On Thu, Jan 12, 2012 at 5:37 PM, Will Drewry <wad@xxxxxxxxxxxx> wrote: > On Thu, Jan 12, 2012 at 7:11 PM, Andrew Lutomirski <luto@xxxxxxx> wrote: >> (Also, preventing dropping of privileges will probably make a patch >> more complicted -- I'll have to find and update all the places that >> allow dropping privileges.) > > An alternative approach might be that the restricted bit drops all > privileges that allows privilege changes in either direction. E.g., > - set restricted bit > -- adds a check anywhere MNT_NOSUID is > -- sets securebit to SECURE_NOROOT|..LOCKED > -- drops CAP_SETUID, CAP_DAC_OVERRIDE, ... > -- set the caps bounding set to the minimum the restricted bit allows > > That may deviate from the intent (by re-using caps), but it could keep some > of the privilege transition checking code the same. I'm not sure it'll be much of a simplification. The entire patch is 45 lines right now :) I'll test it and send it out. FWIW, though, it breaks apparmor (intentionally). Can any of you either explain what *should* happen or (better) volunteer to fix it? It should be about three lines of code for someone who understands what's going on. I don't have an apparmor system, so I can't really test it. --Andy > > Just a thought, > will -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
