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From: Daniel Borkmann <daniel@iogearbox•net>
To: Chenbo Feng <chenbofeng.kernel@gmail•com>,
	netdev@vger•kernel.org, SELinux <Selinux@tycho•nsa.gov>,
	linux-security-module@vger•kernel.org
Cc: Jeffrey Vander Stoep <jeffv@google•com>,
	Lorenzo Colitti <lorenzo@google•com>,
	Alexei Starovoitov <alexei.starovoitov@gmail•com>,
	Chenbo Feng <fengc@google•com>
Subject: Re: [PATCH net-next 4/4] selinux: bpf: Add addtional check for bpf object file receive
Date: Thu, 05 Oct 2017 01:44:35 +0200	[thread overview]
Message-ID: <59D57263.3080601@iogearbox.net> (raw)
In-Reply-To: <20171004182932.140028-5-chenbofeng.kernel@gmail.com>

On 10/04/2017 08:29 PM, Chenbo Feng wrote:
> From: Chenbo Feng <fengc@google•com>
>
> Introduce a bpf object related check when sending and receiving files
> through unix domain socket as well as binder. It checks if the receiving
> process have privilege to read/write the bpf map or use the bpf program.
> This check is necessary because the bpf maps and programs are using a
> anonymous inode as their shared inode so the normal way of checking the
> files and sockets when passing between processes cannot work properly on
> eBPF object. This check only works when the BPF_SYSCALL is configured.

[...]
> +/* This function will check the file pass through unix socket or binder to see
> + * if it is a bpf related object. And apply correspinding checks on the bpf
> + * object based on the type. The bpf maps and programs, not like other files and
> + * socket, are using a shared anonymous inode inside the kernel as their inode.
> + * So checking that inode cannot identify if the process have privilege to
> + * access the bpf object and that's why we have to add this additional check in
> + * selinux_file_receive and selinux_binder_transfer_files.
> + */
[...]

If selinux/lsm folks have some input on this one in particular, would
be great. The issue is not really tied to bpf specifically, but to the
use of anon-inodes wrt fd passing. Maybe some generic resolution can
be found to tackle this ...

  reply	other threads:[~2017-10-04 23:44 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-10-04 18:29 [PATCH 0/4] net-next: security: New file mode and LSM hooks for eBPF object permission control Chenbo Feng
2017-10-04 18:29 ` [PATCH net-next 1/4] bpf: Add file mode configuration into bpf maps Chenbo Feng
2017-10-04 23:29   ` Daniel Borkmann
2017-10-04 23:58     ` Chenbo Feng
2017-10-05  0:51       ` Daniel Borkmann
2017-10-04 18:29 ` [PATCH net-next 2/4] security: bpf: Add LSM hooks for bpf object related syscall Chenbo Feng
2017-10-12  0:31   ` James Morris
2017-10-04 18:29 ` [PATCH net-next 3/4] selinux: bpf: Add selinux check for eBPF syscall operations Chenbo Feng
2017-10-05 13:28   ` Stephen Smalley
2017-10-05 16:12     ` Daniel Borkmann
2017-10-04 18:29 ` [PATCH net-next 4/4] selinux: bpf: Add addtional check for bpf object file receive Chenbo Feng
2017-10-04 23:44   ` Daniel Borkmann [this message]
2017-10-04 23:52     ` Daniel Borkmann
2017-10-05 13:37   ` Stephen Smalley
2017-10-05 18:26     ` Stephen Smalley
2017-10-06 21:10       ` Chenbo Feng
2017-10-06 21:00     ` Chenbo Feng

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