Cihula, Joseph
2009-Mar-02 20:38 UTC
[Xen-devel] [PATCH] txt: 2/3 - Xen per-domain S3 tboot interface
This patch adds the code that performs the per-domain (and frametable and xenheap) MAC on entry into S3 and verification on resume. The MAC algorithm is called VMAC and was developed by Ted Krovetz and Wei Dai (more details are in the files). It is based on a universal hash function. The universal hash is passed through a pseudo-random function, implemented using AES. More details can be found at http://fastcrypto.org/vmac/. The AES code comes from the OpenBSD implementation (which is derived from the implementation referenced in VMAC site). As Xen does not have a good source of entropy to generate its own key (for the keyed hash), it uses the key that tboot passes in. Although the code attempts to MAC all of a domain''s pages (code/data, VT-d tables) based on its s3_integrity flag, some of a domain''s memory may always be MAC''ed, e.g. shadow page tables. Only xenheap pages that are in use are MAC''ed. We believe that the memory MAC''ed by the Xen code and the ranges passed to tboot to MAC cover all of the memory whose integrity needs to be protected on S3. Any suggestions or ranges that we missed are welcome. Signed-off-by: Shane Wang <shane.wang@intel.com> Signed-off-by: Joseph Cihula <joseph.cihula@intel.com> _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel