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authorUdipto Goswami <quic_ugoswami@quicinc.com>2024-01-10 12:58:14 +0300
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2024-01-28 03:38:39 +0300
commit12783c0b9e2c7915a50d5ec829630ff2da50472c (patch)
tree5833392656f750f66a37611888fe28e5c7a77293 /drivers/usb/core
parent7c4650ded49e5b88929ecbbb631efb8b0838e811 (diff)
downloadlinux-12783c0b9e2c7915a50d5ec829630ff2da50472c.tar.xz
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>
Diffstat (limited to 'drivers/usb/core')
-rw-r--r--drivers/usb/core/hub.c16
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);
+ }
}
}