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usb: gadget: f_fs: change ep->status safe in ffs_epfile_io()

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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.

Cc: <stable@vger.kernel.org> # 5.15
Reported-by: Michael Wu <michael@allwinnertech.com>
Tested-by: Michael Wu <michael@allwinnertech.com>
Reviewed-by: John Keeping <john@metanate.com>
Signed-off-by: Linyu Yuan <quic_linyyuan@quicinc.com>
Link: https://lore.kernel.org/r/1654863478-26228-2-git-send-email-quic_linyyuan@quicinc.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Linyu Yuan 2022-06-10 20:17:57 +08:00 committed by Greg Kroah-Hartman
parent 802dcafc42
commit fb1f16d74e
1 changed files with 19 additions and 15 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

34
drivers/usb/gadget/function/f_fs.c
View File

@ -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 +708,15 @@ 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);
}
if (req->status)
io_data->status = req->status;
else
io_data->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 +1054,6 @@ 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 +1069,8 @@ 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 +1079,7 @@ 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 +1087,17 @@ 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;