linux-kernel - Re: [PATCH] bpftool: Use sysfs vmlinux when dumping BTF by ID

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 for Android: free password hash cracker in your pocket

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

Date:   Thu,  5 May 2022 15:56:26 +0200
From:   Larysa Zaremba <larysa.zaremba@...el.com>
To:     andrii.nakryiko@...il.com
Cc:     alexandr.lobakin@...el.com, andrii@...nel.org, ast@...nel.org,
        bpf@...r.kernel.org, daniel@...earbox.net, kafai@...com,
        larysa.zaremba@...el.com, linux-kernel@...r.kernel.org,
        maciej.fijalkowski@...el.com, netdev@...r.kernel.org,
        songliubraving@...com, yhs@...com
Subject: Re: [PATCH] bpftool: Use sysfs vmlinux when dumping BTF by ID

On Thu, 28 Apr 2022 21:58:58 -0700 Andrii Nakryiko <andrii@...nel.org> wrote:
> On Thu, Apr 28, 2022 at 4:17 AM Larysa Zaremba <larysa.zaremba@...el.com> wrote:
> >
> > Currently, dumping almost all BTFs specified by id requires
>
> It should and will work only for kernel modules. It won't and
> shouldn't work for BTFs coming from BPF programs. We shouldn't blindly
> guess and substitute vmlinux BTF as base BTF, let's fetch
> bpf_btf_info, check that BTF is from kernel and is not vmlinux, and
> only in such case substitute vmlinux BTF as base BTF.

I agree, this is taken into account in v2

> > using the -B option to pass the base BTF. For most cases
> > the vmlinux BTF sysfs path should work.
> >
> > This patch simplifies dumping by ID usage by attempting to
> > use vmlinux BTF from sysfs, if the first try of loading BTF by ID
> > fails with certain conditions.
> >
> > Signed-off-by: Larysa Zaremba <larysa.zaremba@...el.com>
> > Reviewed-by: Alexander Lobakin <alexandr.lobakin@...el.com>
> > ---
> >  tools/bpf/bpftool/btf.c | 35 ++++++++++++++++++++++++++---------
> >  1 file changed, 26 insertions(+), 9 deletions(-)
> >

Best Regards,
Larysa Zaremba