From: Oliver Hartkopp socketcan@hartkopp.net

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.

Cc: stable@vger.kernel.org # v5.10 - v5.17 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 --- net/can/isotp.c | 38 ++++++++++++++++++++------------------ 1 file changed, 20 insertions(+), 18 deletions(-)

diff --git a/net/can/isotp.c b/net/can/isotp.c index d2a430b6a13b..f8e3aeb79e3f 100644 --- a/net/can/isotp.c +++ b/net/can/isotp.c @@ -1102,19 +1102,30 @@ static int isotp_bind(struct socket *sock, struct sockaddr *uaddr, int len) struct sock *sk = sock->sk; struct isotp_sock *so = isotp_sk(sk); 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;

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;

lock_sock(sk); @@ -1122,25 +1133,17 @@ static int isotp_bind(struct socket *sock, struct sockaddr *uaddr, int len) /* do not register frame reception for functional addressing */ if (so->opt.flags & CAN_ISOTP_SF_BROADCAST) 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); if (!dev) { err = -ENODEV; @@ -1160,12 +1163,11 @@ static int isotp_bind(struct socket *sock, struct sockaddr *uaddr, int len) notify_enetdown = 1;

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);

if (so->bound && do_rx_reg) { @@ -1181,12 +1183,12 @@ 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: release_sock(sk);