On Fri, Sep 04, 2015 at 01:58:25PM -0700, Alexei Starovoitov wrote: > On Fri, Sep 04, 2015 at 01:50:55PM -0700, Kees Cook wrote: > > On Fri, Sep 4, 2015 at 1:45 PM, Tycho Andersen > > <tycho.ander...@canonical.com> wrote: > > > On Fri, Sep 04, 2015 at 01:17:30PM -0700, Kees Cook wrote: > > >> On Fri, Sep 4, 2015 at 9:04 AM, Tycho Andersen > > >> <tycho.ander...@canonical.com> wrote: > > >> > This commit adds a way to dump eBPF programs. The initial > > >> > implementation > > >> > doesn't support maps, and therefore only allows dumping seccomp ebpf > > >> > programs which themselves don't currently support maps. > > >> > > > >> > We export the GPL bit as well as a unique ID for the program so that > > >> > > >> This unique ID appears to be the heap address for the prog. That's a > > >> huge leak, and should not be done. We don't want to introduce new > > >> kernel address leaks while we're trying to fix the remaining ones. > > >> Shouldn't the "unique ID" be the fd itself? I imagine KCMP_FILE > > >> could be used, for example. > > > > > > No; we acquire the fd per process, so if a task installs a filter and > > > then forks N times, we'll grab N (+1) copies of the filter from N (+1) > > > different file descriptors. Ideally, we'd have some way to figure out > > > that these were all the same. Some sort of prog_id is one way, > > > although there may be others. > > > > If KCMP_FILE or a new KCMP_BPF isn't possible, then we'll probably > > have to add a unique id (counter) to all bpf programs as they're > > created. > > I think tweaking KCMP_FILE for anon_inodes should do the trick > and should work at the end (if it's not working already).
Sounds good. I'll look into that for the next version, thanks. Tycho -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
