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authorBryan O'Donoghue <bryan.odonoghue@linaro.org>2020-01-09 16:17:22 +0300
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2020-02-15 00:32:08 +0300
commit7d0c0dfe866736e221ce1773a6b45b06af945e9b (patch)
tree27647d4aaa0b1876b22b94b6739d3ff389454882 /drivers
parent51f94eb089ee1aed6a846925265bc645dc30a99f (diff)
downloadlinux-7d0c0dfe866736e221ce1773a6b45b06af945e9b.tar.xz
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") 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')
-rw-r--r--drivers/usb/gadget/function/f_ecm.c16
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 dc99ed94f03d..8e3e44382785 100644
--- a/drivers/usb/gadget/function/f_ecm.c
+++ b/drivers/usb/gadget/function/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);
}
@@ -909,6 +912,11 @@ 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);
}