kernel/linux.git/drivers/net/can/dev/netlink.c, branch v6.12.80

can: netlink: can_changelink(): allow disabling of automatic restart

2025-10-29T13:08:56+00:00

commit 8e93ac51e4c6dc399fad59ec21f55f2cfb46d27c upstream. Since the commit c1f3f9797c1f ("can: netlink: can_changelink(): fix NULL pointer deref of struct can_priv::do_set_mode"), the automatic restart delay can only be set for devices that implement the restart handler struct can_priv::do_set_mode. As it makes no sense to configure a automatic restart for devices that doesn't support it. However, since systemd commit 13ce5d4632e3 ("network/can: properly handle CAN.RestartSec=0") [1], systemd-networkd correctly handles a restart delay of "0" (i.e. the restart is disabled). Which means that a disabled restart is always configured in the kernel. On systems with both changes active this causes that CAN interfaces that don't implement a restart handler cannot be brought up by systemd-networkd. Solve this problem by allowing a delay of "0" to be configured, even if the device does not implement a restart handler. [1] https://github.com/systemd/systemd/commit/13ce5d4632e395521e6205c954493c7fc1c4c6e0 Cc: stable@vger.kernel.org Cc: Andrei Lalaev Reported-by: Marc Kleine-Budde Closes: https://lore.kernel.org/all/20251020-certain-arrogant-vole-of-sunshine-141841-mkl@pengutronix.de Fixes: c1f3f9797c1f ("can: netlink: can_changelink(): fix NULL pointer deref of struct can_priv::do_set_mode") Link: https://patch.msgid.link/20251020-netlink-fix-restart-v1-1-3f53c7f8520b@pengutronix.de Signed-off-by: Marc Kleine-Budde Signed-off-by: Greg Kroah-Hartman

can: netlink: can_changelink(): fix NULL pointer deref of struct can_priv::do_set_mode

2025-08-01T08:48:41+00:00

[ Upstream commit c1f3f9797c1f44a762e6f5f72520b2e520537b52 ] Andrei Lalaev reported a NULL pointer deref when a CAN device is restarted from Bus Off and the driver does not implement the struct can_priv::do_set_mode callback. There are 2 code path that call struct can_priv::do_set_mode: - directly by a manual restart from the user space, via can_changelink() - delayed automatic restart after bus off (deactivated by default) To prevent the NULL pointer deference, refuse a manual restart or configure the automatic restart delay in can_changelink() and report the error via extack to user space. As an additional safety measure let can_restart() return an error if can_priv::do_set_mode is not set instead of dereferencing it unchecked. Reported-by: Andrei Lalaev Closes: https://lore.kernel.org/all/20250714175520.307467-1-andrey.lalaev@gmail.com Fixes: 39549eef3587 ("can: CAN Network device driver and Netlink interface") Link: https://patch.msgid.link/20250718-fix-nullptr-deref-do_set_mode-v1-1-0b520097bb96@pengutronix.de Signed-off-by: Marc Kleine-Budde Signed-off-by: Sasha Levin

can: netlink: avoid call to do_set_data_bittiming callback with stale can_priv::ctrlmode

2024-08-30T20:40:23+00:00

This patch moves the evaluation of data[IFLA_CAN_CTRLMODE] in function can_changelink in front of the evaluation of data[IFLA_CAN_BITTIMING]. This avoids a call to do_set_data_bittiming providing a stale can_priv::ctrlmode with a CAN_CTRLMODE_FD flag not matching the requested state when switching between a CAN Classic and CAN-FD bitrate. In the same manner the evaluation of data[IFLA_CAN_CTRLMODE] in function can_validate is also moved in front of the evaluation of data[IFLA_CAN_BITTIMING]. This is a preparation for patches where the nominal and data bittiming may have interdependencies on the driver side depending on the CAN_CTRLMODE_FD flag state. Signed-off-by: Stefan Mätje Link: https://patch.msgid.link/20240808164224.213522-1-stefan.maetje@esd.eu Signed-off-by: Marc Kleine-Budde

can: netlink: Fix TDCO calculation using the old data bittiming

2024-02-14T12:53:03+00:00

The TDCO calculation was done using the currently applied data bittiming, instead of the newly computed data bittiming, which means that the TDCO had an invalid value unless setting the same data bittiming twice. Fixes: d99755f71a80 ("can: netlink: add interface for CAN-FD Transmitter Delay Compensation (TDC)") Signed-off-by: Maxime Jayat Reviewed-by: Vincent Mailhol Link: https://lore.kernel.org/all/40579c18-63c0-43a4-8d4c-f3a6c1c0b417@munic.io Cc: stable@vger.kernel.org Signed-off-by: Marc Kleine-Budde

can: bittiming: can_changelink() pass extack down callstack

2023-02-06T12:57:26+00:00

This is a preparation patch. In order to pass warning/error messages during netlink calls back to user space, pass the extack struct down the callstack of can_changelink(), the actual error messages will be added in the following ptaches. Link: https://lore.kernel.org/all/20230202110854.2318594-10-mkl@pengutronix.de Signed-off-by: Marc Kleine-Budde

can: netlink: can_changelink(): convert from netdev_err() to NL_SET_ERR_MSG_FMT()

2023-02-06T12:57:26+00:00

Since commit 51c352bdbcd2 ("netlink: add support for formatted extack messages") formatted extack messages are supported to inform the user space or warnings/errors during netlink calls. Replace the netdev_err() by NL_SET_ERR_MSG_FMT() to better inform the user about the problem. While there, use %u to print unsigned values and improve error message a bit. Link: https://lore.kernel.org/all/20230202110854.2318594-9-mkl@pengutronix.de Signed-off-by: Marc Kleine-Budde

can: netlink: can_validate(): validate sample point for CAN and CAN-FD

2023-02-06T12:57:26+00:00

The sample point is a value in tenths of a percent. Meaningful values are between 0 and 1000. Invalid values are rejected and an error message is returned to user space via netlink. Link: https://lore.kernel.org/all/20230202110854.2318594-8-mkl@pengutronix.de Signed-off-by: Marc Kleine-Budde

can: netlink: dump bitrate 0 if can_priv::bittiming.bitrate is -1U

2022-07-03T09:34:24+00:00

Upcoming changes on slcan driver will require you to specify a bitrate of value -1 to prevent the open_candev() from failing but at the same time highlighting that it is a fake value. In this case the command `ip --details -s -s link show' would print 4294967295 as the bitrate value. The patch change this value in 0. Link: https://lore.kernel.org/all/20220628163137.413025-5-dario.binacchi@amarulasolutions.com Suggested-by: Marc Kleine-Budde Signed-off-by: Dario Binacchi Tested-by: Jeroen Hofstee Signed-off-by: Marc Kleine-Budde

can: netlink: allow configuring of fixed data bit rates without need for do_set_data_bittiming callback

2022-06-13T16:25:29+00:00

This patch is similar to 7e193a42c37c ("can: netlink: allow configuring of fixed bit rates without need for do_set_bittiming callback") but for data bit rates instead of bit rates. Usually CAN devices support configurable data bit rates. The limits are defined by struct can_priv::data_bittiming_const. Another way is to implement the struct can_priv::do_set_data_bittiming callback. If the bit rate is configured via netlink, the can_changelink() function checks that either can_priv::data_bittiming_const or struct can_priv::do_set_data_bittiming is implemented. In commit 431af779256c ("can: dev: add CAN interface API for fixed bitrates") an API for configuring bit rates on CAN interfaces that only support fixed bit rates was added. The supported bit rates are defined by struct can_priv::bitrate_const. However the above mentioned commit forgot to add the struct can_priv::data_bitrate_const to the check in can_changelink(). In order to avoid to implement a no-op can_priv::do_set_data_bittiming callback on devices with fixed data bit rates, extend the check in can_changelink() accordingly. Link: https://lore.kernel.org/all/20220613143633.4151884-1-mkl@pengutronix.de Fixes: 431af779256c ("can: dev: add CAN interface API for fixed bitrates") Acked-by: Max Staudt Signed-off-by: Marc Kleine-Budde

can: netlink: allow configuring of fixed bit rates without need for do_set_bittiming callback

2022-06-11T15:08:17+00:00

Usually CAN devices support configurable bit rates. The limits are defined by struct can_priv::bittiming_const. Another way is to implement the struct can_priv::do_set_bittiming callback. If the bit rate is configured via netlink, the can_changelink() function checks that either can_priv::bittiming_const or struct can_priv::do_set_bittiming is implemented. In commit 431af779256c ("can: dev: add CAN interface API for fixed bitrates") an API for configuring bit rates on CAN interfaces that only support fixed bit rates was added. The supported bit rates are defined by struct can_priv::bitrate_const. However the above mentioned commit forgot to add the struct can_priv::bitrate_const to the check in can_changelink(). In order to avoid to implement a no-op can_priv::do_set_bittiming callback on devices with fixed bit rates, extend the check in can_changelink() accordingly. Link: https://lore.kernel.org/all/20220611144248.3924903-1-mkl@pengutronix.de Fixes: 431af779256c ("can: dev: add CAN interface API for fixed bitrates") Reported-by: Max Staudt Signed-off-by: Marc Kleine-Budde