FreeBSD -- copy_file_range insufficient capability rights check

Problem Description:
The syscall checked only for the CAP_READ and CAP_WRITE
capabilities on the input and output file descriptors, respectively.
Using an offset is logically equivalent to seeking, and the syscall
must additionally require the CAP_SEEK capability.
Impact:
A sandboxed process with only read or write but no seek capability
on a file descriptor may be able to read data from or write data
to an arbitrary location within the file corresponding to that file
descriptor.