Commit c9a4cb20 authored by Alan Stern's avatar Alan Stern Committed by Greg Kroah-Hartman

USB: handle NULL config in usb_find_alt_setting()

usb_find_alt_setting() takes a pointer to a struct usb_host_config as
an argument; it searches for an interface with specified interface and
alternate setting numbers in that config.  However, it crashes if the
usb_host_config pointer argument is NULL.

Since this is a general-purpose routine, available for use in many
places, we want to to be more robust.  This patch makes it return NULL
whenever the config argument is NULL.
Signed-off-by: default avatarAlan Stern <stern@rowland.harvard.edu>
Reported-by: syzbot+19c3aaef85a89d451eac@syzkaller.appspotmail.com
CC: <stable@vger.kernel.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent bd729f9d
...@@ -228,6 +228,8 @@ struct usb_host_interface *usb_find_alt_setting( ...@@ -228,6 +228,8 @@ struct usb_host_interface *usb_find_alt_setting(
struct usb_interface_cache *intf_cache = NULL; struct usb_interface_cache *intf_cache = NULL;
int i; int i;
if (!config)
return NULL;
for (i = 0; i < config->desc.bNumInterfaces; i++) { for (i = 0; i < config->desc.bNumInterfaces; i++) {
if (config->intf_cache[i]->altsetting[0].desc.bInterfaceNumber if (config->intf_cache[i]->altsetting[0].desc.bInterfaceNumber
== iface_num) { == iface_num) {
......
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