kernel/linux.git/drivers/usb/gadget/function, branch v6.6.150

usb: gadget: uvc: clamp SEND_RESPONSE length to the response buffer

2026-08-03T09:15:16+00:00

commit b70dc75e85ba968b7b76eebfe5d63000080b875b upstream. uvc_send_response() builds the UVC control response from a user-supplied struct uvc_request_data: req->length = min_t(unsigned int, uvc->event_length, data->length); ... memcpy(req->buf, data->data, req->length); req->length is clamped to uvc->event_length, which is taken from the host control request wLength (up to UVC_MAX_REQUEST_SIZE, 64), and to data->length, which comes from the UVCIOC_SEND_RESPONSE ioctl and is only checked for being negative. The source buffer data->data is only 60 bytes, so a response with uvc->event_length and data->length both greater than 60 makes memcpy() read past the end of data->data. Clamp req->length to sizeof(data->data) as well. Fixes: a5eaaa1f33e7 ("usb: gadget: uvc: use capped length value") Cc: stable Signed-off-by: Muhammad Bilal Link: https://patch.msgid.link/20260629195004.148405-1-meatuni001@gmail.com Signed-off-by: Greg Kroah-Hartman Signed-off-by: Greg Kroah-Hartman

usb: gadget: f_ncm: validate datagram bounds in ncm_unwrap_ntb()

2026-08-03T09:15:16+00:00

commit 1febec7e47cdcd01f43fb0211094e3010474666e upstream. When unpacking host-supplied NTBs, ncm_unwrap_ntb() checks datagram length against frame_max but does not verify that the datagram fits within the declared block length. Additionally, when decoding multiple NTBs from a single socket buffer, subsequent block lengths are not checked against the actual remaining buffer data. With these checks missing, a malicious USB host can specify datagram offsets and lengths that point beyond the block, or supply secondary NTB headers declaring lengths larger than the buffer. skb_put_data() then copies adjacent kernel memory from skb_shared_info into the network skb. Fix this by verifying that sufficient buffer space remains for the NTB header before parsing, handling zero-length block declarations, ensuring that block lengths never exceed the remaining buffer space, and verifying that each datagram payload stays strictly within the block boundary. Fixes: 427694cfaafa ("usb: gadget: ncm: Handle decoding of multiple NTB's in unwrap call") Fixes: 2b74b0a04d3e ("USB: gadget: f_ncm: add bounds checks to ncm_unwrap_ntb()") Cc: stable Assisted-by: Jetski:Gemini-2.5-Pro Signed-off-by: Sonali Pradhan Link: https://patch.msgid.link/20260703083725.1903850-1-sonalipradhan@google.com Signed-off-by: Greg Kroah-Hartman

usb: gadget: printer: fix infinite loop in printer_read()

2026-08-03T09:15:16+00:00

commit c2e819be6a5c7f34344926b4bd7e3dfca58cf48a upstream. printer_read() uses the same variable for the requested copy size and the number of bytes actually copied to user space. copy_to_user() returns the number of bytes not copied, so when it fails to copy anything, the computed copied length becomes zero. In that case len, buf, current_rx_bytes and current_rx_buf are left unchanged. If RX data is available and the user buffer remains unwritable, the read loop can repeat indefinitely. Track the copied length separately and return -EFAULT, or the number of bytes already copied, if an iteration makes no progress. Fixes: b185f01a9ab7 ("usb: gadget: printer: factor out f_printer") Cc: stable Reviewed-by: Peter Chen Signed-off-by: Melbin K Mathew Link: https://patch.msgid.link/20260709205622.55700-1-mlbnkm1@gmail.com Signed-off-by: Greg Kroah-Hartman

usb: gadget: f_midi: cancel pending IN work before freeing the midi object

2026-08-03T09:15:16+00:00

commit 5650c18d93a1db7e27cb5a40b394747eb4686d5b upstream. The f_midi driver embeds a work item (midi->work) whose handler, f_midi_in_work(), dereferences the enclosing struct f_midi through container_of(). This work is armed from two sites: f_midi_complete(), on a normal IN-endpoint completion, and f_midi_in_trigger(), on an ALSA rawmidi output-stream start. Neither f_midi_disable() nor f_midi_unbind() cancels midi->work. f_midi_disable() only disables the endpoints and drains the in_req_fifo; it does not synchronize the work item, and the sound card is released asynchronously to the final free of the midi object. The midi object is reference-counted (midi->free_ref) and is freed in f_midi_free() only once both the usb_function reference and the rawmidi private_data reference have been dropped. In f_midi_unbind(), f_midi_disable() runs before the sound card is released, so while the USB endpoints are already disabled the rawmidi device is still usable by an open substream. A concurrent userspace write on such a substream can reach f_midi_in_trigger() and queue midi->work again after f_midi_disable() has returned. A work item armed this way may still be pending when the last reference drops and f_midi_free() proceeds to kfree(midi), letting f_midi_in_work() dereference the struct after it has been freed, a use-after-free. For this reason cancelling midi->work in f_midi_disable() would not be sufficient: the ALSA trigger path can rearm the work after disable() returns. Cancelling at the refcount-zero free site is the boundary after which neither arming source can survive, because by then both references that keep the midi object alive have been dropped: the USB endpoints are already disabled and the rawmidi device has been released. Fix this by calling cancel_work_sync(&midi->work) in the refcount-zero block of f_midi_free(), before the embedded work_struct is freed along with the rest of the structure. opts->lock is a sleeping mutex, so calling cancel_work_sync() under it is permitted, and the handler takes midi->transmit_lock rather than opts->lock, so no self-deadlock can occur while it waits for a running instance of the work to finish. This issue was found by an in-house static analysis tool. Fixes: 8653d71ce3763 ("usb/gadget: f_midi: Replace tasklet with work") Cc: stable Assisted-by: Codex:gpt-5.5 Signed-off-by: Fan Wu Link: https://patch.msgid.link/20260709150717.399083-1-fanwu01@zju.edu.cn Signed-off-by: Greg Kroah-Hartman

usb: gadget: f_fs: Tie read_buffer lifetime to ffs_epfile

2026-07-24T14:03:51+00:00

[ Upstream commit 8bdcf96eb135aebacac319667f87db034fb38406 ] 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 [ adjusted context in ffs_epfiles_destroy() since 6.12 lacks the simple_remove_by_name() rework and still uses dentry-based cleanup ] Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

usb: gadget: f_fs: initialize reset_work at allocation time

2026-07-24T14:03:51+00:00

[ Upstream commit 3137b243c93982fe3460335e12f9247739766e10 ] 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 [ dropped the ffs_func_disable hunk since 6.6 predates the disable-body split and routes disable through ffs_func_set_alt, so removing the single lazy INIT_WORK there covers both paths ] Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

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

2026-07-24T14:02:50+00:00

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 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: function: rndis: add length check for header

2026-07-24T14:02:40+00:00

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 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

2026-07-24T14:02:40+00:00

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

2026-06-19T11:39:41+00:00

[ Upstream commit 68aa70648b625fa684bc0b71bbfd905f4943ca20 ] 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 Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman