On Tue, 22 Jul 2025, Antoni Pokusinski wrote: > > If you get a KASAN warning when using "check=normal" or "check=strict", > > report it and I will fix it; with "check=none" it is not supposed to work. > > > > Mikulas > > > > I'm just wondering what should be the expected kernel behaviour in the situation where > "check=none" and the "ea_offs", "acl_size_s", "ea_size_s" fields of fnode are corrupt? > If we assume that in such case running into some undefined behavior (which is accessing > an unknown memory area) is alright, then the code does not need any changes. > But if we'd like to prevent it, then I think we should always check the extended > attribute address regardless of the "check" parameter, as demonstrated > in the patch. > > Kind regards, > Antoni There is a trade-off between speed and resiliency. If the user wants maximum speed and uses the filesystem only on trusted input, he can choose "check=none". If the user wants less performance and uses the filesystem on untrusted input, he can select "check=normal" (the default). If the user is modifying the code and wants maximum safeguards, he should select "check=strict" (that will degrade performance significantly, but it will stop the filesystem as soon as possible if something goes wrong). I think there is no need to add some middle ground where "check=none" would check some structures and won't check others. Mikulas
