On Thu, Jan 12, 2012 at 5:41 PM, Andrew Lutomirski <luto@xxxxxxx> wrote: > 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. I'm happy to take a look at the AppArmor breakage. What's happening with it at the moment? -- Kees Cook ChromeOS Security -- 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
