On Fri, Jan 27, 2023 at 12:24 PM Richard Guy Briggs <rgb@xxxxxxxxxx> 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 <rgb@xxxxxxxxxx>
> ---
> 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?
> [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.
--
paul-moore.com
