Affected: Linux

In the Linux kernel, the following vulnerability has been resolved:

firmware: arm_scmi: Reject out of range DT protocol IDs

SCMI protocol IDs carried in message headers are limited by MSG_PROTOCOL_ID_MASK. The DT parsing paths noticed protocol IDs outside that range, but only logged an error and then kept processing the invalid value.

That lets a malformed 32-bit DT reg value reach helpers which take a u8 protocol ID, where it can be truncated and/or treated as a different protocol.

For channel setup, two different out-of-range values can also be used as distinct IDR keys while aliasing the generated SCMI protocol identity.

Skip DT protocol nodes whose reg value does not fit the SCMI protocol ID field before setting up channels or creating protocol devices.