[PATCH v3 2/2] usb: udc: core: Error if req->buf is either from vmalloc or stack

From: Florian Fainelli
Date: Tue Apr 25 2017 - 21:05:22 EST


Check that req->buf is a valid DMA capable address, produce a warning
and return an error if it's either coming from vmalloc space or is an on
stack buffer.

Signed-off-by: Florian Fainelli <f.fainelli@xxxxxxxxx>
---
drivers/usb/gadget/udc/core.c | 9 +++++++++
1 file changed, 9 insertions(+)

diff --git a/drivers/usb/gadget/udc/core.c b/drivers/usb/gadget/udc/core.c
index efce68e9a8e0..a03aec574f64 100644
--- a/drivers/usb/gadget/udc/core.c
+++ b/drivers/usb/gadget/udc/core.c
@@ -23,6 +23,7 @@
#include <linux/list.h>
#include <linux/err.h>
#include <linux/dma-mapping.h>
+#include <linux/sched/task_stack.h>
#include <linux/workqueue.h>

#include <linux/usb/ch9.h>
@@ -798,6 +799,14 @@ int usb_gadget_map_request_by_dev(struct device *dev,

req->num_mapped_sgs = mapped;
} else {
+ if (is_vmalloc_addr(req->buf)) {
+ dev_err(dev, "buffer is not dma capable\n");
+ return -EFAULT;
+ } else if (object_is_on_stack(req->buf)) {
+ dev_err(dev, "buffer is on stack\n");
+ return -EFAULT;
+ }
+
req->dma = dma_map_single(dev, req->buf, req->length,
is_in ? DMA_TO_DEVICE : DMA_FROM_DEVICE);

--
2.9.3