diff options
| author | RD Babiera <rdbabiera@google.com> | 2025-06-18 22:49:42 +0000 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2025-06-24 15:42:55 +0100 |
| commit | af4db5a35a4ef7a68046883bfd12468007db38f1 (patch) | |
| tree | 07a620a10bee33b4292d9feb8bbb6d3433c6eb33 | |
| parent | 2831a81077f5162f104ba5a97a7d886eb371c21c (diff) | |
usb: typec: altmodes/displayport: do not index invalid pin_assignments
A poorly implemented DisplayPort Alt Mode port partner can indicate
that its pin assignment capabilities are greater than the maximum
value, DP_PIN_ASSIGN_F. In this case, calls to pin_assignment_show
will cause a BRK exception due to an out of bounds array access.
Prevent for loop in pin_assignment_show from accessing
invalid values in pin_assignments by adding DP_PIN_ASSIGN_MAX
value in typec_dp.h and using i < DP_PIN_ASSIGN_MAX as a loop
condition.
Fixes: 0e3bb7d6894d ("usb: typec: Add driver for DisplayPort alternate mode")
Cc: stable <stable@kernel.org>
Signed-off-by: RD Babiera <rdbabiera@google.com>
Reviewed-by: Badhri Jagan Sridharan <badhri@google.com>
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Link: https://lore.kernel.org/r/20250618224943.3263103-2-rdbabiera@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | drivers/usb/typec/altmodes/displayport.c | 2 | ||||
| -rw-r--r-- | include/linux/usb/typec_dp.h | 1 |
2 files changed, 2 insertions, 1 deletions
diff --git a/drivers/usb/typec/altmodes/displayport.c b/drivers/usb/typec/altmodes/displayport.c index b09b58d7311d..773786129dfb 100644 --- a/drivers/usb/typec/altmodes/displayport.c +++ b/drivers/usb/typec/altmodes/displayport.c @@ -677,7 +677,7 @@ static ssize_t pin_assignment_show(struct device *dev, assignments = get_current_pin_assignments(dp); - for (i = 0; assignments; assignments >>= 1, i++) { + for (i = 0; assignments && i < DP_PIN_ASSIGN_MAX; assignments >>= 1, i++) { if (assignments & 1) { if (i == cur) len += sprintf(buf + len, "[%s] ", diff --git a/include/linux/usb/typec_dp.h b/include/linux/usb/typec_dp.h index f2da264d9c14..acb0ad03bdac 100644 --- a/include/linux/usb/typec_dp.h +++ b/include/linux/usb/typec_dp.h @@ -57,6 +57,7 @@ enum { DP_PIN_ASSIGN_D, DP_PIN_ASSIGN_E, DP_PIN_ASSIGN_F, /* Not supported after v1.0b */ + DP_PIN_ASSIGN_MAX, }; /* DisplayPort alt mode specific commands */ |