netdev - Re: [PATCH bpf-next v3 03/10] bpf: btf: Introduce helpers for dynamic BTF set registration

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20210915180626.a367fkhp2gb23yfb@apollo.localdomain>
Date:   Wed, 15 Sep 2021 23:36:26 +0530
From:   Kumar Kartikeya Dwivedi <memxor@...il.com>
To:     Alexei Starovoitov <alexei.starovoitov@...il.com>
Cc:     bpf@...r.kernel.org, Alexei Starovoitov <ast@...nel.org>,
        Daniel Borkmann <daniel@...earbox.net>,
        Andrii Nakryiko <andrii@...nel.org>,
        Martin KaFai Lau <kafai@...com>,
        Song Liu <songliubraving@...com>, Yonghong Song <yhs@...com>,
        Jesper Dangaard Brouer <brouer@...hat.com>,
        Toke Høiland-Jørgensen <toke@...hat.com>,
        netdev@...r.kernel.org
Subject: Re: [PATCH bpf-next v3 03/10] bpf: btf: Introduce helpers for
 dynamic BTF set registration

On Wed, Sep 15, 2021 at 09:48:35PM IST, Alexei Starovoitov wrote:
> On Wed, Sep 15, 2021 at 10:39:36AM +0530, Kumar Kartikeya Dwivedi wrote:
> > This adds helpers for registering btf_id_set from modules and the
> > check_kfunc_call callback that can be used to look them up.
> >
> > With in kernel sets, the way this is supposed to work is, in kernel
> > callback looks up within the in-kernel kfunc whitelist, and then defers
> > to the dynamic BTF set lookup if it doesn't find the BTF id. If there is
> > no in-kernel BTF id set, this callback can be used directly.
> >
> > Also fix includes for btf.h and bpfptr.h so that they can included in
> > isolation. This is in preparation for their usage in tcp_bbr, tcp_cubic
> > and tcp_dctcp modules in the next patch.
> >
> > Signed-off-by: Kumar Kartikeya Dwivedi <memxor@...il.com>
> > ---
> >  include/linux/bpfptr.h |  1 +
> >  include/linux/btf.h    | 32 ++++++++++++++++++++++++++
> >  kernel/bpf/btf.c       | 51 ++++++++++++++++++++++++++++++++++++++++++
> >  3 files changed, 84 insertions(+)
> >
> > diff --git a/include/linux/bpfptr.h b/include/linux/bpfptr.h
> > index 546e27fc6d46..46e1757d06a3 100644
> > --- a/include/linux/bpfptr.h
> > +++ b/include/linux/bpfptr.h
> > @@ -3,6 +3,7 @@
> >  #ifndef _LINUX_BPFPTR_H
> >  #define _LINUX_BPFPTR_H
> >
> > +#include <linux/mm.h>
>
> Could you explain what this is for?
>

When e.g. tcp_bbr.c includes btf.h and btf_ids.h without this, it leads to this
error.

                 from net/ipv4/tcp_bbr.c:59:
./include/linux/bpfptr.h: In function ‘kvmemdup_bpfptr’:
./include/linux/bpfptr.h:67:19: error: implicit declaration of function ‘kvmalloc’;
 did you mean ‘kmalloc’? [-Werror=implicit-function-declaration]
   67 |         void *p = kvmalloc(len, GFP_USER | __GFP_NOWARN);
      |                   ^~~~~~~~
      |                   kmalloc
./include/linux/bpfptr.h:67:19: warning: initialization of ‘void *’ from ‘int’
	makes pointer from integer without a cast [-Wint-conversion]
./include/linux/bpfptr.h:72:17: error: implicit declaration of function ‘kvfree’;
	did you mean ‘kfree’? [-Werror=implicit-function-declaration]
   72 |                 kvfree(p);
      |                 ^~~~~~
      |                 kfree

> >  #include <linux/sockptr.h>

--
Kartikeya