From fc58fa3ff9944d80be497f264675b9546ab8a318 Mon Sep 17 00:00:00 2001 From: Alan Stern Date: Wed, 18 Oct 2017 12:49:38 -0400 Subject: UPSTREAM: USB: core: fix out-of-bounds access bug in usb_get_bos_descriptor() commit 1c0edc3633b56000e18d82fc241e3995ca18a69e Andrey used the syzkaller fuzzer to find an out-of-bounds memory access in usb_get_bos_descriptor(). The code wasn't checking that the next usb_dev_cap_header structure could fit into the remaining buffer space. This patch fixes the error and also reduces the bNumDeviceCaps field in the header to match the actual number of capabilities found, in cases where there are fewer than expected. Change-Id: Ica990541695ce5ba46ca8d2bd01e8230dcf5dcd4 Reported-by: Andrey Konovalov Signed-off-by: Alan Stern Tested-by: Andrey Konovalov CC: Signed-off-by: Greg Kroah-Hartman --- drivers/usb/core/config.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) (limited to 'drivers') diff --git a/drivers/usb/core/config.c b/drivers/usb/core/config.c index d6481cb46..50649a30d 100644 --- a/drivers/usb/core/config.c +++ b/drivers/usb/core/config.c @@ -897,10 +897,12 @@ int usb_get_bos_descriptor(struct usb_device *dev) for (i = 0; i < num; i++) { buffer += length; cap = (struct usb_dev_cap_header *)buffer; - length = cap->bLength; - if (total_len < length) + if (total_len < sizeof(*cap) || total_len < cap->bLength) { + dev->bos->desc->bNumDeviceCaps = i; break; + } + length = cap->bLength; total_len -= length; if (cap->bDescriptorType != USB_DT_DEVICE_CAPABILITY) { -- cgit v1.2.3