From: Zhang Changzhong <zhangchangzhong@xxxxxxxxxx> commit 379743985ab6cfe2cbd32067cf4ed497baca6d06 upstream. According to SAE-J1939-21, the data length of TP.DT must be 8 bytes, so cancel session when receive unexpected TP.DT message. Fixes: 9d71dd0c7009 ("can: add support of SAE J1939 protocol") Link: https://lore.kernel.org/all/1632972800-45091-1-git-send-email-zhangchangzhong@xxxxxxxxxx Cc: stable@xxxxxxxxxxxxxxx Signed-off-by: Zhang Changzhong <zhangchangzhong@xxxxxxxxxx> Acked-by: Oleksij Rempel <o.rempel@xxxxxxxxxxxxxx> Signed-off-by: Marc Kleine-Budde <mkl@xxxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- net/can/j1939/transport.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) --- a/net/can/j1939/transport.c +++ b/net/can/j1939/transport.c @@ -1770,6 +1770,7 @@ static void j1939_xtp_rx_dpo(struct j193 static void j1939_xtp_rx_dat_one(struct j1939_session *session, struct sk_buff *skb) { + enum j1939_xtp_abort abort = J1939_XTP_ABORT_FAULT; struct j1939_priv *priv = session->priv; struct j1939_sk_buff_cb *skcb; struct sk_buff *se_skb = NULL; @@ -1784,9 +1785,11 @@ static void j1939_xtp_rx_dat_one(struct skcb = j1939_skb_to_cb(skb); dat = skb->data; - if (skb->len <= 1) + if (skb->len != 8) { /* makes no sense */ + abort = J1939_XTP_ABORT_UNEXPECTED_DATA; goto out_session_cancel; + } switch (session->last_cmd) { case 0xff: @@ -1884,7 +1887,7 @@ static void j1939_xtp_rx_dat_one(struct out_session_cancel: kfree_skb(se_skb); j1939_session_timers_cancel(session); - j1939_session_cancel(session, J1939_XTP_ABORT_FAULT); + j1939_session_cancel(session, abort); j1939_session_put(session); }