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. -Kees -- Kees Cook Chrome OS Security -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
