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usb: typec: tcpm: Ignore unsupported/unknown alternate mode requests

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commit 88d02c9ba2 upstream.

TCPM may receive PD messages associated with unknown or unsupported
alternate modes. If that happens, calls to typec_match_altmode()
will return NULL. The tcpm code does not currently take this into
account. This results in crashes.

Unable to handle kernel NULL pointer dereference at virtual address 000001f0
pgd = 41dad9a1
[000001f0] *pgd=00000000
Internal error: Oops: 5 [#1] THUMB2
Modules linked in: tcpci tcpm
CPU: 0 PID: 2338 Comm: kworker/u2:0 Not tainted 5.1.18-sama5-armv7-r2 #6
Hardware name: Atmel SAMA5
Workqueue: 2-0050 tcpm_pd_rx_handler [tcpm]
PC is at typec_altmode_attention+0x0/0x14
LR is at tcpm_pd_rx_handler+0xa3b/0xda0 [tcpm]
...
[<c03fbee8>] (typec_altmode_attention) from [<bf8030fb>]
				(tcpm_pd_rx_handler+0xa3b/0xda0 [tcpm])
[<bf8030fb>] (tcpm_pd_rx_handler [tcpm]) from [<c012082b>]
				(process_one_work+0x123/0x2a8)
[<c012082b>] (process_one_work) from [<c0120a6d>]
				(worker_thread+0xbd/0x3b0)
[<c0120a6d>] (worker_thread) from [<c012431f>] (kthread+0xcf/0xf4)
[<c012431f>] (kthread) from [<c01010f9>] (ret_from_fork+0x11/0x38)

Ignore PD messages if the associated alternate mode is not supported.

Fixes: e9576fe8e6 ("usb: typec: tcpm: Support for Alternate Modes")
Cc: stable <stable@vger.kernel.org>
Reported-by: Douglas Gilbert <dgilbert@interlog.com>
Cc: Douglas Gilbert <dgilbert@interlog.com>
Acked-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Tested-by: Douglas Gilbert <dgilbert@interlog.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/1564761822-13984-1-git-send-email-linux@roeck-us.net
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Guenter Roeck 2019-08-02 09:03:42 -07:00 committed by Greg Kroah-Hartman
parent 3f524b631d
commit 9479a05899
1 changed files with 23 additions and 13 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

36
drivers/usb/typec/tcpm.c
View file

@ -1108,7 +1108,8 @@ static int tcpm_pd_svdm(struct tcpm_port *port, const __le32 *payload, int cnt,
break;
case CMD_ATTENTION:
/* Attention command does not have response */
typec_altmode_attention(adev, p[1]);
if (adev)
typec_altmode_attention(adev, p[1]);
return 0;
default:
break;
@ -1160,20 +1161,26 @@ static int tcpm_pd_svdm(struct tcpm_port *port, const __le32 *payload, int cnt,
}
break;
case CMD_ENTER_MODE:
typec_altmode_update_active(pdev, true);
if (adev && pdev) {
typec_altmode_update_active(pdev, true);
if (typec_altmode_vdm(adev, p[0], &p[1], cnt)) {
response[0] = VDO(adev->svid, 1, CMD_EXIT_MODE);
response[0] |= VDO_OPOS(adev->mode);
return 1;
if (typec_altmode_vdm(adev, p[0], &p[1], cnt)) {
response[0] = VDO(adev->svid, 1,
CMD_EXIT_MODE);
response[0] |= VDO_OPOS(adev->mode);
return 1;
}
}
return 0;
case CMD_EXIT_MODE:
typec_altmode_update_active(pdev, false);
if (adev && pdev) {
typec_altmode_update_active(pdev, false);
/* Back to USB Operation */
WARN_ON(typec_altmode_notify(adev, TYPEC_STATE_USB,
NULL));
/* Back to USB Operation */
WARN_ON(typec_altmode_notify(adev,
TYPEC_STATE_USB,
NULL));
}
break;
default:
break;
@ -1183,8 +1190,10 @@ static int tcpm_pd_svdm(struct tcpm_port *port, const __le32 *payload, int cnt,
switch (cmd) {
case CMD_ENTER_MODE:
/* Back to USB Operation */
WARN_ON(typec_altmode_notify(adev, TYPEC_STATE_USB,
NULL));
if (adev)
WARN_ON(typec_altmode_notify(adev,
TYPEC_STATE_USB,
NULL));
break;
default:
break;
@ -1195,7 +1204,8 @@ static int tcpm_pd_svdm(struct tcpm_port *port, const __le32 *payload, int cnt,
}
/* Informing the alternate mode drivers about everything */
typec_altmode_vdm(adev, p[0], &p[1], cnt);
if (adev)
typec_altmode_vdm(adev, p[0], &p[1], cnt);
return rlen;
}