4.4-stable review patch. If anyone has any objections, please let me know.
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From: Alan Stern stern@rowland.harvard.edu
commit c9a4cb204e9eb7fa7dfbe3f7d3a674fa530aa193 upstream.
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: Alan Stern stern@rowland.harvard.edu Reported-by: syzbot+19c3aaef85a89d451eac@syzkaller.appspotmail.com CC: stable@vger.kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/usb/core/usb.c | 2 ++ 1 file changed, 2 insertions(+)
--- a/drivers/usb/core/usb.c +++ b/drivers/usb/core/usb.c @@ -95,6 +95,8 @@ struct usb_host_interface *usb_find_alt_ struct usb_interface_cache *intf_cache = NULL; int i;
+ if (!config) + return NULL; for (i = 0; i < config->desc.bNumInterfaces; i++) { if (config->intf_cache[i]->altsetting[0].desc.bInterfaceNumber == iface_num) {