ChaCha20 Rekey Frequency

[Damien Miller]

On Thu, 30 Mar 2023, Thorsten Glaser wrote:

> On Thu, 30 Mar 2023, Damien Miller wrote:
> 
> >> >+	return (uint64_t)1 << (c->block_size * 2);
> >> 
> >> … this get an upper bound? This is UB for 256-bit blocksizes
> >> at least…
> >
> >block sizes in struct sshcipher are in bytes, not bits
> 
> Yes, exactly.
> 
> 256 bit = 32 bytes; 32*2 = 64; (uint64_t)1 << 64 is UB.

oops yes

there are no 256-bit block ciphers specified for SSH anyway and none are
likely to be specified any time soon; wide block ciphers are rare outside
of storage encryption