From 8f980122236c1fc8e11ffb57ec73315d01dc88e0 Mon Sep 17 00:00:00 2001 From: Hui Peng Date: Wed, 12 Dec 2018 12:42:24 +0100 Subject: [PATCH] USB: hso: Fix OOB memory access in hso_probe/hso_get_config_data commit 5146f95df782b0ac61abde36567e718692725c89 upstream. The function hso_probe reads if_num from the USB device (as an u8) and uses it without a length check to index an array, resulting in an OOB memory read in hso_probe or hso_get_config_data. Add a length check for both locations and updated hso_probe to bail on error. This issue has been assigned CVE-2018-19985. Reported-by: Hui Peng Reported-by: Mathias Payer Signed-off-by: Hui Peng Signed-off-by: Mathias Payer Reviewed-by: Sebastian Andrzej Siewior Signed-off-by: Greg Kroah-Hartman Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- drivers/net/usb/hso.c | 18 ++++++++++++++++-- 1 file changed, 16 insertions(+), 2 deletions(-) diff --git a/drivers/net/usb/hso.c b/drivers/net/usb/hso.c index 184c24b..d6916f7 100644 --- a/drivers/net/usb/hso.c +++ b/drivers/net/usb/hso.c @@ -2807,6 +2807,12 @@ static int hso_get_config_data(struct usb_interface *interface) return -EIO; } + /* check if we have a valid interface */ + if (if_num > 16) { + kfree(config_data); + return -EINVAL; + } + switch (config_data[if_num]) { case 0x0: result = 0; @@ -2877,10 +2883,18 @@ static int hso_probe(struct usb_interface *interface, /* Get the interface/port specification from either driver_info or from * the device itself */ - if (id->driver_info) + if (id->driver_info) { + /* if_num is controlled by the device, driver_info is a 0 terminated + * array. Make sure, the access is in bounds! */ + for (i = 0; i <= if_num; ++i) + if (((u32 *)(id->driver_info))[i] == 0) + goto exit; port_spec = ((u32 *)(id->driver_info))[if_num]; - else + } else { port_spec = hso_get_config_data(interface); + if (port_spec < 0) + goto exit; + } /* Check if we need to switch to alt interfaces prior to port * configuration */ -- 2.7.4