lkml.org 
[lkml]   [2021]   [Feb]   [8]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH 5.10 009/120] usb: dwc2: Fix endpoint direction check in ep_from_windex
    Date
    From: Heiko Stuebner <heiko.stuebner@theobroma-systems.com>

    commit f670e9f9c8cac716c3506c6bac9e997b27ad441a upstream.

    dwc2_hsotg_process_req_status uses ep_from_windex() to retrieve
    the endpoint for the index provided in the wIndex request param.

    In a test-case with a rndis gadget running and sending a malformed
    packet to it like:
    dev.ctrl_transfer(
    0x82, # bmRequestType
    0x00, # bRequest
    0x0000, # wValue
    0x0001, # wIndex
    0x00 # wLength
    )
    it is possible to cause a crash:

    [ 217.533022] dwc2 ff300000.usb: dwc2_hsotg_process_req_status: USB_REQ_GET_STATUS
    [ 217.559003] Unable to handle kernel read from unreadable memory at virtual address 0000000000000088
    ...
    [ 218.313189] Call trace:
    [ 218.330217] ep_from_windex+0x3c/0x54
    [ 218.348565] usb_gadget_giveback_request+0x10/0x20
    [ 218.368056] dwc2_hsotg_complete_request+0x144/0x184

    This happens because ep_from_windex wants to compare the endpoint
    direction even if index_to_ep() didn't return an endpoint due to
    the direction not matching.

    The fix is easy insofar that the actual direction check is already
    happening when calling index_to_ep() which will return NULL if there
    is no endpoint for the targeted direction, so the offending check
    can go away completely.

    Fixes: c6f5c050e2a7 ("usb: dwc2: gadget: add bi-directional endpoint support")
    Cc: stable@vger.kernel.org
    Reported-by: Gerhard Klostermeier <gerhard.klostermeier@syss.de>
    Signed-off-by: Heiko Stuebner <heiko.stuebner@theobroma-systems.com>
    Link: https://lore.kernel.org/r/20210127103919.58215-1-heiko@sntech.de
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
    ---
    drivers/usb/dwc2/gadget.c | 8 +-------
    1 file changed, 1 insertion(+), 7 deletions(-)

    --- a/drivers/usb/dwc2/gadget.c
    +++ b/drivers/usb/dwc2/gadget.c
    @@ -1543,7 +1543,6 @@ static void dwc2_hsotg_complete_oursetup
    static struct dwc2_hsotg_ep *ep_from_windex(struct dwc2_hsotg *hsotg,
    u32 windex)
    {
    - struct dwc2_hsotg_ep *ep;
    int dir = (windex & USB_DIR_IN) ? 1 : 0;
    int idx = windex & 0x7F;

    @@ -1553,12 +1552,7 @@ static struct dwc2_hsotg_ep *ep_from_win
    if (idx > hsotg->num_of_eps)
    return NULL;

    - ep = index_to_ep(hsotg, idx, dir);
    -
    - if (idx && ep->dir_in != dir)
    - return NULL;
    -
    - return ep;
    + return index_to_ep(hsotg, idx, dir);
    }

    /**

    \
     
     \ /
      Last update: 2021-02-08 17:59    [W:9.932 / U:0.008 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site