This is a note to let you know that I've just added the patch titled
usb: gadget: f_ncm: Use atomic_t to track in-flight request
to my usb git tree which can be found at
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git
in the usb-testing branch.
The patch will show up in the next release of the linux-next tree
(usually sometime within the next 24 hours during the week.)
The patch will be merged to the usb-next branch sometime soon,
after it passes testing, and the merge window is open.
If you have any questions about this process, please let me know.
>From 5b24c28cfe136597dc3913e1c00b119307a20c7e Mon Sep 17 00:00:00 2001
From: Bryan O'Donoghue <bryan.odonoghue@xxxxxxxxxx>
Date: Thu, 9 Jan 2020 13:17:21 +0000
Subject: usb: gadget: f_ncm: Use atomic_t to track in-flight request
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@xxxxxxxxxxxxxxx>
Signed-off-by: Bryan O'Donoghue <bryan.odonoghue@xxxxxxxxxx>
Signed-off-by: Felipe Balbi <balbi@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/usb/gadget/function/f_ncm.c | 17 +++++++++++++----
1 file changed, 13 insertions(+), 4 deletions(-)
diff --git a/drivers/usb/gadget/function/f_ncm.c b/drivers/usb/gadget/function/f_ncm.c
index 2d6e76e4cffa..1d900081b1f0 100644
--- a/drivers/usb/gadget/function/f_ncm.c
+++ b/drivers/usb/gadget/function/f_ncm.c
@@ -53,6 +53,7 @@ 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;
@@ -547,7 +548,7 @@ 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;
@@ -587,7 +588,8 @@ 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,
@@ -597,7 +599,7 @@ 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);
}
}
@@ -632,17 +634,19 @@ 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);
}
@@ -1649,6 +1653,11 @@ 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);
}
--
2.24.1
