On Tue, May 21, 2024 at 01:12:57AM +0300, Jarkko Sakkinen wrote: > On Tue May 21, 2024 at 12:13 AM EEST, Tycho Andersen wrote: > > On Mon, May 20, 2024 at 12:25:27PM -0700, Jonathan Calmels wrote: > > > On Mon, May 20, 2024 at 07:30:14AM GMT, Tycho Andersen wrote: > > > > there is an ongoing effort (started at [0]) to constify the first arg > > > > here, since you're not supposed to write to it. Your usage looks > > > > correct to me, so I think all it needs is a literal "const" here. > > > > > > Will do, along with the suggestions from Jarkko > > > > > > > > + struct ctl_table t; > > > > > + unsigned long mask_array[2]; > > > > > + kernel_cap_t new_mask, *mask; > > > > > + int err; > > > > > + > > > > > + if (write && (!capable(CAP_SETPCAP) || > > > > > + !capable(CAP_SYS_ADMIN))) > > > > > + return -EPERM; > > > > > > > > ...why CAP_SYS_ADMIN? You mention it in the changelog, but don't > > > > explain why. > > > > > > No reason really, I was hoping we could decide what we want here. > > > UMH uses CAP_SYS_MODULE, Serge mentioned adding a new cap maybe. > > > > I don't have a strong preference between SETPCAP and a new capability, > > but I do think it should be just one. SYS_ADMIN is already god mode > > enough, IMO. > > Sometimes I think would it make more sense to invent something > completely new like capabilities but more modern and robust, instead of > increasing complexity of a broken mechanism (especially thanks to > CAP_MAC_ADMIN). > > I kind of liked the idea of privilege tokens both in Symbian and Maemo > (have been involved professionally in both). Emphasis on the idea not > necessarily on implementation. > > Not an LSM but like something that you could use in the place of POSIX > caps. Probably quite tedious effort tho because you would need to pull > the whole industry with the new thing... And then we have LSM hooks, (ns_)capable(), __secure_computing() plus a new set of hooks for this new thing sprinkled around. I guess kernel developers wouldn't be excited about it, let alone the rest of the industry :) Thinking out loud: I wonder if fixing the seccomp TOCTOU against pointers would help here. I guess you'd still have issues where your policy engine resolves a path arg to open() and that inode changes between the decision and the actual vfs access, you have just changed the TOCTOU. Or even scarier: what if you could change the return value at any kprobe? :) Tycho
