[PATCH 7/7] HID: roccat: savu: reject short special reports

[Jiale Yao]

The raw event callback runs before HID core validates and zero-pads the
report.  It passes the buffer to a helper which inspects data[0] and, for a
special report, reads the complete struct savu_mouse_report_special.  A
truncated report can therefore cause an out-of-bounds read.

Require enough data for the special report before calling the helper.
Commit 47669bec44fe ("HID: asus: refactor the two workqueues and init
sequence") added the same kind of raw-event length validation to hid-asus.

Fixes: 6a2a6390cf09 ("HID: roccat: add support for Roccat Savu")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Jiale Yao <yaojiale02@xxxxxxx>
---
 drivers/hid/hid-roccat-savu.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/hid/hid-roccat-savu.c b/drivers/hid/hid-roccat-savu.c
index 679136933560..cfd86267e35b 100644
--- a/drivers/hid/hid-roccat-savu.c
+++ b/drivers/hid/hid-roccat-savu.c
@@ -182,6 +182,9 @@ static int savu_raw_event(struct hid_device *hdev,
 	if (savu == NULL)
 		return 0;
 
+	if (size < sizeof(struct savu_mouse_report_special))
+		return 0;
+
 	if (savu->roccat_claimed)
 		savu_report_to_chrdev(savu, data);
 
-- 
2.34.1