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authorAlan Stern <stern@rowland.harvard.edu>2018-09-10 14:00:53 -0400
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2018-10-10 08:52:07 +0200
commit06fc0ef3ef7f52ea90eb7f3190b261cb0f5b11f9 (patch)
treee853f801079f503571cbfc957f47f047afc73e5e
parentae96945ac60cca9f0045cb7116c7ea231eb48037 (diff)
USB: handle NULL config in usb_find_alt_setting()
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>
-rw-r--r--drivers/usb/core/usb.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/drivers/usb/core/usb.c b/drivers/usb/core/usb.c
index f8bbd0b6d9fe..ad308c8e9af5 100644
--- a/drivers/usb/core/usb.c
+++ b/drivers/usb/core/usb.c
@@ -95,6 +95,8 @@ struct usb_host_interface *usb_find_alt_setting(
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) {