[PATCH AUTOSEL for 4.9 050/219] zd1211rw: fix NULL-deref at probe

From: Sasha Levin
Date: Sat Mar 03 2018 - 18:59:37 EST


From: Johan Hovold <johan@xxxxxxxxxx>

[ Upstream commit ca260ece6a57dc7d751e0685f51fa2c55d851873 ]

Make sure to check the number of endpoints to avoid dereferencing a
NULL-pointer or accessing memory beyond the endpoint array should a
malicious device lack the expected endpoints.

Fixes: a1030e92c150 ("[PATCH] zd1211rw: Convert installer CDROM device into WLAN device")
Cc: Daniel Drake <dsd@xxxxxxxxxx>
Signed-off-by: Johan Hovold <johan@xxxxxxxxxx>
Signed-off-by: Kalle Valo <kvalo@xxxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxxxx>
---
drivers/net/wireless/zydas/zd1211rw/zd_usb.c | 3 +++
1 file changed, 3 insertions(+)

diff --git a/drivers/net/wireless/zydas/zd1211rw/zd_usb.c b/drivers/net/wireless/zydas/zd1211rw/zd_usb.c
index c5effd6c6be9..01ca1d57b3d9 100644
--- a/drivers/net/wireless/zydas/zd1211rw/zd_usb.c
+++ b/drivers/net/wireless/zydas/zd1211rw/zd_usb.c
@@ -1278,6 +1278,9 @@ static int eject_installer(struct usb_interface *intf)
u8 bulk_out_ep;
int r;

+ if (iface_desc->desc.bNumEndpoints < 2)
+ return -ENODEV;
+
/* Find bulk out endpoint */
for (r = 1; r >= 0; r--) {
endpoint = &iface_desc->endpoint[r].desc;
--
2.14.1