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authorNorbert Slusarek <nslusarek@gmx.net>2021-05-12 01:43:54 +0300
committerMarc Kleine-Budde <mkl@pengutronix.de>2021-05-12 09:52:47 +0300
commit2b17c400aeb44daf041627722581ade527bb3c1d (patch)
tree9698aa0e13520c2f97bc508c37a19a98906f751b /net/can
parent440c3247cba3d9433ac435d371dd7927d68772a7 (diff)
downloadlinux-2b17c400aeb44daf041627722581ade527bb3c1d.tar.xz
can: isotp: prevent race between isotp_bind() and isotp_setsockopt()
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-f3609b9b8168-1620773528307@3c-app-gmx-bs06 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>
Diffstat (limited to 'net/can')
-rw-r--r--net/can/isotp.c49
1 files changed, 33 insertions, 16 deletions
diff --git a/net/can/isotp.c b/net/can/isotp.c
index 9f94ad3caee9..253b24417c8e 100644
--- a/net/can/isotp.c
+++ b/net/can/isotp.c
@@ -1062,27 +1062,31 @@ 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;
+
+ if (!addr->can_ifindex)
+ return -ENODEV;
+
+ lock_sock(sk);
+
/* 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)
- return -EADDRNOTAVAIL;
+ 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))
- return -EADDRNOTAVAIL;
+ if (addr->can_addr.tp.rx_id & (CAN_ERR_FLAG | CAN_RTR_FLAG)) {
+ err = -EADDRNOTAVAIL;
+ goto out;
+ }
}
- if (addr->can_addr.tp.tx_id & (CAN_ERR_FLAG | CAN_RTR_FLAG))
- return -EADDRNOTAVAIL;
-
- if (!addr->can_ifindex)
- return -ENODEV;
-
- lock_sock(sk);
-
if (so->bound && addr->can_ifindex == so->ifindex &&
addr->can_addr.tp.rx_id == so->rxid &&
addr->can_addr.tp.tx_id == so->txid)
@@ -1164,16 +1168,13 @@ static int isotp_getname(struct socket *sock, struct sockaddr *uaddr, int peer)
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;
@@ -1248,6 +1249,22 @@ static int isotp_setsockopt(struct socket *sock, int level, int optname,
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)
{