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Re: Proposal: Disable autoload of compat_xyz modules



On Sun, 10 Sep 2017, Maxime Villard wrote:

Re-thinking about this again, it seems to me we could simply add a flags
field in modinfo_t, with a bit that says "if this module is builtin, then
don't load it". To use compat_xyz, you'll have to type modload, and the
kernel will load the module from the builtin list.

Something like [1] (from memory, not tested at all). Obviously this patch
is not complete, since we need to update each MODULE().

While it is clear that it does not solve the cross-dependency issue we're
having, it does reduce the attack surface almost as much as if the module
was not builtin, with very little effort. Cheap, but relevant.

[1] http://m00nbsd.net/garbage/module/noload.diff

Well, probably not quite what you wanted, but if a module is built-in you can disable it by using modunload(8). Any built-in module which has been disabled in this manner needs to be explicitly reload manually, and you'll need to additionally specify the -f option to modload(8).

Perhaps /etc/rc.d/modules can be updated to have both a load and an unload phase, with appropriate syntax for the associated config file.

This would be a lot cleaner IMHO than updating individual modules.



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