On Tue, Apr 16, 2019 at 9:51 AM Conrad Meyer <c...@freebsd.org> wrote:
> Hi Warner, > > On Tue, Apr 16, 2019 at 8:47 AM Warner Losh <i...@bsdimp.com> wrote: > > On Tue, Apr 16, 2019 at 9:16 AM Ian Lepore <i...@freebsd.org> wrote: > >> Isn't a file full of data which is distributed in identical form to > >> everyone the exact opposite of entropy? > > Ian has the right idea. > > > It's just to bootstrap entropy for installs. The CI stuff doesn't matter > if that's the same since the CI images aren't exposed to the internet in > any way that would make it matter. The normal install would have the same > seeds of entropy, but diverge from there fairly quickly. The stuff that's > used early in the install is the don't care sort of things that won't > matter in the installer (which then creates it's own entropy that's > different for every install). > > I agree that it would be safe, although potentially misleading and > potentially dangerous, to create a fake entropy file for the installer > images. We need to be careful *not* to embed such files in .img files > which are installed by 'dd' directly to a disk or flash or VM, for > example. It would be catastrophic to distribute the same entropy file > to all FreeBSD AWS images. > In that case, we're better off having a MD routine that gets called if there's no loader-provided entropy pool. It would be responsible for generating it in a MD defined way. It would handle it or call panic() based on the requirements of the environment. This would answer the issue with embedded systems that do not have any writable store (and requiring an NV store is not even an option to require, so don't go there). It would let hardware with RNG generate something. It would let hardware without get it from wherever which may be highly specific to different scenarios or make the conscious decision not to get it at all vs panic, etc. What we can't do is just hang if the loader can't provide an entropy pool. Warner _______________________________________________ svn-src-head@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/svn-src-head To unsubscribe, send any mail to "svn-src-head-unsubscr...@freebsd.org"
