Process crash during CRL-based revocation check on OS using separate mount point for temp Directory in notation-go

Summary

notion-go is a collection of libraries for supporting sign and verify OCI artifacts. Based on Notary Project specifications. The issue was identified during Quarkslab's security audit on the Certificate Revocation List (CRL) based revocation check feature. After retrieving the CRL, notation-go attempts to update the CRL cache using the os.Rename method. However, this operation may fail due to operating system-specific limitations, particularly when the source and destination paths are on different mount points. This failure could lead to an unexpected program termination. In method `crl.(*FileCache).Set`, a temporary file is created in the OS dedicated area (like /tmp for, usually, Linux/Unix). The file is written and then it is tried to move it to the dedicated `notation` cache directory thanks `os.Rename`. As specified in Go documentation, OS specific restriction may apply. When used with Linux OS, it is relying on rename syscall from the libc and as per the documentation, moving a file to a different mountpoint raises an EXDEV error, interpreted as Cross device link not permitted error. Some Linux distribution, like RedHat use a dedicated filesystem (tmpfs), mounted on a specific mountpoint (usually /tmp) for temporary files. When using such OS, revocation check based on CRL will repeatedly crash notation. As a result the signature verification process is aborted as process crashes. This issue has been addressed in version 1.3.0-rc.2 and all users are advised to upgrade. There are no known workarounds for this vulnerability.