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39 commits

Author SHA1 Message Date
Venkat Yekkirala
5b368e61c2 IPsec: correct semantics for SELinux policy matching
Currently when an IPSec policy rule doesn't specify a security
context, it is assumed to be "unlabeled" by SELinux, and so
the IPSec policy rule fails to match to a flow that it would
otherwise match to, unless one has explicitly added an SELinux
policy rule allowing the flow to "polmatch" to the "unlabeled"
IPSec policy rules. In the absence of such an explicitly added
SELinux policy rule, the IPSec policy rule fails to match and
so the packet(s) flow in clear text without the otherwise applicable
xfrm(s) applied.

The above SELinux behavior violates the SELinux security notion of
"deny by default" which should actually translate to "encrypt by
default" in the above case.

This was first reported by Evgeniy Polyakov and the way James Morris
was seeing the problem was when connecting via IPsec to a
confined service on an SELinux box (vsftpd), which did not have the
appropriate SELinux policy permissions to send packets via IPsec.

With this patch applied, SELinux "polmatching" of flows Vs. IPSec
policy rules will only come into play when there's a explicit context
specified for the IPSec policy rule (which also means there's corresponding
SELinux policy allowing appropriate domains/flows to polmatch to this context).

Secondly, when a security module is loaded (in this case, SELinux), the
security_xfrm_policy_lookup() hook can return errors other than access denied,
such as -EINVAL.  We were not handling that correctly, and in fact
inverting the return logic and propagating a false "ok" back up to
xfrm_lookup(), which then allowed packets to pass as if they were not
associated with an xfrm policy.

The solution for this is to first ensure that errno values are
correctly propagated all the way back up through the various call chains
from security_xfrm_policy_lookup(), and handled correctly.

Then, flow_cache_lookup() is modified, so that if the policy resolver
fails (typically a permission denied via the security module), the flow
cache entry is killed rather than having a null policy assigned (which
indicates that the packet can pass freely).  This also forces any future
lookups for the same flow to consult the security module (e.g. SELinux)
for current security policy (rather than, say, caching the error on the
flow cache entry).

This patch: Fix the selinux side of things.

This makes sure SELinux polmatching of flow contexts to IPSec policy
rules comes into play only when an explicit context is associated
with the IPSec policy rule.

Also, this no longer defaults the context of a socket policy to
the context of the socket since the "no explicit context" case
is now handled properly.

Signed-off-by: Venkat Yekkirala <vyekkirala@TrustedCS.com>
Signed-off-by: James Morris <jmorris@namei.org>
2006-10-11 23:59:37 -07:00
Eric Paris
bc7e982b84 [PATCH] SELinux: convert sbsec semaphore to a mutex
This patch converts the semaphore in the superblock security struct to a
mutex.  No locking changes or other code changes are done.

Signed-off-by: Eric Paris <eparis@redhat.com>
Acked-by: Stephen Smalley <sds@tycho.nsa.gov>
Acked-by: James Morris <jmorris@namei.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-09-26 08:48:53 -07:00
Eric Paris
2397074172 [PATCH] SELinux: change isec semaphore to a mutex
This patch converts the remaining isec->sem into a mutex.  Very similar
locking is provided as before only in the faster smaller mutex rather than a
semaphore.  An out_unlock path is introduced rather than the conditional
unlocking found in the original code.

Signed-off-by: Eric Paris <eparis@redhat.com>
Acked-by: Stephen Smalley <sds@tycho.nsa.gov>
Acked-by: James Morris <jmorris@namei.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-09-26 08:48:53 -07:00
Darrel Goeddel
f3f8771420 [PATCH] selinux: add support for range transitions on object classes
Introduces support for policy version 21.  This version of the binary
kernel policy allows for defining range transitions on security classes
other than the process security class.  As always, backwards compatibility
for older formats is retained.  The security class is read in as specified
when using the new format, while the "process" security class is assumed
when using an older policy format.

Signed-off-by: Darrel Goeddel <dgoeddel@trustedcs.com>
Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
Acked-by: James Morris <jmorris@namei.org>
Acked-by: Eric Paris <eparis@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-09-26 08:48:52 -07:00
Stephen Smalley
016b9bdb81 [PATCH] selinux: enable configuration of max policy version
Enable configuration of SELinux maximum supported policy version to support
legacy userland (init) that does not gracefully handle kernels that support
newer policy versions two or more beyond the installed policy, as in FC3
and FC4.

[bunk@stusta.de: improve Kconfig help text]
Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
Acked-by: James Morris <jmorris@namei.org>
Acked-by: Eric Paris <eparis@redhat.com>
Signed-off-by: Adrian Bunk <bunk@stusta.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-09-26 08:48:52 -07:00
Paul Moore
7a0e1d6022 [NetLabel]: add some missing #includes to various header files
Add some missing include files to the NetLabel related header files.

Signed-off-by: Paul Moore <paul.moore@hp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-09-22 15:18:39 -07:00
Paul Moore
e448e93130 [NetLabel]: uninline selinux_netlbl_inode_permission()
Uninline the selinux_netlbl_inode_permission() at the request of
Andrew Morton.

Signed-off-by: Paul Moore <paul.moore@hp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-09-22 15:18:38 -07:00
Paul Moore
99f59ed073 [NetLabel]: Correctly initialize the NetLabel fields.
Fix a problem where the NetLabel specific fields of the sk_security_struct
structure were not being initialized early enough in some cases.

Signed-off-by: Paul Moore <paul.moore@hp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-09-22 15:18:34 -07:00
Venkat Yekkirala
7420ed23a4 [NetLabel]: SELinux support
Add NetLabel support to the SELinux LSM and modify the
socket_post_create() LSM hook to return an error code.  The most
significant part of this patch is the addition of NetLabel hooks into
the following SELinux LSM hooks:

 * selinux_file_permission()
 * selinux_socket_sendmsg()
 * selinux_socket_post_create()
 * selinux_socket_sock_rcv_skb()
 * selinux_socket_getpeersec_stream()
 * selinux_socket_getpeersec_dgram()
 * selinux_sock_graft()
 * selinux_inet_conn_request()

The basic reasoning behind this patch is that outgoing packets are
"NetLabel'd" by labeling their socket and the NetLabel security
attributes are checked via the additional hook in
selinux_socket_sock_rcv_skb().  NetLabel itself is only a labeling
mechanism, similar to filesystem extended attributes, it is up to the
SELinux enforcement mechanism to perform the actual access checks.

In addition to the changes outlined above this patch also includes
some changes to the extended bitmap (ebitmap) and multi-level security
(mls) code to import and export SELinux TE/MLS attributes into and out
of NetLabel.

Signed-off-by: Paul Moore <paul.moore@hp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-09-22 14:53:36 -07:00
Venkat Yekkirala
a51c64f1e5 [MLSXFRM]: Fix build with SECURITY_NETWORK_XFRM disabled.
The following patch will fix the build problem (encountered by Andrew
Morton) when SECURITY_NETWORK_XFRM is not enabled.

As compared to git-net-selinux_xfrm_decode_session-build-fix.patch in
-mm, this patch sets the return parameter sid to SECSID_NULL in
selinux_xfrm_decode_session() and handles this value in the caller
selinux_inet_conn_request() appropriately.

Signed-off-by: Venkat Yekkirala <vyekkirala@TrustedCS.com>
Acked-by: James Morris <jmorris@namei.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-09-22 14:53:30 -07:00
Venkat Yekkirala
cb969f072b [MLSXFRM]: Default labeling of socket specific IPSec policies
This defaults the label of socket-specific IPSec policies to be the
same as the socket they are set on.

Signed-off-by: Venkat Yekkirala <vyekkirala@TrustedCS.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-09-22 14:53:28 -07:00
Venkat Yekkirala
beb8d13bed [MLSXFRM]: Add flow labeling
This labels the flows that could utilize IPSec xfrms at the points the
flows are defined so that IPSec policy and SAs at the right label can
be used.

The following protos are currently not handled, but they should
continue to be able to use single-labeled IPSec like they currently
do.

ipmr
ip_gre
ipip
igmp
sit
sctp
ip6_tunnel (IPv6 over IPv6 tunnel device)
decnet

Signed-off-by: Venkat Yekkirala <vyekkirala@TrustedCS.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-09-22 14:53:27 -07:00
Venkat Yekkirala
e0d1caa7b0 [MLSXFRM]: Flow based matching of xfrm policy and state
This implements a seemless mechanism for xfrm policy selection and
state matching based on the flow sid. This also includes the necessary
SELinux enforcement pieces.

Signed-off-by: Venkat Yekkirala <vyekkirala@TrustedCS.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-09-22 14:53:24 -07:00
Venkat Yekkirala
892c141e62 [MLSXFRM]: Add security sid to sock
This adds security for IP sockets at the sock level. Security at the
sock level is needed to enforce the SELinux security policy for
security associations even when a sock is orphaned (such as in the TCP
LAST_ACK state).

This will also be used to enforce SELinux controls over data arriving
at or leaving a child socket while it's still waiting to be accepted.

Signed-off-by: Venkat Yekkirala <vyekkirala@TrustedCS.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-09-22 14:53:22 -07:00
Venkat Yekkirala
08554d6b33 [MLSXFRM]: Define new SELinux service routine
This defines a routine that combines the Type Enforcement portion of
one sid with the MLS portion from the other sid to arrive at a new
sid. This would be used to define a sid for a security association
that is to be negotiated by IKE as well as for determing the sid for
open requests and connection-oriented child sockets.

Signed-off-by: Venkat Yekkirala <vyekkirala@TrustedCS.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-09-22 14:53:21 -07:00
Venkat Yekkirala
51bd39860f [MLSXFRM]: Granular IPSec associations for use in MLS environments
The current approach to labeling Security Associations for SELinux
purposes uses a one-to-one mapping between xfrm policy rules and
security associations.

This doesn't address the needs of real world MLS (Multi-level System,
traditional Bell-LaPadula) environments where a single xfrm policy
rule (pertaining to a range, classified to secret for example) might
need to map to multiple Security Associations (one each for
classified, secret, top secret and all the compartments applicable to
these security levels).

This patch set addresses the above problem by allowing for the mapping
of a single xfrm policy rule to multiple security associations, with
each association used in the security context it is defined for. It
also includes the security context to be used in IKE negotiation in
the acquire messages sent to the IKE daemon so that a unique SA can be
negotiated for each unique security context. A couple of bug fixes are
also included; checks to make sure the SAs used by a packet match
policy (security context-wise) on the inbound and also that the bundle
used for the outbound matches the security context of the flow. This
patch set also makes the use of the SELinux sid in flow cache lookups
seemless by including the sid in the flow key itself. Also, open
requests as well as connection-oriented child sockets are labeled
automatically to be at the same level as the peer to allow for use of
appropriately labeled IPSec associations.

Description of changes:

A "sid" member has been added to the flow cache key resulting in the
sid being available at all needed locations and the flow cache lookups
automatically using the sid. The flow sid is derived from the socket
on the outbound and the SAs (unlabeled where an SA was not used) on
the inbound.

Outbound case:
1. Find policy for the socket.

2. OLD: Find an SA that matches the policy.
 NEW: Find an SA that matches BOTH the policy and the flow/socket.
   This is necessary since not every SA that matches the policy
   can be used for the flow/socket. Consider policy range Secret-TS,
   and SAs each for Secret and TS. We don't want a TS socket to
   use the Secret SA. Hence the additional check for the SA Vs. flow/socket.

3. NEW: When looking thru bundles for a policy, make sure the
        flow/socket can use the bundle. If a bundle is not found,
        create one, calling for IKE if necessary. If using IKE,
        include the security context in the acquire message to the IKE
        daemon.

Inbound case:
1. OLD: Find policy for the socket.
 NEW: Find policy for the incoming packet based on the sid of the
      SA(s) it used or the unlabeled sid if no SAs were
      used. (Consider a case where a socket is "authorized" for two
      policies (unclassified-confidential, secret-top_secret). If the
      packet has come in using a secret SA, we really ought to be
      using the latter policy (secret-top_secret).)

2. OLD: BUG: No check to see if the SAs used by the packet agree with
             the policy sec_ctx-wise.

             (It was indicated in selinux_xfrm_sock_rcv_skb() that
              this was being accomplished by
              (x->id.spi == tmpl->id.spi || !tmpl->id.spi) in xfrm_state_ok,
	      but it turns out tmpl->id.spi
              would normally be zero (unless xfrm policy rules specify one
              at the template level, which they usually don't).
 NEW: The socket is checked for access to the SAs used (based on the
      sid of the SAs) in selinux_xfrm_sock_rcv_skb().

Forward case:
 This would be Step 1 from the Inbound case, followed by Steps 2 and 3
from the Outbound case.

Outstanding items/issues:

- Timewait acknowledgements and such are generated in the
  current/upstream implementation using a NULL socket resulting in the
  any_socket sid (SYSTEM_HIGH) to be used. This problem is not addressed
  by this patch set.

This patch: Add new flask definitions to SELinux

Adds a new avperm "polmatch" to arbitrate flow/state access to a xfrm
policy rule.

Signed-off-by: Venkat Yekkirala <vyekkirala@TrustedCS.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-09-22 14:53:20 -07:00
Eric Paris
c312feb293 [PATCH] SELinux: decouple fscontext/context mount options
Remove the conflict between fscontext and context mount options.  If
context= is specified without fscontext it will operate just as before, if
both are specified we will use mount point labeling and all inodes will get
the label specified by context=.  The superblock will be labeled with the
label of fscontext=, thus affecting operations which check the superblock
security context, such as associate permissions.

Signed-off-by: Eric Paris <eparis@parisplace.org>
Acked-by: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: James Morris <jmorris@namei.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-07-10 13:24:13 -07:00
Eric Paris
42c3e03ef6 [PATCH] SELinux: Add sockcreate node to procattr API
Below is a patch to add a new /proc/self/attr/sockcreate A process may write a
context into this interface and all subsequent sockets created will be labeled
with that context.  This is the same idea as the fscreate interface where a
process can specify the label of a file about to be created.  At this time one
envisioned user of this will be xinetd.  It will be able to better label
sockets for the actual services.  At this time all sockets take the label of
the creating process, so all xinitd sockets would just be labeled the same.

I tested this by creating a tcp sender and listener.  The sender was able to
write to this new proc file and then create sockets with the specified label.
I am able to be sure the new label was used since the avc denial messages
kicked out by the kernel included both the new security permission
setsockcreate and all the socket denials were for the new label, not the label
of the running process.

Signed-off-by: Eric Paris <eparis@redhat.com>
Signed-off-by: James Morris <jmorris@namei.org>
Cc: Chris Wright <chrisw@sous-sol.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-26 09:58:26 -07:00
Michael LeMay
4eb582cf1f [PATCH] keys: add a way to store the appropriate context for newly-created keys
Add a /proc/<pid>/attr/keycreate entry that stores the appropriate context for
newly-created keys.  Modify the selinux_key_alloc hook to make use of the new
entry.  Update the flask headers to include a new "setkeycreate" permission
for processes.  Update the flask headers to include a new "create" permission
for keys.  Use the create permission to restrict which SIDs each task can
assign to newly-created keys.  Add a new parameter to the security hook
"security_key_alloc" to indicate whether it is being invoked by the kernel, or
from userspace.  If it is being invoked by the kernel, the security hook
should never fail.  Update the documentation to reflect these changes.

Signed-off-by: Michael LeMay <mdlemay@epoch.ncsc.mil>
Signed-off-by: James Morris <jmorris@namei.org>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-26 09:58:18 -07:00
Michael LeMay
d720024e94 [PATCH] selinux: add hooks for key subsystem
Introduce SELinux hooks to support the access key retention subsystem
within the kernel.  Incorporate new flask headers from a modified version
of the SELinux reference policy, with support for the new security class
representing retained keys.  Extend the "key_alloc" security hook with a
task parameter representing the intended ownership context for the key
being allocated.  Attach security information to root's default keyrings
within the SELinux initialization routine.

Has passed David's testsuite.

Signed-off-by: Michael LeMay <mdlemay@epoch.ncsc.mil>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: James Morris <jmorris@namei.org>
Acked-by: Chris Wright <chrisw@sous-sol.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-22 15:05:55 -07:00
James Morris
4e5ab4cb85 [SECMARK]: Add new packet controls to SELinux
Add new per-packet access controls to SELinux, replacing the old
packet controls.

Packets are labeled with the iptables SECMARK and CONNSECMARK targets,
then security policy for the packets is enforced with these controls.

To allow for a smooth transition to the new controls, the old code is
still present, but not active by default.  To restore previous
behavior, the old controls may be activated at runtime by writing a
'1' to /selinux/compat_net, and also via the kernel boot parameter
selinux_compat_net.  Switching between the network control models
requires the security load_policy permission.  The old controls will
probably eventually be removed and any continued use is discouraged.

With this patch, the new secmark controls for SElinux are disabled by
default, so existing behavior is entirely preserved, and the user is
not affected at all.

It also provides a config option to enable the secmark controls by
default (which can always be overridden at boot and runtime).  It is
also noted in the kconfig help that the user will need updated
userspace if enabling secmark controls for SELinux and that they'll
probably need the SECMARK and CONNMARK targets, and conntrack protocol
helpers, although such decisions are beyond the scope of kernel
configuration.

Signed-off-by: James Morris <jmorris@namei.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-06-17 21:30:05 -07:00
James Morris
29a395eac4 [SECMARK]: Add new flask definitions to SELinux
Secmark implements a new scheme for adding security markings to
packets via iptables, as well as changes to SELinux to use these
markings for security policy enforcement.  The rationale for this
scheme is explained and discussed in detail in the original threads:

 http://thread.gmane.org/gmane.linux.network/34927/
 http://thread.gmane.org/gmane.linux.network/35244/

Examples of policy and rulesets, as well as a full archive of patches
for iptables and SELinux userland, may be found at:

http://people.redhat.com/jmorris/selinux/secmark/

The code has been tested with various compilation options and in
several scenarios, including with 'complicated' protocols such as FTP
and also with the new generic conntrack code with IPv6 connection
tracking.

This patch:

Add support for a new object class ('packet'), and associated
permissions ('send', 'recv', 'relabelto').  These are used to enforce
security policy for network packets labeled with SECMARK, and for
adding labeling rules.

Signed-off-by: James Morris <jmorris@namei.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-06-17 21:29:53 -07:00
Christopher J. PeBenito
3e3ff15e6d [SELINUX]: add security class for appletalk sockets
Add a security class for appletalk sockets so that they can be
distinguished in SELinux policy.  Please apply.

Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
Acked-by: James Morris <jmorris@namei.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-06-17 21:29:51 -07:00
Catherine Zhang
c8c05a8eec [LSM-IPsec]: SELinux Authorize
This patch contains a fix for the previous patch that adds security
contexts to IPsec policies and security associations.  In the previous
patch, no authorization (besides the check for write permissions to
SAD and SPD) is required to delete IPsec policies and security
assocations with security contexts.  Thus a user authorized to change
SAD and SPD can bypass the IPsec policy authorization by simply
deleteing policies with security contexts.  To fix this security hole,
an additional authorization check is added for removing security
policies and security associations with security contexts.

Note that if no security context is supplied on add or present on
policy to be deleted, the SELinux module allows the change
unconditionally.  The hook is called on deletion when no context is
present, which we may want to change.  At present, I left it up to the
module.

LSM changes:

The patch adds two new LSM hooks: xfrm_policy_delete and
xfrm_state_delete.  The new hooks are necessary to authorize deletion
of IPsec policies that have security contexts.  The existing hooks
xfrm_policy_free and xfrm_state_free lack the context to do the
authorization, so I decided to split authorization of deletion and
memory management of security data, as is typical in the LSM
interface.

Use:

The new delete hooks are checked when xfrm_policy or xfrm_state are
deleted by either the xfrm_user interface (xfrm_get_policy,
xfrm_del_sa) or the pfkey interface (pfkey_spddelete, pfkey_delete).

SELinux changes:

The new policy_delete and state_delete functions are added.

Signed-off-by: Catherine Zhang <cxzhang@watson.ibm.com>
Signed-off-by: Trent Jaeger <tjaeger@cse.psu.edu>
Acked-by: James Morris <jmorris@namei.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-06-17 21:29:45 -07:00
Stephen Smalley
30d55280b8 [PATCH] selinux: Clear selinux_enabled flag upon runtime disable.
Clear selinux_enabled flag upon runtime disable of SELinux by userspace,
and make sure it is defined even if selinux= boot parameter support is
not enabled in configuration.

Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
Acked-by: James Morris <jmorris@namei.org>
Tested-by: Jon Smirl <jonsmirl@gmail.com>
Acked-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-05-03 10:08:11 -07:00
Catherine Zhang
e6f507196c [SELINUX]: selinux_socket_getpeer_{stream,dgram} fixup
Signed-off-by: Catherine Zhang <cxzhang@watson.ibm.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
2006-03-20 22:49:00 -08:00
Catherine Zhang
2c7946a7bf [SECURITY]: TCP/UDP getpeersec
This patch implements an application of the LSM-IPSec networking
controls whereby an application can determine the label of the
security association its TCP or UDP sockets are currently connected to
via getsockopt and the auxiliary data mechanism of recvmsg.

Patch purpose:

This patch enables a security-aware application to retrieve the
security context of an IPSec security association a particular TCP or
UDP socket is using.  The application can then use this security
context to determine the security context for processing on behalf of
the peer at the other end of this connection.  In the case of UDP, the
security context is for each individual packet.  An example
application is the inetd daemon, which could be modified to start
daemons running at security contexts dependent on the remote client.

Patch design approach:

- Design for TCP
The patch enables the SELinux LSM to set the peer security context for
a socket based on the security context of the IPSec security
association.  The application may retrieve this context using
getsockopt.  When called, the kernel determines if the socket is a
connected (TCP_ESTABLISHED) TCP socket and, if so, uses the dst_entry
cache on the socket to retrieve the security associations.  If a
security association has a security context, the context string is
returned, as for UNIX domain sockets.

- Design for UDP
Unlike TCP, UDP is connectionless.  This requires a somewhat different
API to retrieve the peer security context.  With TCP, the peer
security context stays the same throughout the connection, thus it can
be retrieved at any time between when the connection is established
and when it is torn down.  With UDP, each read/write can have
different peer and thus the security context might change every time.
As a result the security context retrieval must be done TOGETHER with
the packet retrieval.

The solution is to build upon the existing Unix domain socket API for
retrieving user credentials.  Linux offers the API for obtaining user
credentials via ancillary messages (i.e., out of band/control messages
that are bundled together with a normal message).

Patch implementation details:

- Implementation for TCP
The security context can be retrieved by applications using getsockopt
with the existing SO_PEERSEC flag.  As an example (ignoring error
checking):

getsockopt(sockfd, SOL_SOCKET, SO_PEERSEC, optbuf, &optlen);
printf("Socket peer context is: %s\n", optbuf);

The SELinux function, selinux_socket_getpeersec, is extended to check
for labeled security associations for connected (TCP_ESTABLISHED ==
sk->sk_state) TCP sockets only.  If so, the socket has a dst_cache of
struct dst_entry values that may refer to security associations.  If
these have security associations with security contexts, the security
context is returned.

getsockopt returns a buffer that contains a security context string or
the buffer is unmodified.

- Implementation for UDP
To retrieve the security context, the application first indicates to
the kernel such desire by setting the IP_PASSSEC option via
getsockopt.  Then the application retrieves the security context using
the auxiliary data mechanism.

An example server application for UDP should look like this:

toggle = 1;
toggle_len = sizeof(toggle);

setsockopt(sockfd, SOL_IP, IP_PASSSEC, &toggle, &toggle_len);
recvmsg(sockfd, &msg_hdr, 0);
if (msg_hdr.msg_controllen > sizeof(struct cmsghdr)) {
    cmsg_hdr = CMSG_FIRSTHDR(&msg_hdr);
    if (cmsg_hdr->cmsg_len <= CMSG_LEN(sizeof(scontext)) &&
        cmsg_hdr->cmsg_level == SOL_IP &&
        cmsg_hdr->cmsg_type == SCM_SECURITY) {
        memcpy(&scontext, CMSG_DATA(cmsg_hdr), sizeof(scontext));
    }
}

ip_setsockopt is enhanced with a new socket option IP_PASSSEC to allow
a server socket to receive security context of the peer.  A new
ancillary message type SCM_SECURITY.

When the packet is received we get the security context from the
sec_path pointer which is contained in the sk_buff, and copy it to the
ancillary message space.  An additional LSM hook,
selinux_socket_getpeersec_udp, is defined to retrieve the security
context from the SELinux space.  The existing function,
selinux_socket_getpeersec does not suit our purpose, because the
security context is copied directly to user space, rather than to
kernel space.

Testing:

We have tested the patch by setting up TCP and UDP connections between
applications on two machines using the IPSec policies that result in
labeled security associations being built.  For TCP, we can then
extract the peer security context using getsockopt on either end.  For
UDP, the receiving end can retrieve the security context using the
auxiliary data mechanism of recvmsg.

Signed-off-by: Catherine Zhang <cxzhang@watson.ibm.com>
Acked-by: James Morris <jmorris@namei.org>
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-03-20 22:41:23 -08:00
Stephen Smalley
9ac49d2213 [PATCH] selinux: remove security struct magic number fields and tests
Remove the SELinux security structure magic number fields and tests, along
with some unnecessary tests for NULL security pointers.  These fields and
tests are leftovers from the early attempts to support SELinux as a
loadable module during LSM development.

Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
Acked-by: James Morris <jmorris@namei.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-02-01 08:53:19 -08:00
Trent Jaeger
5f8ac64b15 [LSM-IPSec]: Corrections to LSM-IPSec Nethooks
This patch contains two corrections to the LSM-IPsec Nethooks patches
previously applied.  

(1) free a security context on a failed insert via xfrm_user 
interface in xfrm_add_policy.  Memory leak.

(2) change the authorization of the allocation of a security context
in a xfrm_policy or xfrm_state from both relabelfrom and relabelto 
to setcontext.

Signed-off-by: Trent Jaeger <tjaeger@cse.psu.edu>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-01-06 13:22:39 -08:00
Trent Jaeger
d28d1e0801 [LSM-IPSec]: Per-packet access control.
This patch series implements per packet access control via the
extension of the Linux Security Modules (LSM) interface by hooks in
the XFRM and pfkey subsystems that leverage IPSec security
associations to label packets.  Extensions to the SELinux LSM are
included that leverage the patch for this purpose.

This patch implements the changes necessary to the SELinux LSM to
create, deallocate, and use security contexts for policies
(xfrm_policy) and security associations (xfrm_state) that enable
control of a socket's ability to send and receive packets.

Patch purpose:

The patch is designed to enable the SELinux LSM to implement access
control on individual packets based on the strongly authenticated
IPSec security association.  Such access controls augment the existing
ones in SELinux based on network interface and IP address.  The former
are very coarse-grained, and the latter can be spoofed.  By using
IPSec, the SELinux can control access to remote hosts based on
cryptographic keys generated using the IPSec mechanism.  This enables
access control on a per-machine basis or per-application if the remote
machine is running the same mechanism and trusted to enforce the
access control policy.

Patch design approach:

The patch's main function is to authorize a socket's access to a IPSec
policy based on their security contexts.  Since the communication is
implemented by a security association, the patch ensures that the
security association's negotiated and used have the same security
context.  The patch enables allocation and deallocation of such
security contexts for policies and security associations.  It also
enables copying of the security context when policies are cloned.
Lastly, the patch ensures that packets that are sent without using a
IPSec security assocation with a security context are allowed to be
sent in that manner.

A presentation available at
www.selinux-symposium.org/2005/presentations/session2/2-3-jaeger.pdf
from the SELinux symposium describes the overall approach.

Patch implementation details:

The function which authorizes a socket to perform a requested
operation (send/receive) on a IPSec policy (xfrm_policy) is
selinux_xfrm_policy_lookup.  The Netfilter and rcv_skb hooks ensure
that if a IPSec SA with a securit y association has not been used,
then the socket is allowed to send or receive the packet,
respectively.

The patch implements SELinux function for allocating security contexts
when policies (xfrm_policy) are created via the pfkey or xfrm_user
interfaces via selinux_xfrm_policy_alloc.  When a security association
is built, SELinux allocates the security context designated by the
XFRM subsystem which is based on that of the authorized policy via
selinux_xfrm_state_alloc.

When a xfrm_policy is cloned, the security context of that policy, if
any, is copied to the clone via selinux_xfrm_policy_clone.

When a xfrm_policy or xfrm_state is freed, its security context, if
any is also freed at selinux_xfrm_policy_free or
selinux_xfrm_state_free.

Testing:

The SELinux authorization function is tested using ipsec-tools.  We
created policies and security associations with particular security
contexts and added SELinux access control policy entries to verify the
authorization decision.  We also made sure that packets for which no
security context was supplied (which either did or did not use
security associations) were authorized using an unlabelled context.

Signed-off-by: Trent Jaeger <tjaeger@cse.psu.edu>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-01-03 13:10:25 -08:00
Stephen Smalley
a74574aafe [PATCH] Remove security_inode_post_create/mkdir/symlink/mknod hooks
This patch removes the inode_post_create/mkdir/mknod/symlink LSM hooks as
they are obsoleted by the new inode_init_security hook that enables atomic
inode security labeling.

If anyone sees any reason to retain these hooks, please speak now.  Also,
is anyone using the post_rename/link hooks; if not, those could also be
removed.

Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-09-09 13:57:28 -07:00
Stephen Smalley
5e41ff9e06 [PATCH] security: enable atomic inode security labeling
The following patch set enables atomic security labeling of newly created
inodes by altering the fs code to invoke a new LSM hook to obtain the security
attribute to apply to a newly created inode and to set up the incore inode
security state during the inode creation transaction.  This parallels the
existing processing for setting ACLs on newly created inodes.  Otherwise, it
is possible for new inodes to be accessed by another thread via the dcache
prior to complete security setup (presently handled by the
post_create/mkdir/...  LSM hooks in the VFS) and a newly created inode may be
left unlabeled on the disk in the event of a crash.  SELinux presently works
around the issue by ensuring that the incore inode security label is
initialized to a special SID that is inaccessible to unprivileged processes
(in accordance with policy), thereby preventing inappropriate access but
potentially causing false denials on legitimate accesses.  A simple test
program demonstrates such false denials on SELinux, and the patch solves the
problem.  Similar such false denials have been encountered in real
applications.

This patch defines a new inode_init_security LSM hook to obtain the security
attribute to apply to a newly created inode and to set up the incore inode
security state for it, and adds a corresponding hook function implementation
to SELinux.

Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-09-09 13:57:27 -07:00
Stephen Smalley
782ebb992e [PATCH] selinux: Reduce memory use by avtab
This patch improves memory use by SELinux by both reducing the avtab node
size and reducing the number of avtab nodes.  The memory savings are
substantial, e.g.  on a 64-bit system after boot, James Morris reported the
following data for the targeted and strict policies:

            #objs  objsize   kernmem
Targeted:
  Before:  237888       40     9.1MB
  After:    19968       24     468KB

Strict:
  Before:  571680       40   21.81MB
  After:   221052       24    5.06MB

The improvement in memory use comes at a cost in the speed of security
server computations of access vectors, but these computations are only
required on AVC cache misses, and performance measurements by James Morris
using a number of benchmarks have shown that the change does not cause any
significant degradation.

Note that a rebuilt policy via an updated policy toolchain
(libsepol/checkpolicy) is required in order to gain the full benefits of
this patch, although some memory savings benefits are immediately applied
even to older policies (in particular, the reduction in avtab node size).
Sources for the updated toolchain are presently available from the
sourceforge CVS tree (http://sourceforge.net/cvs/?group_id=21266), and
tarballs are available from http://www.flux.utah.edu/~sds.

Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: James Morris <jmorris@namei.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-09-05 00:05:50 -07:00
James Morris
f5c1d5b2aa [PATCH] SELinux: default labeling of MLS field
Implement kernel labeling of the MLS (multilevel security) field of
security contexts for files which have no existing MLS field.  This is to
enable upgrades of a system from non-MLS to MLS without performing a full
filesystem relabel including all of the mountpoints, which would be quite
painful for users.

With this patch, with MLS enabled, if a file has no MLS field, the kernel
internally adds an MLS field to the in-core inode (but not to the on-disk
file).  This MLS field added is the default for the superblock, allowing
per-mountpoint control over the values via fixed policy or mount options.

This patch has been tested by enabling MLS without relabeling its
filesystem, and seems to be working correctly.

Signed-off-by: James Morris <jmorris@redhat.com>
Signed-off-by: Stephen Smalley <sds@epoch.ncsc.mil>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-07-28 08:39:02 -07:00
Lorenzo Hernández García-Hierro
09ffd94fb1 [PATCH] selinux: add executable heap check
This patch,based on sample code by Roland McGrath, adds an execheap
permission check that controls the ability to make the heap executable so
that this can be prevented in almost all cases (the X server is presently
an exception, but this will hopefully be resolved in the future) so that
even programs with execmem permission will need to have the anonymous
memory mapped in order to make it executable.

The only reason that we use a permission check for such restriction (vs.
making it unconditional) is that the X module loader presently needs it; it
could possibly be made unconditional in the future when X is changed.

The policy patch for the execheap permission is available at:
http://pearls.tuxedo-es.org/patches/selinux/policy-execheap.patch

Signed-off-by: Lorenzo Hernandez Garcia-Hierro <lorenzo@gnu.org>
Acked-by: James Morris <jmorris@redhat.com>
Acked-by:  Stephen Smalley <sds@tycho.nsa.gov>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-06-25 16:24:26 -07:00
Lorenzo Hernandez García-Hierro
6b9921976f [PATCH] selinux: add executable stack check
This patch adds an execstack permission check that controls the ability to
make the main process stack executable so that attempts to make the stack
executable can still be prevented even if the process is allowed the
existing execmem permission in order to e.g.  perform runtime code
generation.  Note that this does not yet address thread stacks.  Note also
that unlike the execmem check, the execstack check is only applied on
mprotect calls, not mmap calls, as the current security_file_mmap hook is
not passed the necessary information presently.

The original author of the code that makes the distinction of the stack
region, is Ingo Molnar, who wrote it within his patch for
/proc/<pid>/maps markers.
(http://marc.theaimsgroup.com/?l=linux-kernel&m=110719881508591&w=2)

The patches also can be found at:
http://pearls.tuxedo-es.org/patches/selinux/policy-execstack.patch
http://pearls.tuxedo-es.org/patches/selinux/kernel-execstack.patch

policy-execstack.patch is the patch that needs to be applied to the policy in
order to support the execstack permission and exclude it
from general_domain_access within macros/core_macros.te.

kernel-execstack.patch adds such permission to the SELinux code within
the kernel and adds the proper permission check to the selinux_file_mprotect() hook.

Signed-off-by: Lorenzo Hernandez Garcia-Hierro <lorenzo@gnu.org>
Acked-by: James Morris <jmorris@redhat.com>
Acked-by: Stephen Smalley <sds@tycho.nsa.gov>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-06-25 16:24:26 -07:00
James Morris
b207a290ea [PATCH] SELinux: add finer grained permissions to Netlink audit processing
This patch provides finer grained permissions for the audit family of
Netlink sockets under SELinux.

1.  We need a way to differentiate between privileged and unprivileged
   reads of kernel data maintained by the audit subsystem.  The AUDIT_GET
   operation is unprivileged: it returns the current status of the audit
   subsystem (e.g.  whether it's enabled etc.).  The AUDIT_LIST operation
   however returns a list of the current audit ruleset, which is considered
   privileged by the audit folk.  To deal with this, a new SELinux
   permission has been implemented and applied to the operation:
   nlmsg_readpriv, which can be allocated to appropriately privileged
   domains.  Unprivileged domains would only be allocated nlmsg_read.

2.  There is a requirement for certain domains to generate audit events
   from userspace.  These events need to be collected by the kernel,
   collated and transmitted sequentially back to the audit daemon.  An
   example is user level login, an auditable event under CAPP, where
   login-related domains generate AUDIT_USER messages via PAM which are
   relayed back to auditd via the kernel.  To prevent handing out
   nlmsg_write permissions to such domains, a new permission has been
   added, nlmsg_relay, which is intended for this type of purpose: data is
   passed via the kernel back to userspace but no privileged information is
   written to the kernel.

Also, AUDIT_LOGIN messages are now valid only for kernel->user messaging,
so this value has been removed from the SELinux nlmsgtab (which is only
used to check user->kernel messages).

Signed-off-by: James Morris <jmorris@redhat.com>
Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-05-01 08:58:40 -07:00
James Morris
0c9b79429c [PATCH] SELinux: add support for NETLINK_KOBJECT_UEVENT
This patch adds SELinux support for the KOBJECT_UEVENT Netlink family, so
that SELinux can apply finer grained controls to it.  For example, security
policy for hald can be locked down to the KOBJECT_UEVENT Netlink family
only.  Currently, this family simply defaults to the default Netlink socket
class.

Note that some new permission definitions are added to sync with changes in
the core userspace policy package, which auto-generates header files.

Signed-off-by: James Morris <jmorris@redhat.com>
Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-04-16 15:24:13 -07:00
Linus Torvalds
1da177e4c3 Linux-2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!
2005-04-16 15:20:36 -07:00