kernel/linux.git/drivers/usb/core/usb.c, branch v6.1.168

usb: Add checks for snprintf() calls in usb_alloc_dev()

2025-07-06T08:57:56+00:00

[ Upstream commit 82fe5107fa3d21d6c3fba091c9dbc50495588630 ] When creating a device path in the driver the snprintf() takes up to 16 characters long argument along with the additional up to 12 characters for the signed integer (as it can't see the actual limits) and tries to pack this into 16 bytes array. GCC complains about that when build with `make W=1`: drivers/usb/core/usb.c:705:25: note: ‘snprintf’ output between 3 and 28 bytes into a destination of size 16 Since everything works until now, let's just check for the potential buffer overflow and bail out. It is most likely a never happen situation, but at least it makes GCC happy. Signed-off-by: Andy Shevchenko Link: https://lore.kernel.org/r/20250321164949.423957-1-andriy.shevchenko@linux.intel.com Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin

USB: core: Add routines for endpoint checks in old drivers

2023-05-30T13:03:20+00:00

commit 13890626501ffda22b18213ddaf7930473da5792 upstream. Many of the older USB drivers in the Linux USB stack were written based simply on a vendor's device specification. They use the endpoint information in the spec and assume these endpoints will always be present, with the properties listed, in any device matching the given vendor and product IDs. While that may have been true back then, with spoofing and fuzzing it is not true any more. More and more we are finding that those old drivers need to perform at least a minimum of checking before they try to use any endpoint other than ep0. To make this checking as simple as possible, we now add a couple of utility routines to the USB core. usb_check_bulk_endpoints() and usb_check_int_endpoints() take an interface pointer together with a list of endpoint addresses (numbers and directions). They check that the interface's current alternate setting includes endpoints with those addresses and that each of these endpoints has the right type: bulk or interrupt, respectively. Although we already have usb_find_common_endpoints() and related routines meant for a similar purpose, they are not well suited for this kind of checking. Those routines find endpoints of various kinds, but only one (either the first or the last) of each kind, and they don't verify that the endpoints' addresses agree with what the caller expects. In theory the new routines could be more general: They could take a particular altsetting as their argument instead of always using the interface's current altsetting. In practice I think this won't matter too much; multiple altsettings tend to be used for transferring media (audio or visual) over isochronous endpoints, not bulk or interrupt. Drivers for such devices will generally require more sophisticated checking than these simplistic routines provide. Signed-off-by: Alan Stern Link: https://lore.kernel.org/r/dd2c8e8c-2c87-44ea-ba17-c64b97e201c9@rowland.harvard.edu Signed-off-by: Greg Kroah-Hartman

USB: fix memory leak with using debugfs_lookup()

2023-03-11T12:55:34+00:00

[ Upstream commit 30374434edab20e25776f8ecb4bc9d1e54309487 ] When calling debugfs_lookup() the result must have dput() called on it, otherwise the memory will leak over time. To make things simpler, just call debugfs_lookup_and_remove() instead which handles all of the logic at once. Cc: Alan Stern Cc: Jilin Yuan Link: https://lore.kernel.org/r/20230106152828.3790902-1-gregkh@linuxfoundation.org Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin

usb/core: fix repeated words in comments

2022-07-27T12:32:29+00:00

Delete the redundant word 'the'. Signed-off-by: Jilin Yuan Link: https://lore.kernel.org/r/20220716132403.35270-1-yuanjilin@cdjrlc.com Signed-off-by: Greg Kroah-Hartman

USB: core: Update kerneldoc for usb_get_dev() and usb_get_intf()

2022-02-25T15:53:41+00:00

The kerneldoc for usb_get_dev() and usb_get_intf() says that drivers should always refcount the references they hold for the usb_device or usb_interface structure, respectively. But this is an overstatement: In many cases drivers do not access these references after they have been unbound, and in such cases refcounting is unnecessary. This patch updates the kerneldoc for the two routines, explaining when a driver does not need to increment and decrement the refcount. This should help dispel misconceptions which might otherwise afflict programmers new to the USB subsystem. Signed-off-by: Alan Stern Link: https://lore.kernel.org/r/Yhjp4Rp9Alipmwtq@rowland.harvard.edu Signed-off-by: Greg Kroah-Hartman

usb: Remove usb_for_each_port()

2021-12-30T11:13:04+00:00

There are no more users for the function. Reviewed-by: Andy Shevchenko Acked-by: Rafael J. Wysocki Signed-off-by: Heikki Krogerus Link: https://lore.kernel.org/r/20211223082432.45653-1-heikki.krogerus@linux.intel.com Signed-off-by: Greg Kroah-Hartman

usb: Iterator for ports

2021-04-09T14:00:00+00:00

Introducing usb_for_each_port(). It works the same way as usb_for_each_dev(), but instead of going through every USB device in the system, it walks through the USB ports in the system. Acked-by: Alan Stern Signed-off-by: Heikki Krogerus Link: https://lore.kernel.org/r/20210407065555.88110-4-heikki.krogerus@linux.intel.com Signed-off-by: Greg Kroah-Hartman

Merge 5.12-rc3 into usb-next

2021-03-15T07:45:20+00:00

We want the USB fixes in here as well. Signed-off-by: Greg Kroah-Hartman

drm: Use USB controller's DMA mask when importing dmabufs

2021-03-11T10:11:33+00:00

USB devices cannot perform DMA and hence have no dma_mask set in their device structure. Therefore importing dmabuf into a USB-based driver fails, which breaks joining and mirroring of display in X11. For USB devices, pick the associated USB controller as attachment device. This allows the DRM import helpers to perform the DMA setup. If the DMA controller does not support DMA transfers, we're out of luck and cannot import. Our current USB-based DRM drivers don't use DMA, so the actual DMA device is not important. Tested by joining/mirroring displays of udl and radeon under Gnome/X11. v8: * release dmadev if device initialization fails (Noralf) * fix commit description (Noralf) v7: * fix use-before-init bug in gm12u320 (Dan) v6: * implement workaround in DRM drivers and hold reference to DMA device while USB device is in use * remove dev_is_usb() (Greg) * collapse USB helper into usb_intf_get_dma_device() (Alan) * integrate Daniel's TODO statement (Daniel) * fix typos (Greg) v5: * provide a helper for USB interfaces (Alan) * add FIXME item to documentation and TODO list (Daniel) v4: * implement workaround with USB helper functions (Greg) * use struct usb_device->bus->sysdev as DMA device (Takashi) v3: * drop gem_create_object * use DMA mask of USB controller, if any (Daniel, Christian, Noralf) v2: * move fix to importer side (Christian, Daniel) * update SHMEM and CMA helpers for new PRIME callbacks Signed-off-by: Thomas Zimmermann Fixes: 6eb0233ec2d0 ("usb: don't inherity DMA properties for USB devices") Tested-by: Pavel Machek Reviewed-by: Greg Kroah-Hartman Acked-by: Christian König Acked-by: Daniel Vetter Acked-by: Noralf Trønnes Cc: Christoph Hellwig Cc: Greg Kroah-Hartman Cc: # v5.10+ Signed-off-by: Thomas Zimmermann Link: https://patchwork.freedesktop.org/patch/msgid/20210303133229.3288-1-tzimmermann@suse.de Signed-off-by: Maarten Lankhorst

USB: core: no need to save usb_devices_root

2021-03-10T08:37:15+00:00

There is no need to save the usb_devices debugfs file as we only need it when removing it, so have the debugfs code look it up when it is needed instead, saving the storage. Link: https://lore.kernel.org/r/YCubCA/trHAF7PtF@kroah.com Signed-off-by: Greg Kroah-Hartman