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Add an ioctl if you need to be able to retrieve >>>>> that info. >>>> >>>> Yeah the problem is an IOCTL is even worse from the security pov. >>>> >>>> This is for an tool which doesn't have access to the file descriptor which provides that information. >>>> >>>> So using pidfd_getfd() or similar to get the FD and then call an IOCTL on it would be a security violation. >>>> >>>> The real question is how should we make this information public available in the system? >>> >>> Don't you have a way to make this info available in sysfs? Just like >>> networking exposes info about network devices in there that may come and >>> go? >> >> Yeah that was already tried as well and Greg summarized it as "sometimes you don't know how horrible something is until you tried it". >> >> So the memory accounting parts for DMA-buf files in sysfs were deprecated and removed again just a few weeks ago. And that was basically just a subset of what David tries to do here. >> >> The requirement is that you want to be able to access the stats for accelerators/GPUs drivers similar to how tools like "top" or "htop" work. E.g. everybody can access /proc/*/stat as well, it's just that some security related information are left out. >> >> As far as I can see we have only a couple of different options to fulfill that requirement and lowering the security for fdinfo like David's patch here suggests still looks like the most defensive one to me. > > It's not acceptable to make /proc//fdinfo accessible just to carve > out an exception for you. You can look at implementing something like > taskstats based on netlink transpart if you want to. What exactly do you mean with that? As far as I can see we can't expose per file descriptor information through netlink. What's actually the problem exposing things through fdinfo? As far as I can see it shouldn't be much of a problem exposing the directory for everybody and letting each file decide what the security checks should be. Regards, Christian.