Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965023AbdCJJ4C (ORCPT ); Fri, 10 Mar 2017 04:56:02 -0500 Received: from mail.linuxfoundation.org ([140.211.169.12]:42670 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S936097AbdCJJeO (ORCPT ); Fri, 10 Mar 2017 04:34:14 -0500 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, David Lechner , Krzysztof Opasiak , Felipe Balbi Subject: [PATCH 4.10 118/167] usb: gadget: f_hid: fix: Prevent accessing released memory Date: Fri, 10 Mar 2017 10:09:21 +0100 Message-Id: <20170310084003.225341723@linuxfoundation.org> X-Mailer: git-send-email 2.12.0 In-Reply-To: <20170310083956.767605269@linuxfoundation.org> References: <20170310083956.767605269@linuxfoundation.org> User-Agent: quilt/0.65 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2784 Lines: 88 4.10-stable review patch. If anyone has any objections, please let me know. ------------------ From: Krzysztof Opasiak commit aa65d11aa008f4de58a9cee7e121666d9d68505e upstream. When we unlock our spinlock to copy data to user we may get disabled by USB host and free the whole list of completed out requests including the one from which we are copying the data to user memory. To prevent from this let's remove our working element from the list and place it back only if there is sth left when we finish with it. Fixes: 99c515005857 ("usb: gadget: hidg: register OUT INT endpoint for SET_REPORT") Tested-by: David Lechner Signed-off-by: Krzysztof Opasiak Signed-off-by: Felipe Balbi Signed-off-by: Greg Kroah-Hartman --- drivers/usb/gadget/function/f_hid.c | 24 ++++++++++++++++++++---- 1 file changed, 20 insertions(+), 4 deletions(-) --- a/drivers/usb/gadget/function/f_hid.c +++ b/drivers/usb/gadget/function/f_hid.c @@ -277,6 +277,13 @@ static ssize_t f_hidg_read(struct file * /* pick the first one */ list = list_first_entry(&hidg->completed_out_req, struct f_hidg_req_list, list); + + /* + * Remove this from list to protect it from beign free() + * while host disables our function + */ + list_del(&list->list); + req = list->req; count = min_t(unsigned int, count, req->actual - list->pos); spin_unlock_irqrestore(&hidg->spinlock, flags); @@ -292,15 +299,20 @@ static ssize_t f_hidg_read(struct file * * call, taking into account its current read position. */ if (list->pos == req->actual) { - spin_lock_irqsave(&hidg->spinlock, flags); - list_del(&list->list); kfree(list); - spin_unlock_irqrestore(&hidg->spinlock, flags); req->length = hidg->report_length; ret = usb_ep_queue(hidg->out_ep, req, GFP_KERNEL); - if (ret < 0) + if (ret < 0) { + free_ep_req(hidg->out_ep, req); return ret; + } + } else { + spin_lock_irqsave(&hidg->spinlock, flags); + list_add(&list->list, &hidg->completed_out_req); + spin_unlock_irqrestore(&hidg->spinlock, flags); + + wake_up(&hidg->read_queue); } return count; @@ -560,14 +572,18 @@ static void hidg_disable(struct usb_func { struct f_hidg *hidg = func_to_hidg(f); struct f_hidg_req_list *list, *next; + unsigned long flags; usb_ep_disable(hidg->in_ep); usb_ep_disable(hidg->out_ep); + spin_lock_irqsave(&hidg->spinlock, flags); list_for_each_entry_safe(list, next, &hidg->completed_out_req, list) { + free_ep_req(hidg->out_ep, list->req); list_del(&list->list); kfree(list); } + spin_unlock_irqrestore(&hidg->spinlock, flags); } static int hidg_set_alt(struct usb_function *f, unsigned intf, unsigned alt)