CVE-2022-49820 Information

Description

In the Linux kernel the following vulnerability has been resolved:

mctp i2c: don’t count unused / invalid keys for flow release

We’re currently hitting the WARN_ON in mctp_i2c_flow_release:

if (midev->release_count > midev->i2c_lock_count) 
    WARN_ONCE(1 
elease count overflow\);

This may be hit if we expire a flow before sending the first packet it contains - as we will not be pairing the increment of release_count (performed on flow release) with the i2c lock operation (only performed on actual TX).

To fix this only release a flow if we’ve encountered it previously (ie dev_flow_state does not indicate NEW) as we will mark the flow as ACTIVE at the same time as accounting for the i2c lock operation. We also need to add an INVALID flow state to indicate when we’ve done the release.

Reference

https://git.kernel.org/stable/c/9cbd48d5fa14e4c65f8580de16686077f7cea02b https://git.kernel.org/stable/c/a5915a9a3ab4067ef8996a57738d156eabeb3a12