| Message ID | 20250618224943.3263103-2-rdbabiera@google.com |
|---|---|
| State | New |
| Headers | show |
| Series | [v1] usb: typec: altmodes/displayport: do not index invalid pin_assignments | expand |
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 */
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@vger.kernel.org Signed-off-by: RD Babiera <rdbabiera@google.com> Reviewed-by: Badhri Jagan Sridharan <badhri@google.com> --- drivers/usb/typec/altmodes/displayport.c | 2 +- include/linux/usb/typec_dp.h | 1 + 2 files changed, 2 insertions(+), 1 deletion(-) base-commit: e04c78d86a9699d136910cfc0bdcf01087e3267e