linux/security/selinux/xfrm.c
Tejun Heo 5a0e3ad6af include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h
percpu.h is included by sched.h and module.h and thus ends up being
included when building most .c files.  percpu.h includes slab.h which
in turn includes gfp.h making everything defined by the two files
universally available and complicating inclusion dependencies.

percpu.h -> slab.h dependency is about to be removed.  Prepare for
this change by updating users of gfp and slab facilities include those
headers directly instead of assuming availability.  As this conversion
needs to touch large number of source files, the following script is
used as the basis of conversion.

  http://userweb.kernel.org/~tj/misc/slabh-sweep.py

The script does the followings.

* Scan files for gfp and slab usages and update includes such that
  only the necessary includes are there.  ie. if only gfp is used,
  gfp.h, if slab is used, slab.h.

* When the script inserts a new include, it looks at the include
  blocks and try to put the new include such that its order conforms
  to its surrounding.  It's put in the include block which contains
  core kernel includes, in the same order that the rest are ordered -
  alphabetical, Christmas tree, rev-Xmas-tree or at the end if there
  doesn't seem to be any matching order.

* If the script can't find a place to put a new include (mostly
  because the file doesn't have fitting include block), it prints out
  an error message indicating which .h file needs to be added to the
  file.

The conversion was done in the following steps.

1. The initial automatic conversion of all .c files updated slightly
   over 4000 files, deleting around 700 includes and adding ~480 gfp.h
   and ~3000 slab.h inclusions.  The script emitted errors for ~400
   files.

2. Each error was manually checked.  Some didn't need the inclusion,
   some needed manual addition while adding it to implementation .h or
   embedding .c file was more appropriate for others.  This step added
   inclusions to around 150 files.

3. The script was run again and the output was compared to the edits
   from #2 to make sure no file was left behind.

4. Several build tests were done and a couple of problems were fixed.
   e.g. lib/decompress_*.c used malloc/free() wrappers around slab
   APIs requiring slab.h to be added manually.

5. The script was run on all .h files but without automatically
   editing them as sprinkling gfp.h and slab.h inclusions around .h
   files could easily lead to inclusion dependency hell.  Most gfp.h
   inclusion directives were ignored as stuff from gfp.h was usually
   wildly available and often used in preprocessor macros.  Each
   slab.h inclusion directive was examined and added manually as
   necessary.

6. percpu.h was updated not to include slab.h.

7. Build test were done on the following configurations and failures
   were fixed.  CONFIG_GCOV_KERNEL was turned off for all tests (as my
   distributed build env didn't work with gcov compiles) and a few
   more options had to be turned off depending on archs to make things
   build (like ipr on powerpc/64 which failed due to missing writeq).

   * x86 and x86_64 UP and SMP allmodconfig and a custom test config.
   * powerpc and powerpc64 SMP allmodconfig
   * sparc and sparc64 SMP allmodconfig
   * ia64 SMP allmodconfig
   * s390 SMP allmodconfig
   * alpha SMP allmodconfig
   * um on x86_64 SMP allmodconfig

8. percpu.h modifications were reverted so that it could be applied as
   a separate patch and serve as bisection point.

Given the fact that I had only a couple of failures from tests on step
6, I'm fairly confident about the coverage of this conversion patch.
If there is a breakage, it's likely to be something in one of the arch
headers which should be easily discoverable easily on most builds of
the specific arch.

Signed-off-by: Tejun Heo <tj@kernel.org>
Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
2010-03-30 22:02:32 +09:00

490 lines
11 KiB
C

/*
* NSA Security-Enhanced Linux (SELinux) security module
*
* This file contains the SELinux XFRM hook function implementations.
*
* Authors: Serge Hallyn <sergeh@us.ibm.com>
* Trent Jaeger <jaegert@us.ibm.com>
*
* Updated: Venkat Yekkirala <vyekkirala@TrustedCS.com>
*
* Granular IPSec Associations for use in MLS environments.
*
* Copyright (C) 2005 International Business Machines Corporation
* Copyright (C) 2006 Trusted Computer Solutions, Inc.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2,
* as published by the Free Software Foundation.
*/
/*
* USAGE:
* NOTES:
* 1. Make sure to enable the following options in your kernel config:
* CONFIG_SECURITY=y
* CONFIG_SECURITY_NETWORK=y
* CONFIG_SECURITY_NETWORK_XFRM=y
* CONFIG_SECURITY_SELINUX=m/y
* ISSUES:
* 1. Caching packets, so they are not dropped during negotiation
* 2. Emulating a reasonable SO_PEERSEC across machines
* 3. Testing addition of sk_policy's with security context via setsockopt
*/
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/security.h>
#include <linux/types.h>
#include <linux/netfilter.h>
#include <linux/netfilter_ipv4.h>
#include <linux/netfilter_ipv6.h>
#include <linux/slab.h>
#include <linux/ip.h>
#include <linux/tcp.h>
#include <linux/skbuff.h>
#include <linux/xfrm.h>
#include <net/xfrm.h>
#include <net/checksum.h>
#include <net/udp.h>
#include <asm/atomic.h>
#include "avc.h"
#include "objsec.h"
#include "xfrm.h"
/* Labeled XFRM instance counter */
atomic_t selinux_xfrm_refcount = ATOMIC_INIT(0);
/*
* Returns true if an LSM/SELinux context
*/
static inline int selinux_authorizable_ctx(struct xfrm_sec_ctx *ctx)
{
return (ctx &&
(ctx->ctx_doi == XFRM_SC_DOI_LSM) &&
(ctx->ctx_alg == XFRM_SC_ALG_SELINUX));
}
/*
* Returns true if the xfrm contains a security blob for SELinux
*/
static inline int selinux_authorizable_xfrm(struct xfrm_state *x)
{
return selinux_authorizable_ctx(x->security);
}
/*
* LSM hook implementation that authorizes that a flow can use
* a xfrm policy rule.
*/
int selinux_xfrm_policy_lookup(struct xfrm_sec_ctx *ctx, u32 fl_secid, u8 dir)
{
int rc;
u32 sel_sid;
/* Context sid is either set to label or ANY_ASSOC */
if (ctx) {
if (!selinux_authorizable_ctx(ctx))
return -EINVAL;
sel_sid = ctx->ctx_sid;
} else
/*
* All flows should be treated as polmatch'ing an
* otherwise applicable "non-labeled" policy. This
* would prevent inadvertent "leaks".
*/
return 0;
rc = avc_has_perm(fl_secid, sel_sid, SECCLASS_ASSOCIATION,
ASSOCIATION__POLMATCH,
NULL);
if (rc == -EACCES)
return -ESRCH;
return rc;
}
/*
* LSM hook implementation that authorizes that a state matches
* the given policy, flow combo.
*/
int selinux_xfrm_state_pol_flow_match(struct xfrm_state *x, struct xfrm_policy *xp,
struct flowi *fl)
{
u32 state_sid;
int rc;
if (!xp->security)
if (x->security)
/* unlabeled policy and labeled SA can't match */
return 0;
else
/* unlabeled policy and unlabeled SA match all flows */
return 1;
else
if (!x->security)
/* unlabeled SA and labeled policy can't match */
return 0;
else
if (!selinux_authorizable_xfrm(x))
/* Not a SELinux-labeled SA */
return 0;
state_sid = x->security->ctx_sid;
if (fl->secid != state_sid)
return 0;
rc = avc_has_perm(fl->secid, state_sid, SECCLASS_ASSOCIATION,
ASSOCIATION__SENDTO,
NULL)? 0:1;
/*
* We don't need a separate SA Vs. policy polmatch check
* since the SA is now of the same label as the flow and
* a flow Vs. policy polmatch check had already happened
* in selinux_xfrm_policy_lookup() above.
*/
return rc;
}
/*
* LSM hook implementation that checks and/or returns the xfrm sid for the
* incoming packet.
*/
int selinux_xfrm_decode_session(struct sk_buff *skb, u32 *sid, int ckall)
{
struct sec_path *sp;
*sid = SECSID_NULL;
if (skb == NULL)
return 0;
sp = skb->sp;
if (sp) {
int i, sid_set = 0;
for (i = sp->len-1; i >= 0; i--) {
struct xfrm_state *x = sp->xvec[i];
if (selinux_authorizable_xfrm(x)) {
struct xfrm_sec_ctx *ctx = x->security;
if (!sid_set) {
*sid = ctx->ctx_sid;
sid_set = 1;
if (!ckall)
break;
} else if (*sid != ctx->ctx_sid)
return -EINVAL;
}
}
}
return 0;
}
/*
* Security blob allocation for xfrm_policy and xfrm_state
* CTX does not have a meaningful value on input
*/
static int selinux_xfrm_sec_ctx_alloc(struct xfrm_sec_ctx **ctxp,
struct xfrm_user_sec_ctx *uctx, u32 sid)
{
int rc = 0;
const struct task_security_struct *tsec = current_security();
struct xfrm_sec_ctx *ctx = NULL;
char *ctx_str = NULL;
u32 str_len;
BUG_ON(uctx && sid);
if (!uctx)
goto not_from_user;
if (uctx->ctx_doi != XFRM_SC_ALG_SELINUX)
return -EINVAL;
str_len = uctx->ctx_len;
if (str_len >= PAGE_SIZE)
return -ENOMEM;
*ctxp = ctx = kmalloc(sizeof(*ctx) +
str_len + 1,
GFP_KERNEL);
if (!ctx)
return -ENOMEM;
ctx->ctx_doi = uctx->ctx_doi;
ctx->ctx_len = str_len;
ctx->ctx_alg = uctx->ctx_alg;
memcpy(ctx->ctx_str,
uctx+1,
str_len);
ctx->ctx_str[str_len] = 0;
rc = security_context_to_sid(ctx->ctx_str,
str_len,
&ctx->ctx_sid);
if (rc)
goto out;
/*
* Does the subject have permission to set security context?
*/
rc = avc_has_perm(tsec->sid, ctx->ctx_sid,
SECCLASS_ASSOCIATION,
ASSOCIATION__SETCONTEXT, NULL);
if (rc)
goto out;
return rc;
not_from_user:
rc = security_sid_to_context(sid, &ctx_str, &str_len);
if (rc)
goto out;
*ctxp = ctx = kmalloc(sizeof(*ctx) +
str_len,
GFP_ATOMIC);
if (!ctx) {
rc = -ENOMEM;
goto out;
}
ctx->ctx_doi = XFRM_SC_DOI_LSM;
ctx->ctx_alg = XFRM_SC_ALG_SELINUX;
ctx->ctx_sid = sid;
ctx->ctx_len = str_len;
memcpy(ctx->ctx_str,
ctx_str,
str_len);
goto out2;
out:
*ctxp = NULL;
kfree(ctx);
out2:
kfree(ctx_str);
return rc;
}
/*
* LSM hook implementation that allocs and transfers uctx spec to
* xfrm_policy.
*/
int selinux_xfrm_policy_alloc(struct xfrm_sec_ctx **ctxp,
struct xfrm_user_sec_ctx *uctx)
{
int err;
BUG_ON(!uctx);
err = selinux_xfrm_sec_ctx_alloc(ctxp, uctx, 0);
if (err == 0)
atomic_inc(&selinux_xfrm_refcount);
return err;
}
/*
* LSM hook implementation that copies security data structure from old to
* new for policy cloning.
*/
int selinux_xfrm_policy_clone(struct xfrm_sec_ctx *old_ctx,
struct xfrm_sec_ctx **new_ctxp)
{
struct xfrm_sec_ctx *new_ctx;
if (old_ctx) {
new_ctx = kmalloc(sizeof(*old_ctx) + old_ctx->ctx_len,
GFP_KERNEL);
if (!new_ctx)
return -ENOMEM;
memcpy(new_ctx, old_ctx, sizeof(*new_ctx));
memcpy(new_ctx->ctx_str, old_ctx->ctx_str, new_ctx->ctx_len);
*new_ctxp = new_ctx;
}
return 0;
}
/*
* LSM hook implementation that frees xfrm_sec_ctx security information.
*/
void selinux_xfrm_policy_free(struct xfrm_sec_ctx *ctx)
{
kfree(ctx);
}
/*
* LSM hook implementation that authorizes deletion of labeled policies.
*/
int selinux_xfrm_policy_delete(struct xfrm_sec_ctx *ctx)
{
const struct task_security_struct *tsec = current_security();
int rc = 0;
if (ctx) {
rc = avc_has_perm(tsec->sid, ctx->ctx_sid,
SECCLASS_ASSOCIATION,
ASSOCIATION__SETCONTEXT, NULL);
if (rc == 0)
atomic_dec(&selinux_xfrm_refcount);
}
return rc;
}
/*
* LSM hook implementation that allocs and transfers sec_ctx spec to
* xfrm_state.
*/
int selinux_xfrm_state_alloc(struct xfrm_state *x, struct xfrm_user_sec_ctx *uctx,
u32 secid)
{
int err;
BUG_ON(!x);
err = selinux_xfrm_sec_ctx_alloc(&x->security, uctx, secid);
if (err == 0)
atomic_inc(&selinux_xfrm_refcount);
return err;
}
/*
* LSM hook implementation that frees xfrm_state security information.
*/
void selinux_xfrm_state_free(struct xfrm_state *x)
{
struct xfrm_sec_ctx *ctx = x->security;
kfree(ctx);
}
/*
* LSM hook implementation that authorizes deletion of labeled SAs.
*/
int selinux_xfrm_state_delete(struct xfrm_state *x)
{
const struct task_security_struct *tsec = current_security();
struct xfrm_sec_ctx *ctx = x->security;
int rc = 0;
if (ctx) {
rc = avc_has_perm(tsec->sid, ctx->ctx_sid,
SECCLASS_ASSOCIATION,
ASSOCIATION__SETCONTEXT, NULL);
if (rc == 0)
atomic_dec(&selinux_xfrm_refcount);
}
return rc;
}
/*
* LSM hook that controls access to unlabelled packets. If
* a xfrm_state is authorizable (defined by macro) then it was
* already authorized by the IPSec process. If not, then
* we need to check for unlabelled access since this may not have
* gone thru the IPSec process.
*/
int selinux_xfrm_sock_rcv_skb(u32 isec_sid, struct sk_buff *skb,
struct common_audit_data *ad)
{
int i, rc = 0;
struct sec_path *sp;
u32 sel_sid = SECINITSID_UNLABELED;
sp = skb->sp;
if (sp) {
for (i = 0; i < sp->len; i++) {
struct xfrm_state *x = sp->xvec[i];
if (x && selinux_authorizable_xfrm(x)) {
struct xfrm_sec_ctx *ctx = x->security;
sel_sid = ctx->ctx_sid;
break;
}
}
}
/*
* This check even when there's no association involved is
* intended, according to Trent Jaeger, to make sure a
* process can't engage in non-ipsec communication unless
* explicitly allowed by policy.
*/
rc = avc_has_perm(isec_sid, sel_sid, SECCLASS_ASSOCIATION,
ASSOCIATION__RECVFROM, ad);
return rc;
}
/*
* POSTROUTE_LAST hook's XFRM processing:
* If we have no security association, then we need to determine
* whether the socket is allowed to send to an unlabelled destination.
* If we do have a authorizable security association, then it has already been
* checked in the selinux_xfrm_state_pol_flow_match hook above.
*/
int selinux_xfrm_postroute_last(u32 isec_sid, struct sk_buff *skb,
struct common_audit_data *ad, u8 proto)
{
struct dst_entry *dst;
int rc = 0;
dst = skb_dst(skb);
if (dst) {
struct dst_entry *dst_test;
for (dst_test = dst; dst_test != NULL;
dst_test = dst_test->child) {
struct xfrm_state *x = dst_test->xfrm;
if (x && selinux_authorizable_xfrm(x))
goto out;
}
}
switch (proto) {
case IPPROTO_AH:
case IPPROTO_ESP:
case IPPROTO_COMP:
/*
* We should have already seen this packet once before
* it underwent xfrm(s). No need to subject it to the
* unlabeled check.
*/
goto out;
default:
break;
}
/*
* This check even when there's no association involved is
* intended, according to Trent Jaeger, to make sure a
* process can't engage in non-ipsec communication unless
* explicitly allowed by policy.
*/
rc = avc_has_perm(isec_sid, SECINITSID_UNLABELED, SECCLASS_ASSOCIATION,
ASSOCIATION__SENDTO, ad);
out:
return rc;
}