user/sven/linux.git/include/linux/can, branch v4.9.309

can: skb: can_skb_set_owner(): fix ref counting if socket was closed before setting skb ownership

2021-03-17T15:10:13Z

commit e940e0895a82c6fbaa259f2615eb52b57ee91a7e upstream. There are two ref count variables controlling the free()ing of a socket: - struct sock::sk_refcnt - which is changed by sock_hold()/sock_put() - struct sock::sk_wmem_alloc - which accounts the memory allocated by the skbs in the send path. In case there are still TX skbs on the fly and the socket() is closed, the struct sock::sk_refcnt reaches 0. In the TX-path the CAN stack clones an "echo" skb, calls sock_hold() on the original socket and references it. This produces the following back trace: | WARNING: CPU: 0 PID: 280 at lib/refcount.c:25 refcount_warn_saturate+0x114/0x134 | refcount_t: addition on 0; use-after-free. | Modules linked in: coda_vpu(E) v4l2_jpeg(E) videobuf2_vmalloc(E) imx_vdoa(E) | CPU: 0 PID: 280 Comm: test_can.sh Tainted: G E 5.11.0-04577-gf8ff6603c617 #203 | Hardware name: Freescale i.MX6 Quad/DualLite (Device Tree) | Backtrace: | [<80bafea4>] (dump_backtrace) from [<80bb0280>] (show_stack+0x20/0x24) r7:00000000 r6:600f0113 r5:00000000 r4:81441220 | [<80bb0260>] (show_stack) from [<80bb593c>] (dump_stack+0xa0/0xc8) | [<80bb589c>] (dump_stack) from [<8012b268>] (__warn+0xd4/0x114) r9:00000019 r8:80f4a8c2 r7:83e4150c r6:00000000 r5:00000009 r4:80528f90 | [<8012b194>] (__warn) from [<80bb09c4>] (warn_slowpath_fmt+0x88/0xc8) r9:83f26400 r8:80f4a8d1 r7:00000009 r6:80528f90 r5:00000019 r4:80f4a8c2 | [<80bb0940>] (warn_slowpath_fmt) from [<80528f90>] (refcount_warn_saturate+0x114/0x134) r8:00000000 r7:00000000 r6:82b44000 r5:834e5600 r4:83f4d540 | [<80528e7c>] (refcount_warn_saturate) from [<8079a4c8>] (__refcount_add.constprop.0+0x4c/0x50) | [<8079a47c>] (__refcount_add.constprop.0) from [<8079a57c>] (can_put_echo_skb+0xb0/0x13c) | [<8079a4cc>] (can_put_echo_skb) from [<8079ba98>] (flexcan_start_xmit+0x1c4/0x230) r9:00000010 r8:83f48610 r7:0fdc0000 r6:0c080000 r5:82b44000 r4:834e5600 | [<8079b8d4>] (flexcan_start_xmit) from [<80969078>] (netdev_start_xmit+0x44/0x70) r9:814c0ba0 r8:80c8790c r7:00000000 r6:834e5600 r5:82b44000 r4:82ab1f00 | [<80969034>] (netdev_start_xmit) from [<809725a4>] (dev_hard_start_xmit+0x19c/0x318) r9:814c0ba0 r8:00000000 r7:82ab1f00 r6:82b44000 r5:00000000 r4:834e5600 | [<80972408>] (dev_hard_start_xmit) from [<809c6584>] (sch_direct_xmit+0xcc/0x264) r10:834e5600 r9:00000000 r8:00000000 r7:82b44000 r6:82ab1f00 r5:834e5600 r4:83f27400 | [<809c64b8>] (sch_direct_xmit) from [<809c6c0c>] (__qdisc_run+0x4f0/0x534) To fix this problem, only set skb ownership to sockets which have still a ref count > 0. Fixes: 0ae89beb283a ("can: add destructor for self generated skbs") Cc: Oliver Hartkopp Cc: Andre Naujoks Link: https://lore.kernel.org/r/20210226092456.27126-1-o.rempel@pengutronix.de Suggested-by: Eric Dumazet Signed-off-by: Oleksij Rempel Reviewed-by: Oliver Hartkopp Signed-off-by: Marc Kleine-Budde Signed-off-by: Greg Kroah-Hartman

can: can_create_echo_skb(): fix echo skb generation: always use skb_clone()

2020-11-18T17:26:24Z

[ Upstream commit 286228d382ba6320f04fa2e7c6fc8d4d92e428f4 ] All user space generated SKBs are owned by a socket (unless injected into the key via AF_PACKET). If a socket is closed, all associated skbs will be cleaned up. This leads to a problem when a CAN driver calls can_put_echo_skb() on a unshared SKB. If the socket is closed prior to the TX complete handler, can_get_echo_skb() and the subsequent delivering of the echo SKB to all registered callbacks, a SKB with a refcount of 0 is delivered. To avoid the problem, in can_get_echo_skb() the original SKB is now always cloned, regardless of shared SKB or not. If the process exists it can now safely discard its SKBs, without disturbing the delivery of the echo SKB. The problem shows up in the j1939 stack, when it clones the incoming skb, which detects the already 0 refcount. We can easily reproduce this with following example: testj1939 -B -r can0: & cansend can0 1823ff40#0123 WARNING: CPU: 0 PID: 293 at lib/refcount.c:25 refcount_warn_saturate+0x108/0x174 refcount_t: addition on 0; use-after-free. Modules linked in: coda_vpu imx_vdoa videobuf2_vmalloc dw_hdmi_ahb_audio vcan CPU: 0 PID: 293 Comm: cansend Not tainted 5.5.0-rc6-00376-g9e20dcb7040d #1 Hardware name: Freescale i.MX6 Quad/DualLite (Device Tree) Backtrace: [] (dump_backtrace) from [] (show_stack+0x20/0x24) [] (show_stack) from [] (dump_stack+0x8c/0xa0) [] (dump_stack) from [] (__warn+0xe0/0x108) [] (__warn) from [] (warn_slowpath_fmt+0xa8/0xcc) [] (warn_slowpath_fmt) from [] (refcount_warn_saturate+0x108/0x174) [] (refcount_warn_saturate) from [] (j1939_can_recv+0x20c/0x210) [] (j1939_can_recv) from [] (can_rcv_filter+0xb4/0x268) [] (can_rcv_filter) from [] (can_receive+0xb0/0xe4) [] (can_receive) from [] (can_rcv+0x48/0x98) [] (can_rcv) from [] (__netif_receive_skb_one_core+0x64/0x88) [] (__netif_receive_skb_one_core) from [] (__netif_receive_skb+0x38/0x94) [] (__netif_receive_skb) from [] (netif_receive_skb_internal+0x64/0xf8) [] (netif_receive_skb_internal) from [] (netif_receive_skb+0x34/0x19c) [] (netif_receive_skb) from [] (can_rx_offload_napi_poll+0x58/0xb4) Fixes: 0ae89beb283a ("can: add destructor for self generated skbs") Signed-off-by: Oleksij Rempel Link: http://lore.kernel.org/r/20200124132656.22156-1-o.rempel@pengutronix.de Acked-by: Oliver Hartkopp Signed-off-by: Marc Kleine-Budde Signed-off-by: Sasha Levin

can: can_dropped_invalid_skb(): ensure an initialized headroom in outgoing CAN sk_buffs

2020-01-14T19:04:28Z

commit e7153bf70c3496bac00e7e4f395bb8d8394ac0ea upstream. KMSAN sysbot detected a read access to an untinitialized value in the headroom of an outgoing CAN related sk_buff. When using CAN sockets this area is filled appropriately - but when using a packet socket this initialization is missing. The problematic read access occurs in the CAN receive path which can only be triggered when the sk_buff is sent through a (virtual) CAN interface. So we check in the sending path whether we need to perform the missing initializations. Fixes: d3b58c47d330d ("can: replace timestamp as unique skb attribute") Reported-by: syzbot+b02ff0707a97e4e79ebb@syzkaller.appspotmail.com Signed-off-by: Oliver Hartkopp Tested-by: Oliver Hartkopp Cc: linux-stable # >= v4.1 Signed-off-by: Marc Kleine-Budde Signed-off-by: Greg Kroah-Hartman

can: dev: can_get_echo_skb(): factor out non sending code to __can_get_echo_skb()

2018-12-01T08:44:19Z

commit a4310fa2f24687888ce80fdb0e88583561a23700 upstream. This patch factors out all non sending parts of can_get_echo_skb() into a seperate function __can_get_echo_skb(), so that it can be re-used in an upcoming patch. Cc: linux-stable Signed-off-by: Marc Kleine-Budde Signed-off-by: Greg Kroah-Hartman

can: Fix kernel panic at security_sock_rcv_skb

2017-02-18T14:11:40Z

[ Upstream commit f1712c73714088a7252d276a57126d56c7d37e64 ] Zhang Yanmin reported crashes [1] and provided a patch adding a synchronize_rcu() call in can_rx_unregister() The main problem seems that the sockets themselves are not RCU protected. If CAN uses RCU for delivery, then sockets should be freed only after one RCU grace period. Recent kernels could use sock_set_flag(sk, SOCK_RCU_FREE), but let's ease stable backports with the following fix instead. [1] BUG: unable to handle kernel NULL pointer dereference at (null) IP: [] selinux_socket_sock_rcv_skb+0x65/0x2a0 Call Trace: [] security_sock_rcv_skb+0x4c/0x60 [] sk_filter+0x41/0x210 [] sock_queue_rcv_skb+0x53/0x3a0 [] raw_rcv+0x2a3/0x3c0 [] can_rcv_filter+0x12b/0x370 [] can_receive+0xd9/0x120 [] can_rcv+0xab/0x100 [] __netif_receive_skb_core+0xd8c/0x11f0 [] __netif_receive_skb+0x24/0xb0 [] process_backlog+0x127/0x280 [] net_rx_action+0x33b/0x4f0 [] __do_softirq+0x184/0x440 [] do_softirq_own_stack+0x1c/0x30 [] do_softirq.part.18+0x3b/0x40 [] do_softirq+0x1d/0x20 [] netif_rx_ni+0xe5/0x110 [] slcan_receive_buf+0x507/0x520 [] flush_to_ldisc+0x21c/0x230 [] process_one_work+0x24f/0x670 [] worker_thread+0x9d/0x6f0 [] ? rescuer_thread+0x480/0x480 [] kthread+0x12c/0x150 [] ret_from_fork+0x3f/0x70 Reported-by: Zhang Yanmin Signed-off-by: Eric Dumazet Acked-by: Oliver Hartkopp Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

can: dev: fix deadlock reported after bus-off

2016-09-22T08:01:21Z

A timer was used to restart after the bus-off state, leading to a relatively large can_restart() executed in an interrupt context, which in turn sets up pinctrl. When this happens during system boot, there is a high probability of grabbing the pinctrl_list_mutex, which is locked already by the probe() of other device, making the kernel suspect a deadlock condition [1]. To resolve this issue, the restart_timer is replaced by a delayed work. [1] https://github.com/victronenergy/venus/issues/24 Signed-off-by: Sergei Miroshnichenko Cc: linux-stable Signed-off-by: Marc Kleine-Budde

can: fix handling of unmodifiable configuration options

2016-05-09T09:07:28Z

As described in 'can: m_can: tag current CAN FD controllers as non-ISO' (6cfda7fbebe) it is possible to define fixed configuration options by setting the according bit in 'ctrlmode' and clear it in 'ctrlmode_supported'. This leads to the incovenience that the fixed configuration bits can not be passed by netlink even when they have the correct values (e.g. non-ISO, FD). This patch fixes that issue and not only allows fixed set bit values to be set again but now requires(!) to provide these fixed values at configuration time. A valid CAN FD configuration consists of a nominal/arbitration bittiming, a data bittiming and a control mode with CAN_CTRLMODE_FD set - which is now enforced by a new can_validate() function. This fix additionally removed the inconsistency that was prohibiting the support of 'CANFD-only' controller drivers, like the RCar CAN FD. For this reason a new helper can_set_static_ctrlmode() has been introduced to provide a proper interface to handle static enabled CAN controller options. Reported-by: Ramesh Shanmugasundaram Signed-off-by: Oliver Hartkopp Reviewed-by: Ramesh Shanmugasundaram Cc: # >= 3.18 Signed-off-by: Marc Kleine-Budde

net/can: can_dropped_invalid_skb can be boolean

2015-10-09T14:49:01Z

This patch makes can_dropped_invalid_skb return bool due to this particular function only using either one or zero as its return value. No functional change. Signed-off-by: Yaowei Bai Acked-by: Marc Kleine-Budde Signed-off-by: David S. Miller

can: headers: make header files self contained

2015-09-21T06:38:22Z

This patch adds the missing #include-s to the dev.h and led.h, so that they can be used without including further header files. Signed-off-by: Marc Kleine-Budde

can: replace timestamp as unique skb attribute

2015-07-12T19:13:22Z

Commit 514ac99c64b "can: fix multiple delivery of a single CAN frame for overlapping CAN filters" requires the skb->tstamp to be set to check for identical CAN skbs. Without timestamping to be required by user space applications this timestamp was not generated which lead to commit 36c01245eb8 "can: fix loss of CAN frames in raw_rcv" - which forces the timestamp to be set in all CAN related skbuffs by introducing several __net_timestamp() calls. This forces e.g. out of tree drivers which are not using alloc_can{,fd}_skb() to add __net_timestamp() after skbuff creation to prevent the frame loss fixed in mainline Linux. This patch removes the timestamp dependency and uses an atomic counter to create an unique identifier together with the skbuff pointer. Btw: the new skbcnt element introduced in struct can_skb_priv has to be initialized with zero in out-of-tree drivers which are not using alloc_can{,fd}_skb() too. Signed-off-by: Oliver Hartkopp Cc: linux-stable Signed-off-by: Marc Kleine-Budde