linux-toradex.git/include/linux/can, branch v5.12-rc5

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

2021-03-01T10:45:04+00:00

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

net: introduce CAN specific pointer in the struct net_device

2021-02-24T22:32:15+00:00

Since 20dd3850bcf8 ("can: Speed up CAN frame receiption by using
ml_priv") the CAN framework uses per device specific data in the AF_CAN
protocol. For this purpose the struct net_device->ml_priv is used. Later
the ml_priv usage in CAN was extended for other users, one of them being
CAN_J1939.

Later in the kernel ml_priv was converted to an union, used by other
drivers. E.g. the tun driver started storing it's stats pointer.

Since tun devices can claim to be a CAN device, CAN specific protocols
will wrongly interpret this pointer, which will cause system crashes.
Mostly this issue is visible in the CAN_J1939 stack.

To fix this issue, we request a dedicated CAN pointer within the
net_device struct.

Reported-by: syzbot+5138c4dd15a0401bec7b@syzkaller.appspotmail.com
Fixes: 20dd3850bcf8 ("can: Speed up CAN frame receiption by using ml_priv")
Fixes: ffd956eef69b ("can: introduce CAN midlayer private and allocate it automatically")
Fixes: 9d71dd0c7009 ("can: add support of SAE J1939 protocol")
Fixes: 497a5757ce4e ("tun: switch to net core provided statistics counters")
Signed-off-by: Oleksij Rempel 
Link: https://lore.kernel.org/r/20210223070127.4538-1-o.rempel@pengutronix.de
Signed-off-by: Jakub Kicinski

can: dev: export can_get_state_str() function

2021-01-27T09:01:46+00:00

The can_get_state_str() function is also relevant to the drivers. Export the
symbol and make it visible in the can/dev.h header.

Link: https://lore.kernel.org/r/20210119170355.12040-1-mailhol.vincent@wanadoo.fr
Signed-off-by: Vincent Mailhol 
Signed-off-by: Marc Kleine-Budde

can: dev: can_rx_offload_get_echo_skb(): extend to return can frame length

2021-01-14T07:43:43+00:00

In order to implement byte queue limits (bql) in CAN drivers, the length of the
CAN frame needs to be passed into the networking stack after queueing and after
transmission completion.

To avoid to calculate this length twice, extend can_rx_offload_get_echo_skb()
to return that value. Convert all users of this function, too.

Reviewed-by: Vincent Mailhol 
Link: https://lore.kernel.org/r/20210111141930.693847-15-mkl@pengutronix.de
Signed-off-by: Marc Kleine-Budde

can: dev: can_get_echo_skb(): extend to return can frame length

2021-01-14T07:43:43+00:00

In order to implement byte queue limits (bql) in CAN drivers, the length of the
CAN frame needs to be passed into the networking stack after queueing and after
transmission completion.

To avoid to calculate this length twice, extend can_get_echo_skb() to return
that value. Convert all users of this function, too.

Reviewed-by: Vincent Mailhol 
Link: https://lore.kernel.org/r/20210111141930.693847-14-mkl@pengutronix.de
Signed-off-by: Marc Kleine-Budde

can: dev: can_put_echo_skb(): extend to handle frame_len

2021-01-14T07:43:43+00:00

Add a frame_len argument to can_put_echo_skb() which is used to save length of
the CAN frame into field frame_len of struct can_skb_priv so that it can be
later used after transmission completion. Convert all users of this function,
too.

Drivers which implement BQL call can_put_echo_skb() with the output of
can_skb_get_frame_len(skb) and drivers which do not simply pass zero as an
input (in the same way that NULL would be given to can_get_echo_skb()). This
way, we have a nice symmetry between the two echo functions.

Link: https://lore.kernel.org/r/20210111061335.39983-1-mailhol.vincent@wanadoo.fr
Signed-off-by: Marc Kleine-Budde 
Reviewed-by: Vincent Mailhol 
Link: https://lore.kernel.org/r/20210111141930.693847-13-mkl@pengutronix.de
Signed-off-by: Vincent Mailhol

can: dev: extend struct can_skb_priv to hold CAN frame length

2021-01-14T07:43:42+00:00

In order to implement byte queue limits (bql) in CAN drivers, the length of the
CAN frame needs to be passed into the networking stack after queueing and after
transmission completion.

To avoid to calculate this length twice, extend the struct can_skb_priv to hold
the length of the CAN frame and extend __can_get_echo_skb() to return that
value.

Reviewed-by: Vincent Mailhol 
Link: https://lore.kernel.org/r/20210111141930.693847-12-mkl@pengutronix.de
Signed-off-by: Marc Kleine-Budde

can: length: can_skb_get_frame_len(): introduce function to get data length of frame in data link layer

2021-01-14T07:43:42+00:00

This patch adds the function can_skb_get_frame_len() which returns the length
of a CAN frame on the data link layer, including Start-of-frame, Identifier,
various other bits, the actual data, the CRC, the End-of-frame, the Inter frame
spacing.

Co-developed-by: Arunachalam Santhanam 
Signed-off-by: Arunachalam Santhanam 
Co-developed-by: Vincent Mailhol 
Signed-off-by: Vincent Mailhol 
Acked-by: Vincent Mailhol 
Reviewed-by: Vincent Mailhol 
Co-developed-by: Marc Kleine-Budde 
Link: https://lore.kernel.org/r/20210111141930.693847-11-mkl@pengutronix.de
Signed-off-by: Marc Kleine-Budde

can: length: canfd_sanitize_len(): add function to sanitize CAN-FD data length

2021-01-14T07:43:41+00:00

The data field in CAN-FD frames have specifig frame length (0, 1, 2, 3, 4, 5,
6, 7, 8, 12, 16, 20, 24, 32, 48, 64). This function "rounds" up a given length
to the next valid CAN-FD frame length.

Reviewed-by: Vincent Mailhol 
Link: https://lore.kernel.org/r/20210111141930.693847-10-mkl@pengutronix.de
Signed-off-by: Marc Kleine-Budde

can: dev: move netlink related code into seperate file

2021-01-13T08:42:59+00:00

This patch moves the netlink related code of the CAN device infrastructure into
a separate file.

Reviewed-by: Vincent Mailhol 
Link: https://lore.kernel.org/r/20210111141930.693847-7-mkl@pengutronix.de
Signed-off-by: Marc Kleine-Budde