From: sdf@google.com
To: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc: davem@davemloft.net, daniel@iogearbox.net,
netdev@vger.kernel.org, bpf@vger.kernel.org, kernel-team@fb.com,
linux-security-module@vger.kernel.org, acme@redhat.com,
jamorris@linux.microsoft.com, jannh@google.com,
kpsingh@google.com
Subject: Re: [PATCH v5 bpf-next 2/3] bpf: implement CAP_BPF
Date: Mon, 11 May 2020 17:12:10 -0700 [thread overview]
Message-ID: <20200512001210.GA235661@google.com> (raw)
In-Reply-To: <20200508215340.41921-3-alexei.starovoitov@gmail.com>
On 05/08, Alexei Starovoitov wrote:
> From: Alexei Starovoitov <ast@kernel.org>
[..]
> @@ -3932,7 +3977,7 @@ SYSCALL_DEFINE3(bpf, int, cmd, union bpf_attr
> __user *, uattr, unsigned int, siz
> union bpf_attr attr;
> int err;
> - if (sysctl_unprivileged_bpf_disabled && !capable(CAP_SYS_ADMIN))
> + if (sysctl_unprivileged_bpf_disabled && !bpf_capable())
> return -EPERM;
This is awesome, thanks for reviving the effort!
One question I have about this particular snippet:
Does it make sense to drop bpf_capable checks for the operations
that work on a provided fd?
The use-case I have in mind is as follows:
* privileged (CAP_BPF) process loads the programs/maps and pins
them at some known location
* unprivileged process opens up those pins and does the following:
* prepares the maps (and will later on read them)
* does SO_ATTACH_BPF/SO_ATTACH_REUSEPORT_EBPF which afaik don't
require any capabilities
This essentially pushes some of the permission checks into a fs layer. So
whoever has a file descriptor (via unix sock or open) can do BPF operations
on the object that represents it.
Thoughts? Am I missing something important?
next prev parent reply other threads:[~2020-05-12 0:12 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-08 21:53 [PATCH v5 bpf-next 0/3] Introduce CAP_BPF Alexei Starovoitov
2020-05-08 21:53 ` [PATCH v5 bpf-next 1/3] bpf, capability: " Alexei Starovoitov
2020-05-08 21:53 ` [PATCH v5 bpf-next 2/3] bpf: implement CAP_BPF Alexei Starovoitov
2020-05-12 0:12 ` sdf [this message]
2020-05-12 2:36 ` Alexei Starovoitov
2020-05-12 12:50 ` Jordan Glover
2020-05-12 15:46 ` Alexei Starovoitov
2020-05-12 15:54 ` sdf
2020-05-12 18:39 ` Alexei Starovoitov
2020-05-12 14:35 ` Daniel Borkmann
2020-05-12 18:25 ` Alexei Starovoitov
2020-05-12 20:07 ` Daniel Borkmann
2020-05-12 22:56 ` Alexei Starovoitov
2020-05-12 15:05 ` Daniel Borkmann
2020-05-12 18:29 ` Alexei Starovoitov
2020-05-12 20:09 ` Daniel Borkmann
2020-05-12 20:27 ` Daniel Borkmann
2020-05-12 23:01 ` Alexei Starovoitov
2020-05-08 21:53 ` [PATCH v5 bpf-next 3/3] selftests/bpf: use CAP_BPF and CAP_PERFMON in tests Alexei Starovoitov
2020-05-08 22:45 ` [PATCH v5 bpf-next 0/3] Introduce CAP_BPF Casey Schaufler
2020-05-08 23:00 ` Alexei Starovoitov
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