From: Alan Stern stern@rowland.harvard.edu
commit a03ff54460817c76105f81f3aa8ef655759ccc9a upstream.
The syzkaller USB fuzzer found a slab-out-of-bounds write bug in the USB core, caused by a failure to check the actual size of a BOS descriptor. This patch adds a check to make sure the descriptor is at least as large as it is supposed to be, so that the code doesn't inadvertently access memory beyond the end of the allocated region when assigning to dev->bos->desc->bNumDeviceCaps later on.
Signed-off-by: Alan Stern stern@rowland.harvard.edu Reported-and-tested-by: syzbot+71f1e64501a309fcc012@syzkaller.appspotmail.com CC: stable@vger.kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/usb/core/config.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
--- a/drivers/usb/core/config.c +++ b/drivers/usb/core/config.c @@ -931,8 +931,8 @@ int usb_get_bos_descriptor(struct usb_de
/* Get BOS descriptor */ ret = usb_get_descriptor(dev, USB_DT_BOS, 0, bos, USB_DT_BOS_SIZE); - if (ret < USB_DT_BOS_SIZE) { - dev_err(ddev, "unable to get BOS descriptor\n"); + if (ret < USB_DT_BOS_SIZE || bos->bLength < USB_DT_BOS_SIZE) { + dev_err(ddev, "unable to get BOS descriptor or descriptor too short\n"); if (ret >= 0) ret = -ENOMSG; kfree(bos);