linux-kernel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Andy Lutomirski <luto@amacapital.net>
To: Will Drewry <wad@chromium.org>, linux-kernel@vger.kernel.org
Cc: Casey Schaufler <casey@schaufler-ca.com>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Jamie Lokier <jamie@shareable.org>,
	keescook@chromium.org, john.johansen@canonical.com,
	serge.hallyn@canonical.com, coreyb@linux.vnet.ibm.com,
	pmoore@redhat.com, eparis@redhat.com, djm@mindrot.org,
	segoon@openwall.com, rostedt@goodmis.org, jmorris@namei.org,
	scarybeasts@gmail.com, avi@redhat.com, penberg@cs.helsinki.fi,
	viro@zeniv.linux.org.uk, mingo@elte.hu,
	akpm@linux-foundation.org, khilman@ti.com,
	borislav.petkov@amd.com, amwang@redhat.com, oleg@redhat.com,
	ak@linux.intel.com, eric.dumazet@gmail.com, gregkh@suse.de,
	dhowells@redhat.com, daniel.lezcano@free.fr,
	linux-fsdevel@vger.kernel.org,
	linux-security-module@vger.kernel.org, olofj@chromium.org,
	mhalcrow@google.com, dlaor@redhat.com, corbet@lwn.net,
	alan@lxorguk.ukuu.org.uk, Al Viro <viro@zeniv.linux.org.uk>,
	Andy Lutomirski <luto@amacapital.net>
Subject: [PATCH v3 0/4] PR_SET_NO_NEW_PRIVS, unshare, and chroot
Date: Mon, 30 Jan 2012 08:17:25 -0800	[thread overview]
Message-ID: <cover.1327858005.git.luto@amacapital.net> (raw)

This adds PR_{GET,SET}_NO_NEW_PRIVS.  As an example of its use, it
allows some unshare operations and (sometimes) chroot when no_new_privs
is set.  Another example is the experimental pam module here:

http://web.mit.edu/luto/www/linux/

After some impressively long mailing list threads, I still think that
blocking setresuid, setuid, and capset in no_new_privs mode is
unnecessary and overcomplicated.  Additionally, blocking those calls
will make my pam module either fail or become a giant security hole
(depending on how carefully the core pam stuff is written -- I haven't
checked).

Changes from v2:
 - Rebased onto a very recent -linus tree.
 - Changed prctl numbering.  (Needed because prctl 35 is now taken.)
 - Fixed a typo or two.
 - Removed explicit propagation of no_new_privs.  dup_task_struct is enough.
 - Reworked the chroot patch.  It now uses hopefully much more sane logic
   to decide whether the user is chrooted.  It also checks that fs is not
   shared (which was a big security hole in the earlier version).

For the git-inclined, this series is here:
https://git.kernel.org/?p=linux/kernel/git/luto/linux.git;a=shortlog;h=refs/heads/security/no_new_privs/patch_v3

Test it like this:

---- begin test case

#include <sys/prctl.h>
#include <stdio.h>
#include <unistd.h>
#include <errno.h>

#define PR_SET_NO_NEW_PRIVS 36
#define PR_GET_NO_NEW_PRIVS 37

int main()
{
  int nnp = prctl(PR_GET_NO_NEW_PRIVS, 0, 0, 0, 0);
  if (nnp == -EINVAL) {
    printf("Failed!\n");
    return 1;
  }

  printf("nnp was %d\n", nnp);

  if (prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0) != 0) {
    printf("Failed!\n");
    return 1;
  }

  nnp = prctl(PR_GET_NO_NEW_PRIVS, 0, 0, 0, 0);
  if (nnp == -EINVAL) {
    printf("Failed!\n");
    return 1;
  }

  printf("nnp is %d\n", nnp);

  printf("here goes...\n");
  execlp("bash", "bash", NULL);
  printf("Failed to exec bash\n");
  return 1;
}

---- end test case

Andy Lutomirski (3):
  Add PR_{GET,SET}_NO_NEW_PRIVS to prevent execve from granting privs
  Allow unprivileged CLONE_NEWUTS and CLONE_NEWIPC with no_new_privs
  Allow unprivileged chroot when safe

John Johansen (1):
  Fix apparmor for PR_{GET,SET}_NO_NEW_PRIVS

 fs/exec.c                  |   10 ++++++++-
 fs/open.c                  |   46 ++++++++++++++++++++++++++++++++++++++++++-
 include/linux/prctl.h      |   15 ++++++++++++++
 include/linux/sched.h      |    2 +
 include/linux/security.h   |    1 +
 kernel/nsproxy.c           |    8 ++++++-
 kernel/sys.c               |   10 +++++++++
 security/apparmor/domain.c |   35 +++++++++++++++++++++++++++++++++
 security/commoncap.c       |    7 ++++-
 security/selinux/hooks.c   |   10 ++++++++-
 10 files changed, 137 insertions(+), 7 deletions(-)

-- 
1.7.7.6


             reply	other threads:[~2012-01-30 16:18 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-01-30 16:17 Andy Lutomirski [this message]
2012-01-30 16:17 ` [PATCH v3 1/4] Add PR_{GET,SET}_NO_NEW_PRIVS to prevent execve from granting privs Andy Lutomirski
2012-02-01 18:14   ` Kees Cook
2012-01-30 16:17 ` [PATCH v3 2/4] Fix apparmor for PR_{GET,SET}_NO_NEW_PRIVS Andy Lutomirski
2012-01-30 16:17 ` [PATCH v3 3/4] Allow unprivileged CLONE_NEWUTS and CLONE_NEWIPC with no_new_privs Andy Lutomirski
2012-02-01 19:02   ` Kees Cook
2012-02-01 20:35     ` Andy Lutomirski
2012-01-30 16:17 ` [PATCH v3 4/4] Allow unprivileged chroot when safe Andy Lutomirski
2012-01-30 21:58   ` Colin Walters
2012-01-30 22:10     ` Andy Lutomirski
2012-01-30 22:41       ` Colin Walters
2012-01-30 22:43         ` Andy Lutomirski
2012-01-30 23:10           ` Colin Walters
2012-01-30 23:15             ` Andy Lutomirski
2012-01-30 23:55               ` Colin Walters
2012-01-31  0:13                 ` Andy Lutomirski
2012-01-30 22:18     ` Steven Rostedt
2012-01-30 22:28       ` Andy Lutomirski
2012-01-30 22:38       ` Will Drewry
2012-01-30 22:48         ` Colin Walters
2012-01-30 22:51         ` Andy Lutomirski
2012-02-09  9:35           ` Vasiliy Kulikov

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=cover.1327858005.git.luto@amacapital.net \
    --to=luto@amacapital.net \
    --cc=ak@linux.intel.com \
    --cc=akpm@linux-foundation.org \
    --cc=alan@lxorguk.ukuu.org.uk \
    --cc=amwang@redhat.com \
    --cc=avi@redhat.com \
    --cc=borislav.petkov@amd.com \
    --cc=casey@schaufler-ca.com \
    --cc=corbet@lwn.net \
    --cc=coreyb@linux.vnet.ibm.com \
    --cc=daniel.lezcano@free.fr \
    --cc=dhowells@redhat.com \
    --cc=djm@mindrot.org \
    --cc=dlaor@redhat.com \
    --cc=eparis@redhat.com \
    --cc=eric.dumazet@gmail.com \
    --cc=gregkh@suse.de \
    --cc=jamie@shareable.org \
    --cc=jmorris@namei.org \
    --cc=john.johansen@canonical.com \
    --cc=keescook@chromium.org \
    --cc=khilman@ti.com \
    --cc=linux-fsdevel@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-security-module@vger.kernel.org \
    --cc=mhalcrow@google.com \
    --cc=mingo@elte.hu \
    --cc=oleg@redhat.com \
    --cc=olofj@chromium.org \
    --cc=penberg@cs.helsinki.fi \
    --cc=pmoore@redhat.com \
    --cc=rostedt@goodmis.org \
    --cc=scarybeasts@gmail.com \
    --cc=segoon@openwall.com \
    --cc=serge.hallyn@canonical.com \
    --cc=torvalds@linux-foundation.org \
    --cc=viro@zeniv.linux.org.uk \
    --cc=wad@chromium.org \
    --subject='Re: [PATCH v3 0/4] PR_SET_NO_NEW_PRIVS, unshare, and chroot' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).