On Thu, 2008-09-18 at 14:34 -0400, Stephen Smalley wrote: > On Thu, 2008-09-18 at 11:09 -0700, Eric W. Biederman wrote: > > Stephen Smalley <sds@xxxxxxxxxxxxx> writes: > > > > > On Thu, 2008-09-18 at 08:38 -0400, Stephen Smalley wrote: > > >> I do however think that the mantra that we can't require users to update > > >> policy for kernel changes is unsupportable in general. The precise set > > >> of permission checks on a given operation is not set in stone and it is > > >> not part of the kernel/userland interface/contract. Policy isn't > > >> "userspace"; it governs what userspace can do, and it has to adapt to > > >> kernel changes. > > > > > > I should note here that for changes to SELinux, we have gone out of our > > > way to avoid such breakage to date through the introduction of > > > compatibility switches, policy flags to enable any new checks, etc > > > (albeit at a cost in complexity and ever creeping compatibility code). > > > But changes to the rest of the kernel can just as easily alter the set > > > of permission checks that get applied on a given operation, and I don't > > > think we are always going to be able to guarantee that new kernel + old > > > policy will Just Work. > > > > I know of at least 2 more directories that I intend to turn into > > symlinks into somewhere under /proc/self. How do we keep from > > breaking selinux policies when I do that? > > I suspect we could tweak the logic in selinux_proc_get_sid() to always > label all symlinks under /proc with the base proc_t type already used > for e.g. /proc/self, at which point existing policies would be ok. FWIW, a fix for this issue has been applied to: git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/security-testing-2.6#next The particular commit can be viewed at: http://git.kernel.org/?p=linux/kernel/git/jmorris/security-testing-2.6.git;a=commit;h=ea6b184f7d521a503ecab71feca6e4057562252b This should address not only the /proc/net breakage but also any future changes to turn existing directories into symlinks. -- Stephen Smalley National Security Agency -- To unsubscribe from this list: send the line "unsubscribe kernel-testers" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
