[rsbac] New request types GET_XATTR and MODIFY_XATTR on FD targets

Hi there,

the system call families getxattr() and setxattr() used to be intercepted with requests GET_PERMISSIONS_DATA and MODIFY_PERMISSIONS_DATA. Since extended attributes do much more than Linux access control with ACLs, we needed a way to distinguish these types of access.

I decided to introduce the new request types GET_XATTR and MODIFY_XATTR for them, valid for all FD targets. The changes are in the kernel Git repos for 6.6, 6.1, 5.15 and 5.10 as well as in the rsbac-admin repo for administration. Older kernels remain unchanged.

Amon.