diff options
author | Bryan O'Donoghue <bryan.odonoghue@linaro.org> | 2020-01-09 16:17:21 +0300 |
---|---|---|
committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2020-02-15 00:29:55 +0300 |
commit | b2e19c795f58b0a516a5d7524407fb2a2c82cba1 (patch) | |
tree | b141a1c9b8f11d6d7c17be94dc8565e150ab6ce6 | |
parent | e1057e28b674e24ecfbce8821625d98d6298b1a3 (diff) | |
download | linux-b2e19c795f58b0a516a5d7524407fb2a2c82cba1.tar.xz |
usb: gadget: f_ncm: Use atomic_t to track in-flight request
commit 5b24c28cfe136597dc3913e1c00b119307a20c7e upstream.
Currently ncm->notify_req is used to flag when a request is in-flight.
ncm->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 NCM driver will
unconditionally free ncm->notify_req leading to a NULL pointer dereference.
Fixes: 40d133d7f542 ("usb: gadget: f_ncm: convert to new function interface with backward compatibility")
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>
-rw-r--r-- | drivers/usb/gadget/function/f_ncm.c | 17 |
1 files changed, 13 insertions, 4 deletions
diff --git a/drivers/usb/gadget/function/f_ncm.c b/drivers/usb/gadget/function/f_ncm.c index 7ad798ace1e5..16908737bff1 100644 --- a/drivers/usb/gadget/function/f_ncm.c +++ b/drivers/usb/gadget/function/f_ncm.c @@ -57,6 +57,7 @@ struct f_ncm { struct usb_ep *notify; struct usb_request *notify_req; u8 notify_state; + atomic_t notify_count; bool is_open; const struct ndp_parser_opts *parser_opts; @@ -480,7 +481,7 @@ static void ncm_do_notify(struct f_ncm *ncm) int status; /* notification already in flight? */ - if (!req) + if (atomic_read(&ncm->notify_count)) return; event = req->buf; @@ -520,7 +521,8 @@ static void ncm_do_notify(struct f_ncm *ncm) event->bmRequestType = 0xA1; event->wIndex = cpu_to_le16(ncm->ctrl_id); - ncm->notify_req = NULL; + atomic_inc(&ncm->notify_count); + /* * In double buffering if there is a space in FIFO, * completion callback can be called right after the call, @@ -530,7 +532,7 @@ static void ncm_do_notify(struct f_ncm *ncm) status = usb_ep_queue(ncm->notify, req, GFP_ATOMIC); spin_lock(&ncm->lock); if (status < 0) { - ncm->notify_req = req; + atomic_dec(&ncm->notify_count); DBG(cdev, "notify --> %d\n", status); } } @@ -565,17 +567,19 @@ static void ncm_notify_complete(struct usb_ep *ep, struct usb_request *req) case 0: VDBG(cdev, "Notification %02x sent\n", event->bNotificationType); + atomic_dec(&ncm->notify_count); break; case -ECONNRESET: case -ESHUTDOWN: + atomic_set(&ncm->notify_count, 0); ncm->notify_state = NCM_NOTIFY_NONE; break; default: DBG(cdev, "event %02x --> %d\n", event->bNotificationType, req->status); + atomic_dec(&ncm->notify_count); break; } - ncm->notify_req = req; ncm_do_notify(ncm); spin_unlock(&ncm->lock); } @@ -1559,6 +1563,11 @@ static void ncm_unbind(struct usb_configuration *c, struct usb_function *f) ncm_string_defs[0].id = 0; usb_free_all_descriptors(f); + if (atomic_read(&ncm->notify_count)) { + usb_ep_dequeue(ncm->notify, ncm->notify_req); + atomic_set(&ncm->notify_count, 0); + } + kfree(ncm->notify_req->buf); usb_ep_free_request(ncm->notify, ncm->notify_req); } |