On Sat, Oct 12, 2019 at 5:12 PM Daniel Colascione <dancol@xxxxxxxxxx> wrote: > > On Sat, Oct 12, 2019 at 4:09 PM Andy Lutomirski <luto@xxxxxxxxxx> wrote: > > > > On Sat, Oct 12, 2019 at 12:16 PM Daniel Colascione <dancol@xxxxxxxxxx> wrote: > > > > > > Use the secure anonymous inode LSM hook we just added to let SELinux > > > policy place restrictions on userfaultfd use. The create operation > > > applies to processes creating new instances of these file objects; > > > transfer between processes is covered by restrictions on read, write, > > > and ioctl access already checked inside selinux_file_receive. > > > > This is great, and I suspect we'll want it for things like SGX, too. > > But the current design seems like it will make it essentially > > impossible for SELinux to reference an anon_inode class whose > > file_operations are in a module, and moving file_operations out of a > > module would be nasty. > > > > Could this instead be keyed off a new struct anon_inode_class, an > > enum, or even just a string? > > The new LSM hook already receives the string that callers pass to the > anon_inode APIs; modules can look at that instead of the fops if they > want. The reason to pass both the name and the fops through the hook > is to allow LSMs to match using fops comparison (which seems less > prone to breakage) when possible and rely on string matching when it > isn't. I suppose that whoever makes the first module that wants to use this mechanism can have the fun task of reworking it. There's nothing user-visible here that would make it hard to change in the future.
