2.0 KiB
CVE-2023-52608
Description
In the Linux kernel, the following vulnerability has been resolved:firmware: arm_scmi: Check mailbox/SMT channel for consistencyOn reception of a completion interrupt the shared memory area is accessedto retrieve the message header at first and then, if the message sequencenumber identifies a transaction which is still pending, the relatedpayload is fetched too.When an SCMI command times out the channel ownership remains with theplatform until eventually a late reply is received and, as a consequence,any further transmission attempt remains pending, waiting for the channelto be relinquished by the platform.Once that late reply is received the channel ownership is given backto the agent and any pending request is then allowed to proceed andoverwrite the SMT area of the just delivered late reply; then the waitfor the reply to the new request starts.It has been observed that the spurious IRQ related to the late reply canbe wrongly associated with the freshly enqueued request: when that happensthe SCMI stack in-flight lookup procedure is fooled by the fact that themessage header now present in the SMT area is related to the new pendingtransaction, even though the real reply has still to arrive.This race-condition on the A2P channel can be detected by looking at thechannel status bits: a genuine reply from the platform will have set thechannel free bit before triggering the completion IRQ.Add a consistency check to validate such condition in the A2P ISR.
POC
Reference
No PoCs from references.