On Fri, Jan 27, 2023 at 5:55 PM Richard Guy Briggs <r...@redhat.com> wrote: > On 2023-01-27 17:35, Paul Moore wrote: > > On Fri, Jan 27, 2023 at 12:24 PM Richard Guy Briggs <r...@redhat.com> wrote: > > > > > > Since FADVISE can truncate files and MADVISE operates on memory, reverse > > > the audit_skip tags. > > > > > > Fixes: 5bd2182d58e9 ("audit,io_uring,io-wq: add some basic audit support > > > to io_uring") > > > Signed-off-by: Richard Guy Briggs <r...@redhat.com> > > > --- > > > io_uring/opdef.c | 2 +- > > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > > > diff --git a/io_uring/opdef.c b/io_uring/opdef.c > > > index 3aa0d65c50e3..a2bf53b4a38a 100644 > > > --- a/io_uring/opdef.c > > > +++ b/io_uring/opdef.c > > > @@ -306,12 +306,12 @@ const struct io_op_def io_op_defs[] = { > > > }, > > > [IORING_OP_FADVISE] = { > > > .needs_file = 1, > > > - .audit_skip = 1, > > > .name = "FADVISE", > > > .prep = io_fadvise_prep, > > > .issue = io_fadvise, > > > }, > > > > I've never used posix_fadvise() or the associated fadvise64*() > > syscalls, but from quickly reading the manpages and the > > generic_fadvise() function in the kernel I'm missing where the fadvise > > family of functions could be used to truncate a file, can you show me > > where this happens? The closest I can see is the manipulation of the > > page cache, but that shouldn't actually modify the file ... right? > > I don't know. I was going on the advice of Steve Grubb. I'm looking > for feedback, validation, correction, here.
Keep in mind it's your name on the patch, not Steve's, and I would hope that you should be able to stand up and vouch for your own patch. Something to keep in mind for the future. As it stands, I think the audit_skip line should stay for IORING_OP_FADVISE, if you feel otherwise please provide more explanation as to why auditing is necessary for this operation. > > > [IORING_OP_MADVISE] = { > > > + .audit_skip = 1, > > > .name = "MADVISE", > > > .prep = io_madvise_prep, > > > .issue = io_madvise, > > > > I *think* this should be okay, what testing/verification have you done > > on this? One of the things I like to check is to see if any LSMs > > might perform an access check and/or generate an audit record on an > > operation, if there is a case where that could happen we should setup > > audit properly. I did a very quick check of do_madvise() and nothing > > jumped out at me, but I would be interested in knowing what testing or > > verification you did here. > > No testing other than build/boot/audit-testsuite. You had a test you > had developed that went through several iterations? There is an io_uring test in the audit-testsuite that verifies basic audit record generation, it is not exhaustive. Patch 2/2 is a no-go from a security perspective (we want to see those records), and I think skipping on IORING_OP_FADVISE is the correct thing to do. It may be that skipping on IORING_OP_MADVISE is the correct thing, but given that it doesn't appear a lot of in-depth investigation has gone into these patches I would really like to see some more reasoning on this before we change the current behavior. -- paul-moore.com -- Linux-audit mailing list Linux-audit@redhat.com https://listman.redhat.com/mailman/listinfo/linux-audit