On Thu, 13 Jan 2022 at 14:46, Jason A. Donenfeld <Jason@xxxxxxxxx> wrote: > > Hi Toke, > > On Thu, Jan 13, 2022 at 2:30 PM Toke Høiland-Jørgensen <toke@xxxxxxxxxx> wrote: > > Right, but that implies we need to work on a transition mechanism. For > > newly deployed systems changing the hash is obviously fine, it's the > > "reboot and you have a new address" problem. > > > > We could introduce new values to the addr_gen_mode? I.e. values of 4 and > > 5 would be equivalent to 2 and 3 (respectively), but with the new > > hashing algorithm? And then document that 2 and 3 are considered > > deprecated to be removed at some point in the future... > > Right, so this is exactly the flow of conversation I anticipated. > "Let's change it!" "No, we can't." "Okay, let's add a knob." > > The knob I was thinking about, though, was actually a compile-time one > CONFIG_NET_OBSOLETE_INSECURE_ADDRCONF_HASH, which itself is a `depends > on CONFIG_OLD_N_CRUSTY` or something. This way we could gate the > inclusion of sha1.c/sha1.o on that at compile time, and shave down > vmlinux a bit, which would make Geert happy. > > Then, at some point down the road, we can talk about removing > CONFIG_NET_OBSOLETE_INSECURE_ADDRCONF_HASH too. > What is the point of having CONFIG_OLD_N_CRUSTY if all distros are going to enable it indefinitely?
