From 0317d1f28cf968ff4ae66efe3a90f49336211cd5 Mon Sep 17 00:00:00 2001 From: Oliver Hartkopp Date: Fri, 19 Mar 2021 11:06:19 +0100 Subject: [PATCH] can: isotp: tx-path: zero initialize outgoing CAN frames Commit 1e9d9a0b5b1c ("can: isotp: TX-path: ensure that CAN frame flags are initialized") ensured the TX flags to be properly set for outgoing CAN frames. In fact the root cause of the issue results from a missing initialization of outgoing CAN frames created by isotp. This is no problem on the CAN bus as the CAN driver only picks the correctly defined content from the struct can(fd)_frame. But when the outgoing frames are monitored (e.g. with candump) we potentially leak some bytes in the unused content of struct can(fd)_frame. Fixes: 28da5a05c8c3 ("can: add ISO 15765-2:2016 transport protocol") Cc: Marc Kleine-Budde Link: https://lore.kernel.org/r/20210319100619.10858-1-socketcan@hartkopp.net Signed-off-by: Oliver Hartkopp Signed-off-by: Marc Kleine-Budde --- net/can/isotp.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/net/can/isotp.c b/net/can/isotp.c index 430976485d957..15ea1234d4573 100644 --- a/net/can/isotp.c +++ b/net/can/isotp.c @@ -196,7 +196,7 @@ static int isotp_send_fc(struct sock *sk, int ae, u8 flowstatus) nskb->dev = dev; can_skb_set_owner(nskb, sk); ncf = (struct canfd_frame *)nskb->data; - skb_put(nskb, so->ll.mtu); + skb_put_zero(nskb, so->ll.mtu); /* create & send flow control reply */ ncf->can_id = so->txid; @@ -779,7 +779,7 @@ isotp_tx_burst: can_skb_prv(skb)->skbcnt = 0; cf = (struct canfd_frame *)skb->data; - skb_put(skb, so->ll.mtu); + skb_put_zero(skb, so->ll.mtu); /* create consecutive frame */ isotp_fill_dataframe(cf, so, ae, 0); @@ -895,7 +895,7 @@ static int isotp_sendmsg(struct socket *sock, struct msghdr *msg, size_t size) so->tx.idx = 0; cf = (struct canfd_frame *)skb->data; - skb_put(skb, so->ll.mtu); + skb_put_zero(skb, so->ll.mtu); /* check for single frame transmission depending on TX_DL */ if (size <= so->tx.ll_dl - SF_PCI_SZ4 - ae - off) { -- 2.39.5