kernel/git/next/linux-next.git/drivers/usb/gadget/function, branch master

usb: gadget: function: rndis: add length check for header

2026-07-08T11:32:16+00:00

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 Signed-off-by: Griffin Kroah-Hartman Link: https://patch.msgid.link/20260708-usb-gadget-rndis-v1-2-e77e026dcc6a@kroah.com Signed-off-by: Greg Kroah-Hartman

usb: gadget: function: rndis: add length check to response query

2026-07-08T11:32:14+00:00

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 Signed-off-by: Griffin Kroah-Hartman Link: https://patch.msgid.link/20260708-usb-gadget-rndis-v1-1-e77e026dcc6a@kroah.com Signed-off-by: Greg Kroah-Hartman

usb: gadget: f_printer: take kref only for successful open

2026-07-08T11:29:57+00:00

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 Signed-off-by: Xu Rao Link: https://patch.msgid.link/80295742B820DA9B+20260626064617.4090626-1-raoxu@uniontech.com Signed-off-by: Greg Kroah-Hartman

usb: gadget: f_fs: Tie read_buffer lifetime to ffs_epfile

2026-06-25T14:24:00+00:00

Currently, ffs_epfile_release unconditionally frees the endpoint's read_buffer when a file descriptor is closed. If userspace explicitly opens the endpoint multiple times and closes one, the read_buffer is destroyed. This can lead to silent data loss if other file descriptors are still actively reading from the endpoint. By tying the lifetime of the read_buffer to the ffs_epfile structure itself (which is destroyed when the functionfs instance is torn down in ffs_epfiles_destroy), we eliminate the brittle dependency on open/release calls while correctly matching the conceptual lifetime of unread data on the hardware endpoint. Fixes: 9353afbbfa7b ("usb: gadget: f_fs: buffer data from ‘oversized’ OUT requests") Cc: stable Assisted-by: Antigravity:gemini-3.1-pro Signed-off-by: Neill Kapron Link: https://patch.msgid.link/20260619040609.4010746-3-nkapron@google.com Signed-off-by: Greg Kroah-Hartman

usb: gadget: f_fs: Initialize epfile->in early to fix endpoint direction checks

2026-06-25T14:23:51+00:00

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 Assisted-by: Antigravity:gemini-3.1-pro Signed-off-by: Neill Kapron Link: https://patch.msgid.link/20260619040609.4010746-2-nkapron@google.com Signed-off-by: Greg Kroah-Hartman

usb: gadget: f_fs: initialize reset_work at allocation time

2026-06-25T14:12:32+00:00

ffs_fs_kill_sb() unconditionally calls cancel_work_sync() on ffs->reset_work when a functionfs instance is unmounted: ffs_data_reset(ffs); cancel_work_sync(&ffs->reset_work); However ffs->reset_work is only ever initialized via INIT_WORK() in ffs_func_set_alt() and ffs_func_disable(), and only on the FFS_DEACTIVATED path. That state is reached solely by ffs_data_closed() when the instance is mounted with the "no_disconnect" option, so for the common case (no "no_disconnect", or mounted and unmounted without ever being deactivated) reset_work is never initialized. ffs_data_new() allocates the ffs_data with kzalloc_obj() and does not initialize reset_work, and ffs_data_reset()/ffs_data_clear() do not touch it either, so reset_work.func is left NULL. cancel_work_sync() on such a work then trips the WARN_ON(!work->func) guard in __flush_work(): WARNING: kernel/workqueue.c:4301 at __flush_work+0x330/0x360, CPU#3: umount Call trace: __flush_work cancel_work_sync ffs_fs_kill_sb [usb_f_fs] deactivate_locked_super deactivate_super cleanup_mnt __cleanup_mnt task_work_run exit_to_user_mode_loop el0_svc On older kernels cancel_work_sync() on a zero-initialized work struct was a silent no-op, which hid the missing initialization. Initialize reset_work once in ffs_data_new() so it is always valid for the lifetime of the ffs_data, and drop the now-redundant INIT_WORK() calls from the two deactivation paths. Fixes: 18d6b32fca38 ("usb: gadget: f_fs: add "no_disconnect" mode") Cc: stable Signed-off-by: Tyler Baker Cc: Loic Poulain Cc: Dmitry Baryshkov Cc: Srinivas Kandagatla Tested-by: Loic Poulain Reviewed-by: Peter Chen Acked-by: Michał Nazarewicz Link: https://patch.msgid.link/20260609193635.2284430-1-tyler.baker@oss.qualcomm.com Signed-off-by: Greg Kroah-Hartman

usb: gadget: f_fs: Fix DMA fence leak

2026-06-25T14:11:56+00:00

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 Signed-off-by: Paul Cercueil Tested-by: Nuno Sá Reviewed-by: Nuno Sá Link: https://patch.msgid.link/20260609152905.729328-1-paul@crapouillou.net Signed-off-by: Greg Kroah-Hartman

usb: gadget: f_fs: serialize DMABUF cancel against request completion

2026-05-22T09:20:43+00:00

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 Assisted-by: Claude:claude-opus-4-7 Signed-off-by: Michael Bommarito Link: https://patch.msgid.link/20260419161227.1587668-1-michael.bommarito@gmail.com Signed-off-by: Greg Kroah-Hartman

usb: gadget: f_fs: copy only received bytes on short ep0 read

2026-05-22T09:20:30+00:00

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 Assisted-by: Claude:claude-opus-4-7 Signed-off-by: Michael Bommarito Link: https://patch.msgid.link/20260419160359.1577270-1-michael.bommarito@gmail.com Signed-off-by: Greg Kroah-Hartman

usb: gadget: uvc: hold opts->lock across XU walks in uvc_function_bind

2026-05-22T08:35:36+00:00

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 Signed-off-by: Kai Aizen Link: https://patch.msgid.link/20260430175643.67120-1-kai.aizen.dev@gmail.com Signed-off-by: Greg Kroah-Hartman