[PATCH AUTOSEL 4.19 26/47] ISDN: hfcsusb: checking idx of ep configuration

Sasha Levin
2019-07-26T13:54:13Z

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 6d05946b445e..060dc7fd66c1 100644
--- a/drivers/isdn/hardware/mISDN/hfcsusb.c
+++ b/drivers/isdn/hardware/mISDN/hfcsusb.c
@@ -1967,6 +1967,9 @@ 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