_INVALID before terminating the request.
Fixes: 4fea593e62 ("fuse: optimize over-io-uring request expiration check")
Cc: stable@kernel.org
Signed-off-by: Joanne Koong <joannelkoong@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
When fuse_resend() moves a request from fpq->processing back to
fiq->pending, it sets FR_PENDING and clears FR_SENT but does not
remove the requests intr_entry from fiq->interrupts. If the
request had FR_INTERRUPTED set from a prior signal, intr_entry
remains dangling on fiq->interrupts. When the requesting task
then receives a fatal signal, fuse_remove_pending_req() sees
FR_PENDING=1, removes the request from fiq->pending and frees it
via the refcount path, also without cleaning intr_entry. The
stale intr_entry causes use-after-free when fuse_read_interrupt()
iterates fiq->interrupts:
- list_del_init(&req->intr_entry) -> UAF write on freed slab
- req->in.h.unique -> UAF read, data leaked to userspace
Remove intr_entry from fiq->interrupts in fuse_resend() for
interrupted requests before they are placed back on fiq->pending.
Add a WARN_ON if the intr_entry is not empty on request destruction.
Fixes: 760eac73f9 ("fuse: Introduce a new notification type for resend pending requests")
Cc: stable@vger.kernel.org # 6.9
Signed-off-by: Ji'an Zhou <eilaimemedsnaimel@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Bad userspace might try to trick us and send commit SQEs request
unique / commit-id of requests that are not even send to
fuse-server (io_uring_cmd_done() not called) yet.
fuse_uring_commit_fetch() ends the fuse request when the ring entry
has a wrong state, but that could have caused a use-after-free
with the memcpy operations in fuse_uring_send_in_task().
In order to avoid such races the call of fuse_uring_add_to_pq()
is moved after the copy operations and just before completing
the io-uring request - malicious userspace cannot find the request
anymore until all prepration work in fuse-client/kernel is completed.
This also moves fuse_uring_add_to_pq() a bit up in the code to
avoid a forward declaration. Also not with a preparation commit,
to make it easier to back port to older kernels.
Reported-by: xlabai <xlabai@tencent.com>
Reported-by: Berkant Koc <me@berkoc.com>
Fixes: c090c8abae ("fuse: Add io-uring sqe commit and fetch support")
Cc: stable@kernel.org # 6.14
Signed-off-by: Bernd Schubert <bernd@bsbernd.com>
Reviewed-by: Joanne Koong <joannelkoong@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
