kernel/linux.git/net/can, branch v6.19.11

can: isotp: fix tx.buf use-after-free in isotp_sendmsg()

2026-04-02T11:25:40+00:00

commit 424e95d62110cdbc8fd12b40918f37e408e35a92 upstream. isotp_sendmsg() uses only cmpxchg() on so->tx.state to serialize access to so->tx.buf. isotp_release() waits for ISOTP_IDLE via wait_event_interruptible() and then calls kfree(so->tx.buf). If a signal interrupts the wait_event_interruptible() inside close() while tx.state is ISOTP_SENDING, the loop exits early and release proceeds to force ISOTP_SHUTDOWN and continues to kfree(so->tx.buf) while sendmsg may still be reading so->tx.buf for the final CAN frame in isotp_fill_dataframe(). The so->tx.buf can be allocated once when the standard tx.buf length needs to be extended. Move the kfree() of this potentially extended tx.buf to sk_destruct time when either isotp_sendmsg() and isotp_release() are done. Fixes: 96d1c81e6a04 ("can: isotp: add module parameter for maximum pdu size") Cc: stable@vger.kernel.org Reported-by: Ali Norouzi Co-developed-by: Ali Norouzi Signed-off-by: Ali Norouzi Signed-off-by: Oliver Hartkopp Link: https://patch.msgid.link/20260319-fix-can-gw-and-can-isotp-v2-2-c45d52c6d2d8@pengutronix.de Signed-off-by: Marc Kleine-Budde Signed-off-by: Greg Kroah-Hartman

can: gw: fix OOB heap access in cgw_csum_crc8_rel()

2026-04-02T11:25:40+00:00

commit b9c310d72783cc2f30d103eed83920a5a29c671a upstream. cgw_csum_crc8_rel() correctly computes bounds-safe indices via calc_idx(): int from = calc_idx(crc8->from_idx, cf->len); int to = calc_idx(crc8->to_idx, cf->len); int res = calc_idx(crc8->result_idx, cf->len); if (from < 0 || to < 0 || res < 0) return; However, the loop and the result write then use the raw s8 fields directly instead of the computed variables: for (i = crc8->from_idx; ...) /* BUG: raw negative index */ cf->data[crc8->result_idx] = ...; /* BUG: raw negative index */ With from_idx = to_idx = result_idx = -64 on a 64-byte CAN FD frame, calc_idx(-64, 64) = 0 so the guard passes, but the loop iterates with i = -64, reading cf->data[-64], and the write goes to cf->data[-64]. This write might end up to 56 (7.0-rc) or 40 (<= 6.19) bytes before the start of the canfd_frame on the heap. The companion function cgw_csum_xor_rel() uses `from`/`to`/`res` correctly throughout; fix cgw_csum_crc8_rel() to match. Confirmed with KASAN on linux-7.0-rc2: BUG: KASAN: slab-out-of-bounds in cgw_csum_crc8_rel+0x515/0x5b0 Read of size 1 at addr ffff8880076619c8 by task poc_cgw_oob/62 To configure the can-gw crc8 checksums CAP_NET_ADMIN is needed. Fixes: 456a8a646b25 ("can: gw: add support for CAN FD frames") Cc: stable@vger.kernel.org Reported-by: Ali Norouzi Reviewed-by: Oliver Hartkopp Acked-by: Oliver Hartkopp Signed-off-by: Ali Norouzi Signed-off-by: Oliver Hartkopp Link: https://patch.msgid.link/20260319-fix-can-gw-and-can-isotp-v2-1-c45d52c6d2d8@pengutronix.de Signed-off-by: Marc Kleine-Budde Signed-off-by: Greg Kroah-Hartman

can: statistics: add missing atomic access in hot path

2026-04-02T11:25:24+00:00

[ Upstream commit 46eee1661aa9b49966e6c43d07126fe408edda57 ] Commit 80b5f90158d1 ("can: statistics: use atomic access in hot path") fixed a KCSAN issue in can_receive() but missed to convert the 'matches' variable used in can_rcv_filter(). Fixes: 80b5f90158d1 ("can: statistics: use atomic access in hot path") Signed-off-by: Oliver Hartkopp Link: https://patch.msgid.link/20260318173413.28235-1-socketcan@hartkopp.net Signed-off-by: Marc Kleine-Budde Signed-off-by: Sasha Levin

can: bcm: fix locking for bcm_op runtime updates

2026-03-12T11:09:47+00:00

[ Upstream commit c35636e91e392e1540949bbc67932167cb48bc3a ] Commit c2aba69d0c36 ("can: bcm: add locking for bcm_op runtime updates") added a locking for some variables that can be modified at runtime when updating the sending bcm_op with a new TX_SETUP command in bcm_tx_setup(). Usually the RX_SETUP only handles and filters incoming traffic with one exception: When the RX_RTR_FRAME flag is set a predefined CAN frame is sent when a specific RTR frame is received. Therefore the rx bcm_op uses bcm_can_tx() which uses the bcm_tx_lock that was only initialized in bcm_tx_setup(). Add the missing spin_lock_init() when allocating the bcm_op in bcm_rx_setup() to handle the RTR case properly. Fixes: c2aba69d0c36 ("can: bcm: add locking for bcm_op runtime updates") Reported-by: syzbot+5b11eccc403dd1cea9f8@syzkaller.appspotmail.com Closes: https://lore.kernel.org/linux-can/699466e4.a70a0220.2c38d7.00ff.GAE@google.com/ Signed-off-by: Oliver Hartkopp Link: https://patch.msgid.link/20260218-bcm_spin_lock_init-v1-1-592634c8a5b5@hartkopp.net Signed-off-by: Marc Kleine-Budde Signed-off-by: Sasha Levin

net: can: j1939: j1939_xtp_rx_rts_session_active(): deactivate session upon receiving the second rts

2026-01-15T08:52:39+00:00

Since j1939_session_deactivate_activate_next() in j1939_tp_rxtimer() is called only when the timer is enabled, we need to call j1939_session_deactivate_activate_next() if we cancelled the timer. Otherwise, refcount for j1939_session leaks, which will later appear as | unregister_netdevice: waiting for vcan0 to become free. Usage count = 2. problem. Reported-by: syzbot Closes: https://syzkaller.appspot.com/bug?extid=881d65229ca4f9ae8c84 Signed-off-by: Tetsuo Handa Tested-by: Oleksij Rempel Acked-by: Oleksij Rempel Fixes: 9d71dd0c7009 ("can: add support of SAE J1939 protocol") Link: https://patch.msgid.link/b1212653-8fa1-44e1-be9d-12f950fb3a07@I-love.SAKURA.ne.jp Cc: stable@vger.kernel.org Signed-off-by: Marc Kleine-Budde

can: raw: instantly reject disabled CAN frames

2026-01-15T08:52:04+00:00

For real CAN interfaces the CAN_CTRLMODE_FD and CAN_CTRLMODE_XL control modes indicate whether an interface can handle those CAN FD/XL frames. In the case a CAN XL interface is configured in CANXL-only mode with disabled error-signalling neither CAN CC nor CAN FD frames can be sent. The checks are now performed on CAN_RAW sockets to give an instant feedback to the user when writing unsupported CAN frames to the interface or when the CAN interface is in read-only mode. Fixes: 1a620a723853 ("can: raw: instantly reject unsupported CAN frames") Cc: Marc Kleine-Budde Cc: Arnd Bergmann Cc: Vincent Mailhol Signed-off-by: Oliver Hartkopp Link: https://patch.msgid.link/20260109144135.8495-4-socketcan@hartkopp.net [mkl: fix dev reference leak] Link: https://lore.kernel.org/all/0636c732-2e71-4633-8005-dfa85e1da445@hartkopp.net Signed-off-by: Marc Kleine-Budde

Revert "can: raw: instantly reject unsupported CAN frames"

2026-01-15T08:52:04+00:00

This reverts commit 1a620a723853a0f49703c317d52dc6b9602cbaa8 and its follow-up fixes for the introduced dependency issues. commit 1a620a723853 ("can: raw: instantly reject unsupported CAN frames") commit cb2dc6d2869a ("can: Kconfig: select CAN driver infrastructure by default") commit 6abd4577bccc ("can: fix build dependency") commit 5a5aff6338c0 ("can: fix build dependency") The entire problem was caused by the requirement that a new network layer feature needed to know about the protocol capabilities of the CAN devices. Instead of accessing CAN device internal data structures which caused the dependency problems a better approach has been developed which makes use of CAN specific ml_priv data which is accessible from both sides. Cc: Marc Kleine-Budde Cc: Arnd Bergmann Cc: Vincent Mailhol Signed-off-by: Oliver Hartkopp Link: https://patch.msgid.link/20260109144135.8495-2-socketcan@hartkopp.net Signed-off-by: Marc Kleine-Budde

can: j1939: make j1939_sk_bind() fail if device is no longer registered

2025-12-17T09:47:33+00:00

There is a theoretical race window in j1939_sk_netdev_event_unregister() where two j1939_sk_bind() calls jump in between read_unlock_bh() and lock_sock(). The assumption jsk->priv == priv can fail if the first j1939_sk_bind() call once made jsk->priv == NULL due to failed j1939_local_ecu_get() call and the second j1939_sk_bind() call again made jsk->priv != NULL due to successful j1939_local_ecu_get() call. Since the socket lock is held by both j1939_sk_netdev_event_unregister() and j1939_sk_bind(), checking ndev->reg_state with the socket lock held can reliably make the second j1939_sk_bind() call fail (and close this race window). Fixes: 7fcbe5b2c6a4 ("can: j1939: implement NETDEV_UNREGISTER notification handler") Signed-off-by: Tetsuo Handa Acked-by: Oleksij Rempel Link: https://patch.msgid.link/5732921e-247e-4957-a364-da74bd7031d7@I-love.SAKURA.ne.jp Signed-off-by: Marc Kleine-Budde

can: j1939: make j1939_session_activate() fail if device is no longer registered

2025-12-17T09:46:39+00:00

syzbot is still reporting unregister_netdevice: waiting for vcan0 to become free. Usage count = 2 even after commit 93a27b5891b8 ("can: j1939: add missing calls in NETDEV_UNREGISTER notification handler") was added. A debug printk() patch found that j1939_session_activate() can succeed even after j1939_cancel_active_session() from j1939_netdev_notify(NETDEV_UNREGISTER) has completed. Since j1939_cancel_active_session() is processed with the session list lock held, checking ndev->reg_state in j1939_session_activate() with the session list lock held can reliably close the race window. Reported-by: syzbot Closes: https://syzkaller.appspot.com/bug?extid=881d65229ca4f9ae8c84 Signed-off-by: Tetsuo Handa Acked-by: Oleksij Rempel Link: https://patch.msgid.link/b9653191-d479-4c8b-8536-1326d028db5c@I-love.SAKURA.ne.jp Signed-off-by: Marc Kleine-Budde

can: fix build dependency

2025-12-10T08:19:34+00:00

A recent bugfix introduced a new problem with Kconfig dependencies: WARNING: unmet direct dependencies detected for CAN_DEV Depends on [n]: NETDEVICES [=n] && CAN [=m] Selected by [m]: - CAN [=m] && NET [=y] Since the CAN core code now links into the CAN device code, that particular function needs to be available, though the rest of it does not. Revert the incomplete fix and instead use Makefile logic to avoid the link failure. Fixes: cb2dc6d2869a ("can: Kconfig: select CAN driver infrastructure by default") Reported-by: kernel test robot Closes: https://lore.kernel.org/oe-kbuild-all/202512091523.zty3CLmc-lkp@intel.com/ Signed-off-by: Arnd Bergmann Tested-by: Oliver Hartkopp Acked-by: Oliver Hartkopp Link: https://patch.msgid.link/20251204100015.1033688-1-arnd@kernel.org [mkl: removed module option from CAN_DEV help text (thanks Vincent)] [mkl: removed '&& CAN' from Kconfig dependency (thanks Vincent)] Signed-off-by: Marc Kleine-Budde