Hey Tyler :) On Wed, Aug 09, 2017 at 03:33:28PM -0500, Tyler Hicks wrote: > Hey Tycho! > > On 08/09/2017 03:22 PM, Tycho Andersen wrote: > > On Wed, Aug 09, 2017 at 12:01:53PM -0700, Kees Cook wrote: > >> This series is the result of Fabricio and I going around a few times > >> on possible solutions for finding a way to enhance RET_KILL to kill > >> the process group. There's a lot of ways this could be done, but I > >> wanted something that felt cleanest. As it happens, Tyler's recent > >> patch series for logging improvement also needs to know a litte bit > >> more during filter runs, and the solution for both is to pass back > >> the matched filter. This lets us examine it here for RET_KILL and > >> in the future for logging changes. > >> > >> The filter passing is patch 1, the new flag for RET_KILL is patch 2. > >> Some test refactoring is in patch 3 for the RET_DATA ordering, and > >> patch 4 is the test for the new RET_KILL flag. > >> > >> One thing missing is that CRIU will likely need to be updated, since > >> saving/restoring seccomp filter _rules_ will not include the filter > >> _flags_ for a process. This can be addressed separately. > > > > Thanks for the heads up, I suppose PTRACE_SECCOMP_GET_FLAGS similar to > > how PTRACE_SECCOMP_GET_FILTER works will be fine for this. One > > question is: would we then also need to keep track of the TSYNC flag? > > I don't think CRIU needs this to be correct, and we can grab the > > KILL_PROCESS flag from filter->kill_process, so perhaps it's moot. > > Note that the logging changes that I'm working on also introduce a new > filter flag (as Kees mentioned above). My filter flag is a lot like the > KILL_PROCESS filter flag in that it is stored as a member of the > seccomp_filter struct. > > I would think that you'd want to be able to do something like > PTRACE_SECCOMP_GET_FILTER to (hopefully) future proof CRIU against all > newly added filter flags. Yep, the theoretical GET_FLAGS above would handle this, I think. What I was wondering about is for TSYNC (or any future flags) which aren't tracked in the struct seccomp_filter; would the existence of GET_FLAGS mean we need to remember such flags as well somewhere? Not necessary for CRIU's correctness right now at least, but... Cheers, Tycho -- To unsubscribe from this list: send the line "unsubscribe linux-api" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
