From 4958cf32f66df854b932b601eef2da3f95973339 Mon Sep 17 00:00:00 2001 From: Alexey Khoroshilov Date: Sun, 10 Aug 2014 23:35:11 +0700 Subject: [PATCH] usb: dbgp gadget: fix use after free in dbgp_unbind() After dbgp_bind()-dbgp_unbind() cycle happens, static variable dbgp contains pointers to already deallocated memory (dbgp.serial and dbgp.req). If the next dbgp_bind() fails, for example in usb_ep_alloc_request(), dbgp_bind() calls dbgp_unbind() on failure path, and dbgp_unbind() frees dbgp.serial that still stores a pointer to already deallocated memory. The patch sets pointers to NULL in dbgp_unbind(). Found by Linux Driver Verification project (linuxtesting.org). Signed-off-by: Alexey Khoroshilov Signed-off-by: Felipe Balbi --- drivers/usb/gadget/legacy/dbgp.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/usb/gadget/legacy/dbgp.c b/drivers/usb/gadget/legacy/dbgp.c index 986fc511a2ed..225e385a6160 100644 --- a/drivers/usb/gadget/legacy/dbgp.c +++ b/drivers/usb/gadget/legacy/dbgp.c @@ -222,10 +222,12 @@ static void dbgp_unbind(struct usb_gadget *gadget) { #ifdef CONFIG_USB_G_DBGP_SERIAL kfree(dbgp.serial); + dbgp.serial = NULL; #endif if (dbgp.req) { kfree(dbgp.req->buf); usb_ep_free_request(gadget->ep0, dbgp.req); + dbgp.req = NULL; } gadget->ep0->driver_data = NULL; -- 2.11.0