From: KP Singh <kpsingh@chromium.org>
To: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc: James Morris <jmorris@namei.org>,
open list <linux-kernel@vger.kernel.org>,
bpf <bpf@vger.kernel.org>,
Linux Security Module list
<linux-security-module@vger.kernel.org>,
Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
Florent Revest <revest@chromium.org>,
Brendan Jackman <jackmanb@chromium.org>,
Mimi Zohar <zohar@linux.ibm.com>
Subject: Re: [PATCH bpf-next 2/3] bpf: Add a BPF helper for getting the IMA hash of an inode
Date: Tue, 24 Nov 2020 12:04:57 +0100 [thread overview]
Message-ID: <CACYkzJ4i9qCgBRm3_pt19Tty4eR0RTMOg66f-_Rb7N3mBvgU8w@mail.gmail.com> (raw)
In-Reply-To: <20201124040220.oyajc7wqn7gqgyib@ast-mbp>
On Tue, Nov 24, 2020 at 5:02 AM Alexei Starovoitov
<alexei.starovoitov@gmail.com> wrote:
>
> On Fri, Nov 20, 2020 at 01:17:07PM +0000, KP Singh wrote:
> > +
> > +static bool bpf_ima_inode_hash_allowed(const struct bpf_prog *prog)
> > +{
> > + return bpf_lsm_is_sleepable_hook(prog->aux->attach_btf_id);
> > +}
> > +
> > +BTF_ID_LIST_SINGLE(bpf_ima_inode_hash_btf_ids, struct, inode)
> > +
> > +const static struct bpf_func_proto bpf_ima_inode_hash_proto = {
> > + .func = bpf_ima_inode_hash,
> > + .gpl_only = false,
> > + .ret_type = RET_INTEGER,
> > + .arg1_type = ARG_PTR_TO_BTF_ID,
> > + .arg1_btf_id = &bpf_ima_inode_hash_btf_ids[0],
> > + .arg2_type = ARG_PTR_TO_UNINIT_MEM,
> > + .arg3_type = ARG_CONST_SIZE_OR_ZERO,
> > + .allowed = bpf_ima_inode_hash_allowed,
> > +};
> > +
> > static const struct bpf_func_proto *
> > bpf_lsm_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
> > {
> > @@ -97,6 +121,8 @@ bpf_lsm_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
> > return &bpf_task_storage_delete_proto;
> > case BPF_FUNC_bprm_opts_set:
> > return &bpf_bprm_opts_set_proto;
> > + case BPF_FUNC_ima_inode_hash:
> > + return &bpf_ima_inode_hash_proto;
>
> That's not enough for correctness.
> Not only hook has to sleepable, but the program has to be sleepable too.
> The patch 3 should be causing all sort of kernel warnings
> for calling mutex from preempt disabled.
> There it calls bpf_ima_inode_hash() from SEC("lsm/file_mprotect") program.
I did actually mean to use SEC("lsm.s/bprm_committed_creds"), my bad.
> "lsm/" is non-sleepable. "lsm.s/" is.
> please enable CONFIG_DEBUG_ATOMIC_SLEEP=y in your config.
Oops, yes I did notice that during recent work on the test cases.
Since we need a stronger check than just warnings, I am doing
something similar to
what we do for bpf_copy_from_user i.e.
return prog->aux->sleepable ? &bpf_ima_inode_hash_proto : NULL;
next prev parent reply other threads:[~2020-11-24 11:05 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-20 13:17 [PATCH bpf-next 1/3] ima: Implement ima_inode_hash KP Singh
2020-11-20 13:17 ` [PATCH bpf-next 2/3] bpf: Add a BPF helper for getting the IMA hash of an inode KP Singh
2020-11-20 17:47 ` Yonghong Song
2020-11-21 0:14 ` KP Singh
2020-11-24 4:02 ` Alexei Starovoitov
2020-11-24 11:04 ` KP Singh [this message]
2020-11-24 15:01 ` KP Singh
2020-11-20 13:17 ` [PATCH bpf-next 3/3] bpf: Update LSM selftests for bpf_ima_inode_hash KP Singh
2020-11-20 18:11 ` Yonghong Song
2020-11-21 0:20 ` KP Singh
2020-11-20 17:32 ` [PATCH bpf-next 1/3] ima: Implement ima_inode_hash Yonghong Song
2020-11-21 0:08 ` KP Singh
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=CACYkzJ4i9qCgBRm3_pt19Tty4eR0RTMOg66f-_Rb7N3mBvgU8w@mail.gmail.com \
--to=kpsingh@chromium.org \
--cc=alexei.starovoitov@gmail.com \
--cc=ast@kernel.org \
--cc=bpf@vger.kernel.org \
--cc=daniel@iogearbox.net \
--cc=jackmanb@chromium.org \
--cc=jmorris@namei.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-security-module@vger.kernel.org \
--cc=revest@chromium.org \
--cc=zohar@linux.ibm.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).