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refactor(chardev.c): Replace numbers (representing the size of data in teleport) with meaningful names #32

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matusjokay opened this issue Oct 17, 2021 · 0 comments

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Programator2 pushed a commit that referenced this issue Jan 11, 2023
By keep sending L2CAP_CONF_REQ packets, chan->num_conf_rsp increases
multiple times and eventually it will wrap around the maximum number
(i.e., 255).
This patch prevents this by adding a boundary check with
L2CAP_MAX_CONF_RSP

Btmon log:
Bluetooth monitor ver 5.64
= Note: Linux version 6.1.0-rc2 (x86_64)                               0.264594
= Note: Bluetooth subsystem version 2.22                               0.264636
@ MGMT Open: btmon (privileged) version 1.22                  {0x0001} 0.272191
= New Index: 00:00:00:00:00:00 (Primary,Virtual,hci0)          [hci0] 13.877604
@ RAW Open: 9496 (privileged) version 2.22                   {0x0002} 13.890741
= Open Index: 00:00:00:00:00:00                                [hci0] 13.900426
(...)
> ACL Data RX: Handle 200 flags 0x00 dlen 1033             #32 [hci0] 14.273106
        invalid packet size (12 != 1033)
        08 00 01 00 02 01 04 00 01 10 ff ff              ............
> ACL Data RX: Handle 200 flags 0x00 dlen 1547             #33 [hci0] 14.273561
        invalid packet size (14 != 1547)
        0a 00 01 00 04 01 06 00 40 00 00 00 00 00        ........@.....
> ACL Data RX: Handle 200 flags 0x00 dlen 2061             #34 [hci0] 14.274390
        invalid packet size (16 != 2061)
        0c 00 01 00 04 01 08 00 40 00 00 00 00 00 00 04  ........@.......
> ACL Data RX: Handle 200 flags 0x00 dlen 2061             #35 [hci0] 14.274932
        invalid packet size (16 != 2061)
        0c 00 01 00 04 01 08 00 40 00 00 00 07 00 03 00  ........@.......
= bluetoothd: Bluetooth daemon 5.43                                   14.401828
> ACL Data RX: Handle 200 flags 0x00 dlen 1033             #36 [hci0] 14.275753
        invalid packet size (12 != 1033)
        08 00 01 00 04 01 04 00 40 00 00 00              ........@...

Signed-off-by: Sungwoo Kim <iam@sung-woo.kim>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
matusjokay pushed a commit that referenced this issue Apr 2, 2023
The conclusion "j1939_session_deactivate() should be called with a
session ref-count of at least 2" is incorrect. In some concurrent
scenarios, j1939_session_deactivate can be called with the session
ref-count less than 2. But there is not any problem because it
will check the session active state before session putting in
j1939_session_deactivate_locked().

Here is the concurrent scenario of the problem reported by syzbot
and my reproduction log.

        cpu0                            cpu1
                                j1939_xtp_rx_eoma
j1939_xtp_rx_abort_one
                                j1939_session_get_by_addr [kref == 2]
j1939_session_get_by_addr [kref == 3]
j1939_session_deactivate [kref == 2]
j1939_session_put [kref == 1]
				j1939_session_completed
				j1939_session_deactivate
				WARN_ON_ONCE(kref < 2)

=====================================================
WARNING: CPU: 1 PID: 21 at net/can/j1939/transport.c:1088 j1939_session_deactivate+0x5f/0x70
CPU: 1 PID: 21 Comm: ksoftirqd/1 Not tainted 5.14.0-rc7+ #32
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1ubuntu1 04/01/2014
RIP: 0010:j1939_session_deactivate+0x5f/0x70
Call Trace:
 j1939_session_deactivate_activate_next+0x11/0x28
 j1939_xtp_rx_eoma+0x12a/0x180
 j1939_tp_recv+0x4a2/0x510
 j1939_can_recv+0x226/0x380
 can_rcv_filter+0xf8/0x220
 can_receive+0x102/0x220
 ? process_backlog+0xf0/0x2c0
 can_rcv+0x53/0xf0
 __netif_receive_skb_one_core+0x67/0x90
 ? process_backlog+0x97/0x2c0
 __netif_receive_skb+0x22/0x80

Fixes: 0c71437 ("can: j1939: j1939_session_deactivate(): clarify lifetime of session object")
Reported-by: syzbot+9981a614060dcee6eeca@syzkaller.appspotmail.com
Signed-off-by: Ziyang Xuan <william.xuanziyang@huawei.com>
Acked-by: Oleksij Rempel <o.rempel@pengutronix.de>
Link: https://lore.kernel.org/all/20210906094200.95868-1-william.xuanziyang@huawei.com
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
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