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path: root/drivers/usb/gadget/function/f_fs.c
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Diffstat (limited to 'drivers/usb/gadget/function/f_fs.c')
-rw-r--r--drivers/usb/gadget/function/f_fs.c42
1 files changed, 34 insertions, 8 deletions
diff --git a/drivers/usb/gadget/function/f_fs.c b/drivers/usb/gadget/function/f_fs.c
index 7c6771d027a2..63314ede7ba6 100644
--- a/drivers/usb/gadget/function/f_fs.c
+++ b/drivers/usb/gadget/function/f_fs.c
@@ -647,15 +647,26 @@ static void ffs_user_copy_worker(struct work_struct *work)
if (io_data->read && ret > 0) {
int i;
size_t pos = 0;
+
+ /*
+ * Since req->length may be bigger than io_data->len (after
+ * being rounded up to maxpacketsize), we may end up with more
+ * data then user space has space for.
+ */
+ ret = min_t(int, ret, io_data->len);
+
use_mm(io_data->mm);
for (i = 0; i < io_data->nr_segs; i++) {
+ size_t len = min_t(size_t, ret - pos,
+ io_data->iovec[i].iov_len);
+ if (!len)
+ break;
if (unlikely(copy_to_user(io_data->iovec[i].iov_base,
- &io_data->buf[pos],
- io_data->iovec[i].iov_len))) {
+ &io_data->buf[pos], len))) {
ret = -EFAULT;
break;
}
- pos += io_data->iovec[i].iov_len;
+ pos += len;
}
unuse_mm(io_data->mm);
}
@@ -687,7 +698,7 @@ static ssize_t ffs_epfile_io(struct file *file, struct ffs_io_data *io_data)
struct ffs_epfile *epfile = file->private_data;
struct ffs_ep *ep;
char *data = NULL;
- ssize_t ret, data_len;
+ ssize_t ret, data_len = -EINVAL;
int halt;
/* Are we still active? */
@@ -787,13 +798,30 @@ static ssize_t ffs_epfile_io(struct file *file, struct ffs_io_data *io_data)
/* Fire the request */
struct usb_request *req;
+ /*
+ * Sanity Check: even though data_len can't be used
+ * uninitialized at the time I write this comment, some
+ * compilers complain about this situation.
+ * In order to keep the code clean from warnings, data_len is
+ * being initialized to -EINVAL during its declaration, which
+ * means we can't rely on compiler anymore to warn no future
+ * changes won't result in data_len being used uninitialized.
+ * For such reason, we're adding this redundant sanity check
+ * here.
+ */
+ if (unlikely(data_len == -EINVAL)) {
+ WARN(1, "%s: data_len == -EINVAL\n", __func__);
+ ret = -EINVAL;
+ goto error_lock;
+ }
+
if (io_data->aio) {
req = usb_ep_alloc_request(ep->ep, GFP_KERNEL);
if (unlikely(!req))
goto error_lock;
req->buf = data;
- req->length = io_data->len;
+ req->length = data_len;
io_data->buf = data;
io_data->ep = ep->ep;
@@ -815,7 +843,7 @@ static ssize_t ffs_epfile_io(struct file *file, struct ffs_io_data *io_data)
req = ep->req;
req->buf = data;
- req->length = io_data->len;
+ req->length = data_len;
req->context = &done;
req->complete = ffs_epfile_io_complete;
@@ -2663,8 +2691,6 @@ static inline struct f_fs_opts *ffs_do_functionfs_bind(struct usb_function *f,
func->conf = c;
func->gadget = c->cdev->gadget;
- ffs_data_get(func->ffs);
-
/*
* in drivers/usb/gadget/configfs.c:configfs_composite_bind()
* configurations are bound in sequence with list_for_each_entry,
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