netdev - [PATCH net-next 02/47] can: isotp: check CAN address family in isotp

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Message-Id: <20230206131620.2758724-3-mkl@pengutronix.de>
Date:   Mon,  6 Feb 2023 14:15:35 +0100
From:   Marc Kleine-Budde <mkl@...gutronix.de>
To:     netdev@...r.kernel.org
Cc:     davem@...emloft.net, kuba@...nel.org, linux-can@...r.kernel.org,
        kernel@...gutronix.de, Oliver Hartkopp <socketcan@...tkopp.net>,
        syzbot+5aed6c3aaba661f5b917@...kaller.appspotmail.com,
        Marc Kleine-Budde <mkl@...gutronix.de>
Subject: [PATCH net-next 02/47] can: isotp: check CAN address family in isotp_bind()

From: Oliver Hartkopp <socketcan@...tkopp.net>

Add missing check to block non-AF_CAN binds.

Syzbot created some code which matched the right sockaddr struct size
but used AF_XDP (0x2C) instead of AF_CAN (0x1D) in the address family
field:

bind$xdp(r2, &(0x7f0000000540)={0x2c, 0x0, r4, 0x0, r2}, 0x10)
                                ^^^^
This has no funtional impact but the userspace should be notified about
the wrong address family field content.

Link: https://syzkaller.appspot.com/text?tag=CrashLog&x=11ff9d8c480000
Reported-by: syzbot+5aed6c3aaba661f5b917@...kaller.appspotmail.com
Signed-off-by: Oliver Hartkopp <socketcan@...tkopp.net>
Link: https://lore.kernel.org/all/20230104201844.13168-1-socketcan@hartkopp.net
Signed-off-by: Marc Kleine-Budde <mkl@...gutronix.de>
---
 net/can/isotp.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/net/can/isotp.c b/net/can/isotp.c
index 608f8c24ae46..a18450ffae01 100644
--- a/net/can/isotp.c
+++ b/net/can/isotp.c
@@ -1225,6 +1225,9 @@ static int isotp_bind(struct socket *sock, struct sockaddr *uaddr, int len)
 	if (len < ISOTP_MIN_NAMELEN)
 		return -EINVAL;
 
+	if (addr->can_family != AF_CAN)
+		return -EINVAL;
+
 	/* sanitize tx CAN identifier */
 	if (tx_id & CAN_EFF_FLAG)
 		tx_id &= (CAN_EFF_FLAG | CAN_EFF_MASK);
-- 
2.39.1