The read access to struct canxl_frame::len inside of a j1939 created skbuff
revealed a missing initialization of reserved and later filled elements in
struct can_frame.
This patch initializes the 8 byte CAN header with zero.
Fixes: 9d71dd0c7009 ("can: add support of SAE J1939 protocol")
Cc: Oleksij Rempel <o.rempel@xxxxxxxxxxxxxx>
Link: https://lore.kernel.org/linux-can/20221104052235.GA6474@xxxxxxxxxxxxxx/T/#t
Reported-by: syzbot+d168ec0caca4697e03b1@xxxxxxxxxxxxxxxxxxxxxxxxx
Signed-off-by: Oliver Hartkopp <socketcan@xxxxxxxxxxxx>
---
net/can/j1939/main.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/net/can/j1939/main.c b/net/can/j1939/main.c
index 144c86b0e3ff..821d4ff303b3 100644
--- a/net/can/j1939/main.c
+++ b/net/can/j1939/main.c
@@ -334,10 +334,13 @@ int j1939_send_one(struct j1939_priv *priv, struct sk_buff *skb)
dlc = skb->len;
/* re-claim the CAN_HDR from the SKB */
cf = skb_push(skb, J1939_CAN_HDR);
+ /* initialize header structure */
+ memset(cf, 0, J1939_CAN_HDR);
+
/* make it a full can frame again */
skb_put(skb, J1939_CAN_FTR + (8 - dlc));
canid = CAN_EFF_FLAG |
(skcb->priority << 26) |
--
2.30.2
