Some types of credentials that a user would want to pass
into the initrd do not depend on the specific kernel/initrd
version. For instance, this can include SSH keys, rootfs
encryption keys, dm-integrity keys, and so on. This
introduces a directory where such credentials can be placed
so that any kernel image will load them
Previously, mangle_filename would write the null terminator, but
then wouldn't increment the pointer. Thus, the pad4 call that comes
immediately after mangle_filename would trample over the null
terminator that mangle_filename wrote. Since the padding is all
0s, this happened to work for the filenames it was tested for
However, in some cases, this would cause the pointer to be a different
position than predicted. Basically, the predicted size would be one
byte bigger than the actual size (the missing null terminator). Usually,
this disappeared into the alignment padding at the end of the buffer,
but if the buffer was already unexpectedly aligned (b/c it was a byte
shorter than expected), this would cause assertion failures.
Also, the c_namesize field in the cpio header was incorrect. It
didn't include the null terminator, as required by the spec.
Adrian Vovk