binfmt_elf: Warn on missing or suspicious regset note names

Now that all regset definitions declare an explicit note name, warn if
the note name is missing when generating a core dump.  Simplify the
fallback to always guess "LINUX", which is appropriate for all
Linux-specific notes (i.e., all newly added notes, for a long time
now).  The one standard exception (PR_FPREG) will no longer have an
"unexpected" note name overridden, but a warning will still be emitted.

Also warn if the specified note name doesn't match the legacy
pattern -- but don't bother to override the name in this case.  This
warning can be removed in future if new note types emerge that require
a specific note name that is not "LINUX".

No functional change, beyond the extra noise in dmesg and not
overriding an unexpected note name for PR_FPREG any more.

Now that all upstream arches are ported to use USER_REGSET_NOTE_TYPE(),
new regsets created by copy-pasting existing code should end up correct
by construction.

Signed-off-by: Dave Martin <[email protected]>
Cc: Oleg Nesterov <[email protected]>
Cc: Kees Cook <[email protected]>
Cc: Akihiko Odaki <[email protected]>
Reviewed-by: Akihiko Odaki <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Kees Cook <[email protected]>

0 files changed, 0 insertions, 0 deletions