On 6/2/21 4:46 PM, Richard Guy Briggs wrote: > On 2021-06-02 09:26, Pavel Begunkov wrote: >> On 5/28/21 5:02 PM, Paul Moore wrote: >>> On Wed, May 26, 2021 at 4:19 PM Paul Moore <paul@xxxxxxxxxxxxxx> wrote: >>>> ... If we moved the _entry >>>> and _exit calls into the individual operation case blocks (quick >>>> openat example below) so that only certain operations were able to be >>>> audited would that be acceptable assuming the high frequency ops were >>>> untouched? My initial gut feeling was that this would involve >50% of >>>> the ops, but Steve Grubb seems to think it would be less; it may be >>>> time to look at that a bit more seriously, but if it gets a NACK >>>> regardless it isn't worth the time - thoughts? >>>> >>>> case IORING_OP_OPENAT: >>>> audit_uring_entry(req->opcode); >>>> ret = io_openat(req, issue_flags); >>>> audit_uring_exit(!ret, ret); >>>> break; >>> >>> I wanted to pose this question again in case it was lost in the >>> thread, I suspect this may be the last option before we have to "fix" >>> things at the Kconfig level. I definitely don't want to have to go >>> that route, and I suspect most everyone on this thread feels the same, >>> so I'm hopeful we can find a solution that is begrudgingly acceptable >>> to both groups. >> >> May work for me, but have to ask how many, and what is the >> criteria? I'd think anything opening a file or manipulating fs: >> >> IORING_OP_ACCEPT, IORING_OP_CONNECT, IORING_OP_OPENAT[2], >> IORING_OP_RENAMEAT, IORING_OP_UNLINKAT, IORING_OP_SHUTDOWN, >> IORING_OP_FILES_UPDATE >> + coming mkdirat and others. >> >> IORING_OP_CLOSE? IORING_OP_SEND IORING_OP_RECV? >> >> What about? >> IORING_OP_FSYNC, IORING_OP_SYNC_FILE_RANGE, >> IORING_OP_FALLOCATE, IORING_OP_STATX, >> IORING_OP_FADVISE, IORING_OP_MADVISE, >> IORING_OP_EPOLL_CTL >> >> >> Another question, io_uring may exercise asynchronous paths, >> i.e. io_issue_sqe() returns before requests completes. >> Shouldn't be the case for open/etc at the moment, but was that >> considered? > > This would be why audit needs to monitor a thread until it wraps up, to > wait for the result code. My understanding is that both sync and async > parts of an op would be monitored. There may be a misunderstanding audit_start(req) ret = io_issue_sqe(req); audit_end(ret); io_issue_sqe() may return 0 but leave the request inflight, which will be completed asynchronously e.g. by IRQ, not going through io_issue_sqe() or any io_read()/etc helpers again, and after last audit_end() had already happened. That's the case with read/write/timeout, but is not true for open/etc. >> I don't see it happening, but would prefer to keep it open >> async reimplementation in a distant future. Does audit sleep? > > Some parts do, some parts don't depending on what they are interacting > with in the kernel. It can be made to not sleep if needed. Ok, good -- Pavel Begunkov
