[PATCH AUTOSEL 4.9 15/30] ISDN: hfcsusb: checking idx of ep configuration

Sasha Levin
2019-07-26T13:49:06Z

From: Phong Tran <tranmanphong@gmail.com>

[ Upstream commit f384e62a82ba5d85408405fdd6aeff89354deaa9 ]

The syzbot test with random endpoint address which made the idx is
overflow in the table of endpoint configuations.

this adds the checking for fixing the error report from
syzbot

KASAN: stack-out-of-bounds Read in hfcsusb_probe [1]
The patch tested by syzbot [2]

Reported-by: syzbot+8750abbc3a46ef47d509@syzkaller.appspotmail.com

[1]:
https://syzkaller.appspot.com/bug?id=30a04378dac680c5d521304a00a86156bb913522
[2]:
https://groups.google.com/d/msg/syzkaller-bugs/_6HBdge8F3E/OJn7wVNpBAAJ

Signed-off-by: Phong Tran <tranmanphong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/isdn/hardware/mISDN/hfcsusb.c | 3 +++
1 file changed, 3 insertions(+)

diff --git a/drivers/isdn/hardware/mISDN/hfcsusb.c b/drivers/isdn/hardware/mISDN/hfcsusb.c
index 114f3bcba1b0..c60c7998af17 100644
--- a/drivers/isdn/hardware/mISDN/hfcsusb.c
+++ b/drivers/isdn/hardware/mISDN/hfcsusb.c
@@ -1963,6 +1963,9 @@ hfcsusb_probe(struct usb_interface *intf, const struct usb_device_id *id)

/* get endpoint base */
idx = ((ep_addr & 0x7f) - 1) * 2;
+ if (idx > 15)
+ return -EIO;
+
if (ep_addr & 0x80)
idx++;
attr = ep->desc.bmAttributes;
--
2.20.1