From: Oliver Hartkopp <socketcan@xxxxxxxxxxxx> commit db2773d65b02aed319a93efdfb958087771d4e19 upstream. The control message provided by isotp support MSG_CMSG_COMPAT but blocked recvmsg() syscalls that have set this flag, i.e. on 32bit user space on 64 bit kernels. Link: https://github.com/hartkopp/can-isotp/issues/59 Cc: Oleksij Rempel <o.rempel@xxxxxxxxxxxxxx> Suggested-by: Marc Kleine-Budde <mkl@xxxxxxxxxxxxxx> Signed-off-by: Oliver Hartkopp <socketcan@xxxxxxxxxxxx> Fixes: 42bf50a1795a ("can: isotp: support MSG_TRUNC flag when reading from socket") Link: https://lore.kernel.org/20230505110308.81087-2-mkl@xxxxxxxxxxxxxx Cc: stable@xxxxxxxxxxxxxxx Signed-off-by: Marc Kleine-Budde <mkl@xxxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- net/can/isotp.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/net/can/isotp.c +++ b/net/can/isotp.c @@ -1018,7 +1018,7 @@ static int isotp_recvmsg(struct socket * int noblock = flags & MSG_DONTWAIT; int ret = 0; - if (flags & ~(MSG_DONTWAIT | MSG_TRUNC | MSG_PEEK)) + if (flags & ~(MSG_DONTWAIT | MSG_TRUNC | MSG_PEEK | MSG_CMSG_COMPAT)) return -EINVAL; if (!so->bound)
