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From: Paul Moore <[email protected]>
To: Jens Axboe <[email protected]>
Cc: Richard Guy Briggs <[email protected]>,
	Linux-Audit Mailing List <[email protected]>,
	LKML <[email protected]>,
	[email protected], Eric Paris <[email protected]>,
	Steve Grubb <[email protected]>, Stefan Roesch <[email protected]>,
	Christian Brauner <[email protected]>,
	Pavel Begunkov <[email protected]>
Subject: Re: [PATCH v1 1/2] io_uring,audit: audit IORING_OP_FADVISE but not IORING_OP_MADVISE
Date: Fri, 27 Jan 2023 17:57:30 -0500	[thread overview]
Message-ID: <CAHC9VhSfG6Oddk3qeFYiwkE5orRKs_PCLAD+F0yK-fRx27UTwg@mail.gmail.com> (raw)
In-Reply-To: <[email protected]>

On Fri, Jan 27, 2023 at 5:45 PM Jens Axboe <[email protected]> wrote:
> On 1/27/23 3:35?PM, Paul Moore wrote:
> > On Fri, Jan 27, 2023 at 12:24 PM Richard Guy Briggs <[email protected]> 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 <[email protected]>
> >> ---
> >>  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?
>
> Yeah, honestly not sure where that came from. Maybe it's being mixed up
> with fallocate?

That was my thought too when I was looking at it.

> All fadvise (or madvise, for that matter) does is
> provide hints on the caching or access pattern. On second thought, both
> of these should be able to set audit_skip as far as I can tell.

Agreed on the fadvise side, and probably the madvise side too,
although the latter has more options/code to sift through so I'm
curious to hear what analysis Richard has done on that one.

-- 
paul-moore.com

  reply	other threads:[~2023-01-27 22:57 UTC|newest]

Thread overview: 32+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-01-27 17:23 [PATCH v1 0/2] two suggested iouring op audit updates Richard Guy Briggs
2023-01-27 17:23 ` [PATCH v1 1/2] io_uring,audit: audit IORING_OP_FADVISE but not IORING_OP_MADVISE Richard Guy Briggs
2023-01-27 22:35   ` Paul Moore
2023-01-27 22:45     ` Jens Axboe
2023-01-27 22:57       ` Paul Moore [this message]
2023-01-28 16:48         ` Steve Grubb
2023-01-27 23:02       ` Richard Guy Briggs
2023-01-27 23:03         ` Jens Axboe
2023-01-27 23:08           ` Richard Guy Briggs
2023-01-27 22:55     ` Richard Guy Briggs
2023-01-27 23:05       ` Paul Moore
2023-01-27 17:23 ` [PATCH v1 2/2] io_uring,audit: do not log IORING_OP_*GETXATTR Richard Guy Briggs
2023-01-27 22:43   ` Paul Moore
2023-01-27 23:01     ` Richard Guy Briggs
2023-01-27 23:05       ` Jens Axboe
2023-01-28  0:07         ` Paul Moore
2023-01-28  0:06       ` Paul Moore
2023-01-28  0:19         ` Richard Guy Briggs
2023-01-28 17:26     ` Steve Grubb
2023-01-29 23:37       ` Paul Moore
2023-01-27 17:40 ` [PATCH v1 0/2] two suggested iouring op audit updates Jens Axboe
2023-01-27 19:42   ` Paul Moore
2023-01-27 19:43     ` Jens Axboe
2023-01-27 22:38       ` Paul Moore
2023-01-27 22:46         ` Jens Axboe
2023-01-27 22:53           ` Paul Moore
2023-01-27 23:02             ` Jens Axboe
2023-01-27 23:07               ` Richard Guy Briggs
2023-01-27 23:08               ` Paul Moore
2023-01-27 23:10                 ` Jens Axboe
2023-01-28 16:47             ` Steve Grubb
2023-01-28 17:03               ` Paul Moore

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