[SRU][F/J][PATCH v2 1/1] can: hi311x: hi3110_can_ist(): fix potential use-after-free

[Massimiliano Pellizzer]

From: Dario Binacchi <dario.binacchi at amarulasolutions.com>

The commit a22bd630cfff ("can: hi311x: do not report txerr and rxerr
during bus-off") removed the reporting of rxerr and txerr even in case
of correct operation (i. e. not bus-off).

The error count information added to the CAN frame after netif_rx() is
a potential use after free, since there is no guarantee that the skb
is in the same state. It might be freed or reused.

Fix the issue by postponing the netif_rx() call in case of txerr and
rxerr reporting.

Fixes: a22bd630cfff ("can: hi311x: do not report txerr and rxerr during bus-off")
Signed-off-by: Dario Binacchi <dario.binacchi at amarulasolutions.com>
Link: https://patch.msgid.link/20241122221650.633981-5-dario.binacchi@amarulasolutions.com
Signed-off-by: Marc Kleine-Budde <mkl at pengutronix.de>
(backported from commit 9ad86d377ef4a19c75a9c639964879a5b25a433b)
[mpellizzer: backported considering missing commits:
- baebdf48c3600 net: dev: Makes sure netif_rx() can be invoked in any context.
- 00f4a0afb7eaf can: Use netif_rx()
- 3e5c291c7942d can: add CAN_ERR_CNT flag to notify availability of error counter]
CVE-2024-56651
Signed-off-by: Massimiliano Pellizzer <massimiliano.pellizzer at canonical.com>
---
 drivers/net/can/spi/hi311x.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/net/can/spi/hi311x.c b/drivers/net/can/spi/hi311x.c
index 28273e84171a2..1cdc05475cda6 100644
--- a/drivers/net/can/spi/hi311x.c
+++ b/drivers/net/can/spi/hi311x.c
@@ -673,9 +673,9 @@ static irqreturn_t hi3110_can_ist(int irq, void *dev_id)
 			tx_state = txerr >= rxerr ? new_state : 0;
 			rx_state = txerr <= rxerr ? new_state : 0;
 			can_change_state(net, cf, tx_state, rx_state);
-			netif_rx_ni(skb);
 
 			if (new_state == CAN_STATE_BUS_OFF) {
+				netif_rx_ni(skb);
 				can_bus_off(net);
 				if (priv->can.restart_ms == 0) {
 					priv->force_quit = 1;
@@ -685,6 +685,7 @@ static irqreturn_t hi3110_can_ist(int irq, void *dev_id)
 			} else {
 				cf->data[6] = txerr;
 				cf->data[7] = rxerr;
+				netif_rx_ni(skb);
 			}
 		}
 
-- 
2.43.0