From 62bd8064fa8820d4fc5dc3c504e25522f9f18f90 Mon Sep 17 00:00:00 2001 From: Dan Carpenter Date: Tue, 5 Jun 2018 14:31:39 +0300 Subject: [PATCH] rndis_wlan: potential buffer overflow in rndis_wlan_auth_indication() [ Upstream commit ae636fb1554833ee5133ca47bf4b2791b6739c52 ] This is a static checker fix, not something I have tested. The issue is that on the second iteration through the loop, we jump forward by le32_to_cpu(auth_req->length) bytes. The problem is that if the length is more than "buflen" then we end up with a negative "buflen". A negative buflen is type promoted to a high positive value and the loop continues but it's accessing beyond the end of the buffer. I believe the "auth_req->length" comes from the firmware and if the firmware is malicious or buggy, you're already toasted so the impact of this bug is probably not very severe. Fixes: 030645aceb3d ("rndis_wlan: handle 802.11 indications from device") Signed-off-by: Dan Carpenter Signed-off-by: Kalle Valo Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- drivers/net/wireless/rndis_wlan.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/net/wireless/rndis_wlan.c b/drivers/net/wireless/rndis_wlan.c index 9935bd0..d4947e3 100644 --- a/drivers/net/wireless/rndis_wlan.c +++ b/drivers/net/wireless/rndis_wlan.c @@ -2928,6 +2928,8 @@ static void rndis_wlan_auth_indication(struct usbnet *usbdev, while (buflen >= sizeof(*auth_req)) { auth_req = (void *)buf; + if (buflen < le32_to_cpu(auth_req->length)) + return; type = "unknown"; flags = le32_to_cpu(auth_req->flags); pairwise_error = false; -- 2.7.4