From cf87b5de4473fdc0735c27ef719abb2e0a6964bb Mon Sep 17 00:00:00 2001 From: Dmitry Torokhov Date: Sat, 7 Oct 2017 11:07:47 -0700 Subject: Input: ims-psu - check if CDC union descriptor is sane commit ea04efee7635c9120d015dcdeeeb6988130cb67a upstream. Before trying to use CDC union descriptor, try to validate whether that it is sane by checking that intf->altsetting->extra is big enough and that descriptor bLength is not too big and not too small. Reported-by: Andrey Konovalov Signed-off-by: Dmitry Torokhov Cc: Ben Hutchings Signed-off-by: Greg Kroah-Hartman --- drivers/input/misc/ims-pcu.c | 16 ++++++++++++++-- 1 file changed, 14 insertions(+), 2 deletions(-) diff --git a/drivers/input/misc/ims-pcu.c b/drivers/input/misc/ims-pcu.c index f4e8fbec6a94..b5304e264881 100644 --- a/drivers/input/misc/ims-pcu.c +++ b/drivers/input/misc/ims-pcu.c @@ -1635,13 +1635,25 @@ ims_pcu_get_cdc_union_desc(struct usb_interface *intf) return NULL; } - while (buflen > 0) { + while (buflen >= sizeof(*union_desc)) { union_desc = (struct usb_cdc_union_desc *)buf; + if (union_desc->bLength > buflen) { + dev_err(&intf->dev, "Too large descriptor\n"); + return NULL; + } + if (union_desc->bDescriptorType == USB_DT_CS_INTERFACE && union_desc->bDescriptorSubType == USB_CDC_UNION_TYPE) { dev_dbg(&intf->dev, "Found union header\n"); - return union_desc; + + if (union_desc->bLength >= sizeof(*union_desc)) + return union_desc; + + dev_err(&intf->dev, + "Union descriptor to short (%d vs %zd\n)", + union_desc->bLength, sizeof(*union_desc)); + return NULL; } buflen -= union_desc->bLength; -- cgit v1.2.3