From: Daniel Borkmann <daniel@iogearbox•net>
To: davem@davemloft•net
Cc: alexei.starovoitov@gmail•com, jannh@google•com, kafai@fb•com,
netdev@vger•kernel.org
Subject: Re: [PATCH net] bpf: don't let ldimm64 leak map addresses on unprivileged
Date: Mon, 08 May 2017 10:44:46 +0200 [thread overview]
Message-ID: <59102FFE.8000701@iogearbox.net> (raw)
In-Reply-To: <793c517a7d163c613ab886eb02d32efea9f902fd.1494194233.git.daniel@iogearbox.net>
On 05/08/2017 12:04 AM, Daniel Borkmann wrote:
> The patch fixes two things at once:
>
> 1) It checks the env->allow_ptr_leaks and only prints the map address to
> the log if we have the privileges to do so, otherwise it just dumps 0
> as we would when kptr_restrict is enabled on %pK. Given the latter is
> off by default and not every distro sets it, I don't want to rely on
> this, hence the 0 by default for unprivileged.
>
> 2) Printing of ldimm64 in the verifier log is currently broken in that
> we don't print the full immediate, but only the 32 bit part of the
> first insn part for ldimm64. Thus, fix this up as well; it's okay to
> access, since we verified all ldimm64 earlier already (including just
> constants) through replace_map_fd_with_map_ptr().
This one is also needed for the log (should come first):
Fixes: 1be7f75d1668 ("bpf: enable non-root eBPF programs")
> Fixes: cbd357008604 ("bpf: verifier (add ability to receive verification log)")
> Reported-by: Jann Horn <jannh@google•com>
> Signed-off-by: Daniel Borkmann <daniel@iogearbox•net>
Thanks,
Daniel
next prev parent reply other threads:[~2017-05-08 8:44 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-05-07 22:04 [PATCH net] bpf: don't let ldimm64 leak map addresses on unprivileged Daniel Borkmann
2017-05-07 22:26 ` Jann Horn
2017-05-07 22:51 ` Daniel Borkmann
2017-05-07 22:54 ` Jann Horn
2017-05-08 8:44 ` Daniel Borkmann [this message]
2017-05-08 17:18 ` Alexei Starovoitov
2017-05-08 19:08 ` David Miller
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