openssh unix dev - Aug 2022 - aadlen in chacha20

In the crypt function is there ever a situation in which the aadlen 
would not be 4?

Just curious. I threw in an assert(aadlen == 4); just before that 
conditional and haven't broken anything yet. Just not sure if I'm 
missing a case where it might be 0.

Chris

rapier wrote:
> In the crypt function is there ever a situation in which the aadlen 
> would not be 4?
A lazy grep says yes:

$ git grep 'aadlen ='
packet.c:       u_int authlen = 0, aadlen = 0;
packet.c:       aadlen = (mac && mac->enabled && mac->etm)
|| authlen ? 4 : 0;
packet.c:       u_int maclen, aadlen = 0, authlen = 0, block_size;
packet.c:       aadlen = (mac && mac->enabled && mac->etm)
|| authlen ? 4 : 0;
sshkey-xmss.c:  aadlen = sshbuf_len(encoded);
sshkey-xmss.c:  aadlen = sshbuf_len(copy) - sshbuf_len(encoded);
$ 


//Peter