On 7/30/20 4:50 PM, Stephen Smalley wrote: > On Thu, Jul 30, 2020 at 10:29 AM peter enderborg > <peter.enderb...@sony.com> wrote: >> I did manage to rebase it but this is about my approach. >> >> Compared to Thiébaud Weksteen patch this adds: >> >> 1 Filtering. Types goes to trace so we can put up a filter for contexts or >> type etc. >> >> 2 It tries also to cover non denies. And upon that you should be able to do >> coverage tools. >> I think many systems have a lot more rules that what is needed, but there is >> good way >> to find out what. A other way us to make a stat page for the rules, but >> this way connect to >> userspace and can be used for test cases. >> >> This code need a lot more work, but it shows how the filter should work >> (extra info is not right) >> and there are memory leaks, extra debug info and nonsense variable etc. > Perhaps the two of you could work together to come up with a common > tracepoint that addresses both needs.
Sounds good to me. > On the one hand, we don't need/want to duplicate the avc message > itself; we just need enough to be able to correlate them. > With respect to non-denials, SELinux auditallow statements can be used > to generate avc: granted messages that can be used to support coverage > tools although you can easily flood the logs that way. One other That is one reason to use trace. I can be used for things that generate a lot of data. Like memory allocations and scheduler etc, and it is a developer tool so you should not have to worry about DOS etc. Both netlink and android logging are too happy to throw away data for developers to be happy. > limitation of the other patch is that it doesn't support generating > trace information for denials silenced by dontaudit rules, which might > be challenging to debug especially on Android where you can't just run > semodule -DB to strip all dontaudits. I think that only work for rooted devices. Many application developers run on commercial devices that are locked, but they do have access to trace. But I have no idea if they (google) have intended the selinux traces to available there.
