Upstream commit 2b17c400aeb44daf041627722581ade527bb3c1d
The fixes tag of the uptream patch points to commit 921ca574cd38 ("can:
isotp: add SF_BROADCAST support for functional addressing") which showed
up in Linux 5.11 but the described issue already existed in Linux 5.10.
Norbert Slusarek writes:
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: e057dd3fc20f ("can: add ISO 15765-2:2016 transport protocol")
Link: https://lore.kernel.org/r/trinity-e6ae9efa-9afb-4326-84c0-f3609b9b8168-1620773528307@3c-app-gmx-bs06
Reported-by: Norbert Slusarek <nslusarek@xxxxxxx>
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@xxxxxxxxxxxxx>
Signed-off-by: Norbert Slusarek <nslusarek@xxxxxxx>
Acked-by: Oliver Hartkopp <socketcan@xxxxxxxxxxxx>
Signed-off-by: Marc Kleine-Budde <mkl@xxxxxxxxxxxxxx>
Signed-off-by: Oliver Hartkopp <socketcan@xxxxxxxxxxxx>
---
net/can/isotp.c | 21 +++++++++++++++++----
1 file changed, 17 insertions(+), 4 deletions(-)
diff --git a/net/can/isotp.c b/net/can/isotp.c
index 37db4d232313..3f11d2b314b6 100644
--- a/net/can/isotp.c
+++ b/net/can/isotp.c
@@ -1191,20 +1191,17 @@ static int isotp_getname(struct socket *sock, struct sockaddr *uaddr, int peer)
addr->can_addr.tp.tx_id = so->txid;
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;
switch (optname) {
case CAN_ISOTP_OPTS:
@@ -1275,10 +1272,26 @@ 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)
{
struct sock *sk = sock->sk;
struct isotp_sock *so = isotp_sk(sk);
--
2.30.2
