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can: isotp: sanitize CAN ID checks in isotp_bind()

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commit 3ea566422cbde9610c2734980d1286ab681bb40e upstream.

Syzbot created an environment that lead to a state machine status that
can not be reached with a compliant CAN ID address configuration.
The provided address information consisted of CAN ID 0x6000001 and 0xC28001
which both boil down to 11 bit CAN IDs 0x001 in sending and receiving.

Sanitize the SFF/EFF CAN ID values before performing the address checks.

Fixes: e057dd3fc20f ("can: add ISO 15765-2:2016 transport protocol")
Link: https://lore.kernel.org/all/20220316164258.54155-1-socketcan@hartkopp.net
Reported-by: syzbot+2339c27f5c66c652843e@syzkaller.appspotmail.com
Signed-off-by: Oliver Hartkopp <socketcan@hartkopp.net>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Oliver Hartkopp 2022-03-16 17:42:56 +01:00 committed by Greg Kroah-Hartman
parent fde8c5cad0
commit d72866a7f5
1 changed files with 20 additions and 18 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

38
net/can/isotp.c
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@ -1102,6 +1102,7 @@ static int isotp_bind(struct socket *sock, struct sockaddr *uaddr, int len)
struct net *net = sock_net(sk);
int ifindex;
struct net_device *dev;
canid_t tx_id, rx_id;
int err = 0;
int notify_enetdown = 0;
int do_rx_reg = 1;
@ -1109,8 +1110,18 @@ static int isotp_bind(struct socket *sock, struct sockaddr *uaddr, int len)
if (len < ISOTP_MIN_NAMELEN)
return -EINVAL;
if (addr->can_addr.tp.tx_id & (CAN_ERR_FLAG | CAN_RTR_FLAG))
return -EADDRNOTAVAIL;
/* sanitize tx/rx CAN identifiers */
tx_id = addr->can_addr.tp.tx_id;
if (tx_id & CAN_EFF_FLAG)
tx_id &= (CAN_EFF_FLAG | CAN_EFF_MASK);
else
tx_id &= CAN_SFF_MASK;
rx_id = addr->can_addr.tp.rx_id;
if (rx_id & CAN_EFF_FLAG)
rx_id &= (CAN_EFF_FLAG | CAN_EFF_MASK);
else
rx_id &= CAN_SFF_MASK;
if (!addr->can_ifindex)
return -ENODEV;
@ -1122,21 +1133,13 @@ static int isotp_bind(struct socket *sock, struct sockaddr *uaddr, int len)
do_rx_reg = 0;
/* do not validate rx address for functional addressing */
if (do_rx_reg) {
if (addr->can_addr.tp.rx_id == addr->can_addr.tp.tx_id) {
err = -EADDRNOTAVAIL;
goto out;
}
if (addr->can_addr.tp.rx_id & (CAN_ERR_FLAG | CAN_RTR_FLAG)) {
err = -EADDRNOTAVAIL;
goto out;
}
if (do_rx_reg && rx_id == tx_id) {
err = -EADDRNOTAVAIL;
goto out;
}
if (so->bound && addr->can_ifindex == so->ifindex &&
addr->can_addr.tp.rx_id == so->rxid &&
addr->can_addr.tp.tx_id == so->txid)
rx_id == so->rxid && tx_id == so->txid)
goto out;
dev = dev_get_by_index(net, addr->can_ifindex);
@ -1160,8 +1163,7 @@ static int isotp_bind(struct socket *sock, struct sockaddr *uaddr, int len)
ifindex = dev->ifindex;
if (do_rx_reg)
can_rx_register(net, dev, addr->can_addr.tp.rx_id,
SINGLE_MASK(addr->can_addr.tp.rx_id),
can_rx_register(net, dev, rx_id, SINGLE_MASK(rx_id),
isotp_rcv, sk, "isotp", sk);
dev_put(dev);
@ -1181,8 +1183,8 @@ static int isotp_bind(struct socket *sock, struct sockaddr *uaddr, int len)
/* switch to new settings */
so->ifindex = ifindex;
so->rxid = addr->can_addr.tp.rx_id;
so->txid = addr->can_addr.tp.tx_id;
so->rxid = rx_id;
so->txid = tx_id;
so->bound = 1;
out: