linux-stable.git/drivers/usb/gadget/function, branch linux-rolling-lts Linux kernel stable tree usb: gadget: f_fs: Initialize epfile->in early to fix endpoint direction checks 2026-07-18T14:53:36+00:00 Neill Kapron nkapron@google.com 2026-06-19T04:06:03+00:00 9e04055ab5fc0470a0031ee6934739f9aa8f34a5 commit 82cfd4739011bdc7e87b5d585703427e89ddfaa5 upstream. When parsing endpoint descriptors, ffs_data_got_descs() generates the eps_addrmap which contains the endpoint direction. However, epfile->in was previously only populated in ffs_func_eps_enable() which executes upon USB host connection. As a result, early userspace ioctls like FUNCTIONFS_DMABUF_ATTACH that run before the host connects would see epfile->in as 0, leading to incorrect DMA directions. By moving the initialization to ffs_epfiles_create(), epfile->in is accurate before userspace opens the endpoint files. Fixes: 7b07a2a7ca02 ("usb: gadget: functionfs: Add DMABUF import interface") Cc: stable <stable@kernel.org> Assisted-by: Antigravity:gemini-3.1-pro Signed-off-by: Neill Kapron <nkapron@google.com> Link: https://patch.msgid.link/20260619040609.4010746-2-nkapron@google.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 82cfd4739011bdc7e87b5d585703427e89ddfaa5 upstream.

When parsing endpoint descriptors, ffs_data_got_descs() generates the
eps_addrmap which contains the endpoint direction. However, epfile->in
was previously only populated in ffs_func_eps_enable() which executes
upon USB host connection. As a result, early userspace ioctls like
FUNCTIONFS_DMABUF_ATTACH that run before the host connects would see
epfile->in as 0, leading to incorrect DMA directions.

By moving the initialization to ffs_epfiles_create(), epfile->in is
accurate before userspace opens the endpoint files.

Fixes: 7b07a2a7ca02 ("usb: gadget: functionfs: Add DMABUF import interface")
Cc: stable <stable@kernel.org>
Assisted-by: Antigravity:gemini-3.1-pro
Signed-off-by: Neill Kapron <nkapron@google.com>
Link: https://patch.msgid.link/20260619040609.4010746-2-nkapron@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
usb: gadget: f_fs: Fix DMA fence leak 2026-07-18T14:53:25+00:00 Paul Cercueil paul@crapouillou.net 2026-06-09T15:29:05+00:00 e086c16962a1b0142e2675610e9c06fcfcd4c3a8 commit baa6b6068a3f2bf2ed525a1cb37975905dadc658 upstream. In ffs_dmabuf_transfer(), a ffs_dma_fence object is kmalloc'd, with the underlying dma_fence later initialized by dma_fence_init(), which sets its kref counter to 1. Then, dma_resv_add_fence() gets a second reference, and a pointer to the ffs_dma_fence is passed as the usb_request's "context" field. The dma-resv mechanism will manage the second reference, but the first reference is never properly released; the ffs_dmabuf_cleanup() function decreases the reference count, but only to balance with the reference grab in ffs_dmabuf_signal_done(). The code will then slowly leak memory as more ffs_dma_fence objects are created without being ever freed. Address this issue by transferring ownership of the fence to the DMA reservation object, by calling dma_fence_put() right after dma_resv_add_fence(). The ffs_dma_fence then gets properly discarded after being signalled. Fixes: 7b07a2a7ca02 ("usb: gadget: functionfs: Add DMABUF import interface") Cc: stable <stable@kernel.org> Signed-off-by: Paul Cercueil <paul@crapouillou.net> Tested-by: Nuno Sá <nuno.sa@analog.com> Reviewed-by: Nuno Sá <nuno.sa@analog.com> Link: https://patch.msgid.link/20260609152905.729328-1-paul@crapouillou.net Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit baa6b6068a3f2bf2ed525a1cb37975905dadc658 upstream.

In ffs_dmabuf_transfer(), a ffs_dma_fence object is kmalloc'd, with the
underlying dma_fence later initialized by dma_fence_init(), which sets
its kref counter to 1. Then, dma_resv_add_fence() gets a second
reference, and a pointer to the ffs_dma_fence is passed as the
usb_request's "context" field.

The dma-resv mechanism will manage the second reference, but the first
reference is never properly released; the ffs_dmabuf_cleanup() function
decreases the reference count, but only to balance with the reference
grab in ffs_dmabuf_signal_done().

The code will then slowly leak memory as more ffs_dma_fence objects are
created without being ever freed.

Address this issue by transferring ownership of the fence to the DMA
reservation object, by calling dma_fence_put() right after
dma_resv_add_fence(). The ffs_dma_fence then gets properly discarded
after being signalled.

Fixes: 7b07a2a7ca02 ("usb: gadget: functionfs: Add DMABUF import interface")
Cc: stable <stable@kernel.org>
Signed-off-by: Paul Cercueil <paul@crapouillou.net>
Tested-by: Nuno Sá <nuno.sa@analog.com>
Reviewed-by: Nuno Sá <nuno.sa@analog.com>
Link: https://patch.msgid.link/20260609152905.729328-1-paul@crapouillou.net
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
usb: gadget: f_printer: take kref only for successful open 2026-07-18T14:53:23+00:00 Xu Rao raoxu@uniontech.com 2026-06-26T06:46:17+00:00 8a5eba992c862b0c94411eecf9b7121e8636db38 commit 30adce93d5c4a5a1ec29d9249e3fdfcc391d406b upstream. printer_open() returns -EBUSY when the character device is already open, but it increments dev->kref regardless of the return value. VFS does not call ->release() for a failed open, so every rejected second open permanently leaks one reference. Move kref_get() into the successful-open branch. Fixes: e8d5f92b8d30 ("usb: gadget: function: printer: fix use-after-free in __lock_acquire") Cc: stable <stable@kernel.org> Signed-off-by: Xu Rao <raoxu@uniontech.com> Link: https://patch.msgid.link/80295742B820DA9B+20260626064617.4090626-1-raoxu@uniontech.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 30adce93d5c4a5a1ec29d9249e3fdfcc391d406b upstream.

printer_open() returns -EBUSY when the character device is already
open, but it increments dev->kref regardless of the return value. VFS
does not call ->release() for a failed open, so every rejected second
open permanently leaks one reference.

Move kref_get() into the successful-open branch.

Fixes: e8d5f92b8d30 ("usb: gadget: function: printer: fix use-after-free in __lock_acquire")
Cc: stable <stable@kernel.org>
Signed-off-by: Xu Rao <raoxu@uniontech.com>
Link: https://patch.msgid.link/80295742B820DA9B+20260626064617.4090626-1-raoxu@uniontech.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
usb: gadget: function: rndis: add length check for header 2026-07-18T14:53:06+00:00 Griffin Kroah-Hartman griffin@kroah.com 2026-07-08T11:08:59+00:00 7515a6d4a9e9e4838b833825882efa00e85f8901 commit 21b5bf155435008e0fb0736795289788e63d426f upstream. Add a length check for the rndis header in rndis_rm_hdr, to ensure that MessageType, MessageLength, DataOffset, and DataLength fields are present before they are accessed. Assisted-by: gkh_clanker_2000 Cc: stable <stable@kernel.org> Signed-off-by: Griffin Kroah-Hartman <griffin@kroah.com> Link: https://patch.msgid.link/20260708-usb-gadget-rndis-v1-2-e77e026dcc6a@kroah.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 21b5bf155435008e0fb0736795289788e63d426f upstream.

Add a length check for the rndis header in rndis_rm_hdr, to ensure that
MessageType, MessageLength, DataOffset, and DataLength fields are
present before they are accessed.

Assisted-by: gkh_clanker_2000
Cc: stable <stable@kernel.org>
Signed-off-by: Griffin Kroah-Hartman <griffin@kroah.com>
Link: https://patch.msgid.link/20260708-usb-gadget-rndis-v1-2-e77e026dcc6a@kroah.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
usb: gadget: function: rndis: add length check to response query 2026-07-18T14:53:06+00:00 Griffin Kroah-Hartman griffin@kroah.com 2026-07-08T11:08:58+00:00 e01e7814b4223560eab0513b7c15b8c82bdc83f3 commit 95f90eea070837f7c72207d5520f805bdefc3bc5 upstream. Add variable representations for BufLength and BufOffset in rndis_query_response(), and perform a length check on them. This is identical to how rndis_set_response() handles these parameters. Assisted-by: gkh_clanker_2000 Cc: stable <stable@kernel.org> Signed-off-by: Griffin Kroah-Hartman <griffin@kroah.com> Link: https://patch.msgid.link/20260708-usb-gadget-rndis-v1-1-e77e026dcc6a@kroah.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 95f90eea070837f7c72207d5520f805bdefc3bc5 upstream.

Add variable representations for BufLength and BufOffset in
rndis_query_response(), and perform a length check on them.

This is identical to how rndis_set_response() handles these parameters.

Assisted-by: gkh_clanker_2000
Cc: stable <stable@kernel.org>
Signed-off-by: Griffin Kroah-Hartman <griffin@kroah.com>
Link: https://patch.msgid.link/20260708-usb-gadget-rndis-v1-1-e77e026dcc6a@kroah.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
usb: gadget: f_fs: serialize DMABUF cancel against request completion 2026-06-09T10:28:46+00:00 Michael Bommarito michael.bommarito@gmail.com 2026-04-19T16:12:27+00:00 c7d421123b98d5e9c1c84bd9957aba36f1cbb4ca commit 2796646f6d892c1eb6818c7ca41fdfa12568e8d1 upstream. ffs_epfile_dmabuf_io_complete() calls usb_ep_free_request() on the completed request but leaves priv->req, the back-pointer that ffs_dmabuf_transfer() set on submission, pointing at the freed memory. A later FUNCTIONFS_DMABUF_DETACH ioctl or ffs_epfile_release() on the close path still sees priv->req non-NULL under ffs->eps_lock: if (priv->ep && priv->req) usb_ep_dequeue(priv->ep, priv->req); so usb_ep_dequeue() is called on a freed usb_request. On dummy_hcd the dequeue path only walks a live queue and pointer-compares, so the freed pointer reads without faulting and KASAN requires an explicit check at the FunctionFS call site to surface the use-after-free. On SG-capable in-tree UDCs the dequeue path dereferences the supplied request immediately: * chipidea's ep_dequeue() does container_of(req, struct ci_hw_req, req) and reads hwreq->req.status before acquiring its own lock. * cdnsp's cdnsp_gadget_ep_dequeue() reads request->status first. The narrower option of clearing priv->req via cmpxchg() in the completion does not close the race: the completion runs without eps_lock, so a cancel path holding eps_lock can still observe priv->req non-NULL, race a concurrent completion that clears and frees, and pass the freed pointer to usb_ep_dequeue(). A slightly longer fix that moves the free into the cleanup work is needed. Same class of lifetime race as the recent usbip-vudc timer fix [1]. Take eps_lock in the sole place that mutates priv->req from the callback direction by moving usb_ep_free_request() out of the completion into ffs_dmabuf_cleanup(), the existing work handler scheduled by ffs_dmabuf_signal_done() on ffs->io_completion_wq. Clear priv->req there under eps_lock before freeing, and only clear if priv->req still names our request (a subsequent ffs_dmabuf_transfer() on the same attachment may have queued a new one). This keeps the existing dummy_hcd sync-dequeue invariant: the completion callback is still invoked by the UDC without eps_lock held (dummy_hcd drops its own lock before calling the callback), and the callback now takes no f_fs lock at all. Serialization against the cancel path happens in cleanup, which runs from the workqueue with no f_fs lock held on entry. The priv ref count protects the containing ffs_dmabuf_priv: ffs_dmabuf_transfer() takes a ref via ffs_dmabuf_get(), cleanup drops it via ffs_dmabuf_put(), so priv stays live for the cleanup even after the cancel path's list_del + ffs_dmabuf_put. The ffs_dmabuf_transfer() error path no longer frees usb_req inline: fence->req and fence->ep are set before usb_ep_queue(), so ffs_dmabuf_cleanup() (scheduled by the error-path ffs_dmabuf_signal_done()) owns the free regardless of whether the queue succeeded. Reproduced under KASAN on both detach and close paths against dummy_hcd with an observability hook (kasan_check_byte(priv->req) immediately before usb_ep_dequeue) at the two FunctionFS cancel sites to surface the stale-pointer access; the hook is not part of this patch. The KASAN allocator / free stacks in the captured splats identify the same request: alloc in dummy_alloc_request, free in dummy_timer, fault reached from ffs_epfile_release (close) and from the FUNCTIONFS_DMABUF_DETACH ioctl (detach). With the patch applied, both paths are silent under the same hook. The bug is reached from the FunctionFS device node, which in real deployments is owned by the privileged gadget daemon (adbd, UMS, composite gadget services, etc.); it is not reachable from unprivileged userspace or from a USB host on the cable. FunctionFS mounts default to GLOBAL_ROOT_UID, but the filesystem supports uid=, gid=, and fmode= delegation to a non-root gadget daemon, so on real deployments the attacker may be a less-privileged service rather than root. Fixes: 7b07a2a7ca02 ("usb: gadget: functionfs: Add DMABUF import interface") Link: https://lore.kernel.org/all/20260417163552.807548-1-michael.bommarito@gmail.com/ [1] Cc: stable <stable@kernel.org> Assisted-by: Claude:claude-opus-4-7 Signed-off-by: Michael Bommarito <michael.bommarito@gmail.com> Link: https://patch.msgid.link/20260419161227.1587668-1-michael.bommarito@gmail.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 2796646f6d892c1eb6818c7ca41fdfa12568e8d1 upstream.

ffs_epfile_dmabuf_io_complete() calls usb_ep_free_request() on the
completed request but leaves priv->req, the back-pointer that
ffs_dmabuf_transfer() set on submission, pointing at the freed
memory.  A later FUNCTIONFS_DMABUF_DETACH ioctl or
ffs_epfile_release() on the close path still sees priv->req
non-NULL under ffs->eps_lock:

    if (priv->ep && priv->req)
            usb_ep_dequeue(priv->ep, priv->req);

so usb_ep_dequeue() is called on a freed usb_request.

On dummy_hcd the dequeue path only walks a live queue and
pointer-compares, so the freed pointer reads without faulting and
KASAN requires an explicit check at the FunctionFS call site to
surface the use-after-free.  On SG-capable in-tree UDCs the
dequeue path dereferences the supplied request immediately:

  * chipidea's ep_dequeue() does
    container_of(req, struct ci_hw_req, req) and reads
    hwreq->req.status before acquiring its own lock.
  * cdnsp's cdnsp_gadget_ep_dequeue() reads request->status first.

The narrower option of clearing priv->req via cmpxchg() in the
completion does not close the race: the completion runs without
eps_lock, so a cancel path holding eps_lock can still observe
priv->req non-NULL, race a concurrent completion that clears and
frees, and pass the freed pointer to usb_ep_dequeue().  A slightly
longer fix that moves the free into the cleanup work is needed.

Same class of lifetime race as the recent usbip-vudc timer fix [1].

Take eps_lock in the sole place that mutates priv->req from the
callback direction by moving usb_ep_free_request() out of the
completion into ffs_dmabuf_cleanup(), the existing work handler
scheduled by ffs_dmabuf_signal_done() on
ffs->io_completion_wq.  Clear priv->req there under eps_lock
before freeing, and only clear if priv->req still names our
request (a subsequent ffs_dmabuf_transfer() on the same
attachment may have queued a new one).

This keeps the existing dummy_hcd sync-dequeue invariant: the
completion callback is still invoked by the UDC without
eps_lock held (dummy_hcd drops its own lock before calling the
callback), and the callback now takes no f_fs lock at all.
Serialization against the cancel path happens in cleanup, which
runs from the workqueue with no f_fs lock held on entry.

The priv ref count protects the containing ffs_dmabuf_priv:
ffs_dmabuf_transfer() takes a ref via ffs_dmabuf_get(), cleanup
drops it via ffs_dmabuf_put(), so priv stays live for the
cleanup even after the cancel path's list_del + ffs_dmabuf_put.

The ffs_dmabuf_transfer() error path no longer frees usb_req
inline: fence->req and fence->ep are set before usb_ep_queue(),
so ffs_dmabuf_cleanup() (scheduled by the error-path
ffs_dmabuf_signal_done()) owns the free regardless of whether
the queue succeeded.

Reproduced under KASAN on both detach and close paths against
dummy_hcd with an observability hook
(kasan_check_byte(priv->req) immediately before usb_ep_dequeue)
at the two FunctionFS cancel sites to surface the stale-pointer
access; the hook is not part of this patch.  The KASAN
allocator / free stacks in the captured splats identify the
same request: alloc in dummy_alloc_request, free in
dummy_timer, fault reached from ffs_epfile_release (close) and
from the FUNCTIONFS_DMABUF_DETACH ioctl (detach).  With the
patch applied, both paths are silent under the same hook.

The bug is reached from the FunctionFS device node, which in
real deployments is owned by the privileged gadget daemon
(adbd, UMS, composite gadget services, etc.); it is not
reachable from unprivileged userspace or from a USB host on the
cable.  FunctionFS mounts default to GLOBAL_ROOT_UID, but the
filesystem supports uid=, gid=, and fmode= delegation to a
non-root gadget daemon, so on real deployments the attacker may
be a less-privileged service rather than root.

Fixes: 7b07a2a7ca02 ("usb: gadget: functionfs: Add DMABUF import interface")
Link: https://lore.kernel.org/all/20260417163552.807548-1-michael.bommarito@gmail.com/ [1]
Cc: stable <stable@kernel.org>
Assisted-by: Claude:claude-opus-4-7
Signed-off-by: Michael Bommarito <michael.bommarito@gmail.com>
Link: https://patch.msgid.link/20260419161227.1587668-1-michael.bommarito@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
usb: gadget: f_fs: copy only received bytes on short ep0 read 2026-06-09T10:28:45+00:00 Michael Bommarito michael.bommarito@gmail.com 2026-04-19T16:03:59+00:00 607730a414773a7cbe3037a64a6c64e72689ff5e commit 4e036c10e7f4df5d951c69cc3697bc8e209c6d02 upstream. ffs_ep0_read() allocates its control-OUT data buffer with kmalloc() (not kzalloc) at the Length value from the Setup packet, then copies that full len to userspace regardless of how many bytes were actually received: data = kmalloc(len, GFP_KERNEL); ... ret = __ffs_ep0_queue_wait(ffs, data, len); if ((ret > 0) && (copy_to_user(buf, data, len))) ret = -EFAULT; __ffs_ep0_queue_wait() returns req->actual, which on a short control OUT transfer is strictly less than len. The copy_to_user() call still copies len bytes, so on a short OUT the last (len - ret) bytes of the kmalloc() buffer -- uninitialised slab residue -- are delivered to the FunctionFS daemon. Short ep0 OUT completions are specified USB control-transfer behavior and are produced by in-tree UDCs: * dwc2 continues on req->actual < req->length for ep0 DATA OUT (short-not-ok is the only ep0-OUT stall path). * aspeed_udc ends ep0 OUT on rx_len < ep->ep.maxpacket. * renesas_usbf logs "ep0 short packet" and completes the request. * dwc3 stalls on short IN but not on short OUT. A short ep0 OUT is therefore not evidence of a broken UDC; it is a normal condition f_fs has to cope with. The sibling gadgetfs implementation in drivers/usb/gadget/legacy/inode.c already does this correctly via min(len, dev->req->actual) before copy_to_user(). This patch brings f_fs.c to the same safe pattern rather than trimming at a defensive layer. The bug is reached from the FunctionFS device node, which in real deployments is owned by the privileged gadget daemon (adbd, UMS, composite gadget services, etc.); it is not reachable from unprivileged userspace. Linux host stacks normally reject short-wLength control OUTs before they reach the gadget, so reproducing this required a build that bypasses that host-side check. With the bypass in place, a 1-byte payload on a 64-byte Setup produces 63 bytes of non-canary slab residue in the daemon's read buffer. Fix by copying only ret (actually received) bytes to userspace. Fixes: ddf8abd25994 ("USB: f_fs: the FunctionFS driver") Cc: stable <stable@kernel.org> Assisted-by: Claude:claude-opus-4-7 Signed-off-by: Michael Bommarito <michael.bommarito@gmail.com> Link: https://patch.msgid.link/20260419160359.1577270-1-michael.bommarito@gmail.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 4e036c10e7f4df5d951c69cc3697bc8e209c6d02 upstream.

ffs_ep0_read() allocates its control-OUT data buffer with
kmalloc() (not kzalloc) at the Length value from the Setup
packet, then copies that full len to userspace regardless of
how many bytes were actually received:

    data = kmalloc(len, GFP_KERNEL);
    ...
    ret = __ffs_ep0_queue_wait(ffs, data, len);
    if ((ret > 0) && (copy_to_user(buf, data, len)))
            ret = -EFAULT;

__ffs_ep0_queue_wait() returns req->actual, which on a short
control OUT transfer is strictly less than len.  The
copy_to_user() call still copies len bytes, so on a short OUT
the last (len - ret) bytes of the kmalloc() buffer --
uninitialised slab residue -- are delivered to the FunctionFS
daemon.

Short ep0 OUT completions are specified USB control-transfer
behavior and are produced by in-tree UDCs:

  * dwc2 continues on req->actual < req->length for ep0 DATA OUT
    (short-not-ok is the only ep0-OUT stall path).
  * aspeed_udc ends ep0 OUT on rx_len < ep->ep.maxpacket.
  * renesas_usbf logs "ep0 short packet" and completes the
    request.
  * dwc3 stalls on short IN but not on short OUT.

A short ep0 OUT is therefore not evidence of a broken UDC; it is
a normal condition f_fs has to cope with.  The sibling gadgetfs
implementation in drivers/usb/gadget/legacy/inode.c already does
this correctly via min(len, dev->req->actual) before
copy_to_user().  This patch brings f_fs.c to the same safe
pattern rather than trimming at a defensive layer.

The bug is reached from the FunctionFS device node, which in
real deployments is owned by the privileged gadget daemon
(adbd, UMS, composite gadget services, etc.); it is not
reachable from unprivileged userspace.  Linux host stacks
normally reject short-wLength control OUTs before they reach
the gadget, so reproducing this required a build that
bypasses that host-side check.  With the bypass in place, a
1-byte payload on a 64-byte Setup produces 63 bytes of
non-canary slab residue in the daemon's read buffer.

Fix by copying only ret (actually received) bytes to
userspace.

Fixes: ddf8abd25994 ("USB: f_fs: the FunctionFS driver")
Cc: stable <stable@kernel.org>
Assisted-by: Claude:claude-opus-4-7
Signed-off-by: Michael Bommarito <michael.bommarito@gmail.com>
Link: https://patch.msgid.link/20260419160359.1577270-1-michael.bommarito@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
usb: gadget: f_hid: fix device reference leak in hidg_alloc() 2026-06-09T10:28:45+00:00 Guangshuo Li lgs201920130244@gmail.com 2026-04-13T14:21:19+00:00 f928630f450be7008e1dce86bf95275b2f92af91 commit 4f88d65def6f3c90121601b4f62a4c967f3063a6 upstream. hidg_alloc() initializes hidg->dev with device_initialize() before calling dev_set_name(). If dev_set_name() fails, the function currently jumps to err_unlock and returns without calling put_device(). This leaves the device reference unbalanced and prevents hidg_release() from being called. Calling put_device() here is also safe, since hidg_release() only frees resources owned by hidg. The issue was identified by a static analysis tool I developed and confirmed by manual review. Route the dev_set_name() failure path through err_put_device so the device reference is dropped properly. Fixes: 89ff3dfac604 ("usb: gadget: f_hid: fix f_hidg lifetime vs cdev") Cc: stable <stable@kernel.org> Reviewed-by: Johan Hovold <johan@kernel.org> Signed-off-by: Guangshuo Li <lgs201920130244@gmail.com> Reviewed-by: Johan Hovold johan@kernel.org Link: https://patch.msgid.link/20260413142119.2977716-1-lgs201920130244@gmail.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 4f88d65def6f3c90121601b4f62a4c967f3063a6 upstream.

hidg_alloc() initializes hidg->dev with device_initialize() before
calling dev_set_name(). If dev_set_name() fails, the function currently
jumps to err_unlock and returns without calling put_device().

This leaves the device reference unbalanced and prevents hidg_release()
from being called. Calling put_device() here is also safe, since
hidg_release() only frees resources owned by hidg.

The issue was identified by a static analysis tool I developed and
confirmed by manual review.

Route the dev_set_name() failure path through err_put_device so the
device reference is dropped properly.

Fixes: 89ff3dfac604 ("usb: gadget: f_hid: fix f_hidg lifetime vs cdev")
Cc: stable <stable@kernel.org>
Reviewed-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Guangshuo Li <lgs201920130244@gmail.com>
Reviewed-by: Johan Hovold johan@kernel.org
Link: https://patch.msgid.link/20260413142119.2977716-1-lgs201920130244@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
usb: gadget: uvc: hold opts->lock across XU walks in uvc_function_bind 2026-06-09T10:28:45+00:00 Kai Aizen kai.aizen.dev@gmail.com 2026-04-30T17:56:43+00:00 caec0145e5974e85fe5192fc6a6f5aa1a98f82a6 commit 68aa70648b625fa684bc0b71bbfd905f4943ca20 upstream. uvc_function_bind() walks &opts->extension_units twice without holding opts->lock: - directly, for the iExtension string-descriptor fixup loop; - indirectly, four times via uvc_copy_descriptors() (once per speed), where the helper iterates uvc->desc.extension_units (which aliases &opts->extension_units) to size and emit XU descriptors. The configfs side (uvcg_extension_make / uvcg_extension_drop, in drivers/usb/gadget/function/uvc_configfs.c) takes opts->lock around its list_add_tail / list_del operations. A privileged userspace process that holds the configfs subtree open and writes the gadget UDC name to bind the function while concurrently rmdir()'ing an extensions subdir can race uvcg_extension_drop() against the bind-time list walks and dereference a freed struct uvcg_extension. Hold opts->lock from the start of the XU string-descriptor fixup through the last uvc_copy_descriptors() call, releasing on the descriptor-error path via a new error_unlock label that drops the lock before falling through to the existing error label. This matches the locking discipline of the configfs callbacks and removes the only remaining unsynchronised reader of the XU list during bind. Reachability: only privileged processes that can mount configfs and write to gadget UDC files can trigger the race, so this is a correctness fix rather than a security boundary. Fixes: 0525210c9840 ("usb: gadget: uvc: Allow definition of XUs in configfs") Cc: stable <stable@kernel.org> Signed-off-by: Kai Aizen <kai.aizen.dev@gmail.com> Link: https://patch.msgid.link/20260430175643.67120-1-kai.aizen.dev@gmail.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 68aa70648b625fa684bc0b71bbfd905f4943ca20 upstream.

uvc_function_bind() walks &opts->extension_units twice without holding
opts->lock:

  - directly, for the iExtension string-descriptor fixup loop;
  - indirectly, four times via uvc_copy_descriptors() (once per speed),
    where the helper iterates uvc->desc.extension_units (which aliases
    &opts->extension_units) to size and emit XU descriptors.

The configfs side (uvcg_extension_make / uvcg_extension_drop, in
drivers/usb/gadget/function/uvc_configfs.c) takes opts->lock around its
list_add_tail / list_del operations.  A privileged userspace process
that holds the configfs subtree open and writes the gadget UDC name
to bind the function while concurrently rmdir()'ing an extensions
subdir can race uvcg_extension_drop() against the bind-time list walks
and dereference a freed struct uvcg_extension.

Hold opts->lock from the start of the XU string-descriptor fixup
through the last uvc_copy_descriptors() call, releasing on the
descriptor-error path via a new error_unlock label that drops the
lock before falling through to the existing error label.  This
matches the locking discipline of the configfs callbacks and removes
the only remaining unsynchronised reader of the XU list during bind.

Reachability: only privileged processes that can mount configfs and
write to gadget UDC files can trigger the race, so this is a
correctness fix rather than a security boundary.

Fixes: 0525210c9840 ("usb: gadget: uvc: Allow definition of XUs in configfs")
Cc: stable <stable@kernel.org>
Signed-off-by: Kai Aizen <kai.aizen.dev@gmail.com>
Link: https://patch.msgid.link/20260430175643.67120-1-kai.aizen.dev@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
usb: gadget: f_hid: don't call cdev_init while cdev in use 2026-04-22T11:22:28+00:00 Michael Zimmermann sigmaepsilon92@gmail.com 2026-03-27T19:22:09+00:00 eb6ef6185f2054a341ec70d7e2165f5381744215 commit 81ebd43cc0d6d106ce7b6ccbf7b5e40ca7f5503d upstream. When calling unbind, then bind again, cdev_init reinitialized the cdev, even though there may still be references to it. That's the case when the /dev/hidg* device is still opened. This obviously unsafe behavior like oopes. This fixes this by using cdev_alloc to put the cdev on the heap. That way, we can simply allocate a new one in hidg_bind. Closes: https://lore.kernel.org/linux-usb/CAN9vWDKZn0Ts5JyV2_xcAmbnBEi0znMLg_USMFrShRryXrgWGQ@mail.gmail.com/T/#m2cb0dba3633b67b2a679c98499508267d1508881 Cc: stable <stable@kernel.org> Signed-off-by: Michael Zimmermann <sigmaepsilon92@gmail.com> Link: https://patch.msgid.link/20260327192209.59945-1-sigmaepsilon92@gmail.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 81ebd43cc0d6d106ce7b6ccbf7b5e40ca7f5503d upstream.

When calling unbind, then bind again, cdev_init reinitialized the cdev,
even though there may still be references to it. That's the case when
the /dev/hidg* device is still opened. This obviously unsafe behavior
like oopes.

This fixes this by using cdev_alloc to put the cdev on the heap. That
way, we can simply allocate a new one in hidg_bind.

Closes: https://lore.kernel.org/linux-usb/CAN9vWDKZn0Ts5JyV2_xcAmbnBEi0znMLg_USMFrShRryXrgWGQ@mail.gmail.com/T/#m2cb0dba3633b67b2a679c98499508267d1508881
Cc: stable <stable@kernel.org>
Signed-off-by: Michael Zimmermann <sigmaepsilon92@gmail.com>
Link: https://patch.msgid.link/20260327192209.59945-1-sigmaepsilon92@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>