From: Norbert Slusarek nslusarek@gmx.net
commit 2b17c400aeb44daf041627722581ade527bb3c1d upstream.
A race condition was found in isotp_setsockopt() which allows to change socket options after the socket was bound. For the specific case of SF_BROADCAST support, this might lead to possible use-after-free because can_rx_unregister() is not called.
Checking for the flag under the socket lock in isotp_bind() and taking the lock in isotp_setsockopt() fixes the issue.
Fixes: 921ca574cd38 ("can: isotp: add SF_BROADCAST support for functional addressing") Link: https://lore.kernel.org/r/trinity-e6ae9efa-9afb-4326-84c0-f3609b9b8168-16207... Reported-by: Norbert Slusarek nslusarek@gmx.net Signed-off-by: Thadeu Lima de Souza Cascardo cascardo@canonical.com Signed-off-by: Norbert Slusarek nslusarek@gmx.net Acked-by: Oliver Hartkopp socketcan@hartkopp.net Signed-off-by: Marc Kleine-Budde mkl@pengutronix.de Signed-off-by: Oliver Hartkopp socketcan@hartkopp.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/can/isotp.c | 21 +++++++++++++++++---- 1 file changed, 17 insertions(+), 4 deletions(-)
--- a/net/can/isotp.c +++ b/net/can/isotp.c @@ -1193,16 +1193,13 @@ static int isotp_getname(struct socket * return ISOTP_MIN_NAMELEN; }
-static int isotp_setsockopt(struct socket *sock, int level, int optname, +static int isotp_setsockopt_locked(struct socket *sock, int level, int optname, sockptr_t optval, unsigned int optlen) { struct sock *sk = sock->sk; struct isotp_sock *so = isotp_sk(sk); int ret = 0;
- if (level != SOL_CAN_ISOTP) - return -EINVAL; - if (so->bound) return -EISCONN;
@@ -1277,6 +1274,22 @@ static int isotp_setsockopt(struct socke return ret; }
+static int isotp_setsockopt(struct socket *sock, int level, int optname, + sockptr_t optval, unsigned int optlen) + +{ + struct sock *sk = sock->sk; + int ret; + + if (level != SOL_CAN_ISOTP) + return -EINVAL; + + lock_sock(sk); + ret = isotp_setsockopt_locked(sock, level, optname, optval, optlen); + release_sock(sk); + return ret; +} + static int isotp_getsockopt(struct socket *sock, int level, int optname, char __user *optval, int __user *optlen) {