[U-Boot] [Patch V2 2/3] gadget: f_thor: check pointers before use in download_tail()

[Przemyslaw Marczak]

Some pointers in function download_tail() were not checked
before the use. This could possibly cause the data abort.
To avoid this, check if the pointers are not null is added.

Signed-off-by: Przemyslaw Marczak <p.marczak at samsung.com>
---
Change v2:
- download_tail(): change printf() to error()
---
 drivers/usb/gadget/f_thor.c | 16 ++++++++++++++--
 1 file changed, 14 insertions(+), 2 deletions(-)

diff --git a/drivers/usb/gadget/f_thor.c b/drivers/usb/gadget/f_thor.c
index 78519fa..2d0410d 100644
--- a/drivers/usb/gadget/f_thor.c
+++ b/drivers/usb/gadget/f_thor.c
@@ -205,12 +205,24 @@ static long long int download_head(unsigned long long total,
 
 static int download_tail(long long int left, int cnt)
 {
-	struct dfu_entity *dfu_entity = dfu_get_entity(alt_setting_num);
-	void *transfer_buffer = dfu_get_buf(dfu_entity);
+	struct dfu_entity *dfu_entity;
+	void *transfer_buffer;
 	int ret;
 
 	debug("%s: left: %llu cnt: %d\n", __func__, left, cnt);
 
+	dfu_entity = dfu_get_entity(alt_setting_num);
+	if (!dfu_entity) {
+		error("Alt setting: %d entity not found!\n", alt_setting_num);
+		return -ENOENT;
+	}
+
+	transfer_buffer = dfu_get_buf(dfu_entity);
+	if (!transfer_buffer) {
+		error("Transfer buffer not allocated!");
+		return -ENXIO;
+	}
+
 	if (left) {
 		ret = dfu_write(dfu_entity, transfer_buffer, left, cnt++);
 		if (ret) {
-- 
1.9.1