On Thu, Jun 22, 2017 at 10:09 AM, Shuah Khan <sh...@kernel.org> wrote: > On 06/22/2017 10:53 AM, Kees Cook wrote: >> On Thu, Jun 22, 2017 at 9:18 AM, Sumit Semwal <sumit.sem...@linaro.org> >> wrote: >>> Hi Kees, Andy, >>> >>> On 15 June 2017 at 23:26, Sumit Semwal <sumit.sem...@linaro.org> wrote: >>>> 3. 'seccomp ptrace hole closure' patches got added in 4.7 [3] - >>>> feature and test together. >>>> - This one also seems like a security hole being closed, and the >>>> 'feature' could be a candidate for stable backports, but Arnd tried >>>> that, and it was quite non-trivial. So perhaps we'll need some help >>>> from the subsystem developers here. >>> >>> Could you please help us sort this out? Our goal is to help Greg with >>> testing stable kernels, and currently the seccomp tests fail due to >>> missing feature (seccomp ptrace hole closure) getting tested via >>> latest kselftest. >>> >>> If you feel the feature isn't a stable candidate, then could you >>> please help make the test degrade gracefully in its absence? >> >> I don't really want to have that change be a backport -- it's quite >> invasive across multiple architectures. >> >> I would say just add a kernel version check to the test. This is >> probably not the only selftest that will need such things. :) > > Adding release checks to selftests is going to problematic for maintenance. > Tests should fail gracefully if feature isn't supported in older kernels. > > Several tests do that now and please find a way to check for dependencies > and feature availability and fail the test gracefully. If there is a test > that can't do that for some reason, we can discuss it, but as a general > rule, I don't want to see kselftest patches that check release.
If a future kernel inadvertently loses the new feature and degrades to the behavior of old kernels, that would be a serious bug and should be caught. --Andy
