[PATCH] ueagle-atm: enforce boundary check for sync_wait[]

["Alexey V. Vissarionov" <gremlin@altlinux.org>]

After several increments of modem_index (e.g. after plugging and
removing the device several times) modem_index may reach NB_MODEM
value causing the out-of-boundary sync_wait[] array access.

Found by ALT Linux Team (altlinux.org) and Linux Verification Center
(linuxtesting.org).

Fixes: b72458a80c75 ("[PATCH] USB: Eagle and ADI 930 usb adsl modem driver")
Signed-off-by: Alexey V. Vissarionov <gremlin@altlinux.org>
---
 drivers/usb/atm/ueagle-atm.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/usb/atm/ueagle-atm.c b/drivers/usb/atm/ueagle-atm.c
index cd0f7b4bd82ab132..436412b62c910e2f 100644
--- a/drivers/usb/atm/ueagle-atm.c
+++ b/drivers/usb/atm/ueagle-atm.c
@@ -2500,7 +2500,9 @@ static int uea_bind(struct usbatm_data *usbatm, struct usb_interface *intf,
 	if (ifnum != UEA_INTR_IFACE_NO)
 		return -ENODEV;
 
-	usbatm->flags = (sync_wait[modem_index] ? 0 : UDSL_SKIP_HEAVY_INIT);
+	usbatm->flags =
+		modem_index < NB_MODEM && sync_wait[modem_index] ?
+		0 : UDSL_SKIP_HEAVY_INIT;
 
 	/* interface 1 is for outbound traffic */
 	ret = claim_interface(usb, usbatm, UEA_US_IFACE_NO);

-- 
Alexey V. Vissarionov
gremlin ПРИ altlinux ТЧК org; +vii-cmiii-ccxxix-lxxix-xlii
GPG: 0D92F19E1C0DC36E27F61A29CD17E2B43D879005 @ hkp://keys.gnupg.net