The error-handling pathways in usb_add_gadget_udc_release() are messed
up. Aside from the uninformative statement labels, they can deallocate
the udc structure after calling put_device(), which is a double-free.
This was observed by KASAN in automatic testing.
This patch cleans up the routine. It preserves the requirement that
when any failure occurs, we call put_device(&gadget->dev).
Signed-off-by: Alan Stern <st...@rowland.harvard.edu>
Reported-by: Fengguang Wu <fengguang...@intel.com>
CC: <sta...@vger.kernel.org>
---
Not having received any feedback on this patch for a while, I have
decided to submit it. The problem it fixes is quite obviously a real
one, when you look at the existing code.
Alan Stern
[as1856]
drivers/usb/gadget/udc/core.c | 28 +++++++++++++---------------
1 file changed, 13 insertions(+), 15 deletions(-)
Index: usb-4.x/drivers/usb/gadget/udc/core.c
===================================================================
--- usb-4.x.orig/drivers/usb/gadget/udc/core.c
+++ usb-4.x/drivers/usb/gadget/udc/core.c
@@ -1147,11 +1147,7 @@ int usb_add_gadget_udc_release(struct de
udc = kzalloc(sizeof(*udc), GFP_KERNEL);
if (!udc)
- goto err1;
-
- ret = device_add(&gadget->dev);
- if (ret)
- goto err2;
+ goto err_put_gadget;
device_initialize(&udc->dev);
udc->dev.release = usb_udc_release;
@@ -1160,7 +1156,11 @@ int usb_add_gadget_udc_release(struct de
udc->dev.parent = parent;
ret = dev_set_name(&udc->dev, "%s", kobject_name(&parent->kobj));
if (ret)
- goto err3;
+ goto err_put_udc;
+
+ ret = device_add(&gadget->dev);
+ if (ret)
+ goto err_put_udc;
udc->gadget = gadget;
gadget->udc = udc;
@@ -1170,7 +1170,7 @@ int usb_add_gadget_udc_release(struct de
ret = device_add(&udc->dev);
if (ret)
- goto err4;
+ goto err_unlist_udc;
usb_gadget_set_state(gadget, USB_STATE_NOTATTACHED);
udc->vbus = true;
@@ -1178,27 +1178,25 @@ int usb_add_gadget_udc_release(struct de
/* pick up one of pending gadget drivers */
ret = check_pending_gadget_drivers(udc);
if (ret)
- goto err5;
+ goto err_del_udc;
mutex_unlock(&udc_lock);
return 0;
-err5:
+ err_del_udc:
device_del(&udc->dev);
-err4:
+ err_unlist_udc:
list_del(&udc->list);
mutex_unlock(&udc_lock);
-err3:
- put_device(&udc->dev);
device_del(&gadget->dev);
-err2:
- kfree(udc);
+ err_put_udc:
+ put_device(&udc->dev);
-err1:
+ err_put_gadget:
put_device(&gadget->dev);
return ret;
}
--
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