* [PATCH v2 1/2] usb: gadget: f_fs: change ep->status safe in ffs_epfile_io()
2022-05-31 14:08 [PATCH v2 0/2] usb: f_fs: safe operation in ffs_epfile_io() Linyu Yuan
@ 2022-05-31 14:08 ` Linyu Yuan
2022-05-31 18:06 ` John Keeping
2022-05-31 14:08 ` [PATCH v2 2/2] usb: gadget: f_fs: change ep->ep " Linyu Yuan
1 sibling, 1 reply; 4+ messages in thread
From: Linyu Yuan @ 2022-05-31 14:08 UTC (permalink / raw)
To: Felipe Balbi, Greg Kroah-Hartman
Cc: linux-usb, Michael Wu, John Keeping, Linyu Yuan
If a task read/write data in blocking mode, it will wait the completion
in ffs_epfile_io(), if function unbind occurs, ffs_func_unbind() will
kfree ffs ep, once the task wake up, it still dereference the ffs ep to
obtain the request status.
Fix it by moving the request status to io_data which is stack-safe.
Signed-off-by: Linyu Yuan <quic_linyyuan@quicinc.com>
---
v2: correct interrupted assignment
drivers/usb/gadget/function/f_fs.c | 32 +++++++++++++++++---------------
1 file changed, 17 insertions(+), 15 deletions(-)
diff --git a/drivers/usb/gadget/function/f_fs.c b/drivers/usb/gadget/function/f_fs.c
index 4585ee3..d4d8940 100644
--- a/drivers/usb/gadget/function/f_fs.c
+++ b/drivers/usb/gadget/function/f_fs.c
@@ -122,8 +122,6 @@ struct ffs_ep {
struct usb_endpoint_descriptor *descs[3];
u8 num;
-
- int status; /* P: epfile->mutex */
};
struct ffs_epfile {
@@ -227,6 +225,9 @@ struct ffs_io_data {
bool use_sg;
struct ffs_data *ffs;
+
+ int status;
+ struct completion done;
};
struct ffs_desc_helper {
@@ -707,12 +708,12 @@ static const struct file_operations ffs_ep0_operations = {
static void ffs_epfile_io_complete(struct usb_ep *_ep, struct usb_request *req)
{
+ struct ffs_io_data *io_data = req->context;
+
ENTER();
- if (req->context) {
- struct ffs_ep *ep = _ep->driver_data;
- ep->status = req->status ? req->status : req->actual;
- complete(req->context);
- }
+
+ io_data->status = req->status ? req->status : req->actual;
+ complete(&io_data->done);
}
static ssize_t ffs_copy_to_iter(void *data, int data_len, struct iov_iter *iter)
@@ -1050,7 +1051,6 @@ static ssize_t ffs_epfile_io(struct file *file, struct ffs_io_data *io_data)
WARN(1, "%s: data_len == -EINVAL\n", __func__);
ret = -EINVAL;
} else if (!io_data->aio) {
- DECLARE_COMPLETION_ONSTACK(done);
bool interrupted = false;
req = ep->req;
@@ -1066,7 +1066,8 @@ static ssize_t ffs_epfile_io(struct file *file, struct ffs_io_data *io_data)
io_data->buf = data;
- req->context = &done;
+ init_completion(&io_data->done);
+ req->context = io_data;
req->complete = ffs_epfile_io_complete;
ret = usb_ep_queue(ep->ep, req, GFP_ATOMIC);
@@ -1075,7 +1076,7 @@ static ssize_t ffs_epfile_io(struct file *file, struct ffs_io_data *io_data)
spin_unlock_irq(&epfile->ffs->eps_lock);
- if (wait_for_completion_interruptible(&done)) {
+ if (wait_for_completion_interruptible(&io_data->done)) {
/*
* To avoid race condition with ffs_epfile_io_complete,
* dequeue the request first then check
@@ -1083,17 +1084,18 @@ static ssize_t ffs_epfile_io(struct file *file, struct ffs_io_data *io_data)
* condition with req->complete callback.
*/
usb_ep_dequeue(ep->ep, req);
- wait_for_completion(&done);
- interrupted = ep->status < 0;
+ wait_for_completion(&io_data->done);
+ interrupted = io_data->status < 0;
}
if (interrupted)
ret = -EINTR;
- else if (io_data->read && ep->status > 0)
- ret = __ffs_epfile_read_data(epfile, data, ep->status,
+ else if (io_data->read && io_data->status > 0)
+ ret = __ffs_epfile_read_data(epfile, data, io_data->status,
&io_data->data);
else
- ret = ep->status;
+ ret = io_data->status;
+
goto error_mutex;
} else if (!(req = usb_ep_alloc_request(ep->ep, GFP_ATOMIC))) {
ret = -ENOMEM;
--
2.7.4
^ permalink raw reply related [flat|nested] 4+ messages in thread* [PATCH v2 2/2] usb: gadget: f_fs: change ep->ep safe in ffs_epfile_io()
2022-05-31 14:08 [PATCH v2 0/2] usb: f_fs: safe operation in ffs_epfile_io() Linyu Yuan
2022-05-31 14:08 ` [PATCH v2 1/2] usb: gadget: f_fs: change ep->status safe " Linyu Yuan
@ 2022-05-31 14:08 ` Linyu Yuan
1 sibling, 0 replies; 4+ messages in thread
From: Linyu Yuan @ 2022-05-31 14:08 UTC (permalink / raw)
To: Felipe Balbi, Greg Kroah-Hartman
Cc: linux-usb, Michael Wu, John Keeping, Linyu Yuan
In ffs_epfile_io(), when read/write data in blocking mode, it will wait
the completion in interruptible mode, if task receive a signal, it will
terminate the wait, at same time, if function unbind occurs,
ffs_func_unbind() will kfree all eps, ffs_epfile_io() still try to
dequeue request by dereferencing ep which may become invalid.
Fix it by add ep spinlock and will not dereference ep if it is not valid.
Reviewed-by: John Keeping <john@metanate.com>
Signed-off-by: Linyu Yuan <quic_linyyuan@quicinc.com>
---
v2: add Reviewed-by from John keeping
drivers/usb/gadget/function/f_fs.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/drivers/usb/gadget/function/f_fs.c b/drivers/usb/gadget/function/f_fs.c
index d4d8940..9bf9287 100644
--- a/drivers/usb/gadget/function/f_fs.c
+++ b/drivers/usb/gadget/function/f_fs.c
@@ -1077,6 +1077,11 @@ static ssize_t ffs_epfile_io(struct file *file, struct ffs_io_data *io_data)
spin_unlock_irq(&epfile->ffs->eps_lock);
if (wait_for_completion_interruptible(&io_data->done)) {
+ spin_lock_irq(&epfile->ffs->eps_lock);
+ if (epfile->ep != ep) {
+ ret = -ESHUTDOWN;
+ goto error_lock;
+ }
/*
* To avoid race condition with ffs_epfile_io_complete,
* dequeue the request first then check
@@ -1084,6 +1089,7 @@ static ssize_t ffs_epfile_io(struct file *file, struct ffs_io_data *io_data)
* condition with req->complete callback.
*/
usb_ep_dequeue(ep->ep, req);
+ spin_unlock_irq(&epfile->ffs->eps_lock);
wait_for_completion(&io_data->done);
interrupted = io_data->status < 0;
}
--
2.7.4
^ permalink raw reply related [flat|nested] 4+ messages in thread