diff mbox series

[v2] can: isotp: tx-path: zero initialize outgoing CAN frames

Message ID 20210319100619.10858-1-socketcan@hartkopp.net (mailing list archive)
State Awaiting Upstream
Delegated to: Netdev Maintainers
Headers show
Series [v2] can: isotp: tx-path: zero initialize outgoing CAN frames | expand

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Commit Message

Oliver Hartkopp March 19, 2021, 10:06 a.m. UTC
Commit d4eb538e1f48 ("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: e057dd3fc20f ("can: add ISO 15765-2:2016 transport protocol")
Cc: Marc Kleine-Budde <mkl@pengutronix.de>
Signed-off-by: Oliver Hartkopp <socketcan@hartkopp.net>
---
 net/can/isotp.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

Comments

Marc Kleine-Budde March 19, 2021, 10:18 a.m. UTC | #1
On 19.03.2021 11:06:19, Oliver Hartkopp wrote:
> Commit d4eb538e1f48 ("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: e057dd3fc20f ("can: add ISO 15765-2:2016 transport protocol")
> Cc: Marc Kleine-Budde <mkl@pengutronix.de>
> Signed-off-by: Oliver Hartkopp <socketcan@hartkopp.net>

Applied to linux-can/testing

thanks,
Marc
diff mbox series

Patch

diff --git a/net/can/isotp.c b/net/can/isotp.c
index 430976485d95..15ea1234d457 100644
--- a/net/can/isotp.c
+++ b/net/can/isotp.c
@@ -194,11 +194,11 @@  static int isotp_send_fc(struct sock *sk, int ae, u8 flowstatus)
 	can_skb_prv(nskb)->skbcnt = 0;
 
 	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;
 
 	if (so->opt.flags & CAN_ISOTP_TX_PADDING) {
@@ -777,11 +777,11 @@  static enum hrtimer_restart isotp_tx_timer_handler(struct hrtimer *hrtimer)
 		can_skb_reserve(skb);
 		can_skb_prv(skb)->ifindex = dev->ifindex;
 		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);
 
 		/* place consecutive frame N_PCI in appropriate index */
@@ -893,11 +893,11 @@  static int isotp_sendmsg(struct socket *sock, struct msghdr *msg, size_t size)
 	so->tx.state = ISOTP_SENDING;
 	so->tx.len = 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) {
 		/* The message size generally fits into a SingleFrame - good.
 		 *