Re: [PATCH v1 1/2] io_uring, audit: audit IORING_OP_FADVISE but not IORING_OP_MADVISE
On Fri, Jan 27, 2023 at 12:24 PM Richard Guy Briggs <rgb(a)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 <rgb(a)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?
[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