* [PATCH 1/2] usb: gadget: f_ncm: Use atomic_t to track in-flight request
2020-01-09 13:17 [PATCH 0/2] Fix two NULL pointer dereferences when role-switching Bryan O'Donoghue
@ 2020-01-09 13:17 ` Bryan O'Donoghue
2020-01-09 13:17 ` [PATCH 2/2] usb: gadget: f_ecm: " Bryan O'Donoghue
1 sibling, 0 replies; 3+ messages in thread
From: Bryan O'Donoghue @ 2020-01-09 13:17 UTC (permalink / raw)
To: balbi, gregkh, linux-usb, linux-kernel; +Cc: Bryan O'Donoghue
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: 40d133d7f5426 ("usb: gadget: f_ncm: convert to new function interface
with backward compatibility")
Signed-off-by: Bryan O'Donoghue <bryan.odonoghue@linaro.org>
---
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);
}
--
2.24.0
^ permalink raw reply related [flat|nested] 3+ messages in thread* [PATCH 2/2] usb: gadget: f_ecm: Use atomic_t to track in-flight request
2020-01-09 13:17 [PATCH 0/2] Fix two NULL pointer dereferences when role-switching Bryan O'Donoghue
2020-01-09 13:17 ` [PATCH 1/2] usb: gadget: f_ncm: Use atomic_t to track in-flight request Bryan O'Donoghue
@ 2020-01-09 13:17 ` Bryan O'Donoghue
1 sibling, 0 replies; 3+ messages in thread
From: Bryan O'Donoghue @ 2020-01-09 13:17 UTC (permalink / raw)
To: balbi, gregkh, linux-usb, linux-kernel; +Cc: Bryan O'Donoghue
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: da741b8c56d61 ("usb ethernet gadget: split CDC Ethernet function")
Signed-off-by: Bryan O'Donoghue <bryan.odonoghue@linaro.org>
---
drivers/usb/gadget/function/f_ecm.c | 16 ++++++++++++----
1 file 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);
}
--
2.24.0
^ permalink raw reply related [flat|nested] 3+ messages in thread