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[1/1,SRU,OEM-OSP1-B] usb: typec: altmode: Fix typec_altmode_get_partner sometimes returning an invalid pointer

Message ID 20200605084604.5188-2-koba.ko@canonical.com
State Accepted
Headers show
Series Kernel NULL pointer dereference when plugging/unpluggin USB-c (power or hub) | expand

Commit Message

Koba Ko June 5, 2020, 8:46 a.m. UTC 
From: Naoki Kiryu <naonaokiryu2@gmail.com>

BugLink: https://bugs.launchpad.net/bugs/1878544 

Before this commit, typec_altmode_get_partner would return a
const struct typec_altmode * pointing to address 0x08 when
to_altmode(adev)->partner was NULL.

Add a check for to_altmode(adev)->partner being NULL to fix this.

BugLink: https://bugzilla.kernel.org/show_bug.cgi?id=206365
BugLink: https://bugzilla.redhat.com/show_bug.cgi?id=1785972
Fixes: 5f54a85db5df ("usb: typec: Make sure an alt mode exist before getting its partner")
Cc: stable@vger.kernel.org
Signed-off-by: Naoki Kiryu <naonaokiryu2@gmail.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Link: https://lore.kernel.org/r/20200422144345.43262-1-hdegoede@redhat.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
(cherry picked from commit 0df9433fcae02215c8fd79690c134d535c7bb905)
Signed-off-by: Koba Ko <koba.ko@canonical.com>
---
 drivers/usb/typec/bus.c | 3 +++
 1 file changed, 3 insertions(+)
diff mbox series

Patch

diff --git a/drivers/usb/typec/bus.c b/drivers/usb/typec/bus.c
index 76299b6ff06d..c950171556d8 100644
--- a/drivers/usb/typec/bus.c
+++ b/drivers/usb/typec/bus.c
@@ -192,6 +192,9 @@  EXPORT_SYMBOL_GPL(typec_altmode_vdm);
 const struct typec_altmode *
 typec_altmode_get_partner(struct typec_altmode *adev)
 {
+	if (!adev || !to_altmode(adev)->partner)
+		return NULL;
+
 	return &to_altmode(adev)->partner->adev;
 }
 EXPORT_SYMBOL_GPL(typec_altmode_get_partner);