This is a note to let you know that I've just added the patch titled

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

to my usb git tree which can be found at git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git in the usb-linus branch.

The patch will show up in the next release of the linux-next tree (usually sometime within the next 24 hours during the week.)

The patch will hopefully also be merged in Linus's tree for the next -rc kernel release.

If you have any questions about this process, please let me know.

From 88d02c9ba2e83fc22d37ccb1f11c62ea6fc9ae50 Mon Sep 17 00:00:00 2001

From: Guenter Roeck linux@roeck-us.net Date: Fri, 2 Aug 2019 09:03:42 -0700 Subject: usb: typec: tcpm: Ignore unsupported/unknown alternate mode requests

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: e9576fe8e605c ("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.n... Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/usb/typec/tcpm/tcpm.c | 38 ++++++++++++++++++++++------------- 1 file changed, 24 insertions(+), 14 deletions(-)

diff --git a/drivers/usb/typec/tcpm/tcpm.c b/drivers/usb/typec/tcpm/tcpm.c index ab6456622120..15abe1d9958f 100644 --- a/drivers/usb/typec/tcpm/tcpm.c +++ b/drivers/usb/typec/tcpm/tcpm.c @@ -1109,7 +1109,8 @@ 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; @@ -1161,20 +1162,26 @@ 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 (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 (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; + } } 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; @@ -1184,8 +1191,10 @@ 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; @@ -1196,7 +1205,8 @@ 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; }