The check only references the original chunk, so for each parsed payload
it checks the same thing. The length of each individual payload is
checked by the parser anyway. So I think this was primarily added for
the IKEv1 "wrong PSK" use case. Let's keep it for now.
Fixes: dd5c3787dc ("Give a hint that decryption failed if payload length invalid")
As described in the previous commit, GCC 15 uses C23 by default and that
changes the meaning of such argument-less function declarations. So
whenever we assign such a function to a pointer that expects a function
with arguments it causes an incompatible pointer type warning. We
could define dedicated functions/callbacks whenever necessary, but this
seems like the simpler approach for now (especially since most uses of
these functions have already been cast).
When using a cipher with sequential IVs, we never must pass an identical IV
to the IV generator. To avoid it when using IKEv2 fragmentation, use the lower
bits of the 64-bit message ID as the fragment number.
Tobias Brunner