diff options
author | Bryan O'Donoghue <bryan.odonoghue@linaro.org> | 2020-01-09 16:17:22 +0300 |
---|---|---|
committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2020-01-15 12:40:22 +0300 |
commit | d710562e01c48d59be3f60d58b7a85958b39aeda (patch) | |
tree | 9b4c503cf335912b6c577807eaa917540a3a915c /drivers/usb/gadget | |
parent | 5b24c28cfe136597dc3913e1c00b119307a20c7e (diff) | |
download | linux-d710562e01c48d59be3f60d58b7a85958b39aeda.tar.xz |
usb: gadget: f_ecm: Use atomic_t to track in-flight request
Currently ecm->notify_req is used to flag when a request is in-flight.
ecm->notify_req is set to NULL and when a request completes it is
subsequently reset.
This is fundamentally buggy in that the unbind logic of the ECM driver will
unconditionally free ecm->notify_req leading to a NULL pointer dereference.
Fixes: da741b8c56d6 ("usb ethernet gadget: split CDC Ethernet function")
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Bryan O'Donoghue <bryan.odonoghue@linaro.org>
Signed-off-by: Felipe Balbi <balbi@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/usb/gadget')
-rw-r--r-- | drivers/usb/gadget/function/f_ecm.c | 16 |
1 files changed, 12 insertions, 4 deletions
diff --git a/drivers/usb/gadget/function/f_ecm.c b/drivers/usb/gadget/function/f_ecm.c index 460d5d7c984f..7f5cf488b2b1 100644 --- a/drivers/usb/gadget/function/f_ecm.c +++ b/drivers/usb/gadget/function/f_ecm.c @@ -52,6 +52,7 @@ struct f_ecm { struct usb_ep *notify; struct usb_request *notify_req; u8 notify_state; + atomic_t notify_count; bool is_open; /* FIXME is_open needs some irq-ish locking @@ -380,7 +381,7 @@ static void ecm_do_notify(struct f_ecm *ecm) int status; /* notification already in flight? */ - if (!req) + if (atomic_read(&ecm->notify_count)) return; event = req->buf; @@ -420,10 +421,10 @@ static void ecm_do_notify(struct f_ecm *ecm) event->bmRequestType = 0xA1; event->wIndex = cpu_to_le16(ecm->ctrl_id); - ecm->notify_req = NULL; + atomic_inc(&ecm->notify_count); status = usb_ep_queue(ecm->notify, req, GFP_ATOMIC); if (status < 0) { - ecm->notify_req = req; + atomic_dec(&ecm->notify_count); DBG(cdev, "notify --> %d\n", status); } } @@ -448,17 +449,19 @@ static void ecm_notify_complete(struct usb_ep *ep, struct usb_request *req) switch (req->status) { case 0: /* no fault */ + atomic_dec(&ecm->notify_count); break; case -ECONNRESET: case -ESHUTDOWN: + atomic_set(&ecm->notify_count, 0); ecm->notify_state = ECM_NOTIFY_NONE; break; default: DBG(cdev, "event %02x --> %d\n", event->bNotificationType, req->status); + atomic_dec(&ecm->notify_count); break; } - ecm->notify_req = req; ecm_do_notify(ecm); } @@ -907,6 +910,11 @@ static void ecm_unbind(struct usb_configuration *c, struct usb_function *f) usb_free_all_descriptors(f); + if (atomic_read(&ecm->notify_count)) { + usb_ep_dequeue(ecm->notify, ecm->notify_req); + atomic_set(&ecm->notify_count, 0); + } + kfree(ecm->notify_req->buf); usb_ep_free_request(ecm->notify, ecm->notify_req); } |