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| author | Udipto Goswami <quic_ugoswami@quicinc.com> | 2024-01-10 15:28:14 +0530 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2024-01-27 16:38:39 -0800 |
| commit | 12783c0b9e2c7915a50d5ec829630ff2da50472c (patch) | |
| tree | 5833392656f750f66a37611888fe28e5c7a77293 | |
| parent | 7c4650ded49e5b88929ecbbb631efb8b0838e811 (diff) | |
| download | linux-stable-12783c0b9e2c7915a50d5ec829630ff2da50472c.tar.gz linux-stable-12783c0b9e2c7915a50d5ec829630ff2da50472c.tar.bz2 linux-stable-12783c0b9e2c7915a50d5ec829630ff2da50472c.zip | |
usb: core: Prevent null pointer dereference in update_port_device_state
Currently, the function update_port_device_state gets the usb_hub from
udev->parent by calling usb_hub_to_struct_hub.
However, in case the actconfig or the maxchild is 0, the usb_hub would
be NULL and upon further accessing to get port_dev would result in null
pointer dereference.
Fix this by introducing an if check after the usb_hub is populated.
Fixes: 83cb2604f641 ("usb: core: add sysfs entry for usb device state")
Cc: stable@vger.kernel.org
Signed-off-by: Udipto Goswami <quic_ugoswami@quicinc.com>
Reviewed-by: Alan Stern <stern@rowland.harvard.edu>
Link: https://lore.kernel.org/r/20240110095814.7626-1-quic_ugoswami@quicinc.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | drivers/usb/core/hub.c | 16 |
1 files changed, 13 insertions, 3 deletions
diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c index ffd7c99e24a3..48409d51ea43 100644 --- a/drivers/usb/core/hub.c +++ b/drivers/usb/core/hub.c @@ -2053,9 +2053,19 @@ static void update_port_device_state(struct usb_device *udev) if (udev->parent) { hub = usb_hub_to_struct_hub(udev->parent); - port_dev = hub->ports[udev->portnum - 1]; - WRITE_ONCE(port_dev->state, udev->state); - sysfs_notify_dirent(port_dev->state_kn); + + /* + * The Link Layer Validation System Driver (lvstest) + * has a test step to unbind the hub before running the + * rest of the procedure. This triggers hub_disconnect + * which will set the hub's maxchild to 0, further + * resulting in usb_hub_to_struct_hub returning NULL. + */ + if (hub) { + port_dev = hub->ports[udev->portnum - 1]; + WRITE_ONCE(port_dev->state, udev->state); + sysfs_notify_dirent(port_dev->state_kn); + } } } |