diff options
| author | Bryan O'Donoghue <bryan.odonoghue@linaro.org> | 2020-01-09 13:17:22 +0000 |
|---|---|---|
| committer | Ben Hutchings <ben@decadent.org.uk> | 2020-05-22 21:19:27 +0100 |
| commit | 583b1fe340caf1eb35c3f65e9fd7c7b03b69c1af (patch) | |
| tree | 7c33de014da11b2daf9799692d790fd0cbdc4cc4 | |
| parent | 2c637d8646422d3566ceaae4427fd461e1b923d6 (diff) | |
| download | linux-stable-583b1fe340caf1eb35c3f65e9fd7c7b03b69c1af.tar.gz | |
usb: gadget: f_ecm: Use atomic_t to track in-flight request
commit d710562e01c48d59be3f60d58b7a85958b39aeda upstream.
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")
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>
[bwh: Backported to 3.16: adjust filename]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
| -rw-r--r-- | drivers/usb/gadget/f_ecm.c | 16 |
1 files changed, 12 insertions, 4 deletions
diff --git a/drivers/usb/gadget/f_ecm.c b/drivers/usb/gadget/f_ecm.c index 798760fa7e702..637f631a66a46 100644 --- a/drivers/usb/gadget/f_ecm.c +++ b/drivers/usb/gadget/f_ecm.c @@ -56,6 +56,7 @@ 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 @@ -384,7 +385,7 @@ 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; @@ -424,10 +425,10 @@ 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); } } @@ -452,17 +453,19 @@ 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); } @@ -922,6 +925,11 @@ 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); } |