[PATCH 1/2] can-isotp: block setsockopt on bound sockets

[Oliver Hartkopp]

The isotp socket can be widely configured in its behaviour regarding
addressing types, fill-ups, receive pattern tests and link layer length.
Usually all these settings need to be fixed before bind() and can not
be changed afterwards.

This patch adds a check to enforce the common usage pattern.

Fixes: e057dd3fc20f ("can: add ISO 15765-2:2016 transport protocol")
Tested-by: Thomas Wagner <th...@web.de>
Signed-off-by: Oliver Hartkopp <socket...@hartkopp.net>
---
 net/can/isotp.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/net/can/isotp.c b/net/can/isotp.c
index d78ab13bd8be..26bdc3c20b7e 100644
--- a/net/can/isotp.c
+++ b/net/can/isotp.c
@@ -1155,10 +1155,13 @@ static int isotp_setsockopt(struct socket *sock, int 
level, int optname,
        int ret = 0;
 
        if (level != SOL_CAN_ISOTP)
                return -EINVAL;
 
+       if (so->bound)
+               return -EISCONN;
+
        switch (optname) {
        case CAN_ISOTP_OPTS:
                if (optlen != sizeof(struct can_isotp_options))
                        return -EINVAL;
 
-- 
2.29.2