From: "Mickaël Salaün" <mic@digikod.net>
To: linux-kernel@vger.kernel.org
Cc: Alexei Starovoitov <ast@kernel.org>,
Andy Lutomirski <luto@amacapital.net>,
Arnd Bergmann <arnd@arndb.de>,
Casey Schaufler <casey@schaufler-ca.com>,
Daniel Borkmann <daniel@iogearbox.net>,
Daniel Mack <daniel@zonque.org>,
David Drysdale <drysdale@google.com>,
"David S . Miller" <davem@davemloft.net>,
Elena Reshetova <elena.reshetova@intel.com>,
"Eric W . Biederman" <ebiederm@xmission.com>,
James Morris <james.l.morris@oracle.com>,
Kees Cook <keescook@chromium.org>, Paul Moore <pmoore@redhat.com>,
Sargun Dhillon <sargun@sargun.me>,
"Serge E . Hallyn" <serge@hallyn.com>, Tejun Heo <tj@kernel.org>,
Will Drewry <wad@chromium.org>,
kernel-hardening@lists.openwall.com, linux-api@vger.kernel.org,
linux-security-module@vger.kernel.org, netdev@vger.kernel.org,
cgroups@vger.kernel.org
Subject: Re: [RFC v3 17/22] cgroup: Add access check for cgroup_get_from_fd()
Date: Thu, 15 Sep 2016 00:06:22 +0200 [thread overview]
Message-ID: <57D9C9DE.3090501@digikod.net> (raw)
In-Reply-To: <20160914072415.26021-18-mic@digikod.net>
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On 14/09/2016 09:24, Mickaël Salaün wrote:
> Add security access check for cgroup backed FD. The "cgroup.procs" file
> of the corresponding cgroup must be readable to identify the cgroup, and
> writable to prove that the current process can manage this cgroup (e.g.
> through delegation). This is similar to the check done by
> cgroup_procs_write_permission().
>
> Signed-off-by: Mickaël Salaün <mic@digikod.net>
> Cc: Alexei Starovoitov <ast@kernel.org>
> Cc: Andy Lutomirski <luto@amacapital.net>
> Cc: Daniel Borkmann <daniel@iogearbox.net>
> Cc: Daniel Mack <daniel@zonque.org>
> Cc: David S. Miller <davem@davemloft.net>
> Cc: Kees Cook <keescook@chromium.org>
> Cc: Tejun Heo <tj@kernel.org>
> ---
> include/linux/cgroup.h | 2 +-
> kernel/bpf/arraymap.c | 2 +-
> kernel/bpf/syscall.c | 6 +++---
> kernel/cgroup.c | 16 +++++++++++++++-
> 4 files changed, 20 insertions(+), 6 deletions(-)
...
> diff --git a/kernel/cgroup.c b/kernel/cgroup.c
> index 48b650a640a9..3bbaf3f02ed2 100644
> --- a/kernel/cgroup.c
> +++ b/kernel/cgroup.c
> @@ -6241,17 +6241,20 @@ EXPORT_SYMBOL_GPL(cgroup_get_from_path);
> /**
> * cgroup_get_from_fd - get a cgroup pointer from a fd
> * @fd: fd obtained by open(cgroup2_dir)
> + * @access_mask: contains the permission mask
> *
> * Find the cgroup from a fd which should be obtained
> * by opening a cgroup directory. Returns a pointer to the
> * cgroup on success. ERR_PTR is returned if the cgroup
> * cannot be found.
> */
> -struct cgroup *cgroup_get_from_fd(int fd)
> +struct cgroup *cgroup_get_from_fd(int fd, int access_mask)
> {
> struct cgroup_subsys_state *css;
> struct cgroup *cgrp;
> struct file *f;
> + struct inode *inode;
> + int ret;
>
> f = fget_raw(fd);
> if (!f)
> @@ -6268,6 +6271,17 @@ struct cgroup *cgroup_get_from_fd(int fd)
> return ERR_PTR(-EBADF);
> }
>
> + ret = -ENOMEM;
> + inode = kernfs_get_inode(f->f_path.dentry->d_sb, cgrp->procs_file.kn);
I forgot to properly move fput(f) after this line… This will be fixed.
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next prev parent reply other threads:[~2016-09-14 22:08 UTC|newest]
Thread overview: 76+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-09-14 7:23 [RFC v3 00/22] Landlock LSM: Unprivileged sandboxing Mickaël Salaün
2016-09-14 7:23 ` [RFC v3 01/22] landlock: Add Kconfig Mickaël Salaün
2016-09-14 7:23 ` [RFC v3 02/22] bpf: Move u64_to_ptr() to BPF headers and inline it Mickaël Salaün
2016-09-14 7:23 ` [RFC v3 03/22] bpf,landlock: Add a new arraymap type to deal with (Landlock) handles Mickaël Salaün
2016-09-14 18:51 ` Alexei Starovoitov
2016-09-14 23:22 ` Mickaël Salaün
2016-09-14 23:28 ` Alexei Starovoitov
2016-09-15 21:51 ` Mickaël Salaün
2016-10-03 23:53 ` Kees Cook
2016-10-05 22:02 ` Mickaël Salaün
2016-09-14 7:23 ` [RFC v3 04/22] bpf: Set register type according to is_valid_access() Mickaël Salaün
2016-10-19 14:54 ` Thomas Graf
2016-10-19 15:10 ` Daniel Borkmann
2016-09-14 7:23 ` [RFC v3 05/22] bpf,landlock: Add eBPF program subtype and is_valid_subtype() verifier Mickaël Salaün
2016-10-19 15:01 ` Thomas Graf
2016-09-14 7:23 ` [RFC v3 06/22] landlock: Add LSM hooks Mickaël Salaün
2016-10-19 15:19 ` Thomas Graf
2016-10-19 22:42 ` Mickaël Salaün
2016-09-14 7:24 ` [RFC v3 07/22] landlock: Handle file comparisons Mickaël Salaün
2016-09-14 19:07 ` Jann Horn
2016-09-14 22:39 ` Mickaël Salaün
2016-09-14 21:06 ` Alexei Starovoitov
2016-09-14 23:02 ` Mickaël Salaün
2016-09-14 23:24 ` Alexei Starovoitov
2016-09-15 21:25 ` Mickaël Salaün
2016-09-20 0:12 ` lsm naming dilemma. " Alexei Starovoitov
2016-09-20 1:10 ` Sargun Dhillon
2016-09-20 16:58 ` Mickaël Salaün
2016-10-03 23:30 ` Kees Cook
2016-09-14 7:24 ` [RFC v3 08/22] seccomp: Fix documentation for struct seccomp_filter Mickaël Salaün
2016-09-14 7:24 ` [RFC v3 09/22] seccomp: Move struct seccomp_filter in seccomp.h Mickaël Salaün
2016-09-14 7:24 ` [RFC v3 10/22] seccomp: Split put_seccomp_filter() with put_seccomp() Mickaël Salaün
2016-09-14 7:24 ` [RFC v3 11/22] seccomp,landlock: Handle Landlock hooks per process hierarchy Mickaël Salaün
2016-09-14 18:43 ` Andy Lutomirski
2016-09-14 22:34 ` Mickaël Salaün
2016-10-03 23:52 ` Kees Cook
2016-10-05 21:05 ` Mickaël Salaün
2016-09-14 7:24 ` [RFC v3 12/22] bpf: Cosmetic change for bpf_prog_attach() Mickaël Salaün
2016-09-14 7:24 ` [RFC v3 13/22] bpf/cgroup: Replace struct bpf_prog with union bpf_object Mickaël Salaün
2016-09-14 7:24 ` [RFC v3 14/22] bpf/cgroup: Make cgroup_bpf_update() return an error code Mickaël Salaün
2016-09-14 21:16 ` Alexei Starovoitov
2016-09-14 7:24 ` [RFC v3 15/22] bpf/cgroup: Move capability check Mickaël Salaün
2016-09-14 7:24 ` [RFC v3 16/22] bpf/cgroup,landlock: Handle Landlock hooks per cgroup Mickaël Salaün
2016-10-03 23:43 ` Kees Cook
2016-10-05 20:58 ` Mickaël Salaün
2016-10-05 21:25 ` Kees Cook
2016-09-14 7:24 ` [RFC v3 17/22] cgroup: Add access check for cgroup_get_from_fd() Mickaël Salaün
2016-09-14 22:06 ` Mickaël Salaün [this message]
2016-09-14 7:24 ` [RFC v3 18/22] cgroup,landlock: Add CGRP_NO_NEW_PRIVS to handle unprivileged hooks Mickaël Salaün
2016-09-14 18:27 ` Andy Lutomirski
2016-09-14 22:11 ` Mickaël Salaün
2016-09-15 1:25 ` Andy Lutomirski
2016-09-15 2:19 ` Alexei Starovoitov
2016-09-15 2:27 ` Andy Lutomirski
2016-09-15 4:00 ` Alexei Starovoitov
2016-09-15 4:08 ` Andy Lutomirski
2016-09-15 4:31 ` Alexei Starovoitov
2016-09-15 4:38 ` Andy Lutomirski
2016-09-15 4:48 ` Alexei Starovoitov
2016-09-15 19:41 ` Mickaël Salaün
2016-09-20 4:37 ` Sargun Dhillon
2016-09-20 17:02 ` Mickaël Salaün
2016-09-15 19:35 ` Mickaël Salaün
2016-09-14 7:24 ` [RFC v3 19/22] landlock: Add interrupted origin Mickaël Salaün
2016-09-14 18:29 ` Andy Lutomirski
2016-09-14 22:14 ` Mickaël Salaün
2016-09-15 1:19 ` Andy Lutomirski
2016-10-03 23:46 ` Kees Cook
2016-10-05 21:01 ` Mickaël Salaün
2016-09-14 7:24 ` [RFC v3 20/22] landlock: Add update and debug access flags Mickaël Salaün
2016-09-14 7:24 ` [RFC v3 21/22] bpf,landlock: Add optional skb pointer in the Landlock context Mickaël Salaün
2016-09-14 21:20 ` Alexei Starovoitov
2016-09-14 22:46 ` Mickaël Salaün
2016-09-14 7:24 ` [RFC v3 22/22] samples/landlock: Add sandbox example Mickaël Salaün
2016-09-14 21:24 ` Alexei Starovoitov
2016-09-14 14:36 ` [RFC v3 00/22] Landlock LSM: Unprivileged sandboxing David Laight
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